Improving Stability and Biocompatibility of Alginate/Chitosan Microcapsule by Fabricating Bi-Functional Membrane

Cell encapsulation technology holds promise for the cell-based therapy. But poor mechanical strength and biocompatibility of microcapsule membrane are still obstacles for the clinical applications. A novel strategy is presented to prepare AC(1)C(2)A microcapsules with bifunctional membrane (that is, both desirable biocompatibility and membrane stability) by sequentially complexing chitosans with higher deacetylation degree (C-1) and lower deacetylation degree (C-2) on alginate (A) gel beads. Both in vitro and in vivo evaluation of AC(1)C(2)A microcapsules demonstrate higher membrane stability and less cell adhesion, because the introduction of C-2 increases membrane strength and decreases surface roughness. Moreover, diffusion test of AC(1)C(2)A microcapsules displays no inward permeation of IgG protein suggesting good immunoisolation function. The results demonstrate that AC(1)C(2)A microcapsules with bi-functional membrane could be a promising candidate for microencapsulated cell implantation with cost effective usage of naturally biocompatible polysaccharides