| Biomedical materials have attracted great attentions during the last several years with the development of science and technology.Among them,PMMA IOL and Mg alloy are two typical biomedical materials.The former exhibits its excellent strength,toughness,high transmittance and chemical stability,and thus it was ever widely taken into application for the treatment of cataract disease.However,when implanted in the eye,this material may lead to more inflammatory cells adhering onto it’s around,and could bring out permanent damage of examined epithelial cells.The latter is a novel biomedical material,and there are potential applications in vessel stenosis treatment in every parts of human body due to its good biocompatibility,unique biodegradable and excellent mechanical properties.But its degradation in human body is too fast to provide enough time for the reconstruction of the lesions.Moreover,it will result in some infections coming from different adhered bacteria on its surface.Therefore,the thesis aims to clear the defects of the materials discussed above in life-applications and improve their practicability,and then fragments or molecules with good bio-compatibility have been assembled onto the surface of PMMA IOL and Mg alloy materials by several methods,e.g.plasma treatment,and plasma combined with sol-gel technology.Furthermore,the thesis has investigated the basic properties of the modified materials surface by several techniques and methods,such as X-ray photoelectron spectroscopy(XPS),attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR),X-ray diffraction(XRD),Raman spectroscopy(Raman),scanning electron microscopy(SEM),atomic force microscopy(AFM),ultraviolet-visible spectroscopy(UV-vis),contact angle measuring instrument(CA),electrochemical corrosion testing,platelet adhesion assays,and cell compatibility assay,etc.The main results will be described as follow.1.Surface modification of PMMA IOLThe thesis choose the abundant active particles induced by plasma discharge,andβ-hydroxyethyl methacrylate(HEMA)as modifying material for the excellent biocompatibility and blood compatibility to modify PMMA IOL.And it is to investigate the process of surface modification for PMMA IOL by changing plasma discharge parameters and HEMA graft concentration.(1)PMMA IOL was modified to improve the biocompatibility by high-frequency dielectric barrier discharge(DBD)plasma technology in the different discharge media,including N2,Ar,O2 and H2O.This section investigated the effects of various parameters(e.g.discharge voltage,electrode spacing and discharge time)on the surface hydrophobicity and free energy,and further examined surface chemical composition,morphologies,hydrophilicity,light transmittance,platelets adhesion and cell compatibility for modified PMMA IOL.XPS measurements show that the oxygen contents in all modified PMMA IOL are increase,O/C mole ratio higher.CA analysis further shows that the water contact angles for modified PMMA IOL in the four media plasma go down clearly and the surface free energy go up.In addition,the water contact angles increase gradually with the first 5 days,whereas a more high hydrophobic stability,with a contact angle of 75.0° up to 10 days,was observed for Ar plasma treated PMMA IOL.It is also shown in UV-vis measurements that light transmittances of the four samples also keep stable values within visible light region,and that their ultraviolet absorptions are improved clearly and up to 78%for the PMMA IOL modified by N2 plasma.Moreover,platelets and cells in vitro assays demonstrate that PMMA IOL modified by four gases plasma can inhibit the platelets and cells adhesion,which can reduce the incidence of posterior capsular opacification phenomenon after PMMA IOL implantation.(2)HEMA was graft-polymerized onto plasma activated PMMA IOL by high-frequency DBD plasma-induced graft polymerization in the Ar discharge medium.This section investigated surface chemical composition,morphologies,hydrophilicity,light transmittance,platelets adhesion and cell compatibility,etc.for the PMMA IOL-g-PHEMA.The results show oxygen content of PMMA IOL-g-PHEMA surface increases,and obtained materials become more hydrophilic due to hydrophilic groups like-COO’ and-OH in HEMA structure.In addition,the results show reasonably good hydrophilic stability in the first few days,whereas a hydrophilic stability,with a low contact angle of 36.5° up to 15 days,was observed for PMMA IOL-g-PHEMA2.Light transmittances keep stable values within visible light region,and their ultraviolet absorptions are also improved clearly,77%.Platelets and cells in vitro assays demonstrate that the PMMA IOL-g-PHEMA2 can inhibit the platelets and cells adhesion,and is more effective than sample modified by pure gas plasma.2.Surface modification of Mg alloyCombining anticorrosive abilities of diamond-like carbon(DLC)and MgO films,antibacterial behaviors of Ti-O films,and blood compatibility of 2-methacryloyl-oxyethyl phosphorylcholine(MPC),this section fabricated DLC films and functional multi-molecular layers onto the Mg alloy surface via radio-frequency plasma chemical vapor deposition and plasma combined with sol-gel technology.As a result,several important properties,such as bio-anticorrosion,antibacterial activities and blood compatibility,have been improved efficiently.(1)Nanostructural DLC films were coated onto the surface of Mg alloy(MgA)through radio-frequency plasma chemical vapor deposition with acetylene as carbon source and Ar as assistant gas.The effects of various parameters,such as discharge power and deposition time,on the surface morphologies of MgA/DLC were investigated,and the surface chemical composition,morphologies,hydrophilic properties and anticorrosion were also examined,respectively.The results show that the films are consisted of sp2/sp3 hybrid non-crystalline carbon nano-particles whose size are about 50 nm,resulting in super-hydrophobic,uniform and dense films.In simulated body fluid(SBF)solution,the MgA/DLC exhibits good anticorrosion.Moreover,platelets in vitro assays demonstrate that the MgA/DLC can inhibit the platelets adhesion,showing excellent blood compatibility.(2)MgO(Mg2SiO4)/Ti-O/PMPC multi-molecule layers were fabricated successfully onto the Mg alloy surface by plasma micro-arc oxidation,sol-gel and high-frequency DBD plasma-induced graft polymerization.This section investigated the effects of discharge voltage and discharge time of micro-arc oxidation on the surface morphologies of the MgO(Mg2SiO4)films,and the chemical composition,morphologies,hydrophilic properties,anticorrosion,platelets adhesion and antibacterial properties on the MgO(Mg2SiO4)/Ti-O/PMPC multi-molecule layers surface,respectively.The results show that the modified surface becomes more hydrophilic due to the hydrophilic groups-N+(CH3)3.The anticorrosion in SBF solution enhance due to the layers of MgO(Mg2SiO4)/Ti-O in assemblied structures.Moreover,introduction of TiO2 and MPC into the modified Mg alloy surface can clearly inhibit blood staphylococcus growths and platelet adhesion,showing excellent antimicrobial activity against staphylococcus aureus and blood compatibility. |
