Enhanced split-type photoelectrochemical aptasensor incorporating a robust antifouling coating derived from four-armed polyethylene glycol.

Antifouling biosensors capable of preventing protein nonspecific adhesion in real human bodily fluids are highly sought-after for precise disease diagnosis and treatment. In this context, an enhanced split-type photoelectrochemical (PEC) aptasensor was developed incorporating a four-armed polyethylene glycol (4A-PEG) to construct a robust antifouling coating, enabling accurate and sensitive bioanalysis. The split-type PEC system involved the photoelectrode and the biocathode, effectively separating signal converter with biorecogniton events. Specifically, the TiO2 electrode underwent sequential modification with ZnIn2S4 (ZIS) and polydopamine (PDA) to form the PDA/ZIS/TiO2 photoelectrode. The cathode substrate was synthesized as a hybrid of N-doped graphene loaded with Pt nanoparticles (NG-Pt), and subsequently modified with 4A-PEG to establish a robust antifouling coating. Following the anchoring of probe DNA (pDNA) on the 4A-PEG-grafted antifouling coating, the biocathode for model target of cancer antigen 125 (CA125) was obtained. Leveraging pronounced photocurrent output of the photoelectrode and commendable antifouling characteristics of the biocathode, the split-type PEC aptasensor showcased exceptional detection performances with high sensitivity, good selectivity, antifouling ability, and potential feasibility.