Renjie Mao, Xueni Yue, Jiajing Li, Peiyu Hou, Xuan Wang, Feixue Sun, Hong Zhou
Among recently emerged bismuth-based nanomaterials, Bi 2 S 3 /BiFeO 3 heterojunctions are promising candidates for improving biomarker detection by enhancing charge separation. Benefitting from this, we have developed a dual-mode system by taking advantage of the photoelectric properties of Bi 2 S 3 /BiFeO 3 and the peroxidase-like activity of BiVO 4, which integrates independent signal transduction for cross-validation and, thus, significantly enhanced the credibility of detection. The target prostate-specific antigen (PSA) was captured through an Ab 1 –PSA–Ab 2 sandwich structure, and Ab 2 was modified with BiVO 4 –alkaline phosphatase (ALP). In organic photoelectrochemical transistor (OPECT) mode, ALP reduces ascorbic acid 2-phosphate (AAP) to ascorbic acid and etches the electroplated MnO 2 film to restore the signal. BiVO 4 oxidizes 3,3,5,5-tetramethylbenzidin in H 2 O 2 by virtue of its inherent peroxidase-like activity for the colorimetric signal. A linear response was received between signal response and PSA in which concentration ranged from 10 fg mL –1 to 50 ng mL –1 in OPECT mode and from 0.1 to 100 ng mL –1 in colorimetric mode. The enhanced charge separation from the ferroelectric polarization of BiFeO 3 and the improved electrical conductivity from Bi 2 S 3 explored the applications of bismuth-based nanomaterials in reliable high-performance bioanalysis.