Effect of CdTe QDs on the protein-drug interactions.

Recently, investigations of biological toxicity of cadmium QDs and their toxic interaction with plasma proteins have attracted great interest. In this work, flavonoids were studied for the affinities for human serum albumin (HSA) in the presence and absence of CdTe G-QDs by fluorescence quenching method. CdTe G-QDs obviously enhanced the binding affinities of kaempferol, genistein and biochanin A by 3.78 to 154.88 times depending on the QDs concentration. However, the affinity of kaempferide for HSA was slightly weakened in the presence of G-QDs. The non-methylated flavonoids were more sensitive to G-QDs than their methylated forms. The affinities of kaempferide and kaempferol for HSA at first were slightly improved and then obviously decreased with increasing G-QDs concentration. For genistein, the affinities for HSA decreased with increasing G-QDs concentration. However, the G-QDs concentration showed no obvious effect on the affinity of biochanin A. The binding affinities of flavonoids for HSA improved with increasing QDs size.