Cryogelation has become an advantageous method to obtain macro-porous materials with well-defined, interconnected pores for tissue engineering applications. Herein, polyvinyl alcohol and chitosan polymers (PVA-CHI) were used to produce cryogel scaffolds via cryogelation. Glutaraldehyde was used as a crosslinking agent and the effect of crosslinking amount on the properties of scaffolds investigated. Glutaraldehyde amount was divided into 5, 10, and 15% total amount of polymer concentration. The optimized pore morphology was obtained as a scaffold containing 5% glutaraldehyde amount. In addition to the FTIR, SEM, swelling, and degradation analyses, mechanical tests were performed to present the characterization properties of the cryogels. Direct and indirect cytotoxicity test and genotoxicity experiments were performed with Mouse Embryonic Fibroblasts (MEF). In addition, cell morphologies on scaffolds were analyzed with SEM. The results showed that PVA-CHI based cryogels had no genotoxic and cytotoxic effects on MEF cells and have a potential for tissue engineering applications.

Cryogel formation is an effective approach to produce porous scaffolds for tissue engineering. In this study, cryogelation was performed to produce boron-containing scaffolds for bone tissue engineering. A combination of the synthetic polymer, poly(vinyl alcohol) (PVA), and the natural polymers, chitosan and starch, was used to formulate the cryogels. Boron was used with a dual purpose: as an additive to alter gelation properties, and to exploit its bioactive effect since boron has been found to be involved in several metabolic pathways, including the promotion of bone growth. This project designs a fabrication protocol enabling the competition of both physical and chemical cross-linking reactions in the cryogels using different molecular weight PVA and borax content (boron source). Using a high ratio of high-molecular-weight PVA resulted in the cryogels exhibiting greater mechanical properties, a lower degradation rate (0.6–1.7% vs. 18–20%) and a higher borax content release (4.98 vs. 1.85, 1.08 nanomole) in contrast to their counterparts with low-molecular-weight PVA. The bioactive impacts of the released borax on cellular behaviour were investigated using MG63 cells seeded into the cryogel scaffolds. It was revealed that the borax-containing scaffolds and their extracts induced MG63 cell migration and the formation of nodule-like aggregates, whilst cryogel scaffolds without borax did not. Moreover, the degradation products of the scaffolds were analysed through the quantification of boron release by the curcumin assay. The impact on cellular response in a scratch assay confirmed that borax released by the scaffold into media (~0.4 mg/mL) induced bone cell migration, proliferation and aggregation. This study demonstrated that boron-containing three-dimensional PVA/starch–chitosan scaffolds can potentially be used within bone tissue engineering applications.