Exploiting new sensing mechanism for multiple signal responses has become an emerging research trend of gas-sensitive photoelectrochemical (PEC) immunoassay. Herein, we design a double-mode visual and PEC immunosensing system for the sensitive detection of prostate-specific antigen (PSA, as a model analyte) on the basis of gasochromic reaction with Pd-MoO₃. As the sandwich immunoreaction progresses, a platinum nanoparticle-labeled detection antibody catalyzes the production of H₂ from the substrate (NH₃BH₃). The resulting H₂ undergoes a gasochromic reaction with Pd-MoO₃, resulting in a change in color of the Pd-MoO₃-coated electrode to provide a visual readout. Meanwhile, the photocurrent intensity of the product increases due to the reduction of the bandgap, which is positively related to the concentration of the analyte. Under optimal conditions, the developed sensing platform presented a high sensitivity for PSA in a dynamic working range of 0.1–50 ng mL⁻¹ with a limit of detection of 76 pg mL⁻¹. Impressively, this work not only presents a new protocol for the application of gasochromic materials but also gives a path for the developing dual signal readout in gas-sensitive PEC immunoassay.

探索多种信号响应的新传感机制已成为气敏光电化学（PEC）免疫分析的新兴研究趋势。_{在此，我们设计了一种基于与Pd-MoO 3}的气相反应灵敏检测前列腺特异性抗原（PSA，作为模型分析物）的双模式视觉和PEC免疫传感系统。随着夹心免疫反应的进行，铂纳米颗粒标记的检测抗体催化从底物（NH ₃ BH ₃）产生H _{2 。}生成的 H _{2与 Pd-MoO 3}发生气致变色反应，导致 Pd-MoO 3 的颜色发生_变化- 涂层电极提供视觉读数。同时，产物的光电流强度由于带隙的减小而增加，这与分析物的浓度呈正相关。^{在最佳条件下，开发的传感平台在 0.1-50 ng mL -1}的动态工作范围内对 PSA 表现出高灵敏度，检测限为 76 pg mL ^-1。令人印象深刻的是，这项工作不仅为气致变色材料的应用提出了一种新的协议，而且为在气敏 PEC 免疫测定中开发双信号读出提供了途径。