Study On Biocompatibility Of Carbon/Carbon Composites

Objectives:This study was aimed to evaluate the biocompatibility of carbon/carbon composites,so as to establish the theoretical foundation of clinical application.Methods:1.Cytotoxicity test:L-929 was incubated with leaching liquor of the samples.Blank and positive control groups were set up.Subsequently,The samples was evaluated by the percentage of S-period cells which were detected by flow cytometry;2.Micronucleus test:30 Kunming mice were randomly divided into experiment group(n=10),negative control group(n=10)and positive control group(n=10).The leaching liquor of samples(50ml/kg)was injected into abdominal cavity of the mice.Bone marrow slides were made after taking drugs four times.The genetic toxicity was assessed by micronucleus frequency;3.Sensitization test:30 albino guinea pigs were randomly divided into experiment group(n=10),negative control group(n=10)and positive control group(n=10).After The induction phase-inspiration stage,allergic skin reaction zone was observed 24h and 48h after the removal of application-inspired,to evaluate the allergic reactions;4.Implantation test:20 rabbits using self-control was implanted carbon/carbon composites(2mm×6mm,cylinder)into the right femur,and commonly used titanium folder into the left femur as control.Histocompatibility and tissue adhesiveness were observed through the pathology section and scanning electron microscopy after 2 weeks,4weeks,8 weeks and 12weeks after the surgery.Results:1.Cytotoxicity test:The leaching liquor of samples has no effect on the proliferation of L-929 cells.Compared with the negative control group,there was no significant difference(p＞0.05);2.Micronucleus test:Medullary micronucleus frequency of bone marrow was 2.3±0.7‰in experiment group,and there was no statistical difference compared with the negative control group(p＞0.05);3.Sensitization test:In the experiment group,the skin of subjects had slight erythema and edema,which was ranged 0.188±0.40 according to Magnusson and Kligman classification. there was no significant differences compared with negative control group (p＞0.05)4.Implantation test:There was slight inflammation around the tissue after the implantation of sample,and there was no significant differences compared with control group(p＞0.05).Fibrous tissue adhesion to the surface of materials was observed by scanning electron microscopy,and the adhesion increased with the period of implantation.Conclusion:Carbon/carbon composites have no cytotoxicity,no genetic toxicity and no sensitization.The inflammation was slight after the implantation of samples,and the fibrous tissue adhere to the surface the materials,showing satisfactory histocompatibility.So these kind of samples have a good biocompatibility and value of clinical application.