UCLA

Hydrogels have been extensively used in tissue engineering applications as they provide versatility in structure and physical properties, which can mimic properties of native tissues. However, most hydrogels exhibit weak compressibility, stretchability, and tend to swell and degrade, which opposes their functionality to be implanted for long periods of time inside the body. Here, we present a strategy to produce macroscopically porous, tough, and elastic poly(vinyl)alcohol (PVA)-based hydrogels using a synergic freeze-thawing and salting-out method that can prepare scaffolds for different load-bearing tissues such as tendons, cartilages, and intervertebral disks. Hydration with inorganic and organic ions actively controlled the stability of the PVA macromolecule and facilitated the formation of micro-structured frameworks with tunable porous structures. The engineered hydrogels showed Young’s modulus in range of 116-500 kPa and compressive modulus between 1-5 MPa, comparable to natural load-bearing tissues. In addition, 10% swelling and degradation rate up to 2 months indicated long-term material stability. With the presence of a quaternary ammonium salt, the engineered hydrogel demonstrated excellent antibacterial property exhibited in vitro using both Gram-positive and Gram-negative bacteria. Meanwhile, cytotoxicity the materials were assessed in vitro with human lung fibroblast cells which showed >95% cell viability and proliferation over 7 days of culture. Our novel material which is formed by freeze-casting and salting out techniques and tested in biological environments proves itself to be translatable for load-bearing tissue applications.