Highly deformable and recoverable cross-linked hydrogels of 1,3-α-d and 1,3-β-d-glucans

We prepared self-standing chemically cross-linked hydrogels from 1,3-α-d-glucan (M_w = 2.0 × 10⁵) and 1,3-β-d-glucans (low-molecular-weight (LMW): M_w = 2.0 × 10⁵, high-molecular-weight (HMW): M_w = 1.0 × 10⁶), using ethylene glycol diglycidyl ether (EGDGE) as a cross-linker. Uniaxial compressive tests using cylindrical hydrogels of the cross-linked glucans were conducted. Both the 1,3-α-d-glucan and LMW-1,3-β-d-glucan hydrogels were highly deformable and shape-deformable; they could be compressed without breaking to 60% and 80% strain, respectively, and recovered 80% of their original height. The Young's moduli of the 1,3-α-d-glucan and LMW-1,3-β-d-glucan hydrogels indicated that the 1,3-α-d-glucan hydrogels were harder than the 1,3-β-d-glucan hydrogels. The HMW-1,3-β-d-glucan hydrogels were more deformable and had better shape recovery than the LMW-1,3-β-d-glucans; they could be compressed by up to 90% maximum strain, and recovered almost 100% of their original height from 80% strain. Cyclic compression tests were performed to study their network structure.