An ultrasensitive photoelectrochemical (PEC) aptasensor based on Bi₄Ti₃O₁₂/Pd@Au/Ag₂S was proposed for the detection of Hg²⁺. The indium tin oxide (ITO) electrode was first decorated with the nested hollow bismuth titanate (Bi₄Ti₃O₁₂) that functioned with Pd@Au as an electron mediator to accelerate the photocurrent conversion, and then silver sulfide (Ag₂S) nanoparticles were grown in-situ to enhance the PEC response. The band gap of Ag₂S is so narrow that photogenerated electrons are easily generated under illumination. Pd@Au acts as an electron medium to facilitate electron transfer from the conduction band of Ag₂S to the valence band of Bi₄Ti₃O₁₂. The quantitative detection of Hg²⁺ was achieved based on the thymidine - Hg²⁺ - thymidine (T- Hg²⁺-T) specific interaction. The results showed that the PEC aptasensor showed a wide linear range (1 mM-0.1 pM) and a low detection limit (19 fM). In addition, the aptasensor has excellent selectivity, reproducibility and stability, providing a feasible method for the detection of Hg²⁺.

提出了一种基于Bi ₄ Ti ₃ O ₁₂ /Pd@Au/Ag ₂ S的超灵敏光电化学(PEC)适体传感器来检测Hg ²⁺。氧化铟锡 (ITO) 电极首先用嵌套的空心钛酸铋 (Bi ₄ Ti ₃ O ₁₂ ) 装饰，该钛酸铋与 Pd@Au 作为电子介质以加速光电流转换，然后是硫化银 (Ag ₂ S)纳米颗粒原位生长以增强PEC响应。_{Ag 2}的带隙S 非常窄，以至于在光照下很容易产生光生电子。Pd@Au 充当电子介质以促进电子从 Ag ₂ S 的导带转移到 Bi ₄ Ti ₃ O ₁₂的价带。^{Hg 2+}的定量检测是基于胸苷-Hg ²⁺ -胸苷（T-Hg ²⁺ -T）特异性相互作用实现的。结果表明，PEC适体传感器具有较宽的线性范围（1 mM-0.1 pM）和较低的检测限（19 fM）。此外，适体传感器具有优异的选择性、重现性和稳定性，为Hg ²⁺的检测提供了可行的方法。