In vivo biodegradation and biocompatibility of photo-cross-linked film based on poly(ε-caprolactone-co-lactide-co-glycolide)

Abstract

Photo-polymerizable, linear poly(ε-caprolactone-co-lactide-co-glycolide) diacrylates (PCLLGA-DA) are potential candidates for various tissue engineering applications because of their in-vitro biocompatibility, controllable biodegradation rates and non-toxic degradation products. In this project, the biocompatibility evaluation of the formula “H-60” PCLLGA was carried out in a subcutaneous rat model. Polymer disks with diameter of 8mm were prepared and implanted subcutaneously into 9 rat models for 2, 4 and 12 weeks. 2 polymer disks were implanted into each rat model. After the specified period of implantation, the polymer disks were excised for biodegradation and histology studies. The in-vivo degradation profiles of the polymer disks were evaluated by monitoring the average percentage weight loss over the implantation duration. The in-vivo degradation of PCLLGA polymer was found to be faster than in-vitro degradation, with a 9.7% average loss in weight after 12 weeks. For histology study, the polymer disks were viewed under light microscope to evaluate the degree of tissue response. The tissue inflammatory responses were classified as minimal, mild or moderate. After 2 and 4 weeks of implantation duration, minimal inflammatory response was observed as there was a minimal presence of neutrophils and eosinophil. However, moderate inflammatory response after 12 weeks of implantation was found and chronic inflammation, due to the large accumulation of lymphocytes and macrophages was observed. Using a published classification system, “H-60” formula is classified as level 2 biocompatible materials, which could cause a moderate inflammatory response.