title: Rapidly recovering hydrogel scaffolds from self-assembling diblock copolypeptide amphiphiles.
abstract: Protein-based hydrogels are used for many applications, ranging from food and cosmetic thickeners to support matrices for drug delivery and tissue replacement. These materials are usually prepared using proteins extracted from natural sources, which can give rise to inconsistent properties unsuitable for medical applications. Recent developments have utilized recombinant DNA methods to prepare artificial protein hydrogels with specific association mechanisms and responsiveness to various stimuli. Here we synthesize diblock copolypeptide amphiphiles containing charged and hydrophobic segments. Dilute solutions of these copolypeptides would be expected to form micelles; instead, they form hydrogels that retain their mechanical strength up to temperatures of about 90 degrees C and recover rapidly after stress. The use of synthetic materials permits adjustment of copolymer chain length and composition, which we varied to study their effect on hydrogel formation and properties. We find that gelation depends not only on the amphiphilic nature of the polypeptides, but also on chain conformations--alpha-helix, beta-strand or random coil. Indeed, shape-specific supramolecular assembly is integral to the gelation process, and provides a new class of peptide-based hydrogels with potential for applications in biotechnology.
authors.affiliation: Department of Materials, University of California, Santa Barbara, California 93106, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Nowak
authors.forename: Victor
authors.initials: V
authors.lastname: Breedveld
authors.forename: Lisa
authors.initials: L
authors.lastname: Pakstis
authors.forename: Bulent
authors.initials: B
authors.lastname: Ozbas
authors.forename: David J
authors.initials: DJ
authors.lastname: Pine
authors.forename: Darrin
authors.initials: D
authors.lastname: Pochan
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Deming
mesh_terms: D001704:Biopolymers / Q000737:chemistry / Q000378:metabolism; D001709:Biotechnology; D002942:Circular Dichroism; D004573:Electrolytes / Q000737:chemistry* / Q000378:metabolism; D006358:Hot Temperature; D020100:Hydrogels / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D012212:Rheology; D055672:Static Electricity; D013314:Stress, Mechanical
chemical_list: D001704:Biopolymers; D004573:Electrolytes; D020100:Hydrogels; D008823:Micelles; D010455:Peptides