Research On Preparation And Properties Of Long Acting And Slow Release Porous MSN@PTFE Antibacterial Materials

In orthopedics and dental surgery,sometimes it is necessary to use a flexible polymer material to fill or shield the affected area.Considering the trauma of the affected part,it is expected that this material has certain antibacterial properties and can slowly release the antibacterial drug for a long time.Porous polytetrafluoroethylene(PTFE)is a wide range of biomedical materials because of its porosity,excellent biocompatibility,high chemical stability and aging resistance.However,due to its extremely low surface energy,it exhibits hydrophobicity.Its application in the field of drug loading and sustained release is limited.This paper intends to explore a preparation method of long-acting and slow-release porous MSN@PTFE antibacterial material,it based on porous PTFE's micron-scale pore structure and nano-scale rules of mesoporous silica nanoparticles(MSN).Seven different porous PTFE were selected as the base material,which were long island-shaped node porous PTFE,round island-shaped porous PTFE,uniform/non-uniform worm-like porous PTFE,and 5?m/3?m hole radial fiber porous PTFE,coral fiber porous PTFE;We chose Polydopamine(PDA),polyvinyl alcohol(PVA),Poly(sodium-p-styrenesulfonate)(PSS)as hydrophilic agents,using PHMB-HCl as an antibacterial drug,the best hydrophilic agent and reaction conditions are optimized through experiments;In order to further improve the drug loading capacity,the second phase MSN is prepared,which is physical imprinted with hydrophilically modified porous PTFE to form a micro-nano nesting structure,and the co-loaded drug has a long-term sustained release effect.The SEM,TEM,EDS,ATR-FTIR,XRD,XPS,contact angle analyzer,visible light spectrophotometer and other test methods were used to characterize and analyze the structural morphology,composition,hydrophilicity and drug release time of each sample.The best porous PTFE pore structure and hydrophilic modification conditions are obtained.Finally,three kinds of mathematical equations and gray system theory GM(1,1)model were used to fit the measured drug release time and release data.The model with the smallest error was selected,which can be used to simulate drug release situation and predict the drug release time.The research results are as follows:(1)By applying different hydrophilic modification methods on a variety of porous PTFE,the water contact angle was measured to obtain a hydrophilic modification methods:PVA is better than PVA-PSS than PDA.For long island shaped porous PTFE:using PDA modification method,the water contact angle is reduced from unmodified 130°to modified 86°,and the drug sustained release time is extended from 1h to 68h,but PDA change the surface of the material to dark brown,not suitable for the application of color requirements,so consider the colorless or white hydrophilic agent;Using PVA modification method,the best modification conditions are PVA1%,GA2%,reaction temperature 70°C,reaction time was 2h.The water contact angle was further reduced to 37°,the drug sustained release time was extended to 140h,the appearance color was transparent,and the drug release rate was fast at first,then got slower.The surface water contact angle was 69.6°by PVA-PSS modification method.The appearance color is light yellow,drug loading capacity is weaker than PVA modification method.(2)Using CTAB as a template and TEOS as a silicon source,MCM-41 MSN with a large specific surface area(1206.712 m~2/g)and a large pore volume(1.022 cm~3/g)was prepared.It has a regular spherical shape under a transmission electron microscope,it's average particle diameter is60nm and average pore diameter is 2nm.MSN physical imprinting with hydrophilically modified porous PTFE to prepare a porous MSN@PTFE drug sustained release material with a micro-nano nesting structure.Comparing the sustained release time of seven kinds of porous MSN@PTFE-PVA,it can be found that the drug release time of long island-shaped node porous PTFE as the substrate material is 176h.In the first 8h,the drug release amount reached 50%.After one week,the drug concentration was still greater than the minimum inhibitory concentration.(3)Taking long island-shaped node porous MSN@PTFE-PVA as the research object,the drug sustained release time and cumulative release percentage were substituted into four mathematical models for linear fitting,studied the drug release mechanism and calculated the coefficient R~2.The accuracy of the model,from high to low,are gray system theory GM(1,1)model,Higuchi model quadratic curve fitting equation,first-order release dynamics model quadratic curve fitting equation,zero-order release dynamic model quadratic curve fitting equation.Therefore,the gray system theory GM(1,1)model has a small difference between the simulated value and the experimental value,which can be used for the simulation and prediction of the porous MSN@PTFE material drug release process.