Polydopamine nanospheres loaded with l-cysteine-coated cadmium sulfide quantum dots as photoelectrochemical signal amplifier for PSA detection.

作者：Deng, Keqin^*; Wang, Hao; Xiao, Jing; Li, Chunxiang; Zhang, Shaowei^*; Huang, Haowen

来源：Analytica Chimica Acta, 2019, 1090: 143-150.

DOI：10.1016/j.aca.2019.09.016

• Electrochemically reduced graphene oxide-TiO(2)
• Photoelectrochemical immunosensor
• Polydopamine nanospheres
• Prostate specific antigen
• l-cysteine-coated cadmium sulfide quantum dots

A sandwich-type photoelectrochemical (PEC) immunosensor was constructed for sensitive detection of prostate specific antigen (PSA). It was based on electrochemically reduced graphene oxide-TiO2 (ERGO-TiO2) as photoelectrochemical platform to immobilize capture antibody (Ab1). Then, quinone-rich polydopamine nanospheres (PDANS) loaded detection antibody (Ab2) and photocurrent signal label, l-cysteine-coated cadmium sulfide quantum dots (CdSQDs). ERGO-TiO2 displayed greatly improved photocurrent response to white light. CdSQDs conjugated with PDANS further amplified photocurrent signal because of the good conductivity of PDANS and ERGO. The increased photocurrent showed a linear correlation with PSA in the concentration range from 0.02pgmL(-1) to 200ngmL(-1) with the detection limit of 6.8fgmL(-1). It also revealed high selectivity and good stability.