Effect of wool keratin on mechanical and morphological characteristics of Polycaprolactone Suture Fibre

Polycaprolactone (PCL) is a non-toxic and slowly biodegradable synthetic polymer, and is used in making biomaterial products such as surgical sutures, scaffolds, fibres and textile mesh for biomedical applications. Compared to materials of biological origin, PCL has no intrinsic biological capability to enhance healing of damaged cells or tissues. Therefore, a variety of bioactive agents such as proteins are incorporated into polymer matrices to improve biological interactions between the implanted device and cells or tissues. However, addition of structurally different proteins can greatly influence the key physicochemical characteristics of biomaterials, such as mechanical performance and surface morphology. In the present study, keratin extracted from wool was added to the PCL matrix and fibres were extruded using a melt-extrusion technique. Pure PCL fibre had an average tensile strength of 981 MPa, elongation of 19% and Young’s modulus of 5.8 GPa. The addition of keratin into the PCL matrix, imposed melt-processing difficulty and reduced tensile strength at higher loadings of keratin (e.g., 10 wt%). However, silane treatment improved the keratin/PCL interfacial adhesion as revealed by electron microscopy and consequently improved melt-spinning, and reduced mechanical stiffness of the material, a key characteristic of suture fibres.