RGD肽修饰TiO2纳米管对成骨细胞黏附的影响

目的：评价RGD肽修饰的TiO2纳米管涂层对小鼠胚胎前成骨细胞MC3T3-E1早期生长粘附的影响。方法：利用化学偶联的方法在TiO2纳米管表面引入活性氨基,然后共价接枝RGDC多肽,采用SEM和荧光显微镜对纳米管改性后的形貌进行观察,并用SEM和活死细胞染色的技术观察MC3T3-E1细胞的早期黏附的细胞行为。结果：黏附肽修饰后的材料表面细胞早期黏附的数目更多,铺展的面积更大,丝足更多。结论：采用化学偶联活性RGD肽修饰可以提高TiO2纳米管对成骨细胞早期附着铺展作用。     

Short-term plasma-cleaning treatments enhance in vitro osteoblast attachment to titanium.

The purpose of this research was to characterize the in vitro cellular behavior of osteoblast-like cells on titanium surfaces prepared with argon plasma-cleaning (PC) treatments for various lengths of time. The highest levels of cell attachment were observed for surfaces which had been plasma-treated for one min. Surface analyses indicated that although PC treatments dramatically improved surface wettability, the presence of inorganic contaminants was observed with longer treatment times and may have interfered with cell attachment. Further work is suggested to investigate the longer-term phenotypic expression of osteoblasts when grown on implant surfaces.     

纤维连接蛋白模拟多肽改进碳磷酸钙骨水泥反应性的体外研究

目的:寻找改进羟基磷灰石类骨修复材料生物活性的方法.方法:用固相法合成了多肽P19和P18,测定了P19与羟基磷灰石的结合特性,测定了P19对于成骨细胞附着的影响以及在P18与P19存在的条件下,成骨细胞的增殖特性,并用扫描电镜观察了附着在碳磷酸钙骨水泥(calcium carbonated phosphate cement,CPCC)材料表面的成骨细胞形态,并用DNA测量法测定了细胞在材料表面增殖特性.结果:P19铺板后能增强P18促进细胞增殖的作用.多肽分子P19对于成骨细胞的作用与纤维连接蛋白类似,多肽和CPCC结合后仍然保持其各自的生物活性,吸附在材料表面的P19能够促进成骨细胞在材料表面的附着,经过P19多肽修饰的CPCC表面能够明显增加成骨细胞吸附的数量,并能够促进成骨细胞的增殖.P18和P19之间存在一定的协同作用.结论:合成的P19融合肽可以作为HA类骨损伤修复材料的生物活性添加成分以及种植体涂层的修饰,这一方法和技术在HA骨修复材料的改进以及种植体涂层修饰方面有着潜在的临床应用前景.     

DICOR surface treatments for enhanced bonding

Treatments for preparing castable ceramic surfaces for enhanced bonding to specially formulated resin-based cements were examined. An ammonium bifluoride etch combined with gamma-methacryloxypropyl-trimethoxysilane produced shear bond strengths higher than when an ammonium bifluoride treatment was used alone. The method of curing the silane was highly significant in the contribution to the cement/substrate bond strength, with the heat-cure producing the highest values. Long-term water storage tests indicated that the cement bond with etch plus silane-treated castable ceramic surfaces (whether heat or chemically cured silane was used) demonstrated no significant decrease in strength after a one-year period.     

Effects of dissolved calcium and phosphorous on osteoblast responses

The dissolution behavior of hydroxyapatite (HA) and its effect on the initial cellular response is of both fundamental and clinical importance. In this study, plasma-sprayed HA coatings were characterized by X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). Calcium (Ca) and inorganic phosphorous (Pi) ions released from plasma-sprayed HA coatings within 3 weeks were measured by flame atomic absorption and colorimetrically molybdenum blue complex, respectively. To investigate the effect of dissolution of HA coatings on osteoblast response, additional Ca and Pi were added into the cell culture media to simulate the dissolution concentrations. Human embryonic palatal mesenchyme cells, an osteoblast precursor cell line, were used to evaluate the biological responses to enhanced Ca and Pi media over 2 weeks. Osteoblast differentiation and mineralization were measured by alkaline phosphatase-specific assay and 1,25 (OH)2 vitamin D3 stimulated osteocalcin production. The coatings exhibited an HA-type structure. FTIR indicated the possible presence of carbonates on the coatings. A dissolution study indicated a continual increase in Ca and Pi over time. In the cell culture study, enhanced osteoblast differentiation occurred in the presence of additional Ca concentration in the cell culture media. However, additional Pi concentration in the cell culture media was suggested to slow down osteoblast differentiation and mineralization.     

Adenovirus encoding BMP-7 immobilized on titanium surface exhibits local delivery ability and regulates osteoblast differentiation in vitro

Objective

The local delivery of growth factors such as bone morphogenetic protein-7 (BMP-7) into the tissues around dental implants may improve their osseointegration. We have designed a new method of attaching BMP-7 to a titanium surface and assessed both the retention of the BMP-7 and its effect on osteoblast differentiation.

Design

Adenoviral vector expressing BMP-7 was attached to dental titanium discs by hexon-specific antibodies in a type I collagen–avidin gel. FITC-labelled secondary antibody was used to measure the continuing adherence of the coating after repeated rinsing. Osteoblasts were harvested and seeded on the titanium discs. Gene transduction efficiency and targeting ability were assessed after 24 h. Surface morphology was observed by SEM. Cell proliferation and alkaline phosphatase (ALP) activities were measured.

Results

The anti-adenohexon antibody adhered strongly to the collagen–avidin gels. BMP-7 gene expression was localized precisely to cells growing on the gels bound by the hexon-specific antibody. Osteoblasts on the titanium containing Ad-BMP-7 had a higher ALP activity than those without Ad-BMP-7.

