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 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.