A Novel Sensor Platform Based on Aptamer-Conjugated
- Yoon, Hyeonseok; June-Hyung, Kim; Nahum, Lee; Byung-Gee, Kim; Jyongsik, Jang
- Issue Date
- ChemBioChem 2008, 9, 634 – 641
- We first present a simple yet versatile strategy for the functionalization of polymer nanotubes in a controlled fashion. Carboxylicacid- 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.
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