Abstract
We have developed a highly-sensitive acetylcholine (ACh) sensor based on a charge-transfer technique (CTT) using a smart biochip. The CCT ACh sensor (CTTAS) involves a charge-accumulation technique for detecting choline and H+ ions, the sensing signals being amplified without an external amplifier.
The CTTAS exhibits excellent performance for ACh detection with high sensitivity 11.6 mV/mM), high signal-to-noise ratio, large span (537 mV), wide linear range (1.5 similar to 12.5 mM), fast response time (<20 s) and very good reproducibility. We obtained a very low limit of detection (similar to 0.01 mM).
Under optimal conditions, the CTTAS outstripped the performance of the widely-used enzyme field-effect transistor (ENFET) with sensitivity more than three times greater than that of the ENFET (3.6 mV/mM). The CTTAS exhibited good selectivity, sensitivity, reproducibility and stability over a large concentration range. Due to its high resolution, fast response, small size and low cost, the CTTAS has tremendous potential for applications in medical research and clinical diagnosis. (C) 2008 Elsevier Ltd. All rights reserved.