Photoelectrochemical sensor consisting of sulfhydryl-borate ester modified A1/B1 type Pillar[5]arene-functionalized gold NPs

Recognition of mitochondrial reactive oxygen species (ROS) in cells is essential for understanding the critical roles of different ROS in biology reaction processes. In this study, an ultrasensitive and specific photoelectrochemical (PEC) sensor is constructed and applied for the capture and identification of H2O2 in cells. For the targeted detection of H2O2 in cells containing similar groups, such as center dot OH and O2 center dot-, a new sulfhydryl-borate ester modified A1/B1 type pillar[5]arene (BP5) with a specific borate group is designed as a specific recognition molecule, and Au nanoparticles (Au NPs) are synthesized as the photoactive material. Specifically, the localized surface plasmon resonance (LSPR) of the Au NPs and host-guest interaction between BP5 and H2O2 increase the photocurrent signal. At the same time, specific groups on BP5 react with H2O2 to specifically recognize it. The Au@BP5/GCE shows strong photoelectrochemical response for the detection of H2O2 with limit of detection (0.33 pM, S/N=3), an extended linear range (1-60 pM), high specificity, good stability and excellent reproducibility.