Synthesis Of The Amphipathic Protein-Polymer Hybridsand Their Self-Assembly

Protein is biological macromolecules with complicated structure. Due to its good biocompatibility,it is used in many fields of biomedical materials. However, the properties in different environments limit the application promotion such as solubility, retention time, stability and so on. Protein modification is an effective way to broaden its applications.Poly(methylmethacrylate)(PMMA) is a stable hydrophobic polymer. Bulk polymerization and emulsion polymerization have been used to prepare PMMA in the industry. The products are called plexiglass, which had good transparency and processability, and are widely used in the field of coatings industrys and optical materials. Meanwhile, PMMA has good biocompatibility so it is used in the biomedical by way of hemodialysis dialysis membrane. The synthetic polymer PMMA combined with protein to prepare protein-polymer hybrid materials by surface “grafting to”. The material can be both of the biocompatible and self-assembly properties. They would be expected to use as intelligent drug delivery.In this paper, we prepared the controllable molecular weight and end-functionalized PMMA by atom transfer radical polymerization(ATRP), and explored the synthesis conditions of grafting bovine serum albumin(BSA) to synthesis amphiphilic BSA-PMMA hybrid. We the self-assembly behavior of BSA-PMMA hybrids through 1H-NMR, gel permeation chromatography(GPC), sodium saltpolyacrylamide gel electrophoresis(SDS-PAGE), scanning electron microscope(SEM), transmission electron microscopy(TEM).Firstly, the end-functionalized PMMA was synthesized using 2-bromo-isobutyric N-hydroxysuccinimide ester(NHS-BIBA) as ATRP initiator, CuBr as catalyst and N,N,N',N,''- penta methyl diethylene triamine(PMDETA) as ligand in the acetone reaction. The initiator and polymer were characterized by 1H-NMR and GPC. The results showed that the ATRP initiator and controllable molecular weightend-functionalized PMMA were synthesized successfully.Secondly, We studied the amphipathic BSA-PMMA hybrids which was prepared by the hydrophilic BSA and hydrophobic PMMA. We explore the optimal conditions for the synthesis of BSA-PMMA hybrid. The SDS-PAGE test showed that BSA-PMMA hybrid was prepared under acetone : water = 1:25, pH=5 condition.Finally, the self-assembly behavior of BSA-PMMA hybrids was investigated by dynamic light scattering(DLS), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The results of the DLS showed that amphiphilic BSA-PMMA hybrids self-assembled into micelles in solution. The particle size of micelles increased with the increasing of the molecular weight and proportion of polymer in hybrids.The Zeta potential of the colloid solution was-44.5mv which revealed that the stability of the colloidal solution was well. From the SEM pictures, distinct vesicular structures(diameter of about 500nm), rod-like structure and a film-like structure were observed clearly. The results indicated that the surface of self-assembled micelles can be formed by a secondary fusion complex spatial structure. The TEM showed that the amphiphilic BSA-PMMA hybrid self-assembled micelles had fluidity outer wall.