Preparation Of Magnetic Spherical Polyelectrolyte Brush And Its Separation Of ACEI

Magnetic nano polyelectrolyte brush has the characteristics of both polyelectrolyte and high specific surface area.It can adsorb and fix biomolecules in solution,which has been widely concerned by scholars in related fields.In this paper,the magnetic spherical polyelectrolyte brush（MSPB）was prepared by heat induced atom transfer radical polymerization and light induced atom transfer radical polymerization,which was used to adsorb bovine serum albumin（BSA）and angiotension converting enzyme inhibitory peptide（FFVAP）,and the adsorption mechanism was discussed.The binary simulation system was established by mixing BSA and FFVAP.The adsorption properties in the mixed simulation system provide a theoretical basis for the separation and purification of ACE inhibitory peptide.The main research contents are as follows:MSPB was prepared by heat induced ATRP and light induced ATRP.After a series of characterization,such as laser nanoparticle size analyzer,X-ray powder diffractometer and Fourier infrared spectrometer,the target product was determined.The chain length of MSPB（TI-MSPB）prepared by thermal induced ATRP method is 40 nm,the grafting density is 0.2259μmol?m^-2,the grafting weight is 135 mg?g^-1,the molecular weight is 13813.68 g?mol^-1,the chain length of MSPB（PI-MSPB）prepared by light induced ATRP method is 90 nm,the grafting density is 0.2744μmol?m^-2,the grafting weight is 180 mg?g^-1,the molecular weight is 15998.89 g?mol^-1.The superparamagnetic MSPB with special structure was prepared.Compared with the polymer brushes prepared by photo induced ATRP,it is found that the MSPB prepared by photo induced ATRP has longer chain length,higher grafting density,more grafting amount,higher molecular weight and less reaction time.The adsorption properties of TI-MSPB and PI-MSPB for BSA were studied.The results showed that the concentration of BSA was 0.4 mg?m L^-1,the time was 3 h,the temperature was 30℃,the concentration of PBS was 0.1 mol?L^-1,p H=7.The adsorption capacity of TI-MSPB and PI-MSPB for BSA was 1.51μmol?g^-1,and 1.06μmol?g^-1 for PI-MSPB.Different concentrations of salt solution can make BSA desorbed from MSPB.After repeated experiments,TI-MSPB has excellent reuse rate of 89.2%,and PI-MSPB has excellent reuse rate of 83.2%.Through zeta potential analysis,fluorescence spectrum analysis and microcalorimetry analysis,it was found that the binding of MSPB to BSA was a static quenching mechanism,and MSPB formed a complex with BSA.The adsorption process is a spontaneous process of endothermic and entropy increasing.The fitting results of isothermal adsorption Langmuir equation showed that the adsorption of BSA by mspb was monolayer adsorption.Before the adsorption equilibrium,the adsorption process conforms to the pseudo first order kinetic model,and the adsorption rate is controlled by BSA concentration.After the adsorption reaches equilibrium,the adsorption rate is controlled by BSA concentration and mspb concentration.The whole adsorption process conforms to the quasi second order kinetic equation model.The adsorption properties of TI-MSPB and PI-MSPB for FFVAP were studied.The results showed that the adsorption capacity of TI-MSPB for FFVAP and PI-MSPB for FFVAP and PI-MSPB were 79.03μmol?g^-1 and 111.78 respectively.BSA and FFVAP were prepared into binary simulation system to investigate the adsorption and separation effect of MSPB for small molecular peptide FFVAP.The adsorption capacity of MSPB for FFVAP was greater than that for BSA,and the adsorption performance of PI-MSPB for FFVAP was better than that of TI-MSPB.Repeated experiments showed that the repeated adsorption rate of TI-MSPB and PI-MSPB were 36.36%and 42.85%,respectively.The results of zeta potential analysis,fluorescence spectrum analysis and microcalorimetry analysis show that the driving force of adsorption of FFVAP by MSPB is electrostatic attraction,which belongs to static quenching.The complex of FFVAP and MSPB was formed.The adsorption process is a spontaneous process of exothermic and entropy increasing.The results of Freundlich equation showed that the adsorption of FFVAP by MSPB was multi-layer adsorption.The adsorption process before adsorption equilibrium was in accordance with the quasi first-order kinetic model,and the adsorption rate was controlled by the concentration of FFVAP.After the adsorption reached equilibrium,the adsorption rate was controlled by both FFVAP concentration and MSPB concentration.The whole adsorption process followed the quasi second-order kinetic equation model.The long-chain structure of MSPB will form larger steric hindrance and semi permeable structure,which will hinder the adsorption of BSA by MSPB.The changes of thermodynamic enthalpy,entropy,Gibbs free energy and binding site analysis show that MSPB preferentially adsorbs FFVAP in the simulated system,so MSPB can be used as a carrier for the separation and purification of ACE hypotensive peptide.