The Toxicity Evalution Of Nano-particles Target To BSA

Nano-material displays an amazing potential in almost every areas because of its uniquephysical and chemical properties. With the reduction of production costs and the continuousdevelopment of new technologies, more and more nano-materials come into people’s lives,but some reports of the toxicity of nano-materials emerge followed. In recent years, numbersof studies show that nanoscale substances have potential biological risk. They can travelthrough the blood-brain and so on, and do harm to human health through a variety of ways.Proteins are important material foundations of life activities and major component ofliving organisms. Various toxic and harmful substances come into human bodies ofteninteract with the biological macromolrcule to show their harmfulness. Therefore, study theinteraction between nanoparticles and biological macromolecules （such as proteins） atfunctional macrobiomolecular level, research the influence of nanoparticles on biologicalmacromoleculars’ structure and funciton will provide important references about the toxicityof nanomaterials on the body and will have significant implications on establish new andreliable evaluation method of nanoparticles toxicity. Also, these researches are propitious tothe widely use of nano-materials.In this paper, we studied the toxicity mechanism of nano-ZnS, nano-Al₂O₃, nano-ZnCO₃and nano-SiO₂targeted to bovine serum albumin （BSA） in molecule level by themethods of resonance light scattering （RLS） spectroscopy, fluorescence spectroscopy,ultraviolet spectra （UV）, circular dichroism （CD） spectroscopy and cyclic voltammetry. TheRLS result shows that nano-ZnS and BSA can aggregate together, making the particle sizeincrease, and the RLS intensity stronger. Fluorescence data revealed that the binding constantis2.622×10³and the number of binding sites is0.706, and the conjugating ratio was1:1.Results of UV spectra, CD spectroscopy and cyclic voltammetry showed that ZnS couldincrease the amount of helix and decrease the beta sheet structure, leading to a loosening ofthe protein skeleton.In the second part, the toxic effect of nano-Al₂O₃on BSA was thoroughly studied.Results showed that Al₂O₃and BSA can aggregate together and the RLS intensity stronger.The fluorescence spectrometry indicates that the conjugating ratio of BSA and nano-Al₂O₃was1:1and the binding constant was7.36×10². From the cyclic voltammograms, we foundthat an electrochemically non-active complex could have been formed. The addition ofnano-Al₂O₃can cause conformational change of BSA, and has the strongest genotoxicityinteraction intensity at the concentration of2.0×10^-7mol/L. The environmental toxic behavior of nano-ZnCO₃to BSA was examined. RLS andcyclic voltammetry results showed that ZnCO₃and BSA can aggregate together and the RLSintensity stronger. Fluorescence data revealed that the binding constant is4.333×10⁵and thenumber of binding sites is1.08877. Results of UV spectra and CD spectroscopy also showedthat ZnCO₃could increase the amount of helix and decrease the beta sheet structure, leadingto a loosening of the protein skeleton.In the last part, we studied the toxicity mechanism of nano-SiO₂targeted to BSA.Results showed that SiO₂and BSA can aggregate together and the RLS intensity stronger.Fluorescence data revealed that the binding constant is3.892×10⁶and the number of bindingsites is1.2687. Results of UV spectra and CD spectroscopy also showed that SiO₂couldincrease the amount of helix and decrease the beta sheet structure, leading to a loosening ofthe protein skeleton.