Poloxamer 188 as a Supplement to Barium Cross-Linked Ultra-High Viscosity Alginate for Immunoisolation of Transplanted Islet Cells

Abstract

elastic gels with high permeability compared to alginates with a high content of mannuronic acid [5]. Therefore, the M:G ratio, length of polymeric chains, and ratio of homologous to heterologous chains must be carefully tuned to optimize the microcapsules [6].A lack of standardization and information from manufacturers about the composition of the alginate (e.g., molecular weight, content, and ratio of D-mannuronic acid and L-guluronic acid) is a major problem for encapsulation experiments; this knowledge is of enormous importance for understanding the physico-chemical characteristics and hence biocompatibility of the alginate. Ba 2+ -gelled capsules comprised of 1:1 mixtures of UHV alginates from the closely related species Lessonia nigrescens and Lessonia trabeculata meet the demands of high stability and flexibility (UHV: 35% M and 65% G) [7].The aims of the current study were 1) to improve the physical features of barium cross-linked UHV alginate by the addition of Poloxamer 188 (P188) as a detergent, and 2) to establish the muscle as a novel transplantation site.Poloxamer is comprised of ABA-type block polymers that consist of a central, hydrophobic block of polypropylene oxide that is edged by two hydrophilic blocks of polyethylene oxide. Poloxamer 188 (P188),