Preparation Of Apatite Coating On Medical Silicon Rubber By Biomimetic Synthesizing

Medical silicon rubber is a kind of polymer rubbery elastomer.Meeting the demands of medical polymer material,it is more and more widely used as substitutes of organs,key parts of medical device,vitro products and for plastic surgery and Restoration.However,due to the low polarity of silicon rubber molecule,it shows a strong hydrophobicity and a poor bond with body after being implanted. Hydroxyapatite,the main mineral matter of hard tissue and tooth of human body,has good biocompatibility.But it is difficult to machining hydroxyapatite ceramic into complex components because of its high embrittlement.However,when hydroxyapatite coating is prepared on the surface of silicon rubber,a composite, which is quite a good medical precutaneous material,is formed.Preparing apatite coating by the biomimetic synthesizing is a newly-developed means to form apatite coating in recent years.Biomimetic synthesis can be applied to various materials of different shapes to prepare apatite coating.When induced by bioactive-glass at the surface of medical silicon rubber,some calcium and silicon salts are formed.When dipped into 1.5s simulated body fluid or CP solution,apatite nuclei is formed quickly induced by the CP preformed precipitation.By consuming the ions of simulated body fluid or CP solution,the nuclei grows,thus a highly-ordered and well-proportioned apatite coating is formed onto the surface of silicon rubber.According to XRD,SEM and infrared spectra analysis,trace amounts of apatite is formed on the surface after the pretreated medical silicon rubber is dipped in the 1.5s simulated body fluid or CP solution for 3 days.Feathery apatite crystals are formed after the silicon rubber is dipped in the 1.5s simulated body fluid for 10 days, and plate-like apatite crystals are formed in CP solution.In order to study the effects of bio-macromolecules(like protein molecular) to the formation of hydroxyapatite,bovine serum albumin(BSA) is added into CP solution to study the growth and formation of apatite coating.XRD,SEM and infrared spectra analysis are used to analyze the characteristics of apatite coating. According to the result,BSA and apatite co-deposit onto the surface of silicon rubber. Under the effect of BSA monolayer,the morphology and orientation of crystal change. The result of biocompatibility experiment shows that all the materials,including untre ated silicon rubber and samples that have been dipped in the CP solution,1.5s simulat ed body fluid or CP/BSA complex solution for 10 days,have no cytotoxicity or hemol ysis.The result of biocompatibility experiment shows that none of the materials, including untreated silicon rubber and samples that have been dipped in the CP solution,1.5s simulated body fluid or CP/BSA complex solution for 10 days,have no cytotoxicity or hemolysis.