Preparation Of Affinity Magnetic Microcarrier & Adsorption Performance

Affinity adsorption technology has been widely applied in purification field of biomacromolecule such as protein and preparation of affinity adsorbent is key to the realization of affinity adsorption. Currently natural polysaccharide polymer gel has been often used to prepare microcarrier for the good biocompatibility and activation. But the softness and poor mechanical performance of polysaccharide gel restrict the preparation application. Magnetic affinity adsorption technology prepares composite microcarrier by polysaccharide gel wrapping magnetic particle, which can improve the mechanical performance of microcarrier and endow microcarrier with magnetic guidance. Currently studies of magnetic affinity adsorption technology are mostly in laboratory stage and this paper aims to provide basic data and research guidance for the preparation application.This paper prepared magnetic agarose microcarrier with core-shell structure by the reversed-phase emulsion embedding method, of which volume average particle diameter was 53.571μm. The microcarrier was activated and coupled ligand to prepare magnetic affinity adsorbent. Then the adsorption performance of affinity adsorbent was investigated using trypsin for model protein. Also adsorption process was optimized and adsorption process mechanism was studied.The study results showed that when trypsin was adsorbed to magnetic affinity adsorbent in 0.1mol/LTris-HCl adsorption buffer solution (pH7.8) and desorbed in 1.0mol/LKCl-0.01mol/L acetic acid (pH3.0) at 30℃, adsorption capacity was 40.45mg/g, purified fold was 5.35, recovery was 93.06%. Affinity adsorption equilibrium of trypsin conformed to Langmuir adsorption isothermal model. Affinity adsorption dynamics conformed to pseudo-second-order kinetics model and adsorption rate decreased with the increase of ionic strength of adsorption buffer solution.This paper studied magnetically stabilized expanded bed and applied it to affinity purification of trypsin. The study results showed that magnetic affinity adsorbent had good expansion performance and low backmixing degree in the magnetically stabilized expanded bed. When magnetic field intensity was 400Gs and fluid flow rate was 105cm/h, bed voidage and dynamic adsorption capacity of trypsin was high and fluid through the bed approximately flowed in plug-flow profile. This study established base for process optimization and scale amplification of magnetically stabilized expanded bed adsorption technology.