Post-self-assembly experimentation on extruded collagen fibres for tissue engineering applications

Extruded collagen fibres have been shown to constitute a biomimetic three-dimensional scaffold with numerous tissue engineering applications. The multi-step fabrication process of this material provides opportunities for further advancements to improve the properties of the final product. Herein we investigated the influence of the post-self-assembly washing baths on the structural, mechanical and thermal properties of these fibres. The surface morphology and the inter-fibre packing were similar for every treatment. The overnight incubation in isopropanol yielded fibres with the highest temperature and energy of denaturation (p < 0.013). Typical s- and j-shape stress-strain curves were obtained for all treatments in the dry and wet state respectively. Rehydration of the fibres resulted in increased fibre diameter (p < 0.006) and reduced stress (p < 0.001), force (p < 0.001) and modulus (p < 0.002) values for every treatment. In the dry state, the alcohol-treated fibres were characterized by the highest stress (p < 0.002) values; whilst in the wet state the Tris-HCl-treated fibres were the weakest (p < 0.006). For every treatment, in both dry and wet state, a strong and inverse relationship between the fibre diameter and the stress at break was observed. Overall, the fibres produced were characterized by properties similar to those of native tissues.