Supermacroporous cryopolymers for tissue regeneration

Objectives: A range of porous synthetic and natural polymer hydrogels were produced using cryopolymerisation method and their potential as biomaterials for tissue regeneration was assessed. Methods: The cryopolymers of polyvinyl alcohol, poly-HEMA, fibrinogen, collagen and gelatin were synthesized in aqueous solutions at temperatures below 273 K. The ice crystals were used as a pore-forming substance and the procedure led to formation of robust macroporous polymer structures capable of retaining their integrity upon multiple hydration-dehydration cycles. The pore structure of cryopolymers was characterized using cryo-NMR, confocal laser scanning microscopy, m-CT and SEM. Infiltration and proliferation of human dermal fibroblasts were used to study potential of cryopolymers as tissue scaffolds for wound healing. Results: The porous structure of cryopolymers was comprised of fully interconnected (super) macropores in the range of 50-200 mm, suitable for cell migration and proliferation. In vitro results in a human skin model followed by experiments using large animal model showed high healing properties of the cryopolymers, which were better than in control experiments using commercial materials. Depending on the application, cryopolymers can be made biodegradable or stable, which depends on the degree of cross-linking and the nature of the polymer. Conclusions: Cryopolymer-based tissue scaffolds have shown high efficiency in wound healing and potential for internal organ regeneration.