In Vitro Study Of The Cytotoxicity Of NdFeB Magnets Coated With DLC

Objective:To evaluate the cytotoxicity of NdFeB magnet with diamond like carbon(DLC)coating through investigating its effect on the proliferation of human gingivalfibroblasts(HGFs), so as to provide some reference for the efficient and safe clinicalapplication of NdFeB magnet.Method:Three groups of magnets--magnets with DLC coating, magnets withtitanium-nitride (TiN) coating and bare magnets were immersed in the serum-freeDMEM culture medium to produce3kinds of extract liquid, then HGFs werecultivated with the extract liquids.MTT assay was used to test OD value of eachgroup, calculate relative growth rate(RGR) and thus evaluate the rank ofcytotoxicity,and Western Blot was used to measured the expression of mTOR andP70s6k of HGFs in each group, in order to evaluate the bio-security of each group bycomparing with the relative gray value of negative control group.Result:1.MTT assay showed the cytotoxicity of magnets with DLC coating rankedbetween the level of0and1, according to different concentrations of extract liquids.Magnets with TiN coating ranked the level of1. Bare magnets ranked the level of2,positive control group ranked the level of4.2.Western Blot showed magnets with DLC coating and TiN coating have noobvious effect on the expression of mTOR and P70s6k.Bare magnets have obviouseffect on the inhibition of the expression of mTOR and P70s6k.Conclusion:1.No significant difference of cytotoxicity between magnets with DLC coatingand magnets with TiN coating, and the cytotoxicity meet the safety-use criterion ofcytotoxicity tests, so both of them have good bio-security.2.Bare magnets have certain cytotoxicity, and have poor bio-security.