title: Characterization and mechanical performance study of silk/PVA cryogels: towards nucleus pulposus tissue engineering.
abstract: Poly (vinyl) alcohol (PVA) cryogels are reported in the literature for application in nucleus pulposus (NP) replacement strategies. However, these studies are mainly limited to acellular approaches-in part due to the high hydrophilicity of PVA gels that renders cellular adhesion difficult. Silk is a versatile biomaterial with excellent biocompatibility. We hypothesize that the incorporation of silk with PVA will (i) improve the cell-hosting abilities of PVA cryogels and (ii) allow better tailoring of physical properties of the composite cryogels for an NP tissue engineering purpose. 5% (wt/vol) PVA is blended with 5% silk fibroin (wt/vol) to investigate the effect of silk : PVA ratios on the cryogels' physical properties. Results show that the addition of silk results in composite cryogels that are able to swell to more than 10 times its original dry weight and rehydrate to at least 70% of its original wet weight. Adding at least 20% silk significantly improves surface hydrophobicity and is correlated with an improvement in cell-hosting abilities. Cell-seeded cryogels also display an increment in compressive modulus and hoop stress values. In all, adding silk to PVA creates cryogels that can be potentially used as NP replacements.
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore.
authors.forename: Puay Yong
authors.initials: PY
authors.lastname: Neo
authors.forename: Pujiang
authors.initials: P
authors.lastname: Shi
authors.forename: James Cho-Hong
authors.initials: JC
authors.lastname: Goh
authors.forename: Siew Lok
authors.initials: SL
authors.lastname: Toh
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002448:Cell Adhesion; D049109:Cell Proliferation; D003432:Cross-Linking Reagents / Q000737:chemistry; D059985:Cryogels / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D005349:Fibroins / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007403:Intervertebral Disc / Q000503:physiopathology*; D055959:Intervertebral Disc Degeneration / Q000503:physiopathology* / Q000628:therapy*; D007405:Intervertebral Disc Displacement / Q000503:physiopathology* / Q000628:therapy*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D016062:Porosity; D013314:Stress, Mechanical; D013499:Surface Properties; D023822:Tissue Engineering / Q000379:methods; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D059985:Cryogels; D014867:Water; D011142:Polyvinyl Alcohol; D004247:DNA; D005349:Fibroins