Study On Bamboo Fiber/Nanoapatite Composite And Its Membrane Materials

The regenerative repair of bone defects has become one of the worldwide medical problems.To develop the natural resources for the application in the field of orthopedic materials,in this dissertation,the preparation and properties of the composite materials of natural bamboo fiber(BF)and nano hydroxyapatite(n-HA)and their membranes were studied,so as to obtain excellent bone repair materials and guided bone regeneration(GBR)membrane,which was expected to be used in the field of bone repair,and provide a new way to develop natural bamboo fiber for biomaterials.Firstly,BF was firstly chosen to replace other polymers to prepare nHA-based nanocomposite,and the effects of different states,treatments methods,the addition amounts and addition methods of BF on the formation of n-HA on BF fiber and the corresponding n-HA/BF composites were investigated by Fourier transform infrared spectroscopy(FT-IR),Xray diffraction(XRD),scanning electron microscopy(SEM),electromechanical universal tester,in vitro soaking in simulated body fluid(SBF)and in vitro cell culture experiment.Results demonstrated that n-HA with the irregular morphology was attached on BF fibers,and it could be hybridized with BF to form n-HA/BF composite,however,there was subtle difference of the crystallinity,size and formed amount of n-HA attached on the different BF fibers,which brought about different surface properties of the n-HA/BF composites.And 30 wt% BF endowed the n-HA/BF composite with the best mechanical properties,and it was by far higher than that of pure n-HA.In addition,in vitro soaking results indicated that n-HA/BF composites displayed different water absorption rates,and all nHA/BF composites could promote the apatite deposit.Meanwhile,the nHA/BF composites exhibited good cytocompatibility,including attachment and proliferation.All results proved that single BF polymer could be used to act as the organic matrix to prepare n-HA-based nanocomposite by replacing collagen component of natural bone,and the alkali treated and undissolved BF with 30 wt% addition amount by precipitated method was the best appropriate condition to prepare the ideal n-HA/BF composite.Secondly,BF was used to prepare n-HA/BF composite membrane,and the effects of different film-forming methods,different drying methods and different amounts of n-HA on the corresponding n-HA/BF membrane were investigated by FTIR,XRD,SEM,electromechanical universal tester,in vitro soaking in simulated body fluid and in vitro cell culture experiment.The results demonstrated that n-HA could be evenly dispersed in the composite membrane without chemical bonding,and the contact angle experiment showed that the composite membrane were hydrophilic materials,but the different film-forming methods,drying methods and nHA contents of the composite membrane brought the difference of contact angle of the composite membrane.Among the preparation,film formation in an oven,freeze drying and high addition content of n-HA were more beneficial to improve the hydrophilicity of the composite membrane.Especially,20 wt% n-HA endowed the n-HA/BF composite membrane with the best mechanical properties.In addition,SBF soaking results indicated that n-HA/BF membrane displayed different water absorption rates and degradability,and all composite membrane materials had good ability to induce bone-like apatite deposition.At the same time,preliminary cell proliferation experimental results showed that the n-HA/BF composite membrane was non-toxic.The above results indicated that a simple casting technique could be used to obtain a controllable n-HA/BF composite film,which was expected to be used as guide bone tissue regeneration membrane.Thirdly,to improve the performance of guide bone tissue regeneration membrane,the bilayer composite membrane was constructed by electrospinning layer and casting laye,which was constituted by nHA/poly(lactide-co-glycolide)(PLGA)composite and bamboo fiber,respectively.And the effects of different addition methods and ratios of nHA on the double-layer composite membrane were investigated.The results of FTIR,XRD and SEM showed that there was no interaction between the cast layer component of BF and the electrospun layer of component of n-HA/PLGA in the composite film material,but the two layers of film were tightly combined.The results showed that the contact angle was mainly determined by the characteristics of electrospun layer,and the n-HA content had little effect.In addition,the tensile test results showed that the strength of the double-layer composite film depended on the support layer of bamboo fiber as the matrix,and had little relationship with the components of the electrospun layer.In vitro degradation results showed that the composite membrane had good degradability,and the bone-like apatite deposited on the surface of the electrospun membrane increased with the increasing of the content of n-HA,indicating that the double-layer structure membrane had good osteoconductivity,and preliminary in vitro cell experiments showed that the double-layer composite membrane displayed better cell proliferation ability and was more likely to be used as guide bone tissue regeneration membrane.Finally,the anti-inflammatory drug-vancomycin(VCM)was further introduced into the double membrane composed of electrospun membrane and cast membrane,and the effects of different adding methods and contents of VCM on the composite membrane were investigated,aimed to solve the inflammation and other problems caused by bone repair surgery,and the corresponding membrane materials were investigated by FTIR,XRD,SEM,electromechanical universal tester,in vitro soaking in simulated body fluid,antibacterial tests and in vitro cell culture experiment.The results demonstrated that the composite membrane contained VCM but no chemical bonding,and the contact angle test results showed that the surface of the electrospun layer of the membrane material changed from hydrophobic to hydrophilic with the increase of VCM content,which was more conducive to cell attachment,and the tensile test showed that the strength depends on the support of the cast layer with bamboo fiber as the matrix,not the content and the way of adding VCM.In addition,in vitro degradation,in vitro cell experiments and antibacterial tests indicated that the drug-loaded composite membrane had good degradability,bone guidance,cell compatibility and certain antibacterial properties,which was expected to be used as a novel guided bone tissue regeneration membrane.