ACS Publications. Most Trusted. Most Cited. Most Read
Microneedle Aptamer-Based Sensors for Continuous, Real-Time Therapeutic Drug Monitoring
My Activity
  • Open Access
ADDITION/CORRECTION. This article has been corrected. View the notice.
Article

Microneedle Aptamer-Based Sensors for Continuous, Real-Time Therapeutic Drug Monitoring
Click to copy article linkArticle link copied!

  • Yao Wu
    Yao Wu
    Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
    More by Yao Wu
  • Farshad Tehrani
    Farshad Tehrani
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • Hazhir Teymourian
    Hazhir Teymourian
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • John Mack
    John Mack
    Biochemistry, Cellular and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
    More by John Mack
  • Alexander Shaver
    Alexander Shaver
    Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
  • Maria Reynoso
    Maria Reynoso
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • Jonathan Kavner
    Jonathan Kavner
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • Nickey Huang
    Nickey Huang
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    More by Nickey Huang
  • Allison Furmidge
    Allison Furmidge
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • Andrés Duvvuri
    Andrés Duvvuri
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
  • Yuhang Nie
    Yuhang Nie
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    More by Yuhang Nie
  • Lori M. Laffel
    Lori M. Laffel
    Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
  • Francis J. Doyle III
    Francis J. Doyle III
    Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States
  • Mary-Elizabeth Patti
    Mary-Elizabeth Patti
    Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
  • Eyal Dassau
    Eyal Dassau
    Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States
    More by Eyal Dassau
  • Joseph Wang*
    Joseph Wang
    Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    *Email: [email protected]
    More by Joseph Wang
  • Netzahualcóyotl Arroyo-Currás*
    Netzahualcóyotl Arroyo-Currás
    Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
    Biochemistry, Cellular and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
    *Email: [email protected]
Open PDFSupporting Information (1)

Analytical Chemistry

Cite this: Anal. Chem. 2022, 94, 23, 8335–8345
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.analchem.2c00829
Published June 2, 2022

Copyright © 2022 The Authors. Published by American Chemical Society. This publication is licensed under

CC-BY-NC-ND 4.0 .

Abstract

Click to copy section linkSection link copied!

The ability to continuously monitor the concentration of specific molecules in the body is a long-sought goal of biomedical research. For this purpose, interstitial fluid (ISF) was proposed as the ideal target biofluid because its composition can rapidly equilibrate with that of systemic blood, allowing the assessment of molecular concentrations that reflect full-body physiology. In the past, continuous monitoring in ISF was enabled by microneedle sensor arrays. Yet, benchmark microneedle sensors can only detect molecules that undergo redox reactions, which limits the ability to sense metabolites, biomarkers, and therapeutics that are not redox-active. To overcome this barrier, here, we expand the scope of these devices by demonstrating the first use of microneedle-supported electrochemical, aptamer-based (E-AB) sensors. This platform achieves molecular recognition based on affinity interactions, vastly expanding the scope of molecules that can be sensed. We report the fabrication of microneedle E-AB sensor arrays and a method to regenerate them for multiple uses. In addition, we demonstrate continuous molecular measurements using these sensors in flow systems in vitro using single and multiplexed microneedle array configurations. Translation of the platform to in vivo measurements is possible as we demonstrate with a first E-AB measurement in the ISF of a rodent. The encouraging results reported in this work should serve as the basis for future translation of microneedle E-AB sensor arrays to biomedical research in preclinical animal models.

This publication is licensed under

CC-BY-NC-ND 4.0 .
  • cc licence
  • by licence
  • nc licence
  • nd licence
Copyright © 2022 The Authors. Published by American Chemical Society

Note Added after ASAP Publication

This paper was originally published ASAP on June 2, 2022, with an error in Figure 6G. The corrected version was reposted on June 3, 2022.

The development of wearable and autonomous sensing technologies enabling continuous, real-time monitoring of clinically relevant therapeutics, metabolites, and biomarkers in the body could dramatically transform the way we study, understand, diagnose, and treat diseases. Such technologies could be used to, for example, achieve highly precise and personalized drug therapy via real-time monitoring of patient-specific pharmacokinetics, pharmacodynamics, and toxicology. (1−6) The in vivo pharmacological data produced could be coupled to drug delivery devices via feedback control, allowing therapeutic dosing to occur at the exact time and dose needed and in response to minute-to-minute fluctuations in an individual’s physiology. (7−9) In contrast, our current approach to drug therapy often relies on population-based physical indexes such as age, weight, or body mass, which are often inaccurate at the individual’s level, or indirect parameters such as genotype, which are poor predictors of a patient’s immediate physiological state and of effective therapeutic dosing. (10,11) In addition, the standard of care for using phlebotomy and laboratory-based molecular measurements is costly, slow, and inconvenient. (12,13) Given the clinical importance of developing therapeutic strategies that effectively address patient-to-patient pharmacokinetic variability (14) and overcome inaccurate pharmacokinetic estimates, (15) there remains a critical need for in vivo sensing platforms that can achieve autonomous, continuous, and individualized molecular monitoring in real time.
The future of personalized medicine will almost certainly involve some form of wearable biochemical monitors. In this context, interstitial fluid (ISF) is an ideal compartment for monitoring systemic molecular levels as it presents biomolecular concentrations and temporal, dynamic profiles that strongly correlate with those of blood. (16,17) For example, continuous glucose monitors have successfully used ISF glucose levels as a proxy for blood glucose concentration. (18) However, the biologic diversity of ISF means that there is ample opportunity to leverage this fluid for molecular monitoring of other clinically important targets, both in continuous or semicontinuous modes. The fact that ISF is immediately available under the outermost layers of the skin makes it an ideal target for minimally invasive and painless technologies for wearable molecular monitors.
A much-highlighted strategy to access ISF without any perceivable pain or skin damage is the use of wearable microneedles. (19,20) By virtue of their sharp microscopic structures, microneedles can pierce the stratum corneum of the skin and reach the ISF within the dermis. Thanks to their shallow depth (∼1 mm), microneedles reach neither nerve endings nor vasculature within the dermis, (19) offering painless and direct tapping into the ISF. To date, this technology has been used to achieve high-volume extraction of ISF for in vitro proteomics, (20) controlled therapeutic delivery, (21,22) and molecular monitoring using microneedle-supported biosensors. (23−25) However, successes in continuous sensing have been limited to a few molecules that either undergo enzymatic conversion via oxidases or reductases (23,24,26,27) or are redox-active and can be directly oxidized or reduced on microneedle surfaces. (28) Thus, there remains a critical need to develop methods that expand the scope of microneedle-supported sensing to health-relevant ISF markers that cannot undergo enzymatic or direct electrochemical conversion.
This work aims to expand the sensing scope of microneedle sensors by coupling the technology with electrochemical, aptamer-based (E-AB) sensors (Figure 1), an affinity-based measurement strategy that does not depend on molecular reactivity. (29) Aptamers are single-stranded nucleic acid sequences that can be selected through systematic evolution of ligands by exponential enrichment (SELEX) for binding to arbitrary targets with high affinity. (30−32) For example, taking advantage of endotoxin-binding aptamers and porous microneedle arrays, Yi et al. (33) achieved extraction of ISF and ex vivo detection of endotoxin based on fluorescence emission. Although these aptamer-decorated porous microneedles enable the extraction and ex vivo detection of biomarkers in ISF, they cannot support continuous, real-time molecular monitoring in vivo. Similarly, the use of immunoassays for expanding the molecular scope of microneedles is hindered by the inability to regenerate the antibody receptor. However, such challenges can be resolved by coupling the high affinity and reversible molecular recognition afforded by aptamers with real-time electrochemical detection. Specifically, the aptamers in E-AB sensors undergo binding-induced conformational changes (Figure 1B), (34) which occur in scales of milliseconds and are reversible. The aptamers are modified with redox reporters that undergo eT at different rates depending on the target concentration. By interrogating the sensors serially using voltammetry (Figure 1C), the platform supports continuous molecular monitoring with second (3) or subsecond (9) resolution both in vitro and in vivo. (3) More detailed descriptions of the working principle of E-AB sensors abound in the published literature. For example, we refer the reader to refs (35) and (36).

Figure 1

Figure 1. Wearable microneedle aptamer-based sensors for continuous, real-time therapeutic drug monitoring. (A) Our wearable microneedle sensor patch is designed to allow painless on-body molecular tracking in research animals. The patch consists of a microneedle sensor array integrated with electronics and a battery, all contained within a wearable case. The sensor array contains 16 gold working, 4 platinum counter, and one central reference microneedles with a form factor that allows painless penetration of the upper strata of the reticular dermis. (B) At the core of our sensing technology are electrochemical aptamer-based (E-AB) sensors, which consist of a mixed self-assembled monolayer of electrode-blocking alkanethiols with alkanethiol- and redox reporter-modified aptamers. In the presence of a target, the aptamers undergo reversible binding-induced conformational changes that affect electron transfer (eT) between the reporter and the gold needles. This sensing mechanism is reversible. (C) To enable continuous drug monitoring, the sensors are serially interrogated by square-wave voltammetry (SWV) with a time interval between 4.5 and 12 s. The sensors can be calibrated at the point of manufacture by building target titration curves, allowing correlation of current changes to changes in target concentration.

Here, we report the first microneedle E-AB sensor arrays for continuous monitoring of therapeutic agents. Specifically, this work reports five key innovations: (1) the design and manufacture of gold microneedle sensors (Figure 1A) that enable E-AB functionalization (Figure 1B) using established methods; (2) 3D-printed fluidic devices that mimic in vivo excretion kinetics to demonstrate that microneedle E-AB arrays achieve continuous drug monitoring in real time; (3) a cleaning protocol to successfully regenerate the surfaces of these highly engineered microneedles to enable reuse; (4) multiplexed monitoring of a prodrug and its metabolite at neighboring microneedles within the same array using a newly reported aptamer; and (5) preliminary deployment of this continuous E-AB monitor for real-time drug tracking in the ISF of one rodent.

Experimental Section

Click to copy section linkSection link copied!

Expanded Methods are provided as the Supporting Information. The main procedures are described in brief below:

Microneedle Preparation

Microneedle electrodes for in vitro experiments were fabricated via 3D printing using a Formlabs 3D printer. Microneedle arrays for in vivo experiments were fabricated using CNC micromachining techniques and poly(methyl methacrylate) materials. We sputtered the microneedles with chromium-supported layers of chromium for 1 min at 100 W (chromium) and gold for 16 min at 100 W.

Microneedle Cleaning Protocol

We incubated newly fabricated microneedle devices in pure ethanol for 10 min, followed by electrochemical cleaning, as described in the Supporting Information under Macroelectrode Cleaning. This step removes gold oxides remaining from the fabrication process. (37) To ensure that gold oxides are removed completely, we repeated the same steps three times. Second, we immersed the microneedles in 600 μL of a 10% commercial gold cleaning solution in water for 10 s (SIGMA #667978). We then measured cyclic voltammograms at a scan rate of 100 mV/s in 0.05 M H2SO4 after each treatment to evaluate the cleanliness and gold area of the microneedles. The resulting voltammograms after each treatment (Figure S1) show that our protocol is effective at cleaning the needles while preventing the loss of sputtered gold.

Sensor Preparation

To prepare E-AB sensors, we first incubated 1 μL of 100 μM thiolated MB-modified DNA with 1 μL of 100 mM tris(2-carboxyethyl)phosphine to reduce disulfide bonds for 1 h. We then incubated working electrodes in the reduced DNA solution for 1 h, followed by a 3 h-long incubation in 30 mM mercaptohexanol at room temperature to force out nonspecifically absorbed probes. All buffers used for sensor preparation are described in the Supporting Information under Expanded Methods. All aptamer solutions were diluted to a final concentration of 200 nM prior to electrode functionalization, which was measured via UV–vis spectroscopy employing an Implen Nanophotometer NP80 (Westlake Village, CA). Sensor calibration procedures are described in the Supporting Information under the Expanded Methods section.

Electrochemical Measurements

A CH Instruments Electrochemical Analyzers (CHI 1040C, Austin, TX) multichannel potentiostat, (CHI 1242, Austin, TX) hand-held potentiostat, and associated software were used for all CV and SWV measurements. We used a three-electrode cell configuration consisting of gold disk working, platinum wire counter, and Ag/AgCl (saturated KCl) reference electrodes. CV measurements were recorded at a scan rate of 100 mV/s for evaluating the cleanliness and gold area of macroelectrodes and microneedles. SWV measurements were performed with a square-wave amplitude of 25 mV, a step size of 1 mV, and various frequencies.

In Vivo Measurements

Adult male Sprague-Dawley rats (300–500 g; Charles River Laboratories, Wilmington, MA, USA) were housed in a temperature-controlled vivarium on a 12 h light–dark cycle and provided ad libitum access to food and water. All animal procedures were consistent with the guidelines of the NIH Guide for Care and Use of Laboratory Animals and approved by the Institutional Animal Care and Use Committee of the Johns Hopkins University School of Medicine.
Microneedle sensor arrays were placed on the rat abdomen after shaving them using a store-bought razor to remove all fur in the area. We pressed and released the arrays 5× to ensure penetration of the microneedles into the skin and then taped them in place for the remainder of the experiment. Once a 30–60 min sensor baseline was established, we slowly infused 0.1 mL of tobramycin sulfate (100 mM, Spectrum Pharmacy Products, New Brunswick, NJ) through a vein catheter. Recordings were taken for 1 h following drug infusions. The real-time plotting and analysis of voltammetric data were carried out using SACMES. (38)

Results and Discussion

Click to copy section linkSection link copied!

Real-Time Molecular Sensing on Microneedles Irrespective of Target Reactivity

Our first goal was to design integrated devices, allowing rapid testing of microneedle E-AB sensor array performance in vitro. To create our rapid-test devices, we 3D-printed flow cells using biocompatible, methyl methacrylate-based resins (Figure 2A). The main inlet of these devices was connected to a peristaltic pump flowing buffered solutions from a beaker. The solutions overfilled the microneedle chamber and slowly flowed out into two external drains located on the sides of each device and open to an underlying waste beaker. This approach allowed us to mimic excretion kinetics as they would occur in a living rodent by the exit of blood drug levels to urine via the kidneys. Moreover, the flow rate is adjustable, allowing us to test sensor performance under different flow conditions (Figure S2). Two additional, secondary inlets are connected to a computer-controlled syringe pump, enabling us to perform drug injections through one and rapid mixing of drug levels (<10 s) through the other (by pulling liquid out and back in). This mixing rate is analogous to the natural mixing of drugs in the bloodstream of rats, as determined by E-AB measurements. (9)

Figure 2

Figure 2. Microneedle E-AB sensor arrays support real-time molecular monitoring in vitro. (A) 3D-printed flow cell for continuous molecular monitoring. The microneedle sensor array is glued at the bottom of the cell and connected to a hand-held potentiostat to enable serial electrochemical interrogation. (B) Micrograph showing blunt microneedles used for rapid testing. The microneedle height is ∼2.3 mm, and the diameter ∼170 μm. We functionalized these using tobramycin-binding aptamers, which are modified to have covalently attached alkanethiol linkers and the redox reporter methylene blue. (C) Microneedle E-AB sensor arrays (MNs) achieve identical calibration curves relative to sensors fabricated on commercial disc macroelectrodes (MEs, 2 mm in diameter). Circles represent the average of six sensors fabricated on MEs; diamonds represent the average of three sensors fabricated on MNs; error bars represent their standard deviation. (D) Continuous, real-time monitoring of tobramycin in the flow system. Voltammetric measurements were performed every 4.5 s in 20 mM Tris, 100 mM NaCl, 5 mM MgCl2 (pH = 7.4). (E) Kinetic differential measurements (KDM) obtained after subtracting the data collected at 150 Hz (signal-off output) from data collected at 800 Hz (signal-on output).

