Reversible Hydrogels from Self-Assembling Artificial Proteins

• Published in: Science (American Association for the Advancement of Science) Vol. 281; no. 5375; pp. 389 - 392
• Main Authors: Petka, Wendy A., Harden, James L., McGrath, Kevin P., Wirtz, Denis, Tirrell, David A.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 17.07.1998; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Amino acids; Aqueous solutions; Biological and medical sciences; Biotechnology; Carrier Proteins - chemistry; Carrier Proteins - isolation & purification; Chemical engineering; Chemical Phenomena; Chemistry, Physical; Circular Dichroism; Climate; Deoxyribonucleic acid; Dimerization; DNA; Electrolytes; Fundamental and applied biological sciences. Psychology; Gelation; Gels; Genes, Synthetic; Genetic engineering; Hydrogel, Polyethylene Glycol Dimethacrylate; Hydrogels; Hydrogen-Ion Concentration; Inhalants; Leucine Zippers; Liquids; Methods. Procedures. Technologies; Molecular Sequence Data; Networks; Physiological aspects; Polyethylene Glycols - chemistry; Polyethylene Glycols - isolation & purification; Polymers; Protein biosynthesis; Protein Engineering; Protein Folding; Protein Structure, Secondary; Protein synthesis; Proteins; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Spectroscopy; Synthesis; Temperature; Viscosity; Protein engineering; Temperature; Gelation; pH; Reversible reaction; Hydrogel; Recombinant protein; Release; Physicochemical properties
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.281.5375.389

Recombinant DNA methods were used to create artificial proteins that undergo reversible gelation in response to changes in pH or temperature. The proteins consist of terminal leucine zipper domains flanking a central, flexible, water-soluble polyelectrolyte segment. Formation of coiled-coil aggregates of the terminal domains in near-neutral aqueous solutions triggers formation of a three-dimensional polymer network, with the polyelectrolyte segment retaining solvent and preventing precipitation of the chain. Dissociation of the coiled-coil aggregates through elevation of pH or temperature causes dissolution of the gel and a return to the viscous behavior that is characteristic of polymer solutions. The mild conditions under which gel formation can be controlled (near-neutral pH and near-ambient temperature) suggest that these materials have potential in bioengineering applications requiring encapsulation or controlled release of molecular and cellular species.