Interfacial Charge Separation Engineering‐Modulated Multichannel Photoelectrochemical Biosensor Enabled by a Triple‐Responsive Nanolabel

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 In 2 S 3 /CuInS 2 (CIS) heterostructured nanotubes for the selective detection of bovine serum albumin (BSA). For the EC mode, the In 2 S 3 /CIS heterostructure exhibits a high differential pulse voltammetry (DPV) response arising from Cu + /Cu 2+ electron transfer, alongside excellent peroxidase‐mimetic activity toward H 2 O 2 . For the PEC mode, the n‐p type semiconducting In 2 S 3 /CIS hollow nanotubes not only quench the photocurrent signals of photoactive ZnIn 2 S 4 (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 In 2 S 3 /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.