The microneedle electrode arrays employed during our rapid testing were fabricated via established, previously reported procedures. (27) The devices are produced with high reproducibility (∼90% efficiency after wiring) and contain 16 working, 4 counter, and 1 reference microneedle electrodes. The two-dimensional design for our microneedle substrate, showing electrode connections for single and dual devices, is provided as the Supporting Information (Figure S3). To produce the integrated device (Figure 2A), we glued the microneedle devices to the bottom of our flow platform using insulating epoxy resin. For rapid testing, we produced blunt microneedles (not intended for skin penetration) with a height of ∼2.264 mm and a diameter of ∼170 μm (Figure 2B). Using these microneedles, we built E-ABs via incubation in solutions of blocking alkanethiols and aptamers modified with hexanethiol at the 5′ end and methylene blue at the 3′ end, as it is established in the field. (39)
The sensing performance of microneedle E-AB sensor arrays is identical to that of benchmark E-ABs fabricated on commercial disc electrodes. We demonstrated this by fabricating in parallel tobramycin-binding E-ABs on both microneedle devices and disc macroelectrodes (2 mm in diameter). We selected the tobramycin-binding aptamer for this comparison because it is one of the most studied ones in the E-AB platform. (2,3,8,40) To evaluate sensing performance, we built calibration curves in static, buffered solutions by challenging the E-ABs with increasing concentrations of tobramycin and measuring their response via SWV, at signal-on and signal-off square-wave frequencies of 800 Hz and 150 Hz, respectively. We determined these optimal square-wave frequencies for sensor interrogation via frequency maps (Figure S4) and previous reports. (3) The resulting traces (Figure 2C) were identical between electrode types, achieving the same signal gain and dynamic range irrespective of electrode geometry. The analytical characterization of all E-AB sensors used in this work is included as Table S2 in the Supporting Information.
Microneedle E-AB sensor arrays readily support continuous molecular monitoring in flowing buffered solutions. To demonstrate this capability, we serially interrogated microneedle E-ABs every 4.5 s, while flowing buffer at a rate of 0.66 mL/min. To achieve real-time data processing and visualization, we used SACMES, (38) an open-access Python script previously reported by our group. To emulate an in vivo titration, we injected three target tobramycin concentrations, 250 μM, 600 μM, and 1 mM, after collecting an initial 9 min-long baseline (Figure 2D). We specifically adjusted the injection (0.1 mL/min) and mixing (0.5 mL/min) rates of the syringe pump to emulate a bolus, followed by rapid mixing, so that each injection will display a short-lived target plateau concentration, followed by first-order excretion kinetics. The maximum response of each bolus matched the corresponding gain from the calibration curve in Figure 2C. In addition, we implemented KDMs, (3,8) a strategy that leverages the strong signaling dependence of E-ABs on square-wave frequency to correct for baseline drift in real time. Using SACMES, we subtracted the data collected at 150 Hz from that measured at 800 Hz in real time to achieve the drift-corrected drug profiles shown in Figure 2E. To demonstrate the versatility of our platform, we also functionalized microelectrode arrays with vancomycin-binding aptamers. (41) Vancomycin, a glycopeptide antibiotic heavily in use in the United States, (42) is vastly different in molecular structure from tobramycin (MWvancomycin = 1449.27 g mol–1 vs MWtobramycin = 467.5 g mol–1). Our results using this aptamer (Figure S5), which show equivalent performance to the tobramycin measurements (Figure 2D,E), highlight the simplicity with which our platform can be adapted to the monitoring of clinically relevant targets. Example raw voltammograms corresponding to the flow data shown in Figure 2D are included in the Supporting Information as Figure S6.

Multiuse Devices Achieving Highly Reproducible Measurements

One caveat of working with heavily engineered devices such as microneedles for sensor prototyping is the relative high cost of fabricating them as the inherent cost comes from the time it takes to produce each batch of devices. To make our technology development process more convenient and cost-effective, we developed a protocol allowing the reuse of each microneedle device for E-AB prototyping over 3 times without an impact on E-AB signaling (exemplified in Figure S1). The detailed cleaning protocol is described in the Experimental Section and Expanded Methods in the Supporting Information. In brief, we take freshly prepared microneedle devices (postmetal deposition) and incubate them in pure ethanol for 10 min. This step removes any gold oxides remaining from the fabrication process according to the relation (37)
(1)
Next, we perform standard electrochemical cleaning steps, as previously reported (34,39) and described in the Supporting Information. Then, we immerse the microneedles in 600 μL of a 10% commercial gold cleaning solution diluted in water (containing 0.1–1% thiourea and 5–10% sulfuric acid per manufacturer instructions) for 10 s. This solution oxidizes the gold surface according to the following equation (43)
(2)
Finally, we repeat the electrochemical cleaning steps immediately prior to aptamer deposition. To illustrate the performance of this protocol, we functionalized the same microneedle device with tobramycin-binding aptamer three independent times and performed continuous measurements of tobramycin as in Figure 2D,E. The resulting measurements had a relative standard deviation within ∼10% at any given target concentration (Figure 3A), demonstrating that our cleaning protocol enables reproducible device reuse. In addition, the implementation of KDM (Figure 3B) to correct for drift resulted in drug profiles with relative standard deviations that were ≤10% at tobramycin concentrations <1 mM. In contrast, measurements performed on untreated microneedles (Figure 3C) showed lower signal outputs at equal target concentrations and higher baseline noise. The aptamer packing density was also lower and highly variable between untreated devices (not shown). We anticipate our protocol will translate well to other electrode geometries.

Figure 3

Figure 3. Microneedle arrays can be reused multiple times. The newly developed chemical and electrochemical cleaning protocol reported in this work allows the reuse of microneedle devices multiple times during rapid prototyping and testing. (A) Here, for example, we show the performance of E-ABs fabricated on a single device that was reused three times. The colored data corresponds to the average of three identical measurements performed on the same device after each round of cleaning and functionalization with aptamers. Baseline peak currents at 800 Hz are ∼9 ± 0.5 mA. The shaded areas indicate the standard deviation between measurements. (B) Use of KDM for baseline correction further highlights the reproducibility achieved via the cleaning protocol. (C) For reference, untreated microneedles show lower signal output and higher baseline noise. Baseline peak currents at 800 Hz are ∼1.8 mA, 80% lower than the currents for treated microneedles.

Multiplexed Monitoring of Molecular Targets via Multichannel Devices

The availability of an array of microneedle sensors makes it possible to interrogate elements of the array either simultaneously, individually or in groups, to enable multiplexed sensing. Here, we illustrate multiplexed detection by dividing the microneedle array into two sections. For these demonstrations, we changed the cell design from Figure 2A to support an additional injection line connected to the syringe pump (Figure 4A). We also fabricated microneedle arrays containing a separating wall to allow for independent target challenges or aptamer depositions on the two sections (Figure 4B). The separating wall was detachable and could be removed prior to the deployment of the devices in the target medium.

Figure 4

Figure 4. Dual-channel microneedle E-AB devices enable simultaneous evaluation of aptamer specificity. (A) Different from Figure 2A, the 3D-printed cell was adapted to have two separate injection lines at opposite sides of the central support. By connecting these lines to the syringe pump, we could automatically inject and mix the prodrug irinotecan and its major metabolite SN-38 in the left and right chambers, respectively. (B) We functionalized the microneedles in both chambers with irinotecan-binding aptamers. In the presence of irinotecan, the E-AB sensors undergo binding-induced changes in eT between the reporter and the microneedles. However, the metabolite SN-38 induces minor conformational changes relative to irinotecan binding. (C) Microneedle E-AB sensor arrays display higher signal gain when challenged with irinotecan than with the metabolite SN-38 at square-wave frequencies of 100 Hz. (D) Demonstration of continuous, reproducible irinotecan monitoring following three boluses at a target concentration of 2 μM irinotecan in the left chamber. (E) Similarly, when challenging the right chamber with the metabolite SN-38, lower gains were obtained following three serial boluses. Voltammetric measurements were performed every 11 s in 20 mM phosphate solution containing 137 mM NaCl, 2.7 mM KCl, 2 mM MgCl2, and 1 mM CaCl2 (pH = 6.0).

We first evaluated the ability of dual-chamber microneedle E-AB sensor arrays to support simultaneous interrogation of two independent arrays functionalized with the same aptamer but exposed to different targets. For this purpose, we employed a new aptamer developed by the company Aptamer Group Ltd. (United Kingdom) that binds to irinotecan (44) (Figure 4B), a chemotherapeutic prodrug. When bound to the E-AB sensing interface and functionalized with methylene blue, this aptamer underwent binding-induced eT changes, readily enabling E-AB sensing. Calibration of the resulting E-ABs with irinotecan and its main metabolite, SN-38, showed that the aptamer binds to both with similar affinity but achieves greater gain at every concentration when challenged with irinotecan (green vs purple markers in Figure 4C). Using this calibration, we were able to estimate an apparent dissociation constant of KD = 723 ± 64 nM based on nonlinear regression of the data to the Langmuir–Hill isotherm (Figure S7). This estimated KD represents a 2 orders-of-magnitude improvement in irinotecan affinity in PBS relative to irinotecan-binding E-ABs previously reported by Plaxco and colleagues, (45) KD = 126 ± 24 μM. In addition, our E-ABs did not require codeposition of unstructured DNA strands to achieve dual-frequency sensing (Figure 4C–E).
When we continuously interrogated these E-ABs in dual-chamber microneedle devices and the chambers were simultaneously challenged with either irinotecan or SN-38, we successfully achieved independent monitoring of E-AB gains from both sensing chambers. Following three serial boluses at a 2 μM irinotecan concentration, we observed 100% reproducible signaling responses from chamber 1 (Figure 4D), similar in magnitude to the gain observed in our calibration curve for the matching 2 μM concentration (Figure 4C). Likewise, the response to 2 μM SN-38 additions performed in chamber 2 showed excellent repeatability but lower gain (Figure 4E), also in agreement with our calibration data. Example raw voltammograms corresponding to the flow data shown in Figure 4D,E are included in the Supporting Information as Figures S8 and S9. These results illustrate the versatility of the microneedle E-AB sensor array platform, which can be easily fabricated with different configurations to allow simultaneous and multiplexed evaluation of aptamer selectivity.
We next evaluated the ability of dual-chamber microneedle E-AB sensor arrays to support simultaneous interrogation of two independent arrays each functionalized with a different aptamer. For this demonstration, we employed the same flow device illustrated in Figure 4A, except that this time, one of the microneedle array chambers was functionalized with the irinotecan-binding aptamer and the other with a doxorubicin-binding aptamer (8) (Figure 5A). Doxorubicin is a chemotherapeutic regularly used for the treatment of certain leukemias and Hodgkin’s lymphoma. (46−48) The idea was to demonstrate the concept that a microneedle E-AB sensor array could be used to simultaneously monitor an array of chemotherapeutic agents, providing an unparalleled route for therapeutic drug monitoring during cancer treatment. We note, however, that irinotecan and doxorubicin are never dosed together; thus, our demonstration here is purely conceptual. Future development of aptamers binding to, for example, fluorouracil, could generate a strong matching pair for irinotecan since these therapeutics are used in combination therapy. (49) Similarly, doxorubicin is often codosed with cyclophosphamide or Taxotere; (50,51) thus, developing aptamers against these targets could result in functional dual devices for chemotherapy monitoring. However, the development of such aptamers is beyond the scope of this work. Instead, the conceptual demonstration we present here aims to highlight the versatility of our microneedle sensor platform to achieve multiplexed monitoring of therapeutic agents.

Figure 5

Figure 5. Dual-channel microneedle E-AB devices enable multiplexed sensing. (A) We functionalized the microneedles in each chamber with either irinotecan-binding or doxorubicin-binding aptamers. (B) Mean calibration curves of six irinotecan-binding and doxorubicin-binding E-ABs obtained using commercial disc macroelectrodes (2 mm in diameter) demonstrate that both sensors showed high affinity when challenged with their targets. (C) When simultaneously injecting irinotecan and doxorubicin in either chamber of the microneedle device, it was possible to successfully monitor E-AB signals induced by target binding to the respective E-ABs. In the case of the irinotecan-binding sensor, irinotecan boluses of increasing concentrations produced corresponding E-AB responses. Challenging the same E-ABs with doxorubicin, a known DNA intercalator, also produced large signal changes. (D) Likewise, challenging the doxorubicin-binding E-ABs with doxorubicin boluses of increasing concentration caused proportional E-AB responses. Challenging these sensors with 4 μM irinotecan did not induce E-AB signal changes. Voltammetric measurements were performed every 12 s in 20 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2 mM MgCl2, and 1 mM CaCl2 (pH = 6.0).

Following dual-chamber E-AB sensor fabrication, we calibrated doxorubicin aptamer-based sensors by challenging the sensors with increasing concentrations of doxorubicin, respectively (Figure 5B). Doing this, we determined an apparent dissociation constant for the doxorubicin aptamer of KD = 969 ± 170 nM (Figure S7), in close agreement with the aptamer’s affinity as first reported by Soh and colleagues (824 ± 18 nM). (8) When we continuously interrogated these dual-chamber microneedle devices and the chambers were simultaneously challenged with either irinotecan or doxorubicin, we successfully achieved independent monitoring of the two drugs. For the case of irinotecan, we observed sharp responses following boluses at 1, 2, and 4 μM irinotecan (Figure 5C), with signaling that, again, matched our calibration curve (Figure 5B) and returned to the baseline. For doxorubicin, in contrast, we observed E-AB responses to each bolus, but the return to the baseline was not complete between target injections (Figure 5D). This effect is potentially due to doxorubicin nonspecifically binding to the plastic walls of our flow devices and slowly leaching back into the solution during the flow experiment. We do not foresee this problem happening when deploying our devices in vivo since all plastic walls will be removed for such applications. In addition, plastic surfaces in contact with doxorubicin could be pretreated with surfactants to prevent nonspecific drug binding. Example raw voltammograms corresponding to the flow data shown in Figure 5C,D are included in the Supporting Information as Figures S10 and S11.
The selectivity of microneedle E-AB sensor arrays is, of course, limited by the selectivity of the parent aptamers used to fabricate the sensors and the nature of the targets. Doxorubicin, for example, is a known DNA intercalator that can bind to any double-stranded DNA. Because both aptamers used in this work present self-complementarity within their sequences and some secondary structure (i.e., double-stranded character), doxorubicin can bind both. We confirmed this in our flow experiments by injecting doxorubicin into the chamber containing the irinotecan-binding E-ABs and observing a sharp response to the drug injection (last bolus in Figure 5C). In contrast, irinotecan is not an intercalation agent. Its mechanism of action is based on specific binding to the topoisomerase I–DNA complex, forming a tertiary structure that prevents replication in cancer cells. (52) As such, injection of irinotecan into the chamber containing doxorubicin-binding E-ABs resulted in minimal response to the drug addition (last bolus in Figure 5D). Overall, these results highlight the potential of microneedle E-AB sensors to enable simultaneous and multiplexed monitoring of therapeutic agents in real time.

