Preparation and physical properties of hyaluronic acid-based cryogels

Macroporous hydrogels based on hyaluronan (HA), a natural polysaccharide occurring in extracellular matrix, have attracted interest over many years owing to their numerous applications in the biomedical area. However, HA hydrogels produced so far suffer from low mechanical strength and slow rate of response against external stimuli, which limit their applications. Here, we prepared macroporous HA cryogels of high mechanical stability and fast responsivity from aqueous HA solutions at subzero temperatures using ethylene glycol diglycidyl ether as a crosslinking agent. HA cryogels are squeezable and no crack development was exhibited when compressed up to 80% strain. Depending on the synthesis parameters, the cryogels exhibit an elastic modulus between 0.2 and 2 kPa, and show fast swelling/deswelling behavior. The microstructure of the cryogels consists of large, interconnected pores on the order of 100 mu m separated by thick pore walls, as observed by scanning electron microscopy and confocal scanning laser microscopy