Multifunctional SnO₂/SnS₂/CdSe heterojunction coupled with CuO nanoenzyme-regulating synergistic strategy enable...

Multimodal detection significantly enhanced detection accuracy in complex biological matrices. In this work, a high-efficiency multimodal biosensor is proposed based on multifunctional SnO₂/SnS₂/CdSe QDs heterojunction and CuO nanoenzyme-regulating synergistic strategy, which achieves ultra-sensitive and specific detection of breast cancer-related BRCA1 gene. A high-performance photoelectrochemical (PEC) SnO₂/SnS₂/CdSe QDs heterojunction was constructed for the first time, which effectively enhances the light absorption capability and photogenerated charge separation efficiency. The heterojunction yields a PEC signal approximately 3.75-fold higher than that of pure SnO₂/SnS₂ and 11.3-fold higher than that of CdSe QDs, realizing stable PEC and electrochemiluminescence (ECL) dual signals. Notably, CuO nanoenzyme with intrinsic oxidase-like activity are introduced onto the sensing interface through target-induced amplification strategies, serving as multifunctional signal regulatory units. The CuO nanoenzyme can not only catalyze the oxidation of ascorbic acid but also trigger the ECL resonance energy transfer effect. This dual functionality enables the simultaneous "shutdown" of PEC and ECL signals and "activation" of fluorescence signals, constructing a self-verifiable triple-modal sensing platform for BRCA1 detection. The developed biosensor has been successfully applied to the quantitative detection of BRCA1 in human serum samples. This report offered a promising and versatile platform for early clinical diagnosis of breast cancer and detection of other important disease biomarkers.