Wearable, Continuous, and Real-Time Molecular Monitoring in Vivo

Microneedle E-AB sensor arrays can readily enable continuous molecular monitoring in vivo. We illustrate this capability here by deploying one microneedle E-AB sensor array on the skin of an anesthetized rat and performing continuous monitoring of the antibiotic tobramycin following IV dosing (Figure 6). We note that the goal of this work was to qualitatively probe whether our microneedle E-AB sensor arrays could support continuous molecular monitoring in vivo, with no goal of performing quantitative or detailed pharmacokinetic measurements at this time. Such efforts will be devoted to future work. For our in vivo measurements, we fabricated new devices devoid of chamber walls and containing smaller microneedles: 170 μm in diameter, a sharp tip end (<20 μm), and 1.1 mm tall (Figure 6A). The electronics behind these devices were encased inside a 3D-printed plastic chamber for convenience (Figure 6B). We placed them onto the shaved skin of rodents by applying a pressure similar in force to a normal handshake and fixed them in place via medical grade tape (not shown). Visual inspection of the deployment site post measurements revealed the correct microwound pattern expected from the microneedle array (Figure 6C). To confirm penetration through the epidermis and into the dermis of the animal where ISF is found, we dissected the skin tissue post measurements, fixed it in p-formaldehyde, and performed histological H&E staining to reveal microneedle tracks (Figure 6D). We note that the fixation and staining protocols strongly dehydrate the tissues, thereby collapsing the microneedle tracks into smaller dimensions than those expected based on physical measurements via scanning electron microscopy (Figure 6A). Nevertheless, we were able to observe clear penetrating tracks with breakage of the epidermis and an approximate length of 500 μm and width of 50 μm. The contrast- and hue-adjusted duplicate image shown in Figure 6E is included to facilitate observation of the penetrating tracks of the microneedle.

Figure 6

Figure 6. Continuous molecular monitoring of tobramycin concentration in ISF. Proof-of-concept monitoring of tobramycin levels in the dermis of one rat following IV administration of the drug at a dose of 20 mg/kg. (A) We fabricated sharper microneedles that were 150 μm in diameter and 1.1 mm in length. (B) The microneedles were placed on the freshly shaved abdomen of one male rat. (C) Removal of the device from the skin revealed the expected pattern of micropunctures. (D) H&E-stained skin tissue illustrating different histological features of the rat’s skin and one penetrating track left after insertion of the microneedles. (E) Hue- and contrast-adjusted duplicate image highlighting the track mark after microneedle removal. (F) Although noisy, electrochemical interrogation of the microneedle array resulted in discernible square-wave voltammograms in ISF that strongly responded to tobramycin following an IV bolus injected into the right jugular vein of the rat (drop from blue to orange). (G) Real-time processing of the voltammograms using SACMES allowed us to visualize the sensor response, here plotted as relative signal after tobramycin dosing. SACMES uses rolling average and polynomial fit algorithms to remove noise from voltammograms, thus enabling the extraction of high signal-to-noise E-AB data. Unfortunately, progressive degradation of the sensors in ISF made it impossible to distinguish signals past t = 60 min. The red line shows a regression analysis to a two-compartment drug absorption pharmacokinetic model using the data points available.

The skin-worn microneedle sensor arrays successfully achieved continuous molecular measurements in ISF. We demonstrate this by serially interrogating one tobramycin-binding microneedle E-AB sensor array via voltammetry while placed on the skin of a rat. We timed the voltammetric sweeps 70 s apart to minimize sensor drift (40,53), and interrogated at square-wave frequencies of 80, 150, 200, and 240 Hz. Unfortunately, the noise level at frequencies higher than 80 Hz was larger in magnitude than the redox wave from the aptamer-bound reporters, thus precluding the use of KDM in this measurement. However, measurements at 80 Hz produced clear voltammograms that could be processed in real time using SACMES. (38) At this frequency, tobramycin-binding E-ABs behaved as signal-off sensors in ISF, responding to increases in drug concentration with corresponding decreases in voltammetric current (Figure 6F). When processing the data in real time, we observed a sudden change in current at the exact time of tobramycin IV dosing (Figure 6G). Even though the skin dermis is a separate compartment from systemic blood, it is highly perfused, and thus, we expected the two compartments to rapidly equilibrate molecular concentrations. In agreement with this, our sensor showed a rapid absorption phase immediately following IV dosing of tobramycin. This phase was succeeded by a short-lived plateau and the beginning of signal decay in response to drug excretion kinetics. Unfortunately, we could not fully resolve the elimination phase of the drug before the sensor signal decayed below noise level due to sensor degradation (green trace in Figure 6F). However, performing regression analysis of the points collected against a two-compartment drug adsorption model resulted in an elimination half-life of 23 ± 2 min, which is in close agreement with the previous E-AB measurements of plasma tobramycin excretion kinetics. (4) Building upon these encouraging in vivo results, we will focus future efforts on mitigating the environmental noise seen in our voltammetric measurements and extending the operational life of our sensors in vivo.

Conclusions

Click to copy section linkSection link copied!

We report the coupling of E-AB sensors with microneedle electrode arrays to demonstrate continuous molecular monitoring. Because aptamer-based sensors achieve molecular recognition via reversible affinity interactions and not reactivity with the target, they offer the possibility to expand the molecular targets that can be sensed beyond the electrocatalytic and enzymatic detection of redox-active molecules. This work demonstrates examples of single and multiplexed molecular measurements achieved via mono- and dual-channel devices. However, the possibility to interrogate individual microneedle electrodes within a large array also exists, potentially allowing for simultaneous multichannel interrogation of a library of molecular targets. In addition, this work shows that 3D printed, gold-coated microneedle electrode arrays can be easily functionalized with E-AB sensing chemistries to enable molecular monitoring in the ISF of research animals. Future demonstrations of the technology will focus on implementing noise reduction and enhanced stability strategies to allow for high-resolution in vivo measurements. We will also devote future efforts to test the resiliency to skin penetration and biocompatibility of in vivo microneedle E-AB sensor arrays.

Supporting Information

Click to copy section linkSection link copied!

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.analchem.2c00829.

  • Expanded Methods cleaning protocol monitoring) and additional data (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

Click to copy section linkSection link copied!

  • Corresponding Authors
    • Joseph Wang - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States Email: [email protected]
    • Netzahualcóyotl Arroyo-Currás - Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United StatesBiochemistry, Cellular and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United StatesOrcidhttps://orcid.org/0000-0002-2740-6276 Email: [email protected]
  • Authors
    • Yao Wu - Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United StatesOrcidhttps://orcid.org/0000-0003-1296-6569
    • Farshad Tehrani - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Hazhir Teymourian - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United StatesOrcidhttps://orcid.org/0000-0003-0025-4732
    • John Mack - Biochemistry, Cellular and Molecular Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United States
    • Alexander Shaver - Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21202, United StatesOrcidhttps://orcid.org/0000-0002-5478-5291
    • Maria Reynoso - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Jonathan Kavner - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Nickey Huang - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Allison Furmidge - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Andrés Duvvuri - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Yuhang Nie - Department of Nanoengineering, University of California San Diego, La Jolla, California 92093, United States
    • Lori M. Laffel - Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
    • Francis J. Doyle III - Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States
    • Mary-Elizabeth Patti - Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, United States
    • Eyal Dassau - Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Allston, Massachusetts 02134, United States
  • Author Contributions

    Y.W. and J.M. fabricated all E-AB sensors and tested them in vitro. F.T. designed all microneedle devices. H.T., M.R., J.K., N.H., A.F., A.D., and Y.N. contributed to the fabrication of both in vitro and in vivo microneedle devices. A.S. performed all animal surgeries and in vivo E-AB trials. J.W. and N.A.C. collaboratively designed the experiments with Y.W. and F.T. and supervised the development of the work. L.M.L., F.J.D., E.D., and M.E.P. analyzed data and contributed to the writing of the manuscript. All authors contributed to the writing of the final version of this manuscript.

  • Notes
    The authors declare the following competing financial interest(s): E.D. reports receiving grants from JDRF, NIH, and Helmsley Charitable Trust, personal fees from Roche and Eli Lilly, patents on artificial pancreas technology, and product support from Dexcom, Insulet, Tandem, and Roche. E.D. is currently an employee and shareholder of Eli Lilly and Company. The work presented in this manuscript was performed as part of his academic appointment and is independent of his employment with Eli Lilly and Company.F.J.D. reports equity, licensed IP and is a member of the Scien-tific Advisory Board of Mode AGC.L.M.L. reports grant support to her institution from NIH, JDRF, Helmsley Charitable Trust, Eli Lilly and Company, Insulet, Dexcom, and Boehringer Ingelheim; she receives con-sulting fees unrelated to the current report from NovoNordisk, Roche, Dexcom, Insulet, Boehringer Ingelheim, Medtronic, Dompe, and Provention. M.E.P. reports receiving grant support, provided to her institution, from NIH, Helmsley Charitable Trust, Chan Zuckerberg Foundation, and Dexcom, patents related to hypoglycemia and pump therapy for hypoglycemia, and advisory board fees from Fractyl (unrelated to the current report).F.T., H.T., E.D., J.W. and N.A.C. are co-inventors of patents filed based on the work reported in this study.

Acknowledgments

Click to copy section linkSection link copied!

This work was supported by The Leona M. and Harry B. Helmsley Charitable Trust under award number 7505508-5108014 (2018PG-TI0061).

References

Click to copy section linkSection link copied!

This article references 53 other publications.

