Page - (000250) - in Biomedical Chemistry: Current Trends and Developments

Fmoc-peptides, self-complementary ionic peptides and hairpin peptides, among others (Matson & Stupp, 2012; Ischakov, 2013). The peptide-based hydrogels are developed through molecular self- assembly of peptides and their derivatives present several advantages over other polymeric gelators. These hydrogels are formed without the use of potentially hazardous chemicals that could affect their biocompatibility. They also comprise nanofibrous networks which imitate the structural architecture of natural ECM. Finally, molecular self-assembling systems can also incorporate features that enhance the overall hydrogel properties (Johnstone, 2013). Short peptide building blocks are easy to manufacture in large quantities and can also be chemically decorated with biologically-active components, facilitating the design of hydrogels with improved targeting and in vivo stability (Zhou, 2009; Ischakov, 2013). A large number of self-assembling materials responsive to biologically relevant stimuli, such as pH or temperature, are being developed based on small molecular building-blocks (Table 3.1.3). Aggeli and colleagues have designed short β-sheet forming peptides that self-assemble into a variety of nanostructures with tunable physical and chemical properties (Aggeli, 2003). Pochan and colleagues have developed β-hairpin peptides that fold to acquire an intramolecular amphiphilic structure to form self-assembled hydrogel networks (Pochan, 2003). Recent studies demonstrated that self-assembled peptides can be used to mimic the structure of natural ECM fibers and to trigger physiological processes in cells. The design of self-assembled scaffolds that can act as anchors to the cultured cells can be achieved by incorporation of short adhesive motifs into the fibers of the backbone of a synthetic ECM-like matrix (O’Leary, 2011; Fleischer & Dvir, 2013). Table 3.1.3: Examples of self-assembling peptides. Peptide Sequence / References Activity β-Hairpin peptides (Loo, 2013) β-Hairpin secondary structures (two β-strands linked by a kink) can be rationally designed to self-assemble into ibrillary macromolecular scaffolds