国产膨体聚四氟乙烯的预处理及其细胞毒性评价

在评价圆产膨体聚四氟乙烯的细胞毒性和预处理方法的优劣的基础上,寻找国产替代材料,并比较国产膨体聚四氟乙烯与进口材料的细胞毒性.采用MTT(四甲基偶氮唑蓝)法检测经过不同方法预处理的国产膨体聚四氟乙烯和进口材料的细胞毒性.按细胞毒性分级的国家标准对其进行分级,评价其细胞毒性.结果表明,以上各组材料毒性级别均为1级,即无细胞毒性.国产膨体聚四氟乙烯具有良好的细胞相容性,以高锰酸钾溶液进行预处理可获得最佳效果.     

泡沫碳化硅的生物相容性

依据国家标准 GB/T16886,评价了用"高分子热解结合可控熔渗反应烧结技术一制备的泡沫碳化硅的生物相容性.结果表明:这种泡沫碳化硅没有细胞毒性,没有潜在的皮肤致敏性,遗传毒性试验、皮下和骨植入试验均未见异常反应,具有良好的生物相容性,可应用在外形复杂和长段承重骨缺损的修复.     

甲基哌嗪的气相缓蚀能力探讨

为了开发无毒和低毒的气相缓蚀剂,通过气相甄别试验和湿热试验研究了甲基哌嗪类化合物对钢铁的气相缓蚀能力.结果表明,呱嗪类化合物具有较好的热稳定性和气相缓蚀性能,毒性较低,性能稳定,可作为黑色金属的中短期气相缓蚀剂应用.     

药物载体PAMAM树状大分子的毒理

聚酰胺-胺(PAMAM)是研究最为广泛的一类非病毒载体,其由一个引发核及径向连接的重复支化单元组成.由于其独特的树状结构,PAMAM在药物运载、基因治疗、重大疾病早期诊断等方面具有广阔的应用前景.但是由于PAMAM端基带正电可能会引起其潜在的生物毒性,从而影响其在生物医药方面的应用.目前关于PAMAM树状聚合物的毒性报道比较少且分散.分别从体外和体内总结归纳了PAMAM树状大分子毒性问题的研究进展,并尝试对毒性机理以及表面修饰降低毒性进行了探讨.     

掺锶对羟磷灰石细胞毒性的影响

探讨掺锶对羟磷灰石细胞毒性的影响.合成含锶量分别为1%、5%、10%、100%的锶磷灰石陶瓷,应用MTT法及流式细胞仪法评价其细胞毒性,以纯羟磷灰石和空白培养液作对照.各实验组细胞毒性评级均为0级或1级,无明显细胞毒性,但随着掺锶量的增加细胞毒性有增大趋势;流式细胞仪法证实,锶羟磷灰石无显著细胞毒性.锶磷灰石没有明显细胞毒性,掺锶对羟磷灰石细胞毒性影响较小,锶磷灰石可能具有良好的生物相容性.     

PAMAM树状聚合物的毒理研究

聚酰胺-胺型(PAMAM)树状聚合物是一种新兴的非病毒类纳米材料载体,在药物运载、基因治疗、重大疾病早期诊断等方面具有广阔的研究前景.但载体材料与其相关的免疫反应、细胞毒性以及安全性等方面的报道比较零散,没有进行过系统地归纳.对PAMAM树状聚合物的体外和体内毒性问题进行了归纳和总结,对通过表面修饰降低其毒性方面也进行了论述.     

毒性气体报警仪标定装置的研制

本文介绍了一种毒性气体报警仪标定装置的原理、组成和结构特点,描述了该装置的工作原理、结构、流量控制方式和浓度计算方法。通过对所配制的标准气体不确定度各影响分量的评估,验证了该装置可用于毒性气体报警仪的标定工作。     

固体废物焚烧技术中二恶英的检测与控制技术

二恶英是目前发现的无意识合成的副产品中毒性最强的化合物,已经成为当今环境界和国际媒体关注的热点.本文介绍了二恶英的结构、理化性质、毒性和环境来源,重点论述了固体废物焚烧炉中二恶英的形成因素以及检测,控制技术.     

磷酸钙涂覆炭织物体外细胞毒性的评价

医用植人体的成功与否常常取决于器件植入后细胞与材料表面间的相互作用.采用生物体外测试法考察了声电化学法制备的磷酸钙涂层对炭织物的骨细胞附着、增殖能力的影响.借助MTS检测技术、扫描电子显微镜,选择人类成骨细胞(MG63)作为细胞模型,通过测定细胞与炭织物、磷酸钙涂覆炭织物、以及其各自的提取液作用后的存活能力,研究了细胞/材料的相互作用,并对基底材料的细胞毒性进行了评价.结果表明,炭织物、磷酸钙涂覆炭织物均不具有细胞毒性,且磷酸钙涂层可提高成骨细胞的附着和增殖.SEM图像显示,细胞形貌正常,与对照组相比较生长增殖情况相似.     

纳米颗粒材料的毒性研究与安全性展望

人类接触纳米材料一般通过下面3条途径:呼吸系统;皮肤接触;其他方式,如食用、注射之类.纳米材料通过上述途径进入人体,可能与体内细胞起反应,引起发炎、病变等,因此目前多针对以上接触方式进行纳米颗粒材料的毒性研究.从不同的接触方式介绍了纳米颗粒生物毒性的一些研究情况,对产生生物毒性的原理进行了探索,并对纳米颗粒材料安全性和降低危险性的方法进行了展望.     

Degradation and miscibility of poly(DL-lactic acid)/poly(glycolic acid) composite films: Effect of poly(DL-lactic-co-glycolic acid)

The in vitro degradation behaviour of poly(glycolic acid) (PGA) and its composite films containing poly(DL-lactic acid) (PDLLA) and poly(DL-lactic-co-glycolic acid) (PDLGA) were investigated via mass loss, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). All the films were prepared by solution casting, using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. Since the degradation rate of PDLLA is lower than that of PGA, those of the PDLLA/PGA composite films decreased. As a compatibilizer, PDLGA improved the compatibility and hydrolytic stability of PDLLA/PGA composite films. Changes in the composite films indicate that this kind of PGA-based composite biomaterial may be applicable to device design for clinical application in the future.     

New biocomposite [biphasic calcium phosphate/ poly-DL-lactide-co-glycolide/biostimulative agent] filler for reconstruction of bone tissue changed by osteoporosis

Biphasic calcium phosphate-poly-DL-lactide-co-glycolide composite biomaterial with and without biostimulative agents (protein-rich plasma or fibrin) was synthesised in the form suitable for reconstruction of bone defects. The composite used as filler was obtained by precipitation in solvent-