【作者】 赵静辉；

【导师】 周延民；

【作者基本信息】 吉林大学 ， 口腔临床医学， 2010， 博士

【摘要】 自从Branemark教授提出骨整合(Osteointegration)理论以来,种植体与周围骨组织的骨性结合是目前人们公认的评价种植义齿成功与否的最重要的标准之一。为了达到这一标准,许多学者在种植体材料及表面处理方面做了大量的工作,目前研究的焦点主要是如何提高种植体周围骨形成速度、缩短骨愈合时间及提高邻近骨组织的矿化程度,从而缩短种植义齿的疗程。传统的种植体表面改性方法,如等离子体喷涂技术由于存在涂层的溶解、剥脱等问题,限制了其在临床的应用。因此本研究采用射频低温等离子体方法,以庚胺为聚合单体,在纯钛种植体表面引入具有生物活性的氨基功能团,利用原子力显微镜、X射线光电子能谱仪、接触角测量仪等对改性后表面的理化性能及稳定性进行分析,筛选、确定了最佳的等离子体放电实验参数。并以未处理的纯钛表面作为对照,研究了三种不同放电模式等离子体改性表面的生物相容性。通过本实验,得出以下结论：1、连续波放电在钛表面产生高度交联的聚合膜,在纯水及75%的酒精中浸泡后最稳定,但表面引入的氨基量最少；2、脉冲放电模式表面引入的氨基较多,但形成的表面不稳定,在纯水及75%酒精中浸泡后表面聚合膜变得不连续；3、连续波偶联脉冲模式表面引入的氨基量最多,并且最稳定,为低温等离子体纯钛表面改性的最佳处理模式；4、通过射频低温等离子体氨基改性,大大改善了纯钛种植体表面的生物相容性,促进了成骨样细胞早期的黏附及伸展,增强了成骨样细胞的增殖活性,同时抑制了成纤维细胞的黏附及生长；5、连续波偶联脉冲模式改性表面具有最佳的细胞相容性。上述结果表明,连续波偶联脉冲的放电模式在纯钛表面引入的氨基密度最高,并且改性后表面最稳定。体外实验证实,等离子体氨基改性后明显提高了纯钛表面的生物相容性,促进了成骨样细胞的黏附及伸展,增强了成骨样细胞在种植体表面的增殖能力。本研究证实此方法作为纯钛种植体表面改性方法是可行的,可以在纯钛种植体表面引入大量、稳定的氨基,为氨基等离子体改性技术在种植体表面的应用奠定了实验基础,提供了理论依据。更多还原

