壳聚糖-g-甲氧基聚乙二醇接枝共聚物的合成和表征及其在海藻酸钠/壳聚糖/海藻酸钠微胶囊的表面修饰

Alginate/chitosan/alginate (ACA) microcapsules made of natural polysaccharides have been widely investigated for cell transplantation because of their non-immunogenic, non-toxic, and biodegradable properties. However, protein adsorption onto the surface of microcapsules will happen after a long-term transplantation in vivo. Polyethylene glycol (PEG) with the unique properties of hydrophilicity, flexibility, shielding of substrate charges, and large exclusion volume has been widely used to reduce protein adsorption. Among the many approaches used to immobilize PEG on surfaces, PEG-grafted copolymers have been shown to spontaneously adsorb to oppositely charged surfaces. The high graft density will make the PEG side-chains like brushes extend from the surfaces to prevent protein adsorption [1]. Therefore, the aim of this work is to study the effects of the molecular weight of Methoxy-PEG (MPEG) and chitosan, the degree of substitution (DS) of the copolymers and the binding conditions on the amount of binding to make the graft density maximum