Mechanically improved porous hydrogels with polysaccharides via polyelectrolyte complexation for bone tissue engineering

Bone tissue engineering aims to design mechanically improved macroporous hydrogels with fibrous topologies using polysaccharides that can provide an appropriate microenvironment in bone defects in order to enhance bone regeneration similar to the native bone extracellular matrix. Herein, we developed hydrogels by intercalation of chitosan (CS) and sodium alginate (SA)-based polyelectrolyte complexes (PECs) (in situ formation using glucuronic acid delta-galactone as an acidifying agent (GDL)) within the poly(acrylamide) (PAM)-crosslinked network (PEC-PAM) during free radical polymerization. The structure and interactions of PEC-PAM were confirmed by FTIR and XRD experiments. The PEC greatly influenced the porosity, pore size, and mechanical properties of hydrogels. Importantly, the PEC within the hydrogels possessed a macroporous structure with a ladder-like fibrous topology, which may provide better cell growth and adhesion. Moreover, the hydrogels showed good bio-mineralization capacity in simulated body fluid solutions as confirmed by FTIR, XRD, FE-SEM, and SEM-EDX. The in vitro performance of the PEC-PAM hydrogels was assessed towards human bone osteoblasts cells in terms of cell proliferation, biocompatibility, and cell adhesion. All of the results suggest that PEC-PAM hydrogels have good potential in bone tissue engineering.