Study of the interaction between bovine serum albumin and ZnS quantum dots with spectroscopic techniques.

The interaction between bovine serum albumin (BSA) and ZnS quantum dots (QDs) was studied by fluorescence, UV-vis spectroscopic techniques. The results showed that the fluorescence of BSA was strongly quenched by ZnS QDs and the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K(q.) The recorded UV-vis data and the fluorescence data quenching by the QDs demonstrated that the interaction between them leads to the formation of QDs-BSA complex. Furthermore, the temperature effects on the structural and spectroscopic properties of individual QDs and protein and their bioconjugates (QDs-BSA) were also researched. It was found that, compared to the monotonically decrease of the individual QDs fluorescence intensity, the temperature dependence of the QDs-BSA emission had a much more complex behavior, highly sensitive to the conformational changes of the protein.