Efficient enhancement of electrochemiluminescence from tin disulfide quantum dots by hollow titanium dioxide spherical shell for highly sensitive detection of chloramphenicol.

In this study, modified hollow titanium dioxide and SnS2 quantum dots (SnS2 QDs) were used to build a novel electrochemiluminescence immunoassay (ECLIA) for ultrasensitive detection of chloramphenicol (CAP). The titanium dioxide hollow spheres (THS) modified with polyethyleneimine (PEI) and gold nanoparticles (Au NPs) was synthesized as a probe material for the novel ECLIA, meanwhile it also could be a coreaction accelerator which could greatly improve the interaction efficiency between SnS2 QDs and S2O82-. Then the modified THS was combined with chloramphenicol antibody to form ECLIA probes, and colloidal gold synthesized as a platform for an ECLIA by ascorbic acid (AA) reduction. A competitive immunoassay strategy was used for the detection of CAP, where CAP in the sample would compete with the coating antigen for the limited antibodies. The proposed ECLIA for CAP detection exhibited high sensitivity with a wide linear range from 0.01 ng mL-1 to 100 ng mL-1 and a low detection limit at 3.1 pg mL-1. Furthermore, it could be seen from electrochemical analysis that the effect of THS on the enhancement of ECL signal is about twice as high as that of ordinary titanium dioxide. Importantly, this work not only successfully applied THS to amplify electrochemical-luminescence signal in the ECLIA, but also successfully prepared a stable and highly selective sensor for ultrasensitive detection of CAP.