A photoelectrochemical sensor for hydrogen sulfide in cancer cells based on the covalently and in situ grafting of CdS nanoparticles onto TiO2 nanotubes

A facile photoelectrochemical sensor for the determination of hydrogen sulfide (H2S) is developed. Photocurrent is generated through the grafting of CdS nanoparticles covalently and in situ onto TiO2 nanotubes. The surface of TiO2 nanotubes was modified by a layer of thioglycolic acid (TGA) to introduce thiol groups which can adsorb and immobilize Cd ions. CdS nanoparticles would be formed onto TiO2 nanotubes after treating with exogenous or endogenous H2S. Both the exogenous and H2S released from cancer cells were detected based on the photoelectric properties of CdS nanoparticles. And a wide linear range (10 nM-106 nM) was achieved with a detection limit of 0.7 nM.