Microwave synthesis of CdTe/TGA quantum dots and their thermodynamic interaction with bovine serum albumin

Abstract

The thioglycollic acid (TGA) as a capping agent, CdTe/TGA quantum dots (QDs) with excellent properties were synthesized under microwave irradiation. The TGA/Cd/Te molar ratios, reaction time, temperature and pH are the crucial factors for properties of QDs. The QDs were characterized by UV-vis absorption and fluorescence spectra, transmission electron microscopy and Fourier transform infrared spectroscopy. The experimental results show that when the pH value is 11.5 and molar ratio of TGA:Cd:Te is 1.2:1:0.4 at 100 °C heating for 15 min, the resulted QDs exhibit a high fluorescence quantum yield of 78%. The fluorescence full width at half maximum (FHMW) of QDs is around 23 nm. The products are spherical with average size of 3-5 nm. There is a strong coordination effect between TGA and Cd²⁺. Moreover, the results of interaction between as-made QDs and bovine serum albumin (BSA) suggest that the QDs-BSA binding reaction is a static quenching. The negative values of free energy (△G<0) suggest that the binding process is spontaneous, △H<0 and △S<0 show that hydrogen bonds and van der Waals interactions play a major role in the binding reaction between QDs and BSA.

Keywords

microwave synthesis / CdTe/TGA quantum dots / bovine serum albumin / interaction / thermodynamics

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