Polymer Micelle And The Interactions Of Proteins Or Inorganic Materials And Its Application

Polymer micelles, whose structure can be easily designed and regulated, usally possess the features of each component, and may be used as emulsifier, drug carrier, etc. Having unique structures and potential applications in polymer science and biomedical technology, polymer micelles have aroused much ineterst in recent years. In this dissertation, by utilizing the changes in the density of interacting groups induced by the formation of micelles, we futher realized their applications as a smart protector for protein protection and an efficient nanosupport of nanoparticle catalyst. Our work mainly includes two parts:1. N-isopropylacrylamide/acrylic acid random copolymer (P(NIPAM-co-AA)) with different compositions was sected for protecting lysozyme at high temperatures. The influence of temperature on the interaction between P(NIPAM-co-AA) and lysozyme was studied, and the thermal protection ability of different P(NIPAM-co-AA) s for lysozyme was evaluated. The results show that, in the copolymer/lysozyme mixed solutions, when the molar fraction of NIPAM (MF) in the copolymer is between67.1%and99.5%, P(NIPAM-co-AA)s do not interact with lysozyme at room temperature. However, as the temperature rises above the LCSTs of the copolymers, they undergo a phase transition and form micelles with concentrated carboxyl groups on the surface. Then the copolymer micelles with aboundant negative charges on the surface strongly interact with and protect positively charged lysozyme molecules at high temperatures. If lysozyme is protected by the copolmer at MF99.5%, when the temperature drops to a mild one, the interaction vanishes due to the dissociation of micelles, and lysozyme is released to free state. Through the reversible thermal-enhanced electrostatic interaction, lysozyme can be smartly protected without hampering its contact with the substrate. It is confirmed that, under the protection of the copolymer at MF of99.5% and a concentration of1mg/mL, the enzymatic activity of lysozyme (0.14mg/mL) can be well preserved by71.0%while the unprotected lysozyme is almost denaturated after being treated under the same conditions.2. The adsorption of PEO-b-P4VP (poly (ethylene oxide)-b-poly (4-vinylpyridine)) micelles onto the surface of yttrium hydroxide nanotubes (YNTs) resulted in hybrid nanotubes with a dense P4VP inner layer and a stretched PEO outer layer surrounding YNTs. The dense P4VP layer was further stabilized by the crosslinking using1,4-dibromobutane as the crosslinker. Then, the crosslinked hybrid nanotubes (CHNTs) were used as a novel nano supporter for loading the catalyst gold nanoparticles (GNPs) within the crosslinked P4VP layer. The resultant GNPs/CHNTs were applied to catalyze the reduction reaction of p-nitrophenol. The results indicate that this novel nano supporter has the advantages such as good dispersity in the suspension, high capacity in loading GNPs (0.87mmol/g), high catalytic activity of the loaded GNPs (12.9μmol-1min-1) and good reusability of GNTs/CHNTs.