Web Release Date: August 10,
Surface Plasmon Resonance Imaging Measurements of Antibody Arrays for the Multiplexed Detection of Low Molecular Weight Protein Biomarkers
and
Department of Chemistry, University of California-Irvine, Irvine, California 92697, and Intrinsic Bioprobes Inc., 625 South Smith Road, Tempe, Arizona 85281
Received for review May 12, 2006. Accepted July 4, 2006.
Abstract:
This paper describes a simple methodology for the creation of high-density multiplexed antibody arrays on gold
surfaces that can be used to detect low molecular weight
protein biomarkers with surface plasmon resonance
imaging (SPRI). A one-step carbonyldiimidazole (CDI)
surface reaction was utilized to attach antibodies onto
alkanethiol-modified gold surfaces and characterized with
polarization modulation FT-IR reflection absorption spectroscopy. The CDI chemistry was then employed to create
an antibody microarray with array element sizes varying
from 750 
m down to 200 m. As a demonstration, a
three-component antibody array was employed to detect
two clinically important protein biomarkers, 
2-microglobulin (11.8 kDa) and cystatin C (13.4 kDa). SPRI
measurements could simultaneously detect both of these
small unlabeled proteins with no cross talk at solution
concentrations from 300 nM down to 1 nM. In addition,
the adsorption strengths of these biomarkers onto an
antibody array were measured with SPRI and compared
to those obtained from the kinetic analysis of single-channel angle shift SPR measurements.
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