Gelatin–fibrinogen cryogel dermal matrices for wound repair: Preparation, optimisation and in vitro study

Macroporous sponge-like gelatin–fibrinogen (Gl–Fg) scaffolds cross-linked with different concentrations (0.05–0.5%) of glutaraldehyde (GA) were produced using cryogelation technology, which allows for the preparation of highly porous scaffolds without compromising their mechanical properties, and is a more cost-efficient process than freeze-drying. The produced Gl–Fg–GA(X) scaffolds had a uniform interconnected open porous structure with a porosity of up to 90–92% and a pore size distribution of 10–120 μm. All of the obtained cryogels were elastic and mechanically stable, except for the Gl–Fg–GA(0.05) scaffolds. Swelling kinetics and degradation rate, but not the porous structure of the cryogels, were strongly dependent on the degree of cross-linking. A ten-fold increase in the degree of cross-linking resulted in an almost 80-fold decrease in the rate of degradation in a solution of protease. Cryogels were seeded with primary dermal fibroblasts and the densities observed on the surface, plus the expression levels of collagen types I and III observed 5 days post-seeding, were similar to those observed on a control dermal substitute material, Integra®. Fibroblast proliferation and migration within the scaffolds were relative to the GA content. Glucose consumption rate was 3-fold higher on Gl–Fg–GA(0.1) than on Gl–Fg–GA(0.5) cryogels 10 days post-seeding. An enhanced cell motility on cryogels with reducing GA crosslinking was obtained after long time culture. Particularly marked cell infiltration was seen in gels using 0.1% GA as a crosslinker. The scaffold started to disintegrate after 42 days of in vitro culturing. The described in vitro studies demonstrated good potential of Gl–Fg–GA(0.1) scaffolds as matrices for wound healing.