Swelling behavior of hyaluronic acid and type II collagen hydrogels prepared by using conventional crosslinking and
1Biomaterials Center, National Institute for Materials Science, Tsukuba, Ibaraki, Japan. TAGUCHI.Tetsushi@nims.go.jp
Abstract:
Polymer-polymer interactions, such as hydrophobic and electrostatic interactions, were introduced into covalently crosslinked composite matrices consisting of an anionic polysaccharide, hyaluronic acid (HyA) and a cationic polypeptide, type II collagen. The matrices were covalently crosslinked using a water soluble carbodiimide (WSC; 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride) and were immersed at different temperatures in excess water or 0.4 M NaCl aqueous solution, i.e. the optimal salt concentration to suppress polyion complex formation. Hydrophobic interaction was introduced in the matrices when the temperature was increased. Matrices with polymer-polymer interactions could be obtained when immersed in water at 37 degrees C without any collagen denaturation. The molar ratios of [OH]/[COOH] and [NH2]/[COOH], and WSC concentration in precursor solutions of HyA-collagen composite matrices influenced the electrostatic interactions. The hydrophobic and electrostatic interactions in the matrix were maintained in water, even at low temperatures, while in salt solutions at elevated temperatures, these interactions were nullified.
