[Investigation of exogenous stimulus effect on the interaction of CdSe/ZnS quantum dots/TiO2 nanocomposites with human serum albumin by resonance light scattering].

The interaction between CdSe/ZnS(quantum dots)/TiO2 nanocomposites and human serum albumin(HSA) was investigated by resonance light scattering (RLS) spectroscopic methods under approximate physiological conditions. Much important information of the interaction between CdSe/ZnS(Quantum Dots)/TiO2 nanocomposites and HSA was obtained by studying comprehensively the Exogenous influence factors of nanocomposites concentration, pH, NaCl concentration, reaction temperature, detection time, coexisting ions, surfactants, sequence of adding to the sample etc. It was showed that the new formation of complex system is likely to enhance the protein hydrophobic cavity and tend to focus the hydrophobic interface in aqueous solution, resulting in strengthening the intensity of resonance light scattering; Also it is very sensitive to the changes in the pH value in the system; The sensitivity of I(RLS) in system can be increased by the appropriate NaCl concentration; The value of IRLS in system would be changed with the change in the concentration of coexisting ions; The value of I(RLS) in system is basically stable when the reaction time reaches 5 min; The value of I(RLS) in system is not exactly the same with a surfactant, and strong electrostatic interaction has occurred between oppositely charged surfactant and nano composites; It is obvious that the value of I(RLS) in complex system is affected by the sequence of adding to sample; It has the incomplete monotonically increasing trend with the changes in temperature. The information is useful for providing theoretical supporting for the mechanism of interaction between nanomaterials and bio-macromolecule, and for understanding the biocompatibility and safety of nano-materials.

Toxicity of CdTe QDs with different sizes targeted to HSA investigated by two electrochemical methods.

QDs have large scale application in many important areas with potential of unintentional exposure to the environment or organism during processing of a nanotechnology containing product's life cycle. In this paper, two classical electrochemical methods, cyclic voltammetry and electrochemical impedance spectroscopy were applied to investigate the influence of particle sizes of CdTe QDs on their toxicity targeted to human serum albumin (HSA) under simulative physiological conditions. The results show that the toxicity of yellow emitting QDs (YQDs) on HSA is slightly stronger than that of the green-emitting (GQDs) and red-emitting QDs (RQDs). We also compared these two classical electrochemical methods with the traditional fluorescence spectroscopy through the above results. The electrochemical methods may be more accurate and comprehensive to investigate the toxicity of QDs at the biomacromolecular level under certain conditions, though fluorescence spectroscopy is simpler and more sensitive.

Studies on the interaction between Oxaprozin-E and bovine serum albumin by spectroscopic methods.

The interaction between Oxaprozin-E and bovine serum albumin (BSA) was studied by spectroscopic methods including fluorescence and UV-vis absorption spectroscopy. The quenching mechanism of fluorescence of BSA by Oxaprozin-E was discussed to be a dynamic quenching procedure. The number of binding sites n and apparent binding constant K was measured by fluorescence quenching method. The thermodynamics parameter DeltaH, DeltaG, DeltaS were calculated. The results indicate the binding reaction was mainly entropy-driven and hydrophobic forces played major role in the binding reaction. The distance r between donor (BSA) and acceptor (Oxaprozin-E) was obtained according to Förster theory of non-radioactive energy transfer.

Interaction of an organic selenium compound with human serum albumin: a spectroscopic study.

The interaction between 4,4'-diselenadibenzoic acid and human serum albumin (HSA) was investigated by fluorescence and absorption spectroscopy. The quenching mechanism of fluorescence of HSA by 4,4'-diselenadibenzoic acid was discussed. It is proved that the fluorescence quenching of HSA by 4,4'-diselenadibenzoic acid is a result of the formation of the HSA-4,4'-diselenadibenzoic acid complex. The binding sites number n, apparent corporation constant K, and corresponding thermodynamic parameters, deltaH(theta), deltaG(theta), and deltaS(theta) were calculated. Results indicate that the electrostatic interactions forces played major role in the reaction.