Biocompatibility assessment of cyclic olefin copolymers

What is it about?

This work reports the biocompatibility evaluation of cyclic olefin copolymers (COC) as candidates for implantable medical devices. The focus was to establish the influence of two major additives (antioxidant and lubricant) on the overall biocompatibility. The cytotoxicity was evaluated according to ISO 10993-5 guidelines using L929 fibroblasts, HUVEC and THP-1-derived macrophages. Oxidative stress (ROS, GSH/GSSG and SOD analysis) and inflammation cytokines (Il-6 and TNF secretion) were quantified using THP-1 cells in direct contact with films. Hemocompatibility was assessed through haemolysis testing, dynamic blood coagulation, platelet adhesion and activation (membranous P-selectin expression). Results show that the different types of COC have successfully passed the in vitro biocompatibility tests. The presence of antioxidant induces however a slight decrease in ROS production in correlation with a high SOD activity and a modification in blood coagulation profile probably linked to antioxidant recrystallization phenomenon on the surface of COC. The lubricant presence reduced haemolysis, fibrinogen adhesion and platelet activation. Surface nanotopography of COC highlights different types of needles and globules according to the present additive. Those primary results indicate that COC are promising biomaterial. However, additives influenced some biological parameters pointing out the necessity of a global approach of risk analysis for biocompatibility evaluation.

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