Immobilization of laminin peptide in molecularly aligned chitosan by covalent bonding

We developed a new biomaterial effective for nerve regeneration consisting of molecularly aligned chitosan with laminin peptides bonded covalently. Molecularly aligned chitosan was prepared from crab (Macrocheira kaempferi) tendons by ethanol treatment and 4 wt%-NaOH aqueous solutions to remove proteins and calcium phosphate, followed by deacetyl treatment using a 50 wt%-NaOH aqueous solution at 100 °C. Molecularly aligned tendon chitosan was chemically thiolated by reacting 4-thiobutyrolactone with the chitosan amino group. The introduction of thiol groups and their distribution to tendon chitosan and chitosan cast film were confirmed using ATR FT-IR, 1H-NMR, and EDS. The 1.24 μmol/g of thiol groups introduced on the surface of tendon chitosan and the chitosan cast film was confirmed using ultraviolet (UV) spectra. Thiol groups of cysteine located at the end of synthetic laminin peptides were then reacted chemically with thiolated chitosan to form chitosan-S-S-laminin peptide. YIGSR estimated at 0.92 μmol/g and IKVAV estimated at 0.28 μmol/g on thiolated tendon chitosan were confirmed using UV spectra. YIGSR was estimated at 0.85 μmol/g and IKVAV was estimated at 0.34 μmol/g on the thiolated chitosan cast film.