Fluorescence Resonance Energy Transfer Between Quantum Dots of CdSe and CdTe and Its Application for Determination of Serum Prostate-Specific Antigen

Fluorescence resonance energy transfer (FRET) from CdSe quantum dots to CdTe quantum dots was studied and used to determine the serum prostate-specific antigen (PSA). The effective energy transfer occurred between CdSe and CdTe in Tris-HCl buffer solution at pH 8.0, at which the CdTe fluorescence intensity increased greatly. When prostate-specific antigen (PSA) was added, the fluorescence intensity of CdSe-CdTe system decreased and the fluorescence was finally quenched because of the specific immunological reaction between the PSA antigen and the CdTe-labelled PSA antibody. There was a linear relationship between the concentrations of the PSA antigen and the fluorescence-quenching intensities. Then a new determination strategy of PSA was built by using the CdSe-CdTe system. Under optimum conditions, the linear range of PSA antigen was 2.8-10 mu g L-1, with a correlation coefficient of r = 0.9992 and a detected limit of 1.5 x 10(-2) mu g L-1 (n = 11).