  1. 1
    Teymourian, H.; Parrilla, M.; Sempionatto, J. R.; Montiel, N. F.; Barfidokht, A.; Van Echelpoel, R.; De Wael, K.; Wang, J. Wearable electrochemical sensors for the monitoring and screening of drugs. ACS Sens. 2020, 5, 26792700,  DOI: 10.1021/acssensors.0c01318
  2. 2
    Arroyo-Currás, N.; Ortega, G.; Copp, D. A.; Ploense, K. L.; Plaxco, Z. A.; Kippin, T. E.; Hespanha, J. P.; Plaxco, K. W. High-precision control of plasma drug levels using feedback-controlled dosing. ACS Pharmacol. Transl. Sci. 2018, 1, 110118,  DOI: 10.1021/acsptsci.8b00033
  3. 3
    Arroyo-Currás, N.; Somerson, J.; Vieira, P. A.; Ploense, K. L.; Kippin, T. E.; Plaxco, K. W. Real-time measurement of small molecules directly in awake, ambulatory animals. Proc. Natl. Acad. Sci. U.S.A. 2017, 114, 645650,  DOI: 10.1073/pnas.1613458114
  4. 4
    Vieira, P. A.; Shin, C. B.; Arroyo-Currás, N.; Ortega, G.; Li, W.; Keller, A. A.; Plaxco, K. W.; Kippin, T. E. Ultra-high-precision, in-vivo pharmacokinetic measurements highlight the need for and a route toward more highly personalized medicine. Front. Mol. Biosci. 2019, 6, 69,  DOI: 10.3389/fmolb.2019.00069
  5. 5
    Wolkowicz, K. L.; Aiello, E. M.; Vargas, E.; Teymourian, H.; Tehrani, F.; Wang, J.; Pinsker, J. E.; Doyle, F. J., 3rd; Patti, M. E.; Laffel, L. M.; Dassau, E. A review of biomarkers in the context of type 1 diabetes: Biological sensing for enhanced glucose control. Bioeng. Transl. Med. 2021, 6, e10201  DOI: 10.1002/btm2.10201
  6. 6
    Aiello, E. M.; Deshpande, S.; Özaslan, B.; Wolkowicz, K. L.; Dassau, E.; Pinsker, J. E.; Doyle, F. J. Review of automated insulin delivery systems for individuals with type 1 diabetes: Tailored solutions for subpopulations. Curr. Opin. Biomed. Eng. 2021, 19, 100312,  DOI: 10.1016/j.cobme.2021.100312
  7. 7
    Li, J.; Liang, J. Y.; Laken, S. J.; Langer, R.; Traverso, G. Clinical opportunities for continuous biosensing and closed-loop therapies. Trends Chem. 2020, 2, 319340,  DOI: 10.1016/j.trechm.2020.02.009
  8. 8
    Ferguson, B. S.; Hoggarth, D. A.; Maliniak, D.; Ploense, K.; White, R. J.; Woodward, N.; Hsieh, K.; Bonham, A. J.; Eisenstein, M.; Kippin, T. E.; Plaxco, K. W.; Soh, H. T. Real-time, aptamer-based tracking of circulating therapeutic agents in living animals. Sci. Transl. Med. 2013, 5, 213ra165,  DOI: 10.1126/scitranslmed.3007095
  9. 9
    Arroyo-Currás, N.; Dauphin-Ducharme, P.; Ortega, G.; Ploense, K. L.; Kippin, T. E.; Plaxco, K. W. Subsecond-resolved molecular measurements in the living body using chronoamperometrically interrogated aptamer-based sensors. ACS Sens. 2018, 3, 360366,  DOI: 10.1021/acssensors.7b00787
  10. 10
    Falagas, M. E.; Karageorgopoulos, D. E. Adjustment of dosing of antimicrobial agents for bodyweight in adults. Lancet 2010, 375, 248251,  DOI: 10.1016/s0140-6736(09)60743-1
  11. 11
    Shuter, B.; Aslani, A. Body surface area: Du bois and du bois revisited. Eur. J. Appl. Physiol. 2000, 82, 250254,  DOI: 10.1007/s004210050679
  12. 12
    Neely, M. N.; Kato, L.; Youn, G.; Kraler, L.; Bayard, D.; van Guilder, M.; Schumitzky, A.; Yamada, W.; Jones, B.; Minejima, E. Prospective trial on the use of trough concentration versus area under the curve to determine therapeutic vancomycin dosing. Antimicrob. Agents Chemother. 2018, 62, e02042  DOI: 10.1128/AAC.02042-17
  13. 13
    Zhang, T.; Cai, S.; Forrest, W. C.; Mohr, E.; Yang, Q.; Forrest, M. L. Development and validation of an inductively coupled plasma mass spectrometry (icp-ms) method for quantitative analysis of platinum in plasma, urine, and tissues. Appl. Spectrosc. 2016, 70, 15291536,  DOI: 10.1177/0003702816662607
  14. 14
    Zhong, X.; Tong, X.; Ju, Y.; Du, X.; Li, Y. Interpersonal factors in the pharmacokinetics and pharmacodynamics of voriconazole: Are cyp2c19 genotypes enough for us to make a clinical decision?. Curr. Drug Metab. 2018, 19, 11521158,  DOI: 10.2174/1389200219666171227200547
  15. 15
    Payne, K. D.; Hall, R. G. Dosing of antibacterial agents in obese adults: does one size fit all?. Expert Rev. Anti-Infect. Ther. 2014, 12, 829854,  DOI: 10.1586/14787210.2014.912942
  16. 16
    Tran, B. Q.; Miller, P. R.; Taylor, R. M.; Boyd, G.; Mach, P. M.; Rosenzweig, C. N.; Baca, J. T.; Polsky, R.; Glaros, T. Proteomic characterization of dermal interstitial fluid extracted using a novel microneedle-assisted technique. J. Proteome Res. 2018, 17, 479485,  DOI: 10.1021/acs.jproteome.7b00642
  17. 17
    Samant, P. P.; Niedzwiecki, M. M.; Raviele, N.; Tran, V.; Mena-Lapaix, J.; Walker, D. I.; Felner, E. I.; Jones, D. P.; Miller, G. W.; Prausnitz, M. R. Sampling interstitial fluid from human skin using a microneedle patch. Sci. Transl. Med. 2020, 12, eaaw0285  DOI: 10.1126/scitranslmed.aaw0285
  18. 18
    Siegmund, T.; Heinemann, L.; Kolassa, R.; Thomas, A. Discrepancies Between Blood Glucose and Interstitial Glucose-Technological Artifacts or Physiology: Implications for Selection of the Appropriate Therapeutic Target. J. Diabetes Sci. Technol. 2017, 11, 766772,  DOI: 10.1177/1932296817699637
  19. 19
    Teymourian, H.; Tehrani, F.; Mahato, K.; Wang, J. Lab under the skin: Microneedle based wearable devices. Adv. Healthcare Mater. 2021, 10, e2002255  DOI: 10.1002/adhm.202002255
  20. 20
    Miller, P. R.; Taylor, R. M.; Tran, B. Q.; Boyd, G.; Glaros, T.; Chavez, V. H.; Krishnakumar, R.; Sinha, A.; Poorey, K.; Williams, K. P.; Branda, S. S.; Baca, J. T.; Polsky, R. Extraction and biomolecular analysis of dermal interstitial fluid collected with hollow microneedles. Commun. Biol. 2018, 1, 173,  DOI: 10.1038/s42003-018-0170-z
  21. 21
    van der Maaden, K.; Jiskoot, W.; Bouwstra, J. Microneedle technologies for (trans)dermal drug and vaccine delivery. J. Controlled Release 2012, 161, 645655,  DOI: 10.1016/j.jconrel.2012.01.042
  22. 22
    Singh, P.; Carrier, A.; Chen, Y.; Lin, S.; Wang, J.; Cui, S.; Zhang, X. Polymeric microneedles for controlled transdermal drug delivery. J. Controlled Release 2019, 315, 97113,  DOI: 10.1016/j.jconrel.2019.10.022
  23. 23
    Goud, K. Y.; Moonla, C.; Mishra, R. K.; Yu, C.; Narayan, R.; Litvan, I.; Wang, J. Wearable electrochemical microneedle sensor for continuous monitoring of levodopa: Toward parkinson management. ACS Sens. 2019, 4, 21962204,  DOI: 10.1021/acssensors.9b01127
  24. 24
    Mohan, A. M. V.; Windmiller, J. R.; Mishra, R. K.; Wang, J. Continuous minimally-invasive alcohol monitoring using microneedle sensor arrays. Biosens. Bioelectron. 2017, 91, 574579,  DOI: 10.1016/j.bios.2017.01.016
  25. 25
    Mishra, R. K.; Vinu Mohan, A. M.; Soto, F.; Chrostowski, R.; Wang, J. A microneedle biosensor for minimally-invasive transdermal detection of nerve agents. Analyst 2017, 142, 918924,  DOI: 10.1039/c6an02625g
  26. 26
    Windmiller, J. R.; Valdés-Ramírez, G.; Zhou, N.; Zhou, M.; Miller, P. R.; Jin, C.; Brozik, S. M.; Polsky, R.; Katz, E.; Narayan, R.; Wang, J. Bicomponent microneedle array biosensor for minimally-invasive glutamate monitoring. Electroanalysis 2011, 23, 23022309,  DOI: 10.1002/elan.201100361
  27. 27
    Teymourian, H.; Moonla, C.; Tehrani, F.; Vargas, E.; Aghavali, R.; Barfidokht, A.; Tangkuaram, T.; Mercier, P. P.; Dassau, E.; Wang, J. Microneedle-based detection of ketone bodies along with glucose and lactate: Toward real-time continuous interstitial fluid monitoring of diabetic ketosis and ketoacidosis. Anal. Chem. 2020, 92, 22912300,  DOI: 10.1021/acs.analchem.9b05109
  28. 28
    Mishra, R. K.; Goud, K. Y.; Li, Z.; Moonla, C.; Mohamed, M. A.; Tehrani, F.; Teymourian, H.; Wang, J. Continuous opioid monitoring along with nerve agents on a wearable microneedle sensor array. J. Am. Chem. Soc. 2020, 142, 59915995,  DOI: 10.1021/jacs.0c01883
  29. 29
    Xiao, Y.; Lubin, A. A.; Heeger, A. J.; Plaxco, K. W. Label-free electronic detection of thrombin in blood serum by using an aptamer-based sensor. Angew. Chem., Int. Ed. 2005, 44, 54565459,  DOI: 10.1002/anie.200500989
  30. 30
    Tuerk, C.; Gold, L. Systematic evolution of ligands by exponential enrichment: Rna ligands to bacteriophage t4 DNA polymerase. Science 1990, 249, 505510,  DOI: 10.1126/science.2200121
  31. 31
    Ellington, A. D.; Szostak, J. W. In vitro selection of rna molecules that bind specific ligands. Nature 1990, 346, 818822,  DOI: 10.1038/346818a0
  32. 32
    Wu, Y.; Belmonte, I.; Sykes, K. S.; Xiao, Y.; White, R. J. Perspective on the future role of aptamers in analytical chemistry. Anal. Chem. 2019, 91, 1533515344,  DOI: 10.1021/acs.analchem.9b03853
  33. 33
    Yi, K.; Wang, Y.; Shi, K.; Chi, J.; Lyu, J.; Zhao, Y. Aptamer-decorated porous microneedles arrays for extraction and detection of skin interstitial fluid biomarkers. Biosens. Bioelectron. 2021, 190, 113404,  DOI: 10.1016/j.bios.2021.113404
  34. 34
    Shaver, A.; Curtis, S. D.; Arroyo-Currás, N. Alkanethiol monolayer end groups affect the long-term operational stability and signaling of electrochemical, aptamer-based sensors in biological fluids. ACS Appl. Mater. Interfaces 2020, 12, 1121411223,  DOI: 10.1021/acsami.9b22385
  35. 35
    Arroyo-Currás, N.; Dauphin-Ducharme, P.; Scida, K.; Chávez, J. L. From the beaker to the body: Translational challenges for electrochemical, aptamer-based sensors. Anal. Methods 2020, 12, 12881310,  DOI: 10.1039/d0ay00026d
  36. 36
    Dauphin-Ducharme, P.; Ploense, K. L.; Arroyo-Currás, N.; Kippin, T. E.; Plaxco, K. W. Electrochemical aptamer-based sensors: A platform approach to high-frequency molecular monitoring in situ in the living body. Biomedical Engineering Technologies; Methods in Molecular Biology; Ossandon, M. R., Baker, H., Rasooly, A., Eds.; Springer US: Humana, New York, NY, 2022; Vol. 2393, pp 479492.
  37. 37
    Carvalhal, R. F.; Sanches Freire, R.; Kubota, L. T. Polycrystalline gold electrodes: A comparative study of pretreatment procedures used for cleaning and thiol self-assembly monolayer formation. Electroanalysis 2005, 17, 12511259,  DOI: 10.1002/elan.200403224
  38. 38
    Curtis, S. D.; Ploense, K. L.; Kurnik, M.; Ortega, G.; Parolo, C.; Kippin, T. E.; Plaxco, K. W.; Arroyo-Currás, N. Open source software for the real-time control, processing, and visualization of high-volume electrochemical data. Anal. Chem. 2019, 91, 1232112328,  DOI: 10.1021/acs.analchem.9b02553
  39. 39
    Xiao, Y.; Lai, R. Y.; Plaxco, K. W. Preparation of electrode-immobilized, redox-modified oligonucleotides for electrochemical DNA and aptamer-based sensing. Nat. Protoc. 2007, 2, 28752880,  DOI: 10.1038/nprot.2007.413
  40. 40
    Pellitero, M. A.; Curtis, S. D.; Arroyo-Currás, N. Interrogation of electrochemical aptamer-based sensors via peak-to-peak separation in cyclic voltammetry improves the temporal stability and batch-to-batch variability in biological fluids. ACS Sens. 2021, 6, 11991207,  DOI: 10.1021/acssensors.0c02455
  41. 41
    Dauphin-Ducharme, P.; Yang, K.; Arroyo-Currás, N.; Ploense, K. L.; Zhang, Y.; Gerson, J.; Kurnik, M.; Kippin, T. E.; Stojanovic, M. N.; Plaxco, K. W. Electrochemical aptamer-based sensors for improved therapeutic drug monitoring and high-precision, feedback-controlled drug delivery. ACS Sens. 2019, 4, 28322837,  DOI: 10.1021/acssensors.9b01616
  42. 42
    Dilworth, T. J.; Schulz, L. T.; Rose, W. E. Vancomycin advanced therapeutic drug monitoring: Exercise in futility or virtuous endeavor to improve drug efficacy and safety?. Clin. Infect. Dis. 2021, 72, E675E681,  DOI: 10.1093/cid/ciaa1354
  43. 43
    Groenewald, T. The dissolution of gold in acidic solutions of thiourea. Hydrometallurgy 1976, 1, 277290,  DOI: 10.1016/0304-386x(76)90004-9
  44. 44
    Puscasu, A.; Zanchetta, M.; Posocco, B.; Bunka, D.; Tartaggia, S.; Toffoli, G. Development and validation of a selective spr aptasensor for the detection of anticancer drug irinotecan in human plasma samples. Anal. Bioanal. Chem. 2021, 413, 12251236,  DOI: 10.1007/s00216-020-03087-5
  45. 45
    Idili, A.; Arroyo-Currás, N.; Ploense, K. L.; Csordas, A. T.; Kuwahara, M.; Kippin, T. E.; Plaxco, K. W. Seconds-resolved pharmacokinetic measurements of the chemotherapeutic irinotecan in situ in the living body. Chem. Sci. 2019, 10, 81648170,  DOI: 10.1039/c9sc01495k
  46. 46
    Chand, V. K.; Link, B. K.; Ritchie, J. M.; Shannon, M.; Wooldridge, J. E. Neutropenia and febrile neutropenia in patients with hodgkin’s lymphoma treated with doxorubicin (adriamycin), bleomycin, vinblastine and dacarbazine (abvd) chemotherapy. Leuk. Lymphoma 2006, 47, 657663,  DOI: 10.1080/10428190500353430
  47. 47
    Pérez-Blanco, J. S.; Santos-Buelga, D.; Fernández de Gatta, M. d. M.; Hernández-Rivas, J. M.; Martín, A.; García, M. J. Population pharmacokinetics of doxorubicin and doxorubicinol in patients diagnosed with non-hodgkin’s lymphoma. Br. J. Clin. Pharmacol. 2016, 82, 15171527,  DOI: 10.1111/bcp.13070
  48. 48
    Zhou, T.; Shen, Q.; Peng, H.; Chao, T.; Zhang, L.; Huang, L.; Yang, K.; Thapa, S.; Yu, S.; Jiang, Y. Incidence of interstitial pneumonitis in non-hodgkin’s lymphoma patients receiving immunochemotherapy with pegylated liposomal doxorubicin and rituximab. Ann. Hematol. 2018, 97, 141147,  DOI: 10.1007/s00277-017-3160-1
  49. 49
    Harris, S. M.; Mistry, P.; Freathy, C.; Brown, J. L.; Charlton, P. A. Antitumour activity of xr5944 in vitro and in vivo in combination with 5-fluorouracil and irinotecan in colon cancer cell lines. Br. J. Cancer 2005, 92, 722728,  DOI: 10.1038/sj.bjc.6602403
  50. 50
    Torrisi, R.; Orlando, L.; Ghisini, R.; Veronesi, P.; Intra, M.; Rocca, A.; Balduzzi, A.; Cardillo, A.; Goldhirsch, A.; Colleoni, M. A phase ii study of primary dose-dense sequential doxorubicin plus cyclophosphamide and docetaxel in ct4 breast cancer. Anticancer Res. 2006, 26, 38613864
  51. 51
    Oakman, C.; Francis, P. A.; Crown, J.; Quinaux, E.; Buyse, M.; De Azambuja, E.; Margeli Vila, M.; Andersson, M.; Nordenskjöld, B.; Jakesz, R.; Thürlimann, B.; Gutiérrez, J.; Harvey, V.; Punzalan, L.; Dell’orto, P.; Larsimont, D.; Steinberg, I.; Gelber, R. D.; Piccart-Gebhart, M.; Viale, G.; Di Leo, A. Overall survival benefit for sequential doxorubicin-docetaxel compared with concurrent doxorubicin and docetaxel in node-positive breast cancer-8-year results of the Breast International Group 02-98 phase III trial. Ann. Oncol. 2013, 24, 12031211,  DOI: 10.1093/annonc/mds627
  52. 52
    Bailly, C. Topoisomerase i poisons and suppressors as anticancer drugs. Curr. Med. Chem. 2000, 7, 3958,  DOI: 10.2174/0929867003375489
  53. 53
    Leung, K. K.; Downs, A. M.; Ortega, G.; Kurnik, M.; Plaxco, K. W. Elucidating the mechanisms underlying the signal drift of electrochemical aptamer-based sensors in whole blood. ACS Sens. 2021, 6, 33403347,  DOI: 10.1021/acssensors.1c01183

Cited By

Click to copy section linkSection link copied!
Citation Statements
Explore this article's citation statements on scite.ai

This article is cited by 107 publications.

