title: Responsive hybrid hydrogels with volume transitions modulated by a titin immunoglobulin module.
abstract: The I28 immunoglobulin (Ig)-like module of human cardiac titin, an elastic muscle protein, was used to cross-link acrylamide (AAm) copolymers into hybrid hydrogels. Cross-linking was accomplished through metal coordination bonding between terminal histidine tags (His tags) of the I28 module and metal-chelating nitrilotriacetic acid (NTA)-containing side chains on the copolymer. In solution, the beta-sheet structure of the I28 module unfolded with a transition midpoint of about 58 degrees C as the temperature was elevated. Hydrogels cross-linked with the I28 module demonstrated positive temperature responsiveness; they swelled to 3 times their initial volume at temperatures above the melting temperature of the cross-links. Positive temperature responsiveness is unusual for synthetic hydrogels. The I28 hybrid hydrogels demonstrate that cross-linking synthetic polymers with natural, well-characterized protein modules is a practical strategy for creating new materials with unique environmental responsiveness predictably determined by the mechanical properties of the protein cross-links. These new materials may be useful for controlled chemical delivery.
authors.affiliation: Department of Bioengineering and Department of Pharmaceutics and Pharmaceutical Chemistry, 20 South 2030 East, Room 506, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Kopecek
authors.forename: R J
authors.initials: RJ
authors.lastname: Stewart
mesh_terms: D000178:Acrylamides; D000595:Amino Acid Sequence; D002614:Chelating Agents; D064211:Connectin; D003432:Cross-Linking Reagents; D006639:Histidine; D006801:Humans; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry; D007136:Immunoglobulins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000737:chemistry*; D009571:Nitrilotriacetic Acid; D011494:Protein Kinases / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D000178:Acrylamides; D002614:Chelating Agents; D064211:Connectin; D003432:Cross-Linking Reagents; D020100:Hydrogels; D007136:Immunoglobulins; D009124:Muscle Proteins; C577285:TTN protein, human; D006639:Histidine; D011494:Protein Kinases; D009571:Nitrilotriacetic Acid