Effect of chitosan deacetylation degree on surface properties and fibrinogen adsorption of alginate/chitosan microcapsules

The surface charge, wettability and roughness of ACA microcapsule membranes were firstly analyzed by streaming potential, contact angle and surface profile measurement. The effect of surface properties on the amount and conformation of fibrinogen adsorbed onto ACA microcapsules was then studied. The results show that there are a negative Zeta potential of ACA microcapsules which decrease with decreasing in chitosan deacetylation degree, indicating less positively charged groups on the surface. The surface wettability of ACA membranes made of chitosans with degree of deacetylation range from 60% to 90% has no statistical difference. ACA membranes have a granular structure surface. The surface roughness decreases with decreasing in chitosan deacetylation degree. Fibrinogen molecules are arranged on the surface of ACA microcapsules in a mixture of side-on and end-on configurations. With the decreasing in deacetylation degree of chitosan, the amount of protein adsorbed decreases, and more fibrinogen molecules adsorbed are in end-on configuration in this case. The results indicate that the surface properties of ACA microcapsules made of chitosans with different deacetylation degree have great effect on the amount and configuration of fibrinogen adsorbed.