Supramolecular Chemistry on Water-Soluble Carbon Nanotubes for Drug Loading and Delivery

Zhuang Liu, Xiaoming Sun, Nozomi Nakayama-Ratchford and Hongjie Dai*
Department of Chemistry, Stanford University, Stanford, California 94305
ACS Nano, 2007, 1 (1), pp 50–56
DOI: 10.1021/nn700040t
Publication Date (Web): August 14, 2007
Copyright © American Chemical Society
* Address correspondence to hdai@stanford.edu.

Abstract

Abstract Image

We show that large surface areas exist for supramolecular chemistry on single-walled carbon nanotubes (SWNTs) prefunctionalized noncovalently or covalently by common surfactant or acid-oxidation routes. Water-soluble SWNTs with poly(ethylene glycol) (PEG) functionalization via these routes allow for surprisingly high degrees of π-stacking of aromatic molecules, including a cancer drug (doxorubicin) with ultrahigh loading capacity, a widely used fluorescence molecule (fluorescein), and combinations of molecules. Binding of molecules to nanotubes and their release can be controlled by varying the pH. The strength of π-stacking of aromatic molecules is dependent on nanotube diameter, leading to a method for controlling the release rate of molecules from SWNTs by using nanotube materials with suitable diameter. This work introduces the concept of “functionalization partitioning” of SWNTs, i.e., imparting multiple chemical species, such as PEG, drugs, and fluorescent tags, with different functionalities onto the surface of the same nanotube. Such chemical partitioning should open up new opportunities in chemical, biological, and medical applications of novel nanomaterials.

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History

  • Published In Issue August 14, 2007
  • Article ASAPAugust 14, 2007
  • Received: May 22, 2007
    Accepted: June 22, 2007

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