Hydrogel Formation in Amphiphilic Triblock Copolypeptides

Abstract

We report the synthesis of a variety of polylysine-b-polyleucine-b-polylysine, KmLnKo triblock copolypeptides and compare their gel forming properties to diblock copolypeptides. The architecture of the KmLnKo triblock copolypeptides forces the hydrophobic α-helical oligoleucine segments to pack perpendicular to extended fibrils in lamellar structure, and the similarity in properties between diblock and triblock copolymers supports the hypothesis that both systems assemble in a similar manner. The triblock architecture, however, allows preparation of samples with greater gel strength and better salt tolerance than diblock samples at similar concentrations. We have found that block architecture provides a means for fine adjustment of hydrogel properties beyond variation of polypeptide composition, concentration, and chain length.