Degradation of Poly(ε-caprolactone) and bio-interactions with mouse bone marrow mesenchymal stem cells

Bio-inspired scaffolds in bone tissue engineering using multipotential mesenchymal stem cells grow at a rapid rate found its successful use in orthopedic injury treatment. Poly(ε-caprolactone)/PCL is widely used in medical devices, tissue engineering, and drug delivery systems. Most desirable property of biodegradable polymer to be employed in medical application is synchronization of degradation with functional tissue regeneration. Limited studies have incorporated the degradation kinetics and implication of degradation products of pure unmodified PCL. The present study analyzes short term in vitro degradation profile of PCL films in physiological condition. The study reports weight loss, changes in molecular weight distribution and morphological variation in PCL thin film over a period of 90-day degradation. When the degradable material is in contact with host tissue, there exists robust and dynamic microenvironment controlling the cell functionality. To comprehend the biocompatibility aspects of polymer material, the study considered mouse bone marrow mesenchymal stem cells (BMSCs) as model system mimicking in vivo. There was no indication of toxicity revealed with MTT, LDH leakage, direct contact assay and clonogenic assay. Absence of oxidative stress and apoptosis denotes BMSCs functional integrity sustained upon exposure to PCL degradation products. Cell cycle analysis and DNA ladder assay confirmed cell survival and genomic stability. The study revealed that the topography of pure unmodified PCL surface is suitable for cell adhesion. It was also observed that the viability of differentiated cells (osteoblasts) was maintained in presence of PCL extract. Furthermore, polymer and its degradation products were proved to be hemocompatible. These results synergistically suggest that pure unmodified PCL and its degradation products are non-toxic at molecular level.