Tissue responses to novel tissue engineering biodegradable cryogel scaffolds: an animal model

Biodegradable macroporous cryogels with highly open and interconnected pore structures were produced from dextran modified with oligo L-lactide bearing hydroxyethylmethacrylate (HEMA) end groups in moderately frozen solutions. Tissue responses to these novel scaffolds were evaluated in rats after dorsal subcutaneous implantation, iliac submuscular implantation, auricular implantation, or in calvarial defect model. In no case, either necrosis or foreign body reaction was observed during histological studies. The cryogel scaffolds integrated with the surrounding tissue and the formation of a new tissue were accompanied with significant ingrowth of connective tissue cells and new blood vessels into the cryogel. The tissue responses were significantly lower in auricular and calvarial implantations when compared with the subcutanous and the submuscular implantations. The degradation of the scaffold was slower in bone comparing to soft tissues. The biodegradable cryogels are highly biocompatible and combine extraordinary properties including having soft and elastic nature, open porous structure, and very rapid and controllable swelling. Therefore, the cryogels could be promising candidates for further clinical applications in tissue regeneration.