  1. Yuexi Lin, Muamer Dervisevic, Hao Zhe Yoh, Keying Guo, Nicolas H. Voelcker. Tailoring Design of Microneedles for Drug Delivery and Biosensing. Molecular Pharmaceutics 2025, 22 (2) , 678-707. https://doi.org/10.1021/acs.molpharmaceut.4c01266
  2. Rashmi Hulimane Shivaswamy, Pranav Binulal, Aloysious Benoy, Kaushik Lakshmiramanan, Nitu Bhaskar, Hardik Jeetendra Pandya. Microneedles as a Promising Technology for Disease Monitoring and Drug Delivery: A Review. ACS Materials Au 2025, 5 (1) , 115-140. https://doi.org/10.1021/acsmaterialsau.4c00125
  3. Navid Rabiee, Mohammad Rabiee. Wearable Aptasensors. Analytical Chemistry 2024, 96 (49) , 19160-19182. https://doi.org/10.1021/acs.analchem.4c05004
  4. Vanshika Gupta, AnhThu Pham, Jeffrey E. Dick. Planar Disk μ-Aptasensors by Monolayer Assembly in a Dissolving Microdroplet. Analytical Chemistry 2024, 96 (34) , 13777-13784. https://doi.org/10.1021/acs.analchem.4c01043
  5. Elsi Verrinder, Julian Gerson, Kaylyn Leung, Tod E. Kippin, Kevin W. Plaxco. Dual-Frequency, Ratiometric Approaches to EAB Sensor Interrogation Support the Calibration-Free Measurement of Specific Molecules In Vivo. ACS Sensors 2024, 9 (6) , 3205-3211. https://doi.org/10.1021/acssensors.4c00516
  6. Jiatao Chen, Fuyun Xia, Xiuting Ding, Dongdong Zhang. Universal Covalent Grafting Strategy of an Aptamer on a Carbon Fiber Microelectrode for Selective Determination of Dopamine In Vivo. Analytical Chemistry 2024, 96 (25) , 10322-10331. https://doi.org/10.1021/acs.analchem.4c01167
  7. Yuyang Wu, Jinyuan Shi, Tod E. Kippin, Kevin W. Plaxco. Codeposition Enhances the Performance of Electrochemical Aptamer-Based Sensors. Langmuir 2024, 40 (16) , 8703-8710. https://doi.org/10.1021/acs.langmuir.4c00585
  8. Jun Li, Meng Wei, Bingbing Gao. A Review of Recent Advances in Microneedle-Based Sensing within the Dermal ISF That Could Transform Medical Testing. ACS Sensors 2024, 9 (3) , 1149-1161. https://doi.org/10.1021/acssensors.4c00142
  9. Monica Wolfe, Alyssa Cramer, Sean Webb, Eva Goorskey, Yaroslav Chushak, Peter Mirau, Netzahualcóyotl Arroyo-Currás, Jorge L. Chávez. Rational Approach to Optimizing Conformation-Switching Aptamers for Biosensing Applications. ACS Sensors 2024, 9 (2) , 717-725. https://doi.org/10.1021/acssensors.3c02004
  10. Mahla Poudineh. Microneedle Assays for Continuous Health Monitoring: Challenges and Solutions. ACS Sensors 2024, 9 (2) , 535-542. https://doi.org/10.1021/acssensors.3c02279
  11. Yu Liu, John O. Mack, Maryam Shojaee, Alexander Shaver, Ankitha George, William Clarke, Neel Patel, Netzahualcóyotl Arroyo-Currás. Analytical Validation of Aptamer-Based Serum Vancomycin Monitoring Relative to Automated Immunoassays. ACS Sensors 2024, 9 (1) , 228-235. https://doi.org/10.1021/acssensors.3c01868
  12. Águeda Molinero-Fernandez, Qianyu Wang, Xing Xuan, Åsa Konradsson-Geuken, Gastón A. Crespo, María Cuartero. Demonstrating the Analytical Potential of a Wearable Microneedle-Based Device for Intradermal CO2 Detection. ACS Sensors 2024, 9 (1) , 361-370. https://doi.org/10.1021/acssensors.3c02086
  13. Alexander Shaver, Kyle Mallires, Jonathan Harris, Jonathan Kavner, Bo Wang, Rebecca Gottlieb, Juan Lión-Villar, María Ángeles Herranz, Nazario Martín, Netzahualcóyotl Arroyo-Currás. Survey of Conductive Polymers for the Fabrication of Conformation Switching Nucleic Acid-Based Electrochemical Biosensors. ACS Applied Polymer Materials 2024, 6 (1) , 541-551. https://doi.org/10.1021/acsapm.3c02206
  14. Marc Parrilla, Usanee Detamornrat, Juan Domínguez-Robles, Sensu Tunca, Ryan F. Donnelly, Karolien De Wael. Wearable Microneedle-Based Array Patches for Continuous Electrochemical Monitoring and Drug Delivery: Toward a Closed-Loop System for Methotrexate Treatment. ACS Sensors 2023, 8 (11) , 4161-4170. https://doi.org/10.1021/acssensors.3c01381
  15. Susana Campuzano, José M. Pingarrón. Electrochemical Affinity Biosensors: Pervasive Devices with Exciting Alliances and Horizons Ahead. ACS Sensors 2023, 8 (9) , 3276-3293. https://doi.org/10.1021/acssensors.3c01172
  16. Tamoghna Saha, Rafael Del Caño, Kuldeep Mahato, Ernesto De la Paz, Chuanrui Chen, Shichao Ding, Lu Yin, Joseph Wang. Wearable Electrochemical Glucose Sensors in Diabetes Management: A Comprehensive Review. Chemical Reviews 2023, 123 (12) , 7854-7889. https://doi.org/10.1021/acs.chemrev.3c00078
  17. David M. E. Freeman, Damien K. Ming, Richard Wilson, Peter L. Herzog, Christopher Schulz, Alfons K. G. Felice, Yu-Chih Chen, Danny O’Hare, Alison H. Holmes, Anthony E. G. Cass. Continuous Measurement of Lactate Concentration in Human Subjects through Direct Electron Transfer from Enzymes to Microneedle Electrodes. ACS Sensors 2023, 8 (4) , 1639-1647. https://doi.org/10.1021/acssensors.2c02780
  18. Vincent Clark, Miguel Aller Pellitero, Netzahualcóyotl Arroyo-Currás. Explaining the Decay of Nucleic Acid-Based Sensors under Continuous Voltammetric Interrogation. Analytical Chemistry 2023, 95 (11) , 4974-4983. https://doi.org/10.1021/acs.analchem.2c05158
  19. Niamat Khuda, Subramaniam Somasundaram, Ajay B. Urgunde, Christopher J. Easley. Ionic Strength and Hybridization Position near Gold Electrodes Can Significantly Improve Kinetics in DNA-Based Electrochemical Sensors. ACS Applied Materials & Interfaces 2023, 15 (4) , 5019-5027. https://doi.org/10.1021/acsami.2c22741
  20. Rongchao Mei, Yunqing Wang, Xizhen Zhao, Shang Shi, Xiaoyan Wang, Na Zhou, Dazhong Shen, Qi Kang, Lingxin Chen. Skin Interstitial Fluid-Based SERS Tags Labeled Microneedles for Tracking of Peritonitis Progression and Treatment Effect. ACS Sensors 2023, 8 (1) , 372-380. https://doi.org/10.1021/acssensors.2c02409
  21. Alexander Shaver, J.D. Mahlum, Karen Scida, Melanie L. Johnston, Miguel Aller Pellitero, Yao Wu, Gregory V. Carr, Netzahualcóyotl Arroyo-Currás. Optimization of Vancomycin Aptamer Sequence Length Increases the Sensitivity of Electrochemical, Aptamer-Based Sensors In Vivo. ACS Sensors 2022, 7 (12) , 3895-3905. https://doi.org/10.1021/acssensors.2c01910
  22. Lucas de Brito Ayres, Jordan Brooks, Kristi Whitehead, Carlos D. Garcia. Rapid Detection of Staphylococcus aureus Using Paper-Derived Electrochemical Biosensors. Analytical Chemistry 2022, 94 (48) , 16847-16854. https://doi.org/10.1021/acs.analchem.2c03970
  23. Daniela Oliveira, Barbara P Correia, Sanjiv Sharma, Felismina Teixeira Coelho Moreira. Molecular Imprinted Polymers on Microneedle Arrays for Point of Care Transdermal Sampling and Sensing of Inflammatory Biomarkers. ACS Omega 2022, 7 (43) , 39039-39044. https://doi.org/10.1021/acsomega.2c04789
  24. Alex M. Downs, Kevin W. Plaxco. Real-Time, In Vivo Molecular Monitoring Using Electrochemical Aptamer Based Sensors: Opportunities and Challenges. ACS Sensors 2022, 7 (10) , 2823-2832. https://doi.org/10.1021/acssensors.2c01428
  25. Jeongse Yun, Shanmuganathan Keerthana, Seung-Ryong Kwon. Miniaturized power-integrated and self-powered sensor systems for advanced biomedical applications. Sensors and Actuators Reports 2025, 9 , 100260. https://doi.org/10.1016/j.snr.2024.100260
  26. Yiming Qin, Feiyun Cui, Yifei Lu, Peng Yang, Weiming Gou, Zixuan Tang, Shan Lu, H. Susan Zhou, Gaoxing Luo, Xiaoyan Lyu, Qing Zhang. Toward precision medicine: End-to-end design and construction of integrated microneedle-based theranostic systems. Journal of Controlled Release 2025, 377 , 354-375. https://doi.org/10.1016/j.jconrel.2024.11.020
  27. Fereshteh Amourizi, Kheibar Dashtian, Rouholah Zare-Dorabei, Shaaker Hajati. Transformative personalized oxalate biomarker analysis through a wrist-worn microneedle device integrated with duplex nanozyme toolbox. Sensors and Actuators B: Chemical 2025, 423 , 136731. https://doi.org/10.1016/j.snb.2024.136731
  28. Haowei Duan, Shuhua Peng, Shuai He, Shi‐Yang Tang, Keisuke Goda, Chun H. Wang, Ming Li. Wearable Electrochemical Biosensors for Advanced Healthcare Monitoring. Advanced Science 2025, 12 (2) https://doi.org/10.1002/advs.202411433
  29. Ezequiel Vidal, Carlos D. García. Micro/millifluidic platforms for electrochemical detection. 2025, 393-424. https://doi.org/10.1016/B978-0-443-15675-5.00016-1
  30. Alejandro Chamorro-Garcia, Gabriel Ortega-Quintanilla, Andrea Idili, Claudio Parolo. Structure Switching Bioreceptors as Novel Tools for Point-of-Care Diagnostics. 2025, 490-510. https://doi.org/10.1016/B978-0-323-99967-0.00266-0
  31. Yuteng Liu, Tingting Luo, Chengbiao Ding, Lei Xuan, Jian Li, Runhuai Yang. Progress in The Application of Flexible and Wearable Electrochemical Sensors in Monitoring Biomarkers of Athletes. Advanced Materials Technologies 2024, 9 (23) https://doi.org/10.1002/admt.202400619
  32. Farangis Shahi, Hana Afshar, Elmuez A. Dawi, Hossein Ali Khonakdar. Smart Microneedles in Biomedical Engineering: Harnessing Stimuli‐Responsive Polymers for Novel Applications. Polymers for Advanced Technologies 2024, 35 (12) https://doi.org/10.1002/pat.70020
  33. Geng Zhong, Qingzhou Liu, Qiyu Wang, Haoji Qiu, Hanlin Li, Tailin Xu. Fully integrated microneedle biosensor array for wearable multiplexed fitness biomarkers monitoring. Biosensors and Bioelectronics 2024, 265 , 116697. https://doi.org/10.1016/j.bios.2024.116697
  34. Zixiong Wu, Zheng Qiao, Shuwen Chen, Shicheng Fan, Yuanchao Liu, Jiaming Qi, Chwee Teck Lim. Interstitial fluid-based wearable biosensors for minimally invasive healthcare and biomedical applications. Communications Materials 2024, 5 (1) https://doi.org/10.1038/s43246-024-00468-6
  35. Shangjie Zou, Guangdun Peng, Zhiqiang Ma. Surface-Functionalizing Strategies for Multiplexed Molecular Biosensing: Developments Powered by Advancements in Nanotechnologies. Nanomaterials 2024, 14 (24) , 2014. https://doi.org/10.3390/nano14242014
  36. Wei Yue, Yunjian Guo, Jia-Kang Wu, Enkhzaya Ganbold, Nagendra Kumar Kaushik, Apurva Jaiswal, Nannan Yu, Yan Wang, Yi-Feng Lei, Byeolnim Oh, Hyun Soo Kim, Young Kee Shin, Jun-Ge Liang, Eun-Seong Kim, Nam-Young Kim. A wireless, battery-free microneedle patch with light-cured swellable hydrogel for minimally-invasive glucose detection. Nano Energy 2024, 131 , 110194. https://doi.org/10.1016/j.nanoen.2024.110194
  37. Yixin Shen, Gangsheng Chen, Yi Chen, Yakun Gao, Chao Hou, Kylin Liao, Biao Ma, Hong Liu. Wearable microfluidic electrochemical sensor integrated with iontophoresis for non-invasive sweat ketone monitoring. Sensors and Actuators B: Chemical 2024, 421 , 136518. https://doi.org/10.1016/j.snb.2024.136518
  38. Sonu Kumari, Neetu Talreja, Divya Chauhan, Mohammad Ashfaq. Microneedle (MN)-based sensing technology: an innovative solution for agriculture. Materials Advances 2024, 5 (22) , 8745-8754. https://doi.org/10.1039/D4MA00479E
  39. Fatemeh Keyvani, Peyman GhavamiNejad, Mahmoud Ayman Saleh, Mohammad Soltani, Yusheng Zhao, Sadegh Sadeghzadeh, Arash Shakeri, Pierre Chelle, Hanjia Zheng, Fasih A. Rahman, Sarah Mahshid, Joe Quadrilatero, Praveen P. N. Rao, Andrea Edginton, Mahla Poudineh. Integrated Electrochemical Aptamer Biosensing and Colorimetric pH Monitoring via Hydrogel Microneedle Assays for Assessing Antibiotic Treatment. Advanced Science 2024, 11 (41) https://doi.org/10.1002/advs.202309027
  40. Yun Cheng, Xi Luan, Jiawu Weng, Lexiang Zhang, Fangfu Ye. Engineering sampling microneedles for biomolecules sensing. Chemical Engineering Journal 2024, 499 , 156130. https://doi.org/10.1016/j.cej.2024.156130
  41. Yiling Yang, Xumei Gao, Bryce Widdicombe, Jana L Zielinski, Alastair G Stewart, Ranjith R Unnithan. Biocompatible, Dual-Purpose Electrochemical Aptamer Based Sensor for Real-Time Phenylalanine and pH Monitoring. 2024, 1-4. https://doi.org/10.1109/SENSORS60989.2024.10784873
  42. Xinmei Zhang, Yuemin Wang, Xinyu He, Yan Yang, Xingyu Chen, Jianshu Li. Advances in microneedle technology for biomedical detection. Biomaterials Science 2024, 12 (20) , 5134-5149. https://doi.org/10.1039/D4BM00794H
  43. Congying Li, Ziyuan Zhu, Jiahong Yao, Zhe Chen, Yishun Huang. Perspectives in Aptasensor-Based Portable Detection for Biotoxins. Molecules 2024, 29 (20) , 4891. https://doi.org/10.3390/molecules29204891
  44. John Mack, Raygan Murray, Kenedi Lynch, Netzahualcóyotl Arroyo-Currás. 3D-printed electrochemical cells for multi-point aptamer-based drug measurements. Sensors & Diagnostics 2024, 3 (9) , 1533-1541. https://doi.org/10.1039/D4SD00192C
  45. Tran N. H. Nguyen, Lisa F. Horowitz, Timothy Krilov, Ethan Lockhart, Heidi L. Kenerson, Taranjit S. Gujral, Raymond S. Yeung, Netzahualcóyotl Arroyo-Currás, Albert Folch. Label-free, real-time monitoring of cytochrome C drug responses in microdissected tumor biopsies with a multi-well aptasensor platform. Science Advances 2024, 10 (36) https://doi.org/10.1126/sciadv.adn5875
  46. Michelle Grace Tetteh, Sumit Gupta, Mukesh Kumar, Hana Trollman, Konstantinos Salonitis, Sandeep Jagtap. Pharma 4.0: A deep dive top management commitment to successful Lean 4.0 implementation in Ghanaian pharma manufacturing sector. Heliyon 2024, 10 (17) , e36677. https://doi.org/10.1016/j.heliyon.2024.e36677
  47. Fatemeh Bakhshandeh, Hanjia Zheng, Nicole G. Barra, Sadegh Sadeghzadeh, Irfani Ausri, Payel Sen, Fatemeh Keyvani, Fasih Rahman, Joe Quadrilatero, Juewen Liu, Jonathan D. Schertzer, Leyla Soleymani, Mahla Poudineh. Wearable Aptalyzer Integrates Microneedle and Electrochemical Sensing for In Vivo Monitoring of Glucose and Lactate in Live Animals. Advanced Materials 2024, 36 (35) https://doi.org/10.1002/adma.202313743
  48. Irfani Rahmi Ausri, Sadegh Sadeghzadeh, Subhamoy Biswas, Hanjia Zheng, Peyman GhavamiNejad, Michelle Dieu Thao Huynh, Fatemeh Keyvani, Erfan Shirzadi, Fasih A Rahman, Joe Quadrilatero, Amin GhavamiNejad, Mahla Poudineh. Multifunctional Dopamine‐Based Hydrogel Microneedle Electrode for Continuous Ketone Sensing. Advanced Materials 2024, 36 (32) https://doi.org/10.1002/adma.202402009
  49. Georgeta Vulpe, Guoyi Liu, Sam Oakley, Dimitrios Pletsas, Guanghao Yang, Rosa Dutra, Owen Guy, Yufei Liu, Mark Waldron, Joe Neary, Arjun Ajith Mohan, Sanjiv Sharma. Wearable technology for one health: Charting the course of dermal biosensing. Biosensors and Bioelectronics: X 2024, 19 , 100500. https://doi.org/10.1016/j.biosx.2024.100500