Conclusions

This study describes a novel technique for the precise attachment of BMP-7 to titanium surfaces. The process may enhance the osseointegration of dental implants.     

Effect of storage media upon the surface micromorphology of resin-based restorative materials

The aim of this study was to evaluate the effect of different storage media upon the surface micromorphology of resin-based restoratives. One resin-modified glass-ionomer (Fuji II LC Improved), one polyacid-modified composite resin (Dyract AP), one microfilled composite resin (Durafill VS), and one hybrid composite resin (Filtek Z250) were tested. For each material, 45 standardized cylindrical specimens were randomly made. After 24 h, samples were finished and polished, and their surface roughness measured to obtain Ra (micro m) baseline values (Bv). Fifteen specimens of each material were then stored at 37 +/- 1 degrees C, for 24 h, either in distilled deionized water or in artificial saliva, or else subjected to a pH-cycling regimen. At the end of 10 days of storage, final readings (Fv) of surface roughness were obtained. The Analysis of Covariance (alpha=0.05), considering the covariate Bv showed a significant interaction between restorative materials and storage media (P value=0.0000). Multiple comparison Tukey's test revealed that the surface roughness of resin-based restoratives subjected to a pH-cycling model was significantly higher compared with both distilled deionized water and artificial saliva. Micromorphological changes were noticed in a situation of acid challenge.     

微弧氧化钛基种植材料对成骨细胞早期黏附的影响

目的：检测纯钛种植体材料微弧氧化（microarc oxidation，MAO）表面改性后的成骨细胞生物相容性，探讨微弧氧化技术在钛种植体表面改性中的价值。方法：在纯钛种植体材料表面用微弧氧化法制备羟基磷灰石陶瓷薄膜，将MAO改性钛种植体材料作为实验组Ⅰ，将纯钛表面阳极氧化改性处理的种植体材料作为实验组Ⅱ．并设立对照组Ⅰ（纯钛种植体材料）和对照组Ⅱ（即细胞直接生长在培养板上），分别进行扫描电镜（SEM）、能谱分析（EDS）、X射线衍射图谱分析（XRD）等检测，比较成骨细胞的黏附水平，对数据采用SPSS11．0统计软件包进行单因素方差分析。结果：MAO改性后生成粗糙、多孔的陶瓷薄膜层，与处理前电解液成分相比，钙磷比无显著改变。MAO改性钛组黏附的细胞密度显著高于其他组（P〈0．01），而对照组Ⅰ、Ⅱ的细胞密度无显著差异（P〉0．05）。结论：与阳极氧化表面改性材料相比，该钛基微弧氧化薄膜层能够显著促进成骨细胞的附着，具有良好的细胞相容性。     

牵张应力特征和成骨细胞生物学效应的体外研究现状

成骨细胞的体外培养,有助于研究和阐明牵张应力下骨组织适应性改建的机制。牵张力能有效促进成骨细胞的活性,因此是近年来研究的热点。尽管直接施加在骨骼上的力能够测量,但是成骨细胞周围的机械力学微环境却很难估计。迄今为止,已经设计出多种机械装置,能够产生单轴或双轴牵张力。根据实验目的不同,研究者常选择不同的加力参数,如力值大小、波形、频率、周期数及加力时间等。尽管这些体外实验的结果不尽相同,但仍然可以归纳出成骨细胞在牵张应力下的一些生物学特征。本文就牵张应力及其相应的力学装置、牵张力调控成骨细胞增殖分化的机制和牵张应力各施力参数对成骨细胞的影响做一综述。理解这些特性,对于骨再生和骨生物工程的临床应用具有重要指导意义。     

Cellular responses to the dispersion amalgams in vitro.

Three dispersion amalgams were tested in vitro. Spherical-D and Dialloy showed very similar effects on the cells as did the Spherical and fine cut amalgams. The other disperison amalgam, Dispersalloy, had intense and persistent cytotoxicity even 24 hours after trituration. Difference of the results was presumed to result from different alloy composition.     

脂多糖刺激小鼠成骨细胞表达白细胞介素-23的实验研究

目的:研究小鼠成骨细胞能否在细菌毒素产物脂多糖刺激下表达白介素-23(IL-23).方法:分别以小鼠骨髓基质干细胞(BMSCs)及小鼠成骨前体细胞系MC3T3-El体外诱导为成骨细胞后,加以l0ng/ml LPS刺激,采用ELISA法检测IL-23的蛋白表达.并采用RT-PCR方法检测脂多糖刺激下小鼠BMSCs诱导成骨...     

In vitro preliminary study of osteoblast response to surface roughness of titanium discs and topical application of melatonin

Objectives: To observe human osteoblast behavior cultured in vitro on titanium discs (Ti) in relation to surface roughness and melatonin application. Study Design: Human osteoblasts (MG-63) were cultured on 60 Ti6Al4V discs divided into three groups: Group I: discs treated with dual acid etching; Group II dual acid etching and blasting with calcium phosphate particles; Group III (control) machined discs. Surface roughness and topography of the discs were examined with scanning electron microscope (SEM) and confocal laser scanning electron microscope( CLSM). Osteoblast adhesion, proliferation and cell morphology were determined by means of fluorescence microscopy with Image-Pro Plus software and SEM. Results: Group II presented the roughest discs, while the least rough were Group III. Cell adhesion was greatest in Group II. The addition of melatonin improved cell proliferation. Conclusions: 1. Surface treatments (dual acid etching, calcium phosphate impaction) increase surface roughness in comparison with machined titanium. 2. Greater surface roughness tends to favor cell adhesion after 24-hour cell culture. 3. The addition of melatonin tends to favor osteoblast proliferation. Key words:Osteoblasts, titanium, roughness, melatonin, dental implants, osseointegration.