【Abstract】 Experimental research on amine-containing plasma modification of pure titanium implant surfaceSince Professor Branemark proposed the Osteointegration theory, the direct contact between implant and bone has been regarded as one of the most important standards to evaluate whether the implant is successful or not. Therefore, to conform to this standard, many scholars have put lots of effort on the fundamental and clinical research to get the best healing effect. At present, more attentions are paid to surface modification of dental implants, to get the better biocompatibility on dental implant surface through physical, chemical or biological methods. As a result, the speed of formation of new bone around implant will be accelerated and the connection of implant and bone will be strengthened, which will improve the stability and success rate of implant.Presently the surface modification methods mainly include:the methods to change the roughness of implant surface (for example sand blasting, acid etching, sand blasting+acid etching and so on), surface coating technology (plasma spray coating, sol-gel coating, ion beam assistance deposition, electrical deposition and so on), oxidation treatment (for example anodic oxidation, micro arc oxidation, thermal oxidization and so on), nitriding, alkali or alkali heat treatment, ion implanting, biochemical modification, self-assembling monolayers technology, physical vapor deposition, chemical vapor deposition and so on. Although some methods have been used in clinical work, most of methods above are still in research stage, and there are some problems about them, such as the unstable coating, dissolution, delamination, the release increase of titanium ion, the acid, alkali or electrolyte remaining, the complex operation, the unstable modified surface and the difficult controlled effect. Therefore, it is urgent to seek an effective and easily controlled method to modify the implant surface without high-temperature treatment or stress on interface of implant and coating.Some research indicated that the chemical character of biomaterial surface will influence the adsorption of protein and molecule, such as fibronectn、integrin、ECM、paxillin、actin and so on, and adjust the response of cell on it, deciding the healing response and speed of implant. This experiment is precisely based on this point, to seek a method to improve the adhesion and growth of osteoblast-like cells and accelerate the osteointegration of implant.The amino group is one of organic functional groups of organism. In human body, protein and many carbohydrate compound contain massive amino groups, thus the amino group has the high affinity in the structure with tissue. Moreover, the amino groups could be the locating site of protein and enzyme. Obviously, modification with amino group will improve the biocompatibility of biomaterial.The low temperature discharge plasma, namely the plasma enhanced chemistry vapor deposition (PECVD), means under high energy from discharge the chemical bond of vapor will be broken and recombine on material surface, and develop a functional coating with different chemical composition. This method has following merits:firstly, the radio frequency does not need the electrode in the plasma reaction chamber, which cannot introduce the impurity from the electrode, avoiding the contamination to modified surface; secondly, the modification is conducted at low temperature, which results in no-stress interface between polymer film and Ti; thirdly, low temperature plasma can modify all kinds of shape materials, especially complicated implant surface, with ultra thin, uniform and pinhole-free film, and the film bonding substrate by covalent bond with strong connection; finally, the most important thing is the low temperature plasma modification belongs to dry chemical method, which is easy to operate with well-controlled result, and the repeatability of result is good. At the same time, plasma can sterilize samples while surface modified. In addition, the low-temperature treatment combined with pulse, which introduces duty cycle, will activate some sole organic molecule and do not destroy their basic chemistry function, which result in producing stable, specific and functional surface. This experiment is mainly divided into two parts as followed:The first part:to determine plasma parameters and to analyze the physics and chemistry performance and stability of modified surface with different parameters.The present experiment mainly studied low-temperature plasma polymerization on titanium implant surface and its biological application. Using Heptylamine as monomer, through the radio frequency (RF,13.56 MHz) low temperature plasma, we modified titanium surface with the-NH2 functional group, to improve its biocompatibility. Firstly, to determine the plasma experiment parameter, we modified titanium surface with different plasma parameters, such as the electric discharge power, the discharge time, the electric discharge pattern, the duty cycle and the sample position and so on. We studied the effect of these parameters on the structure, chemical composition and density of functional group of polymer film and the stability of polymer film in pure water and 75% ethanol. The X-ray photoelectron spectroscopy, atomic force microscopy and contact angle measurement instruments were used to study the structure, composition, texture, solubility, stability of modified surface.The second part:taking untreated titanium as a control group, to evaluate the biocompatibility in vitro of modified surface with different plasma parameters.The inverted microscope, the fluorescence microscope and scanning electronic microscope were used to investigate the initial adhesion, shape and distribution of osteoblast (SaOs-2) and fibroblast (L929) on modified surface. The cells on samples were automaticlly counted with ImageXpress system. The functional state of actin on different samples dyed with FITC was analyzed with laser scanning confocal microscope, and the shape and adhesion area of SaOs-2 dyed with PKH26 on different modified surface were analyzed. In addition, the effect of different modification on the proliferation of SaOs-2 was statistical analyzed with MTT method.The results indicated as follows:1. Comparing three different plasma discharge modes, the continuous wave discharge produced cross-linked polymer film with the best stability in pure water and 75% ethanol, but the amino groups introduced were least;2. The pulse discharge introduced more amino groups, but the modified surface was unstable, and the polymer film became not continuous with signal of substrate emerging in XPS result after soaking in pure water and 75% ethanol for 30 min;3. The continuous wave coupled pulse mode discharge introduced the most amino groups with better stability in pure water and 75% ethanol, which means this is the optimal mode for modifying titanium with plasma;4. Through the radio frequency low temperature plasma modification with amino groups, the biocompatibility of titanium was improved, facilitating the adhesion, spreading and proliferation of osteoblast. At the same time inhibited the adhesion and growth of fibroblast;5. The cell compatibility of titanium modified with continuous wave coupled pulse mode was the best.On the base of the results above, we can conclude as follows:The biocompatibility of titanium implant modified with amino-containing plasma functionalization was improved significantly, developing the functional surface with bioactivity; in which continuous wave coupled pulse mode was the best condition for modifying titanium with plasma discharge. The radio frequency low temperature plasma modification was practicable to introduce amino group on titanium surface, and as a new method for titanium implant surface modification, it has a broad prospect.更多还原