Freezing influence on physical properties of glucomannan hydrogels

Freezing is an interesting technique to modify the mechanical properties and morphology of hydrogels. Konjac glucomannan (KGM) is a polysaccharide that has potential use in cutting-edge areas as biomaterials and tissue engineering. In this work, we deeply investigated the influence of freezing on KGM. For that, KGM hydrogels were frozen at several freezing rates and temperatures. Results show that the freezing rate was the most important factor in the final physical properties of the KGM hydrogels. Slow freezing rate produced structures with isotropic and large pores, while fast freezing resulted in hydrogels with small and aligned pores. In addition, hydrogels frozen at high temperature (-8 °C) exhibited higher penetration modulus than hydrogels frozen at low temperature (-28 °C), since dense polymer regions are formed due to higher molecules dehydration caused by slow freezing. KGM hydrogels that underwent freezing can be explored as scaffolds for tissue engineering, with improved structural and mechanical properties.