  50. Tyler Hack, Joel Bisarra, Saeromi Chung, Shekher Kummari, Drew A. Hall. Mitigating Medication Tampering and Diversion via Real-Time Intravenous Opioid Quantification. IEEE Transactions on Biomedical Circuits and Systems 2024, 18 (4) , 756-770. https://doi.org/10.1109/TBCAS.2024.3405815
  51. Ruier Xue, Fei Deng, Tianruo Guo, Alexander Epps, Nigel H. Lovell, Mohit N. Shivdasani. Needle-Shaped Biosensors for Precision Diagnoses: From Benchtop Development to In Vitro and In Vivo Applications. Biosensors 2024, 14 (8) , 391. https://doi.org/10.3390/bios14080391
  52. Cui Ye, Heather Lukas, Minqiang Wang, Yerim Lee, Wei Gao. Nucleic acid-based wearable and implantable electrochemical sensors. Chemical Society Reviews 2024, 53 (15) , 7960-7982. https://doi.org/10.1039/D4CS00001C
  53. Tuba Bedir, Sachin Kadian, Shubhangi Shukla, Oguzhan Gunduz, Roger Narayan. Additive manufacturing of microneedles for sensing and drug delivery. Expert Opinion on Drug Delivery 2024, 21 (7) , 1053-1068. https://doi.org/10.1080/17425247.2024.2384696
  54. Zifeng Wang, Min Xiao, Zhanhong Li, Xinghao Wang, Fangjie Li, Huayuan Yang, Yu Chen, Zhigang Zhu. Microneedle Patches‐Integrated Transdermal Bioelectronics for Minimally Invasive Disease Theranostics. Advanced Healthcare Materials 2024, 13 (17) https://doi.org/10.1002/adhm.202303921
  55. Pillalamarri Srikrishnarka, Joonas Haapasalo, Juan P. Hinestroza, Zhipei Sun, Nonappa. Wearable Sensors for Physiological Condition and Activity Monitoring. Small Science 2024, 4 (7) https://doi.org/10.1002/smsc.202300358
  56. Shihao Pei, Samuel Babity, Ana Sara Cordeiro, Davide Brambilla. Integrating microneedles and sensing strategies for diagnostic and monitoring applications: The state of the art. Advanced Drug Delivery Reviews 2024, 210 , 115341. https://doi.org/10.1016/j.addr.2024.115341
  57. Julia Chung, Adriana Billante, Charlotte Flatebo, Kaylyn K. Leung, Julian Gerson, Nicole Emmons, Tod E. Kippin, Lior Sepunaru, Kevin W. Plaxco. Effects of storage conditions on the performance of an electrochemical aptamer-based sensor. Sensors & Diagnostics 2024, 3 (6) , 1044-1050. https://doi.org/10.1039/D4SD00066H
  58. Kaylyn K. Leung, Julian Gerson, Nicole Emmons, Jennifer M. Heemstra, Tod E. Kippin, Kevin W. Plaxco. The Use of Xenonucleic Acids Significantly Reduces the In Vivo Drift of Electrochemical Aptamer‐Based Sensors. Angewandte Chemie International Edition 2024, 63 (21) https://doi.org/10.1002/anie.202316678
  59. Kaylyn K. Leung, Julian Gerson, Nicole Emmons, Jennifer M. Heemstra, Tod E. Kippin, Kevin W. Plaxco. The Use of Xenonucleic Acids Significantly Reduces the In Vivo Drift of Electrochemical Aptamer‐Based Sensors. Angewandte Chemie 2024, 136 (21) https://doi.org/10.1002/ange.202316678
  60. Susana Campuzano, Rodrigo Barderas, Maria Teresa Moreno-Casbas, Ángeles Almeida, José M. Pingarrón. Pursuing precision in medicine and nutrition: the rise of electrochemical biosensing at the molecular level. Analytical and Bioanalytical Chemistry 2024, 416 (9) , 2151-2172. https://doi.org/10.1007/s00216-023-04805-5
  61. Mengjia Zheng, Tao Sheng, Jicheng Yu, Zhen Gu, Chenjie Xu. Microneedle biomedical devices. Nature Reviews Bioengineering 2024, 2 (4) , 324-342. https://doi.org/10.1038/s44222-023-00141-6
  62. Surinya Traipop, Whitchuta Jesadabundit, Wisarut Khamcharoen, Tavechai Pholsiri, Sarida Naorungroj, Sakda Jampasa, Orawon Chailapakul. Nanomaterial-based Electrochemical Sensors for Multiplex Medicinal Applications. Current Topics in Medicinal Chemistry 2024, 24 (11) , 986-1009. https://doi.org/10.2174/0115680266304711240327072348
  63. Yubing Hu, Eleni Chatzilakou, Zhisheng Pan, Giovanni Traverso, Ali K. Yetisen. Microneedle Sensors for Point‐of‐Care Diagnostics. Advanced Science 2024, 11 (12) https://doi.org/10.1002/advs.202306560
  64. Haowei Duan, Shi-Yang Tang, Keisuke Goda, Ming Li. Enhancing the sensitivity and stability of electrochemical aptamer-based sensors by AuNPs@MXene nanocomposite for continuous monitoring of biomarkers. Biosensors and Bioelectronics 2024, 246 , 115918. https://doi.org/10.1016/j.bios.2023.115918
  65. Tran N. H. Nguyen, Lisa Horowitz, Timothy Krilov, Ethan Lockhart, Heidi L Kenerson, Raymond S Yeung, Netzahualcóyotl Arroyo-Currás, Albert Folch. Label-Free, Real-Time Monitoring of Cytochrome C Responses to Drugs in Microdissected Tumor Biopsies with a Multi-Well Aptasensor Platform. 2024https://doi.org/10.1101/2024.01.31.578278
  66. Rajendra Kumar Reddy Gajjala, Sara Muñana-González, Pello Núñez-Marinero, Joseba Totoricaguena-Gorriño, Leire Ruiz-Rubio, Francisco Javier del Campo. Design and Fabrication of Wearable Biosensors: Materials, Methods, and Prospects. 2024, 317-378. https://doi.org/10.1007/978-981-99-8122-9_15
  67. Lakshmi R. Panicker, M. R. Keerthanaa, Kotagiri Yugender Goud. Recent Progress in Wearable Microneedle Sensor Devices for Continuous Screening of Interstitial Fluid: A Journey Toward Lab Under the Skin. 2024, 135-149. https://doi.org/10.1007/978-981-99-8122-9_7
  68. Marc Parrilla. Microneedle-based electrochemical sensors for health monitoring. 2024, 481-520. https://doi.org/10.1016/B978-0-443-13881-2.00020-5
  69. Maria Reynoso, An-Yi Chang, Yao Wu, Raygan Murray, Smrithi Suresh, Yuma Dugas, Joseph Wang, Netzahualcóyotl Arroyo-Currás. 3D-printed, aptamer-based microneedle sensor arrays using magnetic placement on live rats for pharmacokinetic measurements in interstitial fluid. Biosensors and Bioelectronics 2024, 244 , 115802. https://doi.org/10.1016/j.bios.2023.115802
  70. Ahmad Mobed, Bita Abdi, Sajjad Masoumi, Mohammad Mikaeili, Elham Shaterian, Hamed Shaterian, Esmat Sadat Kazemi, Mahdiye Shirafkan. Advances in human reproductive biomarkers. Clinica Chimica Acta 2024, 552 , 117668. https://doi.org/10.1016/j.cca.2023.117668
  71. Andrés F. Cruz-Pacheco, Danilo Echeverri, Jahir Orozco. Role of electrochemical nanobiosensors in colorectal cancer precision medicine. TrAC Trends in Analytical Chemistry 2024, 170 , 117467. https://doi.org/10.1016/j.trac.2023.117467
  72. Hongyi Sun, Youbin Zheng, Guoyue Shi, Hossam Haick, Min Zhang. Wearable Clinic: From Microneedle‐Based Sensors to Next‐Generation Healthcare Platforms. Small 2023, 19 (51) https://doi.org/10.1002/smll.202207539
  73. Irfani R. Ausri, Yael Zilberman, Sarah Schneider, Xiaowu (Shirley) Tang. Recent advances and challenges: Translational research of minimally invasive wearable biochemical sensors. Biosensors and Bioelectronics: X 2023, 15 , 100405. https://doi.org/10.1016/j.biosx.2023.100405
  74. Mark Friedel, Ian A. P. Thompson, Gerald Kasting, Ronen Polsky, David Cunningham, Hyongsok Tom Soh, Jason Heikenfeld. Opportunities and challenges in the diagnostic utility of dermal interstitial fluid. Nature Biomedical Engineering 2023, 7 (12) , 1541-1555. https://doi.org/10.1038/s41551-022-00998-9
  75. Shuwen Chen, Zheng Qiao, Yan Niu, Joo Chuan Yeo, Yuanchao Liu, Jiaming Qi, Shicheng Fan, Xiaoyan Liu, Jee Yeon Lee, Chwee Teck Lim. Wearable flexible microfluidic sensing technologies. Nature Reviews Bioengineering 2023, 1 (12) , 950-971. https://doi.org/10.1038/s44222-023-00094-w
  76. Ellie Wilson, David Probst, Koji Sode. In vivo continuous monitoring of peptides and proteins: Challenges and opportunities. Applied Physics Reviews 2023, 10 (4) https://doi.org/10.1063/5.0154637
  77. Celeste R. Rousseau, Hope Kumakli, Ryan J. White. Perspective—Assessing Electrochemical, Aptamer-Based Sensors for Dynamic Monitoring of Cellular Signaling. ECS Sensors Plus 2023, 2 (4) , 042401. https://doi.org/10.1149/2754-2726/ad15a1
  78. Blaise J. Ostertag, Ashley E. Ross. Editors’ Choice—Review—The Future of Carbon-Based Neurochemical Sensing: A Critical Perspective. ECS Sensors Plus 2023, 2 (4) , 043601. https://doi.org/10.1149/2754-2726/ad15a2
  79. Asmita Veronica, Yanan Li, Yue Li, I-Ming Hsing, Hnin Yin Yin Nyein. Dermal-fluid-enabled detection platforms for non-invasive ambulatory monitoring. Sensors & Diagnostics 2023, 2 (6) , 1335-1359. https://doi.org/10.1039/D3SD00165B
  80. Quanfang Wang, Sihan Li, Jiaojiao Chen, Luting Yang, Yulan Qiu, Qian Du, Chuhui Wang, Mengmeng Teng, Taotao Wang, Yalin Dong. A novel strategy for therapeutic drug monitoring: application of biosensors to quantify antimicrobials in biological matrices. Journal of Antimicrobial Chemotherapy 2023, 78 (11) , 2612-2629. https://doi.org/10.1093/jac/dkad289
  81. Xiangpeng Meng, Jiexin Li, Yue Wu, Xiaolin Cao, Ziping Zhang. Rational design of hairpin aptamer using intrinsic disorder mechanism to enhance sensitivity of aptamer folding-based electrochemical sensor for tobramycin. Sensors and Actuators B: Chemical 2023, 394 , 134354. https://doi.org/10.1016/j.snb.2023.134354
  82. Guangfu Wu, Eric T. Zhang, Yingqi Qiang, Colin Esmonde, Xingchi Chen, Zichao Wei, Yang Song, Xincheng Zhang, Michael J. Schneider, Huijie Li, He Sun, Zhengyan Weng, Sabato Santaniello, Jie He, Rebecca Y. Lai, Yan Li, Michael R. Bruchas, Yi Zhang. Long-Term In Vivo Molecular Monitoring Using Aptamer-Graphene Microtransistors. 2023https://doi.org/10.1101/2023.10.18.562080
  83. Tyler Hack, Joel Bisarra, Saeromi Chung, Drew A. Hall. Ensuring pain medication dosage: A real-time intravenous opioid monitoring system. 2023, 1-5. https://doi.org/10.1109/BioCAS58349.2023.10388932
  84. Anamika Paul, Krishnendu Acharya, Nilanjan Chakraborty. Biosynthesis, extraction, detection and pharmacological attributes of vinblastine and vincristine, two important chemotherapeutic alkaloids of Catharanthus roseus (L.) G. Don: A review. South African Journal of Botany 2023, 161 , 365-376. https://doi.org/10.1016/j.sajb.2023.08.034
  85. Ruvimbo Dephine Mishi, Michael Andrew Stokes, Craig Anthony Campbell, Kevin William Plaxco, Sophie Lena Stocker. Real-Time Monitoring of Antibiotics in the Critically Ill Using Biosensors. Antibiotics 2023, 12 (10) , 1478. https://doi.org/10.3390/antibiotics12101478
  86. Alex M. Downs, Adam Bolotsky, Bryan M. Weaver, Haley Bennett, Nathan Wolff, Ronen Polsky, Philip R. Miller. Microneedle electrochemical aptamer-based sensing: Real-time small molecule measurements using sensor-embedded, commercially-available stainless steel microneedles. Biosensors and Bioelectronics 2023, 236 , 115408. https://doi.org/10.1016/j.bios.2023.115408
  87. Ramy Ghanim, Anika Kaushik, Jihoon Park, Alex Abramson. Communication protocols integrating wearables, ingestibles, and implantables for closed-loop therapies. Device 2023, 1 (3) , 100092. https://doi.org/10.1016/j.device.2023.100092
  88. Sara R. Nixon, Imon Kanta Phukan, Brian J. Armijo, Sasha B. Ebrahimi, Devleena Samanta. Proximity-Driven DNA Nanosensors. ECS Sensors Plus 2023, 2 (3) , 030601. https://doi.org/10.1149/2754-2726/ace068
  89. Kon Son, Takanori Uzawa, Yoshihiro Ito, Tod Kippin, Kevin W. Plaxco, Toshinori Fujie. Survey of oligoethylene glycol-based self-assembled monolayers on electrochemical aptamer-based sensor in biological fluids. Biochemical and Biophysical Research Communications 2023, 668 , 1-7. https://doi.org/10.1016/j.bbrc.2023.05.032
  90. Mahmoud Amouzadeh Tabrizi. A Facile Method for the Fabrication of the Microneedle Electrode and Its Application in the Enzymatic Determination of Glutamate. Biosensors 2023, 13 (8) , 828. https://doi.org/10.3390/bios13080828
  91. Zeyi Tang, Tianrui Cui, Houfang Liu, Jinming Jian, Ding Li, Yi Yang, Tianling Ren. Wearable Chemosensors in Physiological Monitoring. Chemosensors 2023, 11 (8) , 459. https://doi.org/10.3390/chemosensors11080459
  92. Mark Friedel, Benjamin Werbovetz, Amy Drexelius, Zach Watkins, Ahilya Bali, Kevin W. Plaxco, Jason Heikenfeld. Continuous molecular monitoring of human dermal interstitial fluid with microneedle-enabled electrochemical aptamer sensors. Lab on a Chip 2023, 23 (14) , 3289-3299. https://doi.org/10.1039/D3LC00210A
  93. Yuqiao Liu, Junmin Li, Shenghao Xiao, Yanhui Liu, Mingxia Bai, Lixiu Gong, Jiaqian Zhao, Dajing Chen. Revolutionizing Precision Medicine: Exploring Wearable Sensors for Therapeutic Drug Monitoring and Personalized Therapy. Biosensors 2023, 13 (7) , 726. https://doi.org/10.3390/bios13070726
  94. Miguel Aller Pellitero, Noemí de-los-Santos-Álvarez, María Jesús Lobo-Castañón. Aptamer-based electrochemical approaches to meet some of the challenges in the fight against cancer. Current Opinion in Electrochemistry 2023, 39 , 101286. https://doi.org/10.1016/j.coelec.2023.101286
  95. Charlotte Flatebo, William R. Conkright, Meaghan E. Beckner, Robert H. Batchelor, Tod E. Kippin, Jason Heikenfeld, Kevin W. Plaxco. Efforts toward the continuous monitoring of molecular markers of performance. Journal of Science and Medicine in Sport 2023, 26 , S46-S53. https://doi.org/10.1016/j.jsams.2023.01.010
  96. Thomas Young, Vincent Clark, Netzahualcóyotl Arroyo-Currás, Jason Heikenfeld. Perspective—The Feasibility of Continuous Protein Monitoring in Interstitial Fluid. ECS Sensors Plus 2023, 2 (2) , 027001. https://doi.org/10.1149/2754-2726/accd7e
  97. Zhimin Song, Shu Zhou, Yanxia Qin, Xiangjiao Xia, Yanping Sun, Guanghong Han, Tong Shu, Liang Hu, Qiang Zhang. Flexible and Wearable Biosensors for Monitoring Health Conditions. Biosensors 2023, 13 (6) , 630. https://doi.org/10.3390/bios13060630
  98. Shang Shi, Yunqing Wang, Rongchao Mei, Xizhen Zhao, Xifang Liu, Lingxin Chen. Revealing drug release and diffusion behavior in skin interstitial fluid by surface-enhanced Raman scattering microneedles. Journal of Materials Chemistry B 2023, 11 (14) , 3097-3105. https://doi.org/10.1039/D2TB02600G
  99. Kaylyn K. Leung, Julian Gerson, Nicole Emmons, Brian Roehrich, Elsi Verrinder, Lisa C. Fetter, Tod E. Kippin, Kevin W. Plaxco. A tight squeeze: geometric effects on the performance of three-electrode electrochemical-aptamer based sensors in constrained, in vivo placements. The Analyst 2023, 148 (7) , 1562-1569. https://doi.org/10.1039/D2AN02096C
  100. Nathalia O. Gomes, Paulo A. Raymundo‐Pereira. On‐Site Therapeutic Drug Monitoring of Paracetamol Analgesic in Non‐Invasively Collected Saliva for Personalized Medicine. Small 2023, 19 (12) https://doi.org/10.1002/smll.202206753
Load all citations

