title: Preparation of keratin and chemically modified keratin hydrogels and their evaluation as cell substrate with drug releasing ability.
abstract: Keratin was extracted as a reduced form from wool, which was then subjected to acetamidation, carboxymethylation or aminoethylation at abundant free cysteine residues to give acetamidated keratin (AAK), carboxymethylated keratin (CMK) and aminoethylated keratin (AEK). Hydrogels were prepared from intact and three chemically modified keratins simply by concentrating their aqueous solution and subsequent cooling. The lowest concentration to form a hydrogel without fluidity was 110 mg/ml for AAK, 120 mg/ml for AEK, 130 mg/ml for keratin and 180 mg/ml for CMK. Comparing with a hydrogel just prepared (swelling ratio: 600-700), each hydrogel slightly shrank in an acidic solution. While AAK hydrogel little swelled in neutral and basic solutions, other hydrogels became swollen and CMK hydrogel reached to dissolution. Hydrogels of keratin, AAK and AEK were found to support cell proliferation, although cell elongation on AAK and AEK hydrogel was a little suppressed. On the other hand, CMK hydrogel did not seem to be suitable for a cell substrate because of its high swelling in culture medium. Evaluation of the hydrogels as a drug carrier showed that keratin and AAK hydrogels were good sustained drug release carriers, which showed the drug release for more than three days, while the release from AEK and CMK hydrogels completed within one day. Thus, keratin and chemically modified keratin hydrogels, especially keratin and AAK hydrogels, were promising biomaterials as a cell substrate and a sustained drug release carrier.
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Nakata
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Osumi
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Miyagawa
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Tachibana
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan. Electronic address: tanabe@bioa.eng.osaka-cu.ac.jp.
authors.forename: Toshizumi
authors.initials: T
authors.lastname: Tanabe
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry; D002448:Cell Adhesion; D002460:Cell Line; D049109:Cell Proliferation; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D065546:Drug Liberation; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007633:Keratins / Q000737:chemistry* / Q000302:isolation & purification; D014935:Wool / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D020100:Hydrogels; D007633:Keratins
keywords: Cell substrate; Chemical modification; Hydrogel; Keratin; Sustained drug release