Nano Archive

A novel sensor platform based on aptamer-conjugated polypyrrole nanotubes for label-free electrochemical protein detection

Yoon, Hyeonseok and Kim, June-Hyung and Lee, Nahum and Kim, Byung-Gee and Jang, Jyongsik (2008) A novel sensor platform based on aptamer-conjugated polypyrrole nanotubes for label-free electrochemical protein detection. CHEMBIOCHEM, 9 (4). pp. 634-641.

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We first present a simple yet versatile strategy for the functionalization of polymer nanotubes in a controlled fashion. Carboxylic-acid-functionalized polypyrrole (CPPy) nanotubes were fabricated by using cylindrical micelle templates in a water-in-oil emulsion system, and the functional carboxyl groups were effectively incorporated into the polymer backbone during the polymerization by using pyrrole-3-carboxylic acid (P3CA) as a co-monomer without a sophisticated functionalization process. It was noteworthy that the chemical functionality of CPPy nanotubes was readily controlled in both qualitative and quantitative aspects. On the basis of the controlled functionality of CPPy nanotubes, a field-effect transistor (FET) sensor platform was constructed to detect specific biological entities by using a buffer solution as a liquid-ion gate. The CPPy nanotubes were covalently immobilized onto the microelectrode substrate to make a good electrical contact with the metal electrodes, and thrombin aptamers were bonded to the nanotube surface via covalent linkages as the molecular recognition element. The selective recognition ability of thrombin aptamers combined with the charge transport property of CPPy nanotubes enabled the direct and label-free electrical detection of thrombin proteins. Upon exposure to thrombin, the CPPy nanotube FET sensors showed a decrease in current flow, which was probably attributed to the dipole-dipole or dipole-charge interaction between thrombin proteins and the aptamer-conjugated polymer chains. Importantly, the sensor response was tuned by adjusting the chemical functionality of CPPy nanotubes. The efficacy of CPPy nanotube FET sensors was also demonstrated in human blood serum; this suggests that they may be used for practical diagnosis applications after further optimization.

Item Type:Article
Uncontrolled Keywords:aptamers; biosensors; field-effect transistors; nanotubes; polypyrrole
Subjects:Material Science > Functional and hybrid materials
Analytical Science > Nanotechnology for sensing and actuating
Biomedical Science > Nanobiotechnology
ID Code:2453
Deposited By:Farnush Anwar
Deposited On:23 Dec 2008 15:51
Last Modified:09 Jan 2009 14:53

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