Analytical Chemistry

Cite this: Anal. Chem. 2022, 94, 23, 8335–8345
Click to copy citationCitation copied!
https://doi.org/10.1021/acs.analchem.2c00829
Published June 2, 2022

Copyright © 2022 The Authors. Published by American Chemical Society. This publication is licensed under

CC-BY-NC-ND 4.0 .

Article Views

13k

Altmetric

-

Citations

Learn about these metrics

Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.

  • Abstract

    Figure 1

    Figure 1. Wearable microneedle aptamer-based sensors for continuous, real-time therapeutic drug monitoring. (A) Our wearable microneedle sensor patch is designed to allow painless on-body molecular tracking in research animals. The patch consists of a microneedle sensor array integrated with electronics and a battery, all contained within a wearable case. The sensor array contains 16 gold working, 4 platinum counter, and one central reference microneedles with a form factor that allows painless penetration of the upper strata of the reticular dermis. (B) At the core of our sensing technology are electrochemical aptamer-based (E-AB) sensors, which consist of a mixed self-assembled monolayer of electrode-blocking alkanethiols with alkanethiol- and redox reporter-modified aptamers. In the presence of a target, the aptamers undergo reversible binding-induced conformational changes that affect electron transfer (eT) between the reporter and the gold needles. This sensing mechanism is reversible. (C) To enable continuous drug monitoring, the sensors are serially interrogated by square-wave voltammetry (SWV) with a time interval between 4.5 and 12 s. The sensors can be calibrated at the point of manufacture by building target titration curves, allowing correlation of current changes to changes in target concentration.

    Figure 2

    Figure 2. Microneedle E-AB sensor arrays support real-time molecular monitoring in vitro. (A) 3D-printed flow cell for continuous molecular monitoring. The microneedle sensor array is glued at the bottom of the cell and connected to a hand-held potentiostat to enable serial electrochemical interrogation. (B) Micrograph showing blunt microneedles used for rapid testing. The microneedle height is ∼2.3 mm, and the diameter ∼170 μm. We functionalized these using tobramycin-binding aptamers, which are modified to have covalently attached alkanethiol linkers and the redox reporter methylene blue. (C) Microneedle E-AB sensor arrays (MNs) achieve identical calibration curves relative to sensors fabricated on commercial disc macroelectrodes (MEs, 2 mm in diameter). Circles represent the average of six sensors fabricated on MEs; diamonds represent the average of three sensors fabricated on MNs; error bars represent their standard deviation. (D) Continuous, real-time monitoring of tobramycin in the flow system. Voltammetric measurements were performed every 4.5 s in 20 mM Tris, 100 mM NaCl, 5 mM MgCl2 (pH = 7.4). (E) Kinetic differential measurements (KDM) obtained after subtracting the data collected at 150 Hz (signal-off output) from data collected at 800 Hz (signal-on output).

    Figure 3

    Figure 3. Microneedle arrays can be reused multiple times. The newly developed chemical and electrochemical cleaning protocol reported in this work allows the reuse of microneedle devices multiple times during rapid prototyping and testing. (A) Here, for example, we show the performance of E-ABs fabricated on a single device that was reused three times. The colored data corresponds to the average of three identical measurements performed on the same device after each round of cleaning and functionalization with aptamers. Baseline peak currents at 800 Hz are ∼9 ± 0.5 mA. The shaded areas indicate the standard deviation between measurements. (B) Use of KDM for baseline correction further highlights the reproducibility achieved via the cleaning protocol. (C) For reference, untreated microneedles show lower signal output and higher baseline noise. Baseline peak currents at 800 Hz are ∼1.8 mA, 80% lower than the currents for treated microneedles.

    Figure 4

    Figure 4. Dual-channel microneedle E-AB devices enable simultaneous evaluation of aptamer specificity. (A) Different from Figure 2A, the 3D-printed cell was adapted to have two separate injection lines at opposite sides of the central support. By connecting these lines to the syringe pump, we could automatically inject and mix the prodrug irinotecan and its major metabolite SN-38 in the left and right chambers, respectively. (B) We functionalized the microneedles in both chambers with irinotecan-binding aptamers. In the presence of irinotecan, the E-AB sensors undergo binding-induced changes in eT between the reporter and the microneedles. However, the metabolite SN-38 induces minor conformational changes relative to irinotecan binding. (C) Microneedle E-AB sensor arrays display higher signal gain when challenged with irinotecan than with the metabolite SN-38 at square-wave frequencies of 100 Hz. (D) Demonstration of continuous, reproducible irinotecan monitoring following three boluses at a target concentration of 2 μM irinotecan in the left chamber. (E) Similarly, when challenging the right chamber with the metabolite SN-38, lower gains were obtained following three serial boluses. Voltammetric measurements were performed every 11 s in 20 mM phosphate solution containing 137 mM NaCl, 2.7 mM KCl, 2 mM MgCl2, and 1 mM CaCl2 (pH = 6.0).

    Figure 5

    Figure 5. Dual-channel microneedle E-AB devices enable multiplexed sensing. (A) We functionalized the microneedles in each chamber with either irinotecan-binding or doxorubicin-binding aptamers. (B) Mean calibration curves of six irinotecan-binding and doxorubicin-binding E-ABs obtained using commercial disc macroelectrodes (2 mm in diameter) demonstrate that both sensors showed high affinity when challenged with their targets. (C) When simultaneously injecting irinotecan and doxorubicin in either chamber of the microneedle device, it was possible to successfully monitor E-AB signals induced by target binding to the respective E-ABs. In the case of the irinotecan-binding sensor, irinotecan boluses of increasing concentrations produced corresponding E-AB responses. Challenging the same E-ABs with doxorubicin, a known DNA intercalator, also produced large signal changes. (D) Likewise, challenging the doxorubicin-binding E-ABs with doxorubicin boluses of increasing concentration caused proportional E-AB responses. Challenging these sensors with 4 μM irinotecan did not induce E-AB signal changes. Voltammetric measurements were performed every 12 s in 20 mM phosphate, 137 mM NaCl, 2.7 mM KCl, 2 mM MgCl2, and 1 mM CaCl2 (pH = 6.0).

    Figure 6

    Figure 6. Continuous molecular monitoring of tobramycin concentration in ISF. Proof-of-concept monitoring of tobramycin levels in the dermis of one rat following IV administration of the drug at a dose of 20 mg/kg. (A) We fabricated sharper microneedles that were 150 μm in diameter and 1.1 mm in length. (B) The microneedles were placed on the freshly shaved abdomen of one male rat. (C) Removal of the device from the skin revealed the expected pattern of micropunctures. (D) H&E-stained skin tissue illustrating different histological features of the rat’s skin and one penetrating track left after insertion of the microneedles. (E) Hue- and contrast-adjusted duplicate image highlighting the track mark after microneedle removal. (F) Although noisy, electrochemical interrogation of the microneedle array resulted in discernible square-wave voltammograms in ISF that strongly responded to tobramycin following an IV bolus injected into the right jugular vein of the rat (drop from blue to orange). (G) Real-time processing of the voltammograms using SACMES allowed us to visualize the sensor response, here plotted as relative signal after tobramycin dosing. SACMES uses rolling average and polynomial fit algorithms to remove noise from voltammograms, thus enabling the extraction of high signal-to-noise E-AB data. Unfortunately, progressive degradation of the sensors in ISF made it impossible to distinguish signals past t = 60 min. The red line shows a regression analysis to a two-compartment drug absorption pharmacokinetic model using the data points available.

  • References


    This article references 53 other publications.

