The Study Of The Interaction Between Nanoparticles And Bovine Serum Albumin By Spectroscopic Techniques

In recent decades,the research on the binding of nanoparticles and bovine serum albumin has become a hot topic in the research of life,biology and physical sciences.The use of inorganic nanoparticles?silica nanoparticles?and metal nanoparticles?silver nanoparticles?as drug carriers for potential risks in vivo is still worth studying.Spectroscopic techniques are used to study the binding of the above two kinds of nanoparticles and proteins,which provides theoretical guidance for the development of new nanomedicine,biosensor,drug delivery,imaging and new functional materials.In this study,the relationship between the surface charge density and the size of nanoparticles is firstly studied,and the best particle sizes for experiments conditions are selected.UV-visible absorption spectroscopy,steady-state fluorescence spectroscopy,and time-resolved fluorescencespectroscopy were used to systematically study the binding interaction between nanoparticles and bovine serum albumin.The main contents are as follows:?1?The relationship between surface charge density and particle size of negatively charged silica nanoparticle has been studied.The Zeta potential values measured by experiment were subdivided into two models?Poisson Boltzmann model and surface complexation model?,then the corresponding surface charge density was obtained.The results showed that the absolute value of Zeta potential increased with the increase of nanoparticle size,and then tended to be stable.When the size of the nanoparticles increases gradually,the absolute value of the surface charge density tends to be stable.When the particle size is greater than 30 nm,the surface charge density is almost independent of the size.Therefore,it is better to choose the size of silica nanoparticle more than 30nm?like 60nm,250nm and 500nm?,which is not affected by surface charge density.?2?The steady-state fluorescence of negatively charged silica nanoparticle?with 3 kinds of different particle size?with aromatic amino acids?tryptophan,tyrosine and phenylalanine?and bovine serum proteins were studied.The study shows that silica nanoparticle has a slight effect on the microenvironment of tryptophan and tyrosine,with the increase of the size of the particle size,the influence is increasing first and then decreasing.For phenylalanine,silica nanoparticle has little effect on its fluorescence intensity.With the addition of silica nanoparticle in the BSA solution,the hypochromic effect and fluorescence quenching can be produced.With the increase of particle size,the strength of the nanoparticles increases first and then decreases.?3?Using steady-state fluorescence and time-resolved fluorescence spectra of positively,we measured interaction of one kind of particle size?about 20 nm?positively charged silver nanoparticles and tryptophan,tyrosine and phenylalanine and bovine serum albumin.The effects of temperature on the fluorescence life of silver nanoparticles and bovine serum albumin were investigated.The study shows that when the silver nanoparticles were added,the microenvironment of bovine serum albumin in the 212^thh tryptophan residues was changed simultaneously,and the fluorescence quenching type was static quenching.The silver nanoparticles changed the microenvironment of BSA in 212^thtryptophan residues,thereby increasing the exposure of 212^thh tryptophan residues and 134^thh tryptophan residues.The 212^thh tryptophan residue may be the target of nanoparticles.