Colorimetric-Assisted Photoelectrochemical Sensing for Dual-Mode Detection of Neuron-Specific Enolase via the Photoanode-Photocathode System

Convenient and accurate detection of neuron-specific enolase (NSE) is crucial for small cell lung cancer. However, due to the shortcomings of a single detection mode such as insufficient reliability, a dual-mode signal response system based on photoelectrochemical (PEC) and colorimetric methods was developed in this paper for the ultrasensitive detection of NSE. In the PEC method, the ITO/Nb2O5/CdS composite was used as the photoanode and ITO/BiOI as the photocathode based on the energy level matching principle, which greatly enhanced the anti-interference ability of the photocurrent. In addition, MnO2 has oxidase-like property and can effectively oxidize 3, 3', 5, 5'-tetramethylbenzidine to produce a blue product, thus enabling colorimetric detection of NSE. The constructed PEC immunosensor demonstrated commendable performance within the linear range of 1.0 pg/mL-100 ng/mL, achieving the detection limit of NSE at 0.25 pg/mL. For the colorimetric analysis, effective detection was accomplished within the range of 0.5 ng/mL-30 ng/mL, with a detection limit of 0.13 ng/mL. The dual-mode analysis strategy that combines photoelectrochemistry and colorimetry realized highly sensitive and accurate detection of NSE.