    1. 1
      Teymourian, H.; Parrilla, M.; Sempionatto, J. R.; Montiel, N. F.; Barfidokht, A.; Van Echelpoel, R.; De Wael, K.; Wang, J. Wearable electrochemical sensors for the monitoring and screening of drugs. ACS Sens. 2020, 5, 26792700,  DOI: 10.1021/acssensors.0c01318
    2. 2
      Arroyo-Currás, N.; Ortega, G.; Copp, D. A.; Ploense, K. L.; Plaxco, Z. A.; Kippin, T. E.; Hespanha, J. P.; Plaxco, K. W. High-precision control of plasma drug levels using feedback-controlled dosing. ACS Pharmacol. Transl. Sci. 2018, 1, 110118,  DOI: 10.1021/acsptsci.8b00033
    3. 3
      Arroyo-Currás, N.; Somerson, J.; Vieira, P. A.; Ploense, K. L.; Kippin, T. E.; Plaxco, K. W. Real-time measurement of small molecules directly in awake, ambulatory animals. Proc. Natl. Acad. Sci. U.S.A. 2017, 114, 645650,  DOI: 10.1073/pnas.1613458114
    4. 4
      Vieira, P. A.; Shin, C. B.; Arroyo-Currás, N.; Ortega, G.; Li, W.; Keller, A. A.; Plaxco, K. W.; Kippin, T. E. Ultra-high-precision, in-vivo pharmacokinetic measurements highlight the need for and a route toward more highly personalized medicine. Front. Mol. Biosci. 2019, 6, 69,  DOI: 10.3389/fmolb.2019.00069
    5. 5
      Wolkowicz, K. L.; Aiello, E. M.; Vargas, E.; Teymourian, H.; Tehrani, F.; Wang, J.; Pinsker, J. E.; Doyle, F. J., 3rd; Patti, M. E.; Laffel, L. M.; Dassau, E. A review of biomarkers in the context of type 1 diabetes: Biological sensing for enhanced glucose control. Bioeng. Transl. Med. 2021, 6, e10201  DOI: 10.1002/btm2.10201
    6. 6
      Aiello, E. M.; Deshpande, S.; Özaslan, B.; Wolkowicz, K. L.; Dassau, E.; Pinsker, J. E.; Doyle, F. J. Review of automated insulin delivery systems for individuals with type 1 diabetes: Tailored solutions for subpopulations. Curr. Opin. Biomed. Eng. 2021, 19, 100312,  DOI: 10.1016/j.cobme.2021.100312
    7. 7
      Li, J.; Liang, J. Y.; Laken, S. J.; Langer, R.; Traverso, G. Clinical opportunities for continuous biosensing and closed-loop therapies. Trends Chem. 2020, 2, 319340,  DOI: 10.1016/j.trechm.2020.02.009
    8. 8
      Ferguson, B. S.; Hoggarth, D. A.; Maliniak, D.; Ploense, K.; White, R. J.; Woodward, N.; Hsieh, K.; Bonham, A. J.; Eisenstein, M.; Kippin, T. E.; Plaxco, K. W.; Soh, H. T. Real-time, aptamer-based tracking of circulating therapeutic agents in living animals. Sci. Transl. Med. 2013, 5, 213ra165,  DOI: 10.1126/scitranslmed.3007095
    9. 9
      Arroyo-Currás, N.; Dauphin-Ducharme, P.; Ortega, G.; Ploense, K. L.; Kippin, T. E.; Plaxco, K. W. Subsecond-resolved molecular measurements in the living body using chronoamperometrically interrogated aptamer-based sensors. ACS Sens. 2018, 3, 360366,  DOI: 10.1021/acssensors.7b00787
    10. 10
      Falagas, M. E.; Karageorgopoulos, D. E. Adjustment of dosing of antimicrobial agents for bodyweight in adults. Lancet 2010, 375, 248251,  DOI: 10.1016/s0140-6736(09)60743-1
    11. 11
      Shuter, B.; Aslani, A. Body surface area: Du bois and du bois revisited. Eur. J. Appl. Physiol. 2000, 82, 250254,  DOI: 10.1007/s004210050679
    12. 12
      Neely, M. N.; Kato, L.; Youn, G.; Kraler, L.; Bayard, D.; van Guilder, M.; Schumitzky, A.; Yamada, W.; Jones, B.; Minejima, E. Prospective trial on the use of trough concentration versus area under the curve to determine therapeutic vancomycin dosing. Antimicrob. Agents Chemother. 2018, 62, e02042  DOI: 10.1128/AAC.02042-17
    13. 13
      Zhang, T.; Cai, S.; Forrest, W. C.; Mohr, E.; Yang, Q.; Forrest, M. L. Development and validation of an inductively coupled plasma mass spectrometry (icp-ms) method for quantitative analysis of platinum in plasma, urine, and tissues. Appl. Spectrosc. 2016, 70, 15291536,  DOI: 10.1177/0003702816662607
    14. 14
      Zhong, X.; Tong, X.; Ju, Y.; Du, X.; Li, Y. Interpersonal factors in the pharmacokinetics and pharmacodynamics of voriconazole: Are cyp2c19 genotypes enough for us to make a clinical decision?. Curr. Drug Metab. 2018, 19, 11521158,  DOI: 10.2174/1389200219666171227200547
    15. 15
      Payne, K. D.; Hall, R. G. Dosing of antibacterial agents in obese adults: does one size fit all?. Expert Rev. Anti-Infect. Ther. 2014, 12, 829854,  DOI: 10.1586/14787210.2014.912942
    16. 16
      Tran, B. Q.; Miller, P. R.; Taylor, R. M.; Boyd, G.; Mach, P. M.; Rosenzweig, C. N.; Baca, J. T.; Polsky, R.; Glaros, T. Proteomic characterization of dermal interstitial fluid extracted using a novel microneedle-assisted technique. J. Proteome Res. 2018, 17, 479485,  DOI: 10.1021/acs.jproteome.7b00642
    17. 17
      Samant, P. P.; Niedzwiecki, M. M.; Raviele, N.; Tran, V.; Mena-Lapaix, J.; Walker, D. I.; Felner, E. I.; Jones, D. P.; Miller, G. W.; Prausnitz, M. R. Sampling interstitial fluid from human skin using a microneedle patch. Sci. Transl. Med. 2020, 12, eaaw0285  DOI: 10.1126/scitranslmed.aaw0285
    18. 18
      Siegmund, T.; Heinemann, L.; Kolassa, R.; Thomas, A. Discrepancies Between Blood Glucose and Interstitial Glucose-Technological Artifacts or Physiology: Implications for Selection of the Appropriate Therapeutic Target. J. Diabetes Sci. Technol. 2017, 11, 766772,  DOI: 10.1177/1932296817699637
    19. 19
      Teymourian, H.; Tehrani, F.; Mahato, K.; Wang, J. Lab under the skin: Microneedle based wearable devices. Adv. Healthcare Mater. 2021, 10, e2002255  DOI: 10.1002/adhm.202002255
    20. 20
      Miller, P. R.; Taylor, R. M.; Tran, B. Q.; Boyd, G.; Glaros, T.; Chavez, V. H.; Krishnakumar, R.; Sinha, A.; Poorey, K.; Williams, K. P.; Branda, S. S.; Baca, J. T.; Polsky, R. Extraction and biomolecular analysis of dermal interstitial fluid collected with hollow microneedles. Commun. Biol. 2018, 1, 173,  DOI: 10.1038/s42003-018-0170-z
    21. 21
      van der Maaden, K.; Jiskoot, W.; Bouwstra, J. Microneedle technologies for (trans)dermal drug and vaccine delivery. J. Controlled Release 2012, 161, 645655,  DOI: 10.1016/j.jconrel.2012.01.042
    22. 22
      Singh, P.; Carrier, A.; Chen, Y.; Lin, S.; Wang, J.; Cui, S.; Zhang, X. Polymeric microneedles for controlled transdermal drug delivery. J. Controlled Release 2019, 315, 97113,  DOI: 10.1016/j.jconrel.2019.10.022
    23. 23
      Goud, K. Y.; Moonla, C.; Mishra, R. K.; Yu, C.; Narayan, R.; Litvan, I.; Wang, J. Wearable electrochemical microneedle sensor for continuous monitoring of levodopa: Toward parkinson management. ACS Sens. 2019, 4, 21962204,  DOI: 10.1021/acssensors.9b01127
    24. 24
      Mohan, A. M. V.; Windmiller, J. R.; Mishra, R. K.; Wang, J. Continuous minimally-invasive alcohol monitoring using microneedle sensor arrays. Biosens. Bioelectron. 2017, 91, 574579,  DOI: 10.1016/j.bios.2017.01.016
    25. 25
      Mishra, R. K.; Vinu Mohan, A. M.; Soto, F.; Chrostowski, R.; Wang, J. A microneedle biosensor for minimally-invasive transdermal detection of nerve agents. Analyst 2017, 142, 918924,  DOI: 10.1039/c6an02625g
    26. 26
      Windmiller, J. R.; Valdés-Ramírez, G.; Zhou, N.; Zhou, M.; Miller, P. R.; Jin, C.; Brozik, S. M.; Polsky, R.; Katz, E.; Narayan, R.; Wang, J. Bicomponent microneedle array biosensor for minimally-invasive glutamate monitoring. Electroanalysis 2011, 23, 23022309,  DOI: 10.1002/elan.201100361
    27. 27
      Teymourian, H.; Moonla, C.; Tehrani, F.; Vargas, E.; Aghavali, R.; Barfidokht, A.; Tangkuaram, T.; Mercier, P. P.; Dassau, E.; Wang, J. Microneedle-based detection of ketone bodies along with glucose and lactate: Toward real-time continuous interstitial fluid monitoring of diabetic ketosis and ketoacidosis. Anal. Chem. 2020, 92, 22912300,  DOI: 10.1021/acs.analchem.9b05109
    28. 28
      Mishra, R. K.; Goud, K. Y.; Li, Z.; Moonla, C.; Mohamed, M. A.; Tehrani, F.; Teymourian, H.; Wang, J. Continuous opioid monitoring along with nerve agents on a wearable microneedle sensor array. J. Am. Chem. Soc. 2020, 142, 59915995,  DOI: 10.1021/jacs.0c01883
    29. 29
      Xiao, Y.; Lubin, A. A.; Heeger, A. J.; Plaxco, K. W. Label-free electronic detection of thrombin in blood serum by using an aptamer-based sensor. Angew. Chem., Int. Ed. 2005, 44, 54565459,  DOI: 10.1002/anie.200500989
    30. 30
      Tuerk, C.; Gold, L. Systematic evolution of ligands by exponential enrichment: Rna ligands to bacteriophage t4 DNA polymerase. Science 1990, 249, 505510,  DOI: 10.1126/science.2200121
    31. 31
      Ellington, A. D.; Szostak, J. W. In vitro selection of rna molecules that bind specific ligands. Nature 1990, 346, 818822,  DOI: 10.1038/346818a0
    32. 32
      Wu, Y.; Belmonte, I.; Sykes, K. S.; Xiao, Y.; White, R. J. Perspective on the future role of aptamers in analytical chemistry. Anal. Chem. 2019, 91, 1533515344,  DOI: 10.1021/acs.analchem.9b03853
    33. 33
      Yi, K.; Wang, Y.; Shi, K.; Chi, J.; Lyu, J.; Zhao, Y. Aptamer-decorated porous microneedles arrays for extraction and detection of skin interstitial fluid biomarkers. Biosens. Bioelectron. 2021, 190, 113404,  DOI: 10.1016/j.bios.2021.113404
    34. 34
      Shaver, A.; Curtis, S. D.; Arroyo-Currás, N. Alkanethiol monolayer end groups affect the long-term operational stability and signaling of electrochemical, aptamer-based sensors in biological fluids. ACS Appl. Mater. Interfaces 2020, 12, 1121411223,  DOI: 10.1021/acsami.9b22385
    35. 35
      Arroyo-Currás, N.; Dauphin-Ducharme, P.; Scida, K.; Chávez, J. L. From the beaker to the body: Translational challenges for electrochemical, aptamer-based sensors. Anal. Methods 2020, 12, 12881310,  DOI: 10.1039/d0ay00026d
    36. 36
      Dauphin-Ducharme, P.; Ploense, K. L.; Arroyo-Currás, N.; Kippin, T. E.; Plaxco, K. W. Electrochemical aptamer-based sensors: A platform approach to high-frequency molecular monitoring in situ in the living body. Biomedical Engineering Technologies; Methods in Molecular Biology; Ossandon, M. R., Baker, H., Rasooly, A., Eds.; Springer US: Humana, New York, NY, 2022; Vol. 2393, pp 479492.
    37. 37
      Carvalhal, R. F.; Sanches Freire, R.; Kubota, L. T. Polycrystalline gold electrodes: A comparative study of pretreatment procedures used for cleaning and thiol self-assembly monolayer formation. Electroanalysis 2005, 17, 12511259,  DOI: 10.1002/elan.200403224
    38. 38
      Curtis, S. D.; Ploense, K. L.; Kurnik, M.; Ortega, G.; Parolo, C.; Kippin, T. E.; Plaxco, K. W.; Arroyo-Currás, N. Open source software for the real-time control, processing, and visualization of high-volume electrochemical data. Anal. Chem. 2019, 91, 1232112328,  DOI: 10.1021/acs.analchem.9b02553
    39. 39
      Xiao, Y.; Lai, R. Y.; Plaxco, K. W. Preparation of electrode-immobilized, redox-modified oligonucleotides for electrochemical DNA and aptamer-based sensing. Nat. Protoc. 2007, 2, 28752880,  DOI: 10.1038/nprot.2007.413
    40. 40
      Pellitero, M. A.; Curtis, S. D.; Arroyo-Currás, N. Interrogation of electrochemical aptamer-based sensors via peak-to-peak separation in cyclic voltammetry improves the temporal stability and batch-to-batch variability in biological fluids. ACS Sens. 2021, 6, 11991207,  DOI: 10.1021/acssensors.0c02455
    41. 41
      Dauphin-Ducharme, P.; Yang, K.; Arroyo-Currás, N.; Ploense, K. L.; Zhang, Y.; Gerson, J.; Kurnik, M.; Kippin, T. E.; Stojanovic, M. N.; Plaxco, K. W. Electrochemical aptamer-based sensors for improved therapeutic drug monitoring and high-precision, feedback-controlled drug delivery. ACS Sens. 2019, 4, 28322837,  DOI: 10.1021/acssensors.9b01616
    42. 42
      Dilworth, T. J.; Schulz, L. T.; Rose, W. E. Vancomycin advanced therapeutic drug monitoring: Exercise in futility or virtuous endeavor to improve drug efficacy and safety?. Clin. Infect. Dis. 2021, 72, E675E681,  DOI: 10.1093/cid/ciaa1354
    43. 43
      Groenewald, T. The dissolution of gold in acidic solutions of thiourea. Hydrometallurgy 1976, 1, 277290,  DOI: 10.1016/0304-386x(76)90004-9
    44. 44
      Puscasu, A.; Zanchetta, M.; Posocco, B.; Bunka, D.; Tartaggia, S.; Toffoli, G. Development and validation of a selective spr aptasensor for the detection of anticancer drug irinotecan in human plasma samples. Anal. Bioanal. Chem. 2021, 413, 12251236,  DOI: 10.1007/s00216-020-03087-5
    45. 45
      Idili, A.; Arroyo-Currás, N.; Ploense, K. L.; Csordas, A. T.; Kuwahara, M.; Kippin, T. E.; Plaxco, K. W. Seconds-resolved pharmacokinetic measurements of the chemotherapeutic irinotecan in situ in the living body. Chem. Sci. 2019, 10, 81648170,  DOI: 10.1039/c9sc01495k
    46. 46
      Chand, V. K.; Link, B. K.; Ritchie, J. M.; Shannon, M.; Wooldridge, J. E. Neutropenia and febrile neutropenia in patients with hodgkin’s lymphoma treated with doxorubicin (adriamycin), bleomycin, vinblastine and dacarbazine (abvd) chemotherapy. Leuk. Lymphoma 2006, 47, 657663,  DOI: 10.1080/10428190500353430
    47. 47
      Pérez-Blanco, J. S.; Santos-Buelga, D.; Fernández de Gatta, M. d. M.; Hernández-Rivas, J. M.; Martín, A.; García, M. J. Population pharmacokinetics of doxorubicin and doxorubicinol in patients diagnosed with non-hodgkin’s lymphoma. Br. J. Clin. Pharmacol. 2016, 82, 15171527,  DOI: 10.1111/bcp.13070
    48. 48
      Zhou, T.; Shen, Q.; Peng, H.; Chao, T.; Zhang, L.; Huang, L.; Yang, K.; Thapa, S.; Yu, S.; Jiang, Y. Incidence of interstitial pneumonitis in non-hodgkin’s lymphoma patients receiving immunochemotherapy with pegylated liposomal doxorubicin and rituximab. Ann. Hematol. 2018, 97, 141147,  DOI: 10.1007/s00277-017-3160-1
    49. 49
      Harris, S. M.; Mistry, P.; Freathy, C.; Brown, J. L.; Charlton, P. A. Antitumour activity of xr5944 in vitro and in vivo in combination with 5-fluorouracil and irinotecan in colon cancer cell lines. Br. J. Cancer 2005, 92, 722728,  DOI: 10.1038/sj.bjc.6602403
    50. 50
      Torrisi, R.; Orlando, L.; Ghisini, R.; Veronesi, P.; Intra, M.; Rocca, A.; Balduzzi, A.; Cardillo, A.; Goldhirsch, A.; Colleoni, M. A phase ii study of primary dose-dense sequential doxorubicin plus cyclophosphamide and docetaxel in ct4 breast cancer. Anticancer Res. 2006, 26, 38613864
    51. 51
      Oakman, C.; Francis, P. A.; Crown, J.; Quinaux, E.; Buyse, M.; De Azambuja, E.; Margeli Vila, M.; Andersson, M.; Nordenskjöld, B.; Jakesz, R.; Thürlimann, B.; Gutiérrez, J.; Harvey, V.; Punzalan, L.; Dell’orto, P.; Larsimont, D.; Steinberg, I.; Gelber, R. D.; Piccart-Gebhart, M.; Viale, G.; Di Leo, A. Overall survival benefit for sequential doxorubicin-docetaxel compared with concurrent doxorubicin and docetaxel in node-positive breast cancer-8-year results of the Breast International Group 02-98 phase III trial. Ann. Oncol. 2013, 24, 12031211,  DOI: 10.1093/annonc/mds627
    52. 52
      Bailly, C. Topoisomerase i poisons and suppressors as anticancer drugs. Curr. Med. Chem. 2000, 7, 3958,  DOI: 10.2174/0929867003375489
    53. 53
      Leung, K. K.; Downs, A. M.; Ortega, G.; Kurnik, M.; Plaxco, K. W. Elucidating the mechanisms underlying the signal drift of electrochemical aptamer-based sensors in whole blood. ACS Sens. 2021, 6, 33403347,  DOI: 10.1021/acssensors.1c01183
  • Supporting Information

    Supporting Information


    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.analchem.2c00829.

    • Expanded Methods cleaning protocol monitoring) and additional data (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.