Interaction Of CdTe Quantum Dots And Drug With Proteins By Fluorescence Spectroscopy

The thiolglycolic acid (TGA)-capped CdTe quantum dots are successfully synthesized in aqueous solution in this work. We discuss the influences of reaction time, concentration ratio and pH on preparation process and to obtain the optimal operating conditions. After that, the interaction between CdTe QDs and proteins were studied by fluorescence spectrometry.The prepared CdTe QDs were characterized by X-ray powder diffraction (XRD), UV-visible absorption spectroscopy (UV-vis), photoluminescence spectroscopy (PL), circular dichroism spectrum (CD) and transmission electron microscopy (TEM) to study their structures, properties、morphology and optical properties. The results showed that CdTe QDs prepared in aqueous solution have excellent optical stability. Its average particles size was about5nm and owned a uniform particle size.We investigated the mechanism of interaction between the prepared TMBS Ⅱ and protein by spectroscopic methods at three different temperatures (293、298、303K). The results showed that the binding constants (Ka) between TBMS Ⅱ and HSA at three different temperatures (293,298,303,308K) were obtained1.00×105、0.70×105.0.51、105、0.41×105L·mol-1respectively. And according to van’t Hoff equation, the hydrogen bonds and hydrophobic interactions play a dominant role in the binding of TBMS to HSA. The results of Synchronous fluorescence spectra and CD reveal tat the conformation of HSA been turbulent. And the interaction between HSA and TMBS Ⅱ was researched in the presence of Fe34+、Cu2+、Mg2+、.Zn2+. From our study, the binding constant increased when Fe3+Cu2+、Mg2+exist, while decreased in the presence of Zn2+. The results give our insight into sustained-release drug research.In this part, we explored security of CdTe QDs. LYS with high isoelectric point of around9.5. And the result can be proved by three-dimensional fluorescence spectroscopy, from the fluorescence spectroscopy, the Rayleigh scattering peak exhibits a dramatically increase with almost2-fold after the addition of CdTe while the spectral characteristic of Trp and Tyr residues (peak b) is quenched by90%. From CD results, the a-helical structure of LYS range from26.9%to15.3%and HSA vary from37.5%to29.8%. The fluorescence change in combination with the CD spectral results suggested that the interaction between proteins and CdTe lead to the loosening and unfolding of the proteins backbone and decreases the hydrophobicity of the microenvironment of proteins.In this paper, the TGA-capped CdTe QDs were synthesized in aqueous solution, and the process condition was optimized. From spectroscopic studies, we found that the CdTe QDs HSA side-effect on HSA and LYS, which is unfavorable to human health.