Fabrication Of Stimuli-responsive Polymer Protein Hybrid Materials And Their Applications As Protein Carriers

Researches on protein carriers has received more and more attention in recent years.The types of protein carriers mainly include inorganic nanoparticles,liposomes,vesicles,and nanogels.The design and synthesis of protein carriers with specific functional properties for proteins protection and transportation are of great significance.Protein carriers with special stimuli responsiveness have become research hotspots in this field due to their unique structure and performance in recent years.This paper mainly studied the preparation methods of polymer-protein hybrid nanogel with thermo-and redox-responsiveness as well as its application as a protein carrier and explored the self-assembly behavior of hyperbranched polymer-peptide complex.The specific research content are as follows:(1)A small molecule comonomer dithiodiethyl methacrylate(HODMA)with a hydroxyl group and a disulfide bond was designed and synthesized,a thermo-responsive polymer diethanol methacrylate was selected as a copolymerization monomer,and a binary linear random copolymer was prepared by reversible addition fragmentation chain transfer(RAFT)polymerization method,and then the polymer was modified to afford the polymer with 4-nitrophenyl carbonate groups.A polymer protein hybrid nanogel was prepared through the reaction between the amino groups of the protein and the carbonate groups of the polymer.The lipase was used as the cross-linking agent.The ratio between the polymer and protein was adjusted to obtain the nanogels with different sizes and therom-responsiveness.The nanogel’s activity,cytotoxicity,redox responsiveness,encapsulation efficiency and loading efficiency were investigated.The nanogel can be broken under reducing conditions,so that the protein was released again,and the activity was also restored,and there were no residual groups.The nanogel can maintain high activity under the high temperature and acid conditions,which may have potential applications on the delivery of protein drugs and traceless release.(2)On the basis of the previous study,a greater degree of diethanol methacrylate were selected,therefore the LCST of the polymer were greatly improved and solved the problem of the participation of organic solvents in the previous study.The entire experiment process were completed in the water system,which greatly reduced the toxicity of the nanogels.The Bovine serum albumin(BSA)and lysozyme(lysozyme)were selected as the template proteins.Nanogels with transition temperature closed to body temperature were successfully prepared.The related properties such as activity,redox responsiveness,encapsulation efficiency,loading refficiency,etc.,which made a good foundation for the protein protection and traceless release.(3)A series of hyperbranched polymers with different monomer ratios,branching degrees,and molecular weights were successfully prepared through a photoinduced atom transfer radical polymerization(ATRP)without metal participation at room temperature.Thermo-responsive methacrylate monomers were chosen to prepare hyperbranched polymers.After that,the hyperbranched polymers were further polymerized with the dithiopyridine-containing(pyridyl disulfanyl)ethylmethacrylate(PDSMA)monomer and then reacted with glutathione through the exchange reaction of thiol and disulfide bonds to prepare a hyperbranched polymer with peptides.The self-assembly of the hyperbranched polymers were explored,which have a certain foundation for exploring the applications of hyperbranched polymer-peptide complex in biology.