Mechanical properties of PVA material for tissue engineering applications

The paper presents the first scientific study of the quasi-linear viscoelastic (QLV) model of poly(vinyl alcohol) (PVA) sponges. The PVA sponges have been considered as a potential implant material for replacement and repair of the soft tissues, including cartilage, liver and kidney. It is also used in ophthalmic surgical treatment, such as Lasik, cataract and refractive surgeries, to manipulate tissue during incision procedures in the eye to absorb fluid. However, a critical barrier to the use of the PVA sponge as a tissue replacement material is the lack of sufficient mechanical properties. In this study, the non-linear mechanical behaviour of a PVA sponge is investigated experimentally and computationally. A series of tension tests are designed and conducted for the PVA sponge. Hyperelastic strain energy density functions, including Yeoh, Ogden, Mooney-Rivlin and Neo-Hookean, are calibrated using the experimental data. A hyperelastic constitutive model is selected to best fit the axial behaviour of the sponge. Its general prediction ability is verified using finite element simulations of PVA tensile experiments. The results in terms of the maximum stress before the holding for the P sponge demonstrate that it can bear 11.94% and 20.17% more stress compared to the EYETEC and CENEFOM sponges respectively. The swelling ratio of the P sponge was 26.78 and 1.78% more than that of the CENEFOM and EYETEC sponges respectively. Moreover, the Yeoh model was selected to represent the non-linear behaviour of the PVA material, which can be used in future biomechanical simulations of the soft tissues. These results can be utilised to understand the QLV and swelling mechanism of PVA sponges and have implications for ophthalmic and plastic surgeries, as well as wound healing and tissue engineering purposes.