Detection of alkaline phosphatase activity with a CsPbBr₃/Y6 heterojunction-based photoelectrochemical sensor

An ultra-sensitive photoelectrochemical (PEC) sensor based on perovskite composite was developed for the determination of alkaline phosphatase (ALP) in human serum. In contrast to CsPbBr₃ or Y6 that generated anodic current, the heterojunction of CsPbBr₃/Y6 promoted photocarriers to separate and generated cathodic photocurrent. Ascorbic acid (AA) was produced by ALP hydrolyzing L-ascorbic acid 2-phosphate trisodium salt (AAP), which can combine with the holes on the photoelectrode surface, accelerating the transmission of photogenerated carriers, leading to enhanced photocurrent intensity. Thus, the enhancement of PEC current was linked to ALP activity. The PEC sensor exhibits good sensitivity for detection of ALP owing to the unique photoelectric properties of the CsPbBr₃/Y6 heterojunction. The detection limit of the sensor was 0.012 U·L^-1 with a linear dynamic range of 0.02-2000 U·L^-1. Therefore, this PEC sensing platform shows great potential for the development of different PEC sensors.