IN-VITRO SORPTION AND DESORPTION OF BASIC FIBROBLAST-GROWTH-FACTOR FROM BIODEGRADABLE HYDROGELS

In vitro interaction of basic fibroblast growth factor (bFGF) with bio degradable gelatin hydrogels was investigated, focusing on its sorptio n into the hydrogels and desorption from them. Basic bFGF was sorbed t o the hydrogel of acidic gelatin with an isoelectric point (IEP) of 5. 0 over time at 4 degrees C, in contrast to that of basic gelatin with an IEP of 9.0 and type I collagen. The bFGF sorption was almost indepe ndent of the sorption temperature except for 4 degrees C and the hydro gel water content. Fluorescent microscopic observation revealed that b FGF was sorbed into the interior of the acidic gelatin hydrogel. The b inding molar ratio of bFGF to the acidic gelatin was around 1.0. The b FGF sorption to the acidic gelatin hydrogel increased when gelatin was further carboxylated. bFCF was sorbed into the acidic gelatin hydroge l more slowly than into the poly(acrylic acid) (PAAc) hydrogel, probab ly because of the lower density of negative charge of gelatin. The bFG F sorption decreased with an increase in solution ionic strength, indi cating that an electrostatic interaction was the main driving force fo r bFGF sorption to the acidic gelatin hydrogel. However, even at highe r ionic strengths of solution, the sorbed bFGF was not desorbed from t he acidic gelatin hydrogel, in contrast to the PAAc hydrogel. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.