Abstract
Background
Auxetic materials have a negative poisons ratio, and a number of native biological tissues are proposed to possess auxetic properties. One such tissue is annulus fibrosus (AF), the fibrous outer layers of the intervertebral disc (IVD). However, few studies to date have investigated the potential of these materials as tissue engineering scaffolds. Here we describe the potential of manually converted polyurethane (PU) foams as three dimensional cellular scaffolds for AF repair.
Methods
Rat MSCs were seeded onto fibronectin coated auxetic foams at a cell density of 6.4 × 103 cells/mm3, and cultured for up to 3 weeks. Cell viability was assessed throughout culture and following culture scanning electron microscopy (SEM) was used to assess morphological characteristics. Histological assessment was performed to assess production of matrix proteins.
Results
Cells adhered to the surface auxetic foams and remained viable for the 3 weeks investigated. Histology and SEM demonstrated cells within the full thickness of the auxetic foams, where extracellular matrix was starting to be produced following 3 weeks, including collagens suggesting differentiation of the MSCs.
Conclusion
Auxetic PU foams have a significant potential for use in tissue engineering applications, potentially mimicking the multiaxial strains of annulus fibrous tissue. MSCs were shown to adhere, survive and produce matrix within the foams after 3 weeks, future work will focus on longer term studies and in depth analysis of the phenotype of the cells.
No conflicts of interest
Funding provided by a grant from Sheffield Children's Hospital NHS trust.
