Photoelectrochemical Aptasensors for Biosensing: A Review

Biodetection, the basis of many biotechnologies, has rapidly developed in recent years. Among various biodetection methods, the photoelectrochemical (PEC) sensor is an emerging analytical method and has been applied in biodetection widely because of its high sensitivity, low cost, expandability into multichannel sensor arrays, and many other superior properties. Unlike conventional electrochemical aptasensors, the PEC aptasensor uses light as the excitation and an electrical photocurrent as the readout, which separates the stimulus from the measurement and reduces the excitation-related background. By modulating the light and demodulating the current, the PEC aptasensor improves the signal-to-noise ratio and lowers the limit of detection in complex matrices. Compared with optical aptasensors, the PEC aptasensor relies on simple light sources and electrodes rather than bulky imaging optics, enabling easier miniaturization and light-addressed multiplexed arrays. Therefore, aptamer-based PEC aptasensors have become a new hotspot in the field of biodetection. In this review, the development history of PEC aptasensors was presented. Then, this paper focuses on the photoactive nanomaterials, aptamers as sensing films, and sensing strategies of PEC aptasensors. The applications of PEC aptasensors in biodetection were also discussed. Finally, current challenges are discussed and opportunities in the future are prospected.