Study on the interaction between bovine serum albumin and CdTe quantum dots with spectroscopic techniques

The interaction between bovine serum albumin (BSA) and CdTe quantum dots (QDs) was studied by fluorescence, UV-vis and Raman spectroscopic techniques. The results showed that the fluorescence of BSA was strongly quenched by CdTe QDs. The quenching mechanism was discussed to be a static quenching procedure, which was proved by the quenching rate constant (K,,) and UV-vis absorption spectra. According to Lineweaver-Burk equations at different temperatures, the thermodynamic parameters, Delta H-0, Delta S-0 and Delta G(0) were observed to be -23.69 kJ mol(-1), 48.39 J mol(-1) K-1 and -38.04 kJ mol(-1), respectively. The binding constant (K-A) and the number of binding sites (n) were obtained by Scatchard equation. It was found that hydrophobic force and sulfhydryl group played a key role in the interaction process. Further results from Raman spectra indicated that the alpha-helical content in BSA reduced after binding with CdTe QDs. (C) 2008 Published by Elsevier B.V.