Synthesis Of Diblock Spherical Polymer Brushes And Research On The Interaction With Protein

The adsorption and release of proteins on the surface of biological materials play a vital role in biomedical relevant applications.Spherical polymer brushes have high stability and large specific surface area,which are ideal protein carrier.Among them,the diblock polymer brushes combine two kinds of polymer chains with different results and functions,which could achieve controlled protein adsorption through proper structure design and optimization.Negatively charged poly(acrylic acid)(PAA)can adsorb a large amount of protein through electrostatic interaction.Poly(N-2-hydroxyethyl acrylamide)(PHEAA)is a hydrophilic and non-ionic polymer with excellent resistance to protein adsorption.Controllable protein adsorption could be achieved by combining these two polymers in diblock spherical polymer brushes system and controlling the block chain length.Our research contents and results include:(1)Nano-spherical poly(acrylic)-b-poly(N-2-hydroxyethyl acrylamide)(PSV@PAA-b-PHEAA)and poly(N-2-hydroxyethyl acrylamide)-b-poly(acrylic acid)(PSV@PHEAA-b-PAA)are based on PSV core which is copolymer of styrene and photoiniferter.These polymer brushes are prepared by surface-initiated photoiniferter-mediated polymerization(SI-PIMP).We explored the morphology and size by Transmission Electron Microscope(TEM)and Dynamic Light Scattering(DLS)and characterized the block structure by Fourier Infrared Spectroscopy(FTIR)and elemental analysis.(2)The measurement results of DLS and Zeta potential show the behavior of the structure of PSV@PAA-b-PHEAA as a function of pH value and the results of elemental analysis showed large differences,which are due to the combined effect of electrostatic repulsion and steric hindrance.The block sequence also affects the electrostatic interaction and steric hindrance.The apparent graft density decreases when the block is in the outer layer.The electrostatic force between chains decreases,and the steric hindrance also decreases.(3)High-resolution turbidimetric titration and DLS are used to study the interaction between bovine serum albumin(BSA)and diblock spherical polymer brushes.For PSV@PAA-b-PHEAA,PHEAA block weakens the adsorption of BSA at high pH conditions and hinders the release of BSA under low pH conditions.For the PSV@PHEAA-b-PAA system,PAA block is in the outer layer,the apparent graft density is significantly reduced.Therefore,the adsorption with BSA is also significantly reduced.The experimental results of diblock spherical polymer brushes show that protein adsorption could be adjusted by the introduction of PHEAA and the change of apparent graft density of PAA.