Hydrogels prepared by crosslinking of gelatin with dextran dialdehyde

Hydrogels were prepared by reaction of gelatin with partial periodate oxidized dextran. It was found that the rate of gelation depends on the molecular weight and on the degree of oxidation of dextran, the type of gelatin and on the reaction conditions. Rheological measurements demonstrate that the gel strength is governed by two factors: chemical crosslinking by reaction with polyaldehyde and physical structuring of the gelatin. By proper selection of the reaction conditions, in particular storage temperature, the contribution of both processes to the final material strength can be varied. It was observed that short cryogenic treatment significantly enhances the chemical crosslinking.