A Highly Sensitive Amperometric Aptamer Biosensor for Adenosine Triphosphate Detection on a 64 Channel Gold Multielectrode Array

Abstract

Herein, an electrochemical aptamer biosensor based on a gold multielectrode array is reported for the detection of adenosine triphosphate (ATP), which is an important neurotransmitter in the central nervous system. The aptasensor possesses 64 individually addressable microelectrodes with a diameter of 24 μm, which is distributed over an area of 1 mm2. The electrodes are modified with an ATP‐specific aptamer, which is labeled with a ferrocene redox probe. It is demonstrated that the used chip fabrication and cleaning process generate microelectrode channels with similar electrochemical responses and electroactive surface areas. The immobilization of the aptamer on gold microelectrodes is optimized and the receptor density is determined to be (1.0 ± 0.44) × 1013 molecules cm−2. Concentration‐dependent alternating current voltammetry measurements exhibit a limit of detection of 0.30 × 10−9 m and a sensitivity of 2.4 nA logC. Furthermore, the sensor shows a high selectivity over analogous molecules and reproducible detection results in artificial cerebrospinal fluid. The sensor array is used to detect ATP via several channels of the same chip, showing high signal redundancy. A label‐free electrochemical, multichannel ATP aptasensor is demonstrated with high selectivity and subnanomolar sensitivity, which may be conducive to record this neurotransmitter in neuronal cell‐culture systems.