The influence of a natural cross-linking agent (Myrica rubra) on the properties of extruded collagen fibres for tissue engineering applications

Extruded collagen fibres have been shown to be a competitive biomaterial for both soft and hard tissue repair. The natural cross-linking pathway of collagen does not occur in vitro and consequently reconstituted forms of collagen lack sufficient strength. Numerous cross-linking approaches have been investigated through the years, but still there is no ideal method accepted. The use of plant extracts to cross-link collagen scaffolds has been advocated due to superior mechanical properties. As first herein we investigate the stabilisation effect of Myrica rubra on extruded collagen fibres. Fibres treated with M. rubra exhibited higher denaturation temperature (p < 0.005) and lower enthalpy of denaturation (p < 0.034) than formaldehyde of glutaraldehyde. Uniaxial tensile tests of wet tested fibres revealed j-shape curves similar to those of native tissues. Thin fibres exhibited high stress/low strain graphs, whilst thick fibres yielded low stress/high strain graphs. Cross-linking reduced significantly the fibre diameter (p < 0.005) and increased significantly the stress (p < 0.004) and force (p < 0.001) at break and the modulus at 2.0% strain (p < 0.003). An inverse relationship between stress at break and fibre diameter was observed for every treatment. Overall, our findings demonstrate the potential of M. rubra in stabilisation of collagen-based materials for tissue engineering applications.