Interfacial Charge Separation Engineering-Modulated Multichannel Photoelectrochemical Biosensor Enabled by a...

Accurate biomarker detection is crucial for early and accurate disease diagnosis. Herein, a multiplexed biosensor capable of simultaneous electrochemical (EC) and photoelectrochemical (PEC) operation is fabricated using efficient, self-templated In₂S₃/CuInS₂ (CIS) heterostructured nanotubes for the selective detection of bovine serum albumin (BSA). For the EC mode, the In₂S₃/CIS heterostructure exhibits a high differential pulse voltammetry (DPV) response arising from Cu⁺/Cu²⁺ electron transfer, alongside excellent peroxidase-mimetic activity toward H₂O₂. For the PEC mode, the n-p type semiconducting In₂S₃/CIS hollow nanotubes not only quench the photocurrent signals of photoactive ZnIn₂S₄ (ZIS) nanoflowers due to the competitive capture of light energy and consumption of electron donors; but also act as a peroxidase mimetic to generate insoluble precipitation. Furthermore, the steric hindrance effect from the In₂S₃/CIS heterostructure will further decrease the photocurrent signal output of ZIS. By integrating molecular imprinting technology, BSA can be specifically recognized and captured the imprinted cavities, leading to a significant decrease in both EC and photocurrent signals. Based on these multifunctional nanotubes, BSA is detected accurately with a wide linear range from 10^-20 mg·mL^-1 to 10^-1 mg·mL^-1 and a detection limit of 8.5 × 10^-21 mg·mL^-1. This multiplexed strategy provides a universal and efficient platform for clinical biomedicine and bioanalysis.