Comparison and characterization of different polyester nano/micro fibres for use in tissue engineering applications

Abstract

The study focuses on a comparison of the electrospinning of various polylactide and polycaprolactone (PLCL) copolymers and poly-L-lactide (PLLA) and polycaprolactone (PCL) homopolymers. The chemical characterisation, electrospinnability, fibrous morphology, degradation rate and interactions with fibroblasts were assessed with respect to copolymers and homopolymers with both lower (around 50,000) and higher (around 95,000) molecular weights. The research investigated commercially available as well as synthesised copolymers. The results revealed that the electrospinnability of polymeric solutions depends on both the molecular weight and the PLA/PCL ratio in the final copolymer. It was determined that PLCL copolymers with a higher content of PCL (≥20%) were not spinnable via the electrospinning process. With the exception of PCL, the resulting fibrous materials were found to be homogeneous and with fibre diameters of slightly more than 1 µm with respect to both the tested molecular weights. The degradation rate was tested under simulation conditions via the utilisation of the lipase and Proteinase K enzymes. The degree of degradation was found to depend on the molecular weight, the crystallinity of the polymer and the specificity of the enzyme applied. While lipase was responsible for the degradation of the PCL polymer, it exerted a minor impact on the PLLA and the copolymers. Proteinase K degraded all the tested polymers with a higher specificity towards PLLA and the PLCL copolymers. All the tested polymers were affected by the surface erosion degradation process via fibrous morphology changes and mass loss with no accompanying shift in the molar mass. The electrospun PLLA materials supported both fibroblast adhesion and proliferation. All the tested materials were determined to be cytocompatible with 3T3 mouse fibroblasts.