A self-powered photoelectrochemical cathodic molecular imprinting sensor based on Au@TiO2 nanorods photoanode and Cu2O photocathode for sensitive detection of sarcosine.

Quantitative determination of sarcosine (SAR) in biological liquids is of great importance, as SAR has been recently suggested as a promising biomarker for prostate cancer diagnostics. Herein, a self-powered photoelectrochemical (PEC) molecular imprinted sensor integrated with photoanode (Au@TiO2 nanorods) and photocathode (Cu2O) is proposed for the first time towards the specific and sensitive detection of SAR. With the benefits of strong photocurrent driving force attributed to a large inherent deviation between the Fermi levels of photoanode and photocathode in this system, the photogenerated electrons of Au@TiO2 can rapidly transferred along the outer circuit and attracted by the holes in the valence band of the photocathode, forming a self-powered PEC system and improve the photocurrent of the cathode. Under the optimal conditions, the constructed cathode imprinted sensor has a linear range of 10 nM - 10 μM, and the limitation of detection is 0.19 nM. This work proved that the PEC sensing platform has great potential in the field of miniaturized biosensing without external power supply.