The investigation of the interactions between CdSe quantum dots and human serum albumin by resonance Rayleigh scattering and second-order scattering spectra

Human serum albumin (HSA) was the most abundant protein in human plasma and has significant physiological function. In Tris-HCl buffer solution (pH 7.4), water-soluble semiconductor CdSe quantum dots (QDs) reacted with HSA and the products resulted in a great enhancement of the intensity of resonance Rayleigh scattering (RRS) and second-order scattering (SOS). Based on this, a new method was developed to investigate the interactions between QDs and HSA. The parameters with regard to determination were optimized, and the reaction mechanism was discussed. Under optimal conditions, the increments of scattering intensity (Delta I) were directly proportional to the concentrations of HSA in the range of 0.4-48.0 mu mol L-1. The detection limits were 0.10 mu mol L-1 for RRS method and 0.25 mu mol L-1 for SOS method. The proposed method was sensitive, simple and rapid. It has been successfully applied to the determination of HSA in human urine samples. Analytical results obtained with this novel assay were satisfactory. (C) 2009 Elsevier B.V. All rights reserved.