Development Of New Bioactive Coating Applied To Pipeline System Of Cardiac Surgery

Object Prepare new style anticoagulant composite coating and anti-inflammatory composite coating.Select the optimum condition and optimum coating mode.Evaluate the biocompatibility,blood compatibility and controlled release property of composite coatings.Create systemic coating mode and method of extracorporeal circulation(ECC)circuits,evaluating the effect of systemic coating.Method The ECC circuits were pretreated with potassium permanganate-concentrated sulfuric acid(KMnO4-H2SO4)solution.The optimum pretreated surface with fine transmittance was selected.Polyethylenimine(PEI)react with pretreated ECC circuits surface in which positive amino-group were bond on ECC surface,"Space Arms" of multi amino-groups were formed.Sodium alginate with multi aldehyde groups(OSA)were obtained by periodate oxidation.OSA coating was created in which OSA were bond on PEI-pretreated ECC circuits surface through end-point bond method.The optimum preparation condition of OSA coating was selected by orthogonal screening.Heparin with multi amino-group(LMDH)was obtained by diazotization process,the best diazotization processing conditions were selected by orthogonal screening.The OSA coating and LMDH coating with optimal prepared conditions were compared by evaluating their biocompatibility,blood compatibility,etc.OSA and LMDH were bond on ECC circuits surface through three coating patterns including OSA1LMDH2,LMDH1OSA2 and OSA1.LMDH1.The optimal coating pattern was selected by evaluating the surface biocompatibility,blood compatibility and dynamic loss index of three different coating patterns.Dexamethasone sodium phosphate(DSP)were bond on PEI pretreated ECC cirtuits surface through ionic bond,creating PPD single coating mode.DSP were bond on OSA coating surface by ionic bonding and space winding,creating the PPI composite coating mode.DSP and OSA were premixed by ionic bond and space winding,creating the combined composite coatings.The composite coatings were then bond on PEI pretreated ECC circuits surface by ionic bond,covalent bond and space winding,creating the PPC composite coating mode.The optimal coating pattern was selected by evaluating the surface biocompatibility,blood compatibility and dynamic loss index of three different coating patterns including PPD,PPI and PPC.Long ECC circuits(LPVC),artery filter and constant temperature flask were connected with series mode.The coating solution,driven by roller pump,were reacted with LPVC and artery filter equally.Evaluate the feasibility and safety of systematic coating methods through the quantitative and dynamic loss experiments,pump pressure test,etc.Results OSA obtained by periodate oxidation and LMDH obtained by diazotization reaction were feasible and safe.OSA and LMDH coatings were effectively bond on ECC circuits surface through chemical modification and end-point bond,confirmed by infrared scanning.Quantitative experiments have shown that alginate and heparin coating density of OSA.LMDH group had no significant difference(p>0.05)compared with OSA and LMDH single coating groups,indicating that composite coating mode did not affect the coating quantity of OSA and LMDH.In the evaluation of biocompatibility,the surface contact angle of OSA.LMDH group were significantly decreased(p<0.05)compared with LMDH group,indicating that OSA coating can significantly improve the hydrophilcity of ECC circuits surface while LMDH coating cannot improve the hydrophilcity of ECC circuits surface.The protein adsorption test results perform the same trend with surface contact angle test.OSA coating can significantly decrease the protein adsorption on ECC circuits surface(p<0.05),while LMDH coating cannot improve the protein adsorption.The composite coating retain the effect of decreasing protein adsorption.In the evaluation of blood compatibility,LMDH coating has significant anticoagulant effect,characterized by prolonged APTT and TT(p<0.05).OSA coating has slightly anticoagulant effect,characterized by significantly prolonging ATPP(p<0.05).The anticoagulant effect of OSA.LMDH coating,inferior to LMDH coating,is still better,characterized by significantly prolonged APTT and TT(p<0.05).Macromolecular fragmentation did not change the anticoagulant property of sodium alginate and heparin.In the evaluation of platelet adhesion,OSA.LMDH composite coating decrease the platelet adhesion,improving the blood compatibility of blank ECC circuits and preventing the further formation of thrombosis.In the evaluation of thrombosis,OSA.LMDH composite coating can significantly decrease the thrombosis(p<0.05).In the research of DSP composite coating,PPD,PPI and PPC coating modes can all make DSP bond on ECC circuits surface.PPI and PPC groups possess properties of anticoatulation,anti-platelet and anti-protein adhesion.In the evaluation of DSP control release,PPC group is superior to PPI and PPD groups.Series coating method,imitating the ECC,can achieve acidification pretreatment,PEI coating and coatings bond.The prepared LPVC and artery filter after systemic coating mode has stable coating quantity and less dynamic release.The inlet pressure,filter pressure and flux/rotate speed of coated artery filter slightly changed compared with uncoated artery filter.Conclusion LMDH coating possess fine anticoagulant property,but bad biocompatibility and anti-protein adhesion.OSA coating has better biocompatibility and slightly anticoagulant effect.OSA.LMDH composite coating can improve the biocompatibility of ECC circuits surface and possess double anticoagulant effect.OSA.LMDH composite coatings possess good biocompatibility and blood compatibility simultaneously.OSA-DSP composite coatings possess good blood compatibility and biocompatibility.The covalently bond DSP can be controlled released.The new constructed systemic coating mode is safe and effective.