Among materials used in biomedical applications, hydrogels have received consistent linear growth in interest over the past decade due to their large water volume and saliency to the natural extracellular matrix. These materials are often limited due to their sub-optimal mechanical properties which are typically improved via chemical or physical crosslinking. Chemical crosslinking forms strong inter-polymer bonds but typically uses reagents that are cytotoxic while physical crosslinking is more temperamental to environmental changes but can be formed without these toxic reagents. In this study, we added a fiber-reinforcement phase to a poly(vinyl alcohol) (PVA) hydrogel formed through successive freezing-thawing cycles by incorporating a non-woven microfiber mat formed by the wet-lay process. By reinforcing the hydrogel with a wet-laid fibrous mat, the ultimate tensile strength and modulus increased from 0.11 ± 0.01 MPa and 0.17 ± 0.02 kPa to 0.24 ± 0.02 MPa and 5.76 ± 1.12 kPa, respectively. An increase in toughness and elongation was also found increasing from 2.52 ± 0.37 MPa to 25.6 ± 3.84 and 51.89 ± 5.16% to 111.16 ± 9.68%, respectively. The soy fibers were also found to induce minimal cytotoxicity with endothelial cell viability showing 96.51% ± 1.91 living cells after a 48 h incubation. This approach to hydrogel-reinforcement presents a rapid, tunable method by which hydrogels can attain increased mechanical properties without sacrificing their inherent biologically favorable properties.
Keywords: Hydrogels; Mechanical properties; Natural fiber; Poly(vinyl alcohol); Regenerative medicine; Tissue engineering; Wet-laid process.
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