Drug-lubrication System Based On Gels With Its Application In Biotribology And Study On Improving The Osteogenesis Of Electrospun PCL Nanofibers

Osteoarthritis is considered to be a typical joint disease associated with lubrication defects characterized by destruction of articular cartilage on the joint surface and inflammation of the joint capsule.Synergistic treatment with combined lubrication and drug intervention is considered a potential strategy for the treatment of osteoarthritis.This thesis is divided into two parts.The first part is based on the drug-carrying capacity of microgels,which is modified with the copolymerization of lubricating molecules to make it have good lubricating ability,and then injected into the joints of the disease to improve the internal lubrication conditions of the joints.At the same time,medication is used in order to achieve the goal of comprehensive treatment of early osteoarthritis.For this purpose,we use the temperature-sensitive molecular nitrogen isopropyl acrylamide(NIPAM)to copolymerize with the biocompatible,water-and lubricating molecule 2-methacryloyloxyethylphosphocholine(MPC).It was confirmed by drug sustained release and friction experiments that the microgel materials can achieve the effects of lubrication and drug release at the same time,and the effects of drug release at different temperatures and different experimental conditions on the lubrication effect were explored.The lubrication effect and mechanism of nano materials.In addition,the wear condition under this nanomaterial was compared and the in vitro simulated anti-inflammatory experiment was carried out,which confirmed that the microgel material can be used as a drug carrier to treat osteoarthritis.Following the microgel is aimed at cartilage defects and joint capsule inflammation caused by long-term joint wear.Modification of methacrylic anhydride modified gelatin,introduction of acrylamide(AM)increases mechanical strength and MPC increases lubrication effect and has excellent mechanical properties.Modified gelatin/polyacrylamide/poly-2-methacryloyloxyethylphosphocholine(GelMA-PAM-PMPC)composite hydrogel with controlled lubrication effect.In this part of the work,GelMA synthesis was first carried out and then the GelMA-PAM-PMPC composite hydrogel was prepared by UV-initiated free radical polymerization and its properties such as compression,swelling and surface roughness were characterized.Secondly,it is studied whether the lubricating properties are controllable under different conditions,the mechanism of friction behavior under different loads is discussed,and the drug release test is used to study the sustained release effect of diclofenac sodium as an anti-inflammatory drug.Finally,the biological phase of porous hydrogel material is tested.Capacitive and in vitro anti-inflammatory experiments have confirmed that this hydrogel material can be used as a drug carrier for the replacement of cartilage defects and achieve therapeutic effects on osteoarthritis.The third part is about improving the osteogenesis of electrospun PCL nanofibers.Electrospun nanofibers,with a typical interconnected porous structure mimicking the extracellular matrix,are commonly used in bone tissue engineering.However,to the best of our knowledge few studies have been reported to investigate the enhancement of osteogenesis capability of electrospun polycaprolactone(PCL)nanofibers based on bio-inspired surface functionalization.In this study,a universal and versatile approach was proposed to spontaneously modify the electrospun PCL nanofibers with bioactive nano-hydroxyapatite(nHA),using dopamine as an effective bio-adhesive agent.The evaluation of scanning electron microscopy,energy dispersive spectroscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis and surface wettability indicated that nHA was successfully coated onto electrospun nanofibers(PCL-PDHA).Furthermore,in vitro cell experiment including adhesion,proliferation and osteogenic capability and in vitro biomineralization test in simulated body fluid revealed that the PCL-PDHA nanofibers were biocompatible to MC3T3-E1 cells,and the osteogenesis and biomineralization capabilities were greatly improved in comparison with that of PCL nanofibers.In summary,the facile bio-inspired surface functionalization method introduced in the present study,due to its universality and versatility,not only can be used to improve osteogenesis of electrospun nanofibers,but also can be regarded as an avenue to achieve other pre-designed purposes in biomedical engineering.