Poly(Vinyl Alcohol) Cryogels for Biomedical Applications

Poly(vinyl alcohol) (PVA) is a hydrophilic and biocompatible polymer that can be crosslinked to form a hydrogel. When physically crosslinked using a freeze-thaw cycling process, the product hydrogel or cryogel (PVA-C) possesses unique mechanical properties that can be tuned to closely match those of soft tissues, thus making it an attractive candidate for biomedical and especially medical device applications. We review the freeze-thaw cycling process and processing parameters that impact on the properties of PVA-C and its nanocomposite products. Both the mechanical properties and diffusion properties relevant to biomedical application are discussed. Applications to orthopedic and cardiovascular devices are summarized and discussed. The concept of biomaterial-tissue hybrids that can impart the necessary hemocompatibility to PVA-C for cardiovascular device is introduced and demonstrated.