HIGHLY SENSITIVE PHOTOELECTROCHEMICA IMMUNOASSAY FOR INTERLEUKIN-6 DETECTION BASED ON TIO_2/CDS/CDSE CO-SENSITIZED STRUCTURE

摘要

Dual co-sensitized structure of TiO_2/CdS/CdSe was designed to develop a novel competitive photoelectrochemical immunoassay for highly sensitive detection of human interleukin-6 (IL-6). In the sening system, TiO_2/CdS hybrid was employed as matrix for immobilization of anti-IL-6 antibody, whereas CdSe QDs linked to IL-6 was used for signal amplification. The greatly enhanced sensitivity for IL-6 detection was attributed to the following reasons. Firstly, the TiO_2/CdS/CdSe co-sensitized structure extended the absorption range to long-wavelength light, which adequately utilized the light energy. Secondly, the TiO_2/CdS/CdSe co-sensitized structure possessed stepwise band-edge levels favoring ultrafast transfer of photogenerated electrons. Besides, introduction of CdSe effectively prevented the recombination of photogenerated electrons in the conduction band of CdS. Upon the co-sensitization strategy, a novel competitive immunoassay was developed and it exhibited a low detection limit of 0.38 pg/mL for IL-6 detection. The proposed co-sensitization strategy presented high sensitivity, reproducibility, specificity and stability, and also opened up a new promising platform for detection of other biomarkers. We gratefully appreciate the National Natural Science Foundation and the National Basic Research Program of China.