Chem. J. Chinese Universities ›› 2012, Vol. 33 ›› Issue (06): 1195.doi: 10.3969/j.issn.0251-0790.2012.06.014

• Analytical Chemistry • Previous Articles     Next Articles

Ligand Effects on Selective Interaction of CdTe Quantum Dots with BSA

WANG Shan-Shan, WANG Xue-Ting, GUO Ming-Ming, YU Jun-Sheng   

  1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
  • Received:2011-06-22 Online:2012-06-10 Published:2012-06-10

Abstract: Five water-soluble CdTe quantum dots(QDs) were synthesized using thioglycolic acid(TGA), 3-mercaptopropionic acid(MPA), 1-thioglycerol(TG), L-cysteine(L-cys) and glutathione(GSH) as stabili-zers, respectively. The interaction of CdTe QDs with bovine serum albumin(BSA) was studied by UV-Vis absorption and photoluminescence spectroscopy. Experimental results demonstrated that fluorescence of BSA could be markedly quenched by all these five CdTe QDs in Tris-HCl buffer solution(pH=7.40). The quenching ability of CdTe QDs to BSA is as GSH>L-cys>TGA>TG>MPA in the order of ligands. However, when BSA was added into CdTe QDs solution, five CdTe QDs exhibited apparently selective responses to BSA. As the concentration of BSA increased, fluorescence intensity of CdTe QDs capped by TGA and MPA were both significantly enhanced firstly, then declined sharply. Under the same experimental conditions, fluore-scence intensity of L-cys-capped CdTe QDs was significantly quenched by BSA, and that of TG-capped CdTe QDs was only slightly quenched by BSA. While almost no change of GSH-capped QDs fluorescence was observed in the presence of BSA. These results indicated that ligand molecular structure of CdTe QDs played an important role in the interaction between BSA and CdTe QDs. Time-resolved luminescence dynamics suggested that the ground state complex of BSA and CdTe QDs could form by electrostatic interaction. Possible interaction mechanism of BSA with CdTe QDs was proposed based on the molecular structure of ligands.

Key words: CdTe quantum dots(QDs), Ligand effect, Bovine serum albumin(BSA), Selective interaction, Photoluminescence

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