Studies On The Interaction Between Nanoparticles And BMP-2and The Applications Of Nanoparticles/BMP-2Mixture System

As the excellent performance of bone morphogenetic protein-2in the field of bone repair, large numbers of studies about carrier material, drug and controlled-release system, biomechanism were carried on. The surface plasmon resonance of noble metallic nanophase materials is a hot research direction in recent years. It was applied to the detection of biological macromolecules, the immune response studies, and was becoming a very useful technique in the study of biological macromolecules or small molecules that react with biological macromolecules.This dissertation mainly focused on interaction between nanoparticles and BMP-2in nanospheres/BMP-2mixture system and nanocubes/BMP-2mixture system. At the same time, a preliminary study LSPR sensor based on silver nanospheres and a kind of fluorescence enhancement substrate based on silver nanospheres or silver nanocube were studied. The main research contents are as follows.Silver nanospheres approximately50-60nm in average diameter and silver nanocubes approximately100-120nm in average edge length were prepared. And the interaction between these two kinds of nanoparticles and the BMP-2was also studied. Zeta potential and particle size analysis results showed that, silver nanospheres was easier to combine with BMP-2than nanocubes in aqueous phase, in the meantime the dispersed phase are in stable condition within a certain range of concentration. The UV absorption spectra results indicated that, the LSPR peak of silver nanospheres or silver nanocube was weakened after the BMP-2binding to the surface of the nanospheres. Especially when BMP-2binding to the surface of the nanospheres, free electron on the surface of nanospheres transfer to BMP-2,and the density electron on the surface of silver nanospheres changes, then the change of dielectric environment on the surface cause the red shift of the plasma resonance absorption peak. The fluorescence spectroscopy results showed that, the fluorescence intensity of BMP-2has been enhanced by the silver nanospheres and silver nanocubes, with the maximum enhanced multiples of1.5and2.8. The apparent equilibrium constant results also indicated that the silver nanospheres was easier to combine with BMP-2than nanocubes. Circular dichroism spectra results indicated that, the interaction between silver nanospheres and BMP-2made a reduction of hydrophobic structure in the second level structure of BMP-2and the protein became more hydrophilic. Which was different that the interaction between silver nanocubes and BMP-2only made a small change in the content of folded segment. Comprehensive various phenomena upon, this dissertation considered that, Silver nanoparticles combined with BMP-2was the result of electrostatic interactions and the Ag-S bond, and the electrostatic interaction had a big portion in the comprehensive results. But the Ag-S bond was the major influence factors of silver Nanocube combined with BMP-2.A LSPR sensor basen on silver nanospheres/BMP-2aqueous system was prepared which can be used to detect the concentration of BMP-2. A kind of BMP-2fluorescence Enhancement substrate was prepared. It was based on self-assembled silver nanospheres or silver nanocubes with a enhanced multiples of1.2or3.0.