As a main contaminant in fish, microcystin-LR (MC-LR) leads to serious liver problems; therefore, the development of MC-LR sensors is important to guarantee aquatic food safety. In this work, a near-infrared (NIR) light-excited photoelectrochemical (PEC) immunosensor was developed through conjugation of Ag₂S cubes with Au nanoparticles (NPs) to determine MC-LR residues in fish. Specifically, as a narrow-band semiconducting material, Ag₂S is capable of absorbing NIR light. Taking advantage of the localized surface plasmon resonance (LSPR) effect along with good conductivity of AuNPs, the developed AuNP/Ag₂S/fluorine-doped tin oxide (FTO) owns much higher photoelectric conversion efficiency, and the photocurrent is 5.3 times that of Ag₂S FTO. Subsequently, the NIR-driven AuNP/Ag₂S/FTO was used to immobilize antibodies (Abs) for MC-LR. Their specificity to MC-LR led to steric effects and limited surface electron transfer, causing reduce of the photocurrent. Through AuNP/Ag₂S-composite amplification and immunological specificity, the PEC immunosensor can quantitatively measure MC-LR with a wide linear range, 10 pg L⁻¹ to 10 μg L⁻¹, and a much low detection limit, 7 pg L⁻¹ (S/N = 3). Finally, the NIR PEC sensor was employed in the analysis of MC-LR contents in fish. This work reveals the NIR-responsive ability of Ag₂S cubes and deepens understanding the role of AuNPs in the PEC process. Due to the superior properties, the developed NIR PEC immunosensor has been demonstrated as a promising method for analysis of biological samples.

作为鱼类的主要污染物，微囊藻毒素-LR (MC-LR) 会导致严重的肝脏问题；因此，开发MC-LR传感器对于保障水产食品安全具有重要意义。_{在这项工作中，通过将 Ag 2} S 立方体与 Au 纳米粒子 (NPs)结合，开发了一种近红外 (NIR) 光激发光电化学 (PEC) 免疫传感器，以测定鱼类中的 MC-LR 残留物。具体而言，作为窄带半导体材料，Ag ₂ S能够吸收近红外光。利用局域表面等离子共振（LSPR）效应和AuNPs良好的导电性，所开发的AuNP/Ag ₂ S/氟掺杂氧化锡（FTO）具有更高的光电转换效率，光电流是金纳米粒子的5.3倍。银₂S FTO。随后，NIR 驱动的 AuNP/Ag ₂ S/FTO 用于固定 MC-LR 的抗体 (Abs)。它们对 MC-LR 的特异性导致空间效应和有限的表面电子转移，导致光电流降低。通过AuNP/Ag ₂ S-复合扩增和免疫特异性，PEC免疫传感器可以定量测量MC-LR，线性范围宽，10 pg L ^-1至10 μg L ^-1，检测限低得多，7 pg L ^-1（信噪比 = 3）。最后，将 NIR PEC 传感器用于鱼中 MC-LR 含量的分析。这项工作揭示了 Ag _{2的 NIR 响应能力}S 立方体并加深了对 AuNP 在 PEC 过程中的作用的理解。由于优越的性能，开发的 NIR PEC 免疫传感器已被证明是一种有前途的生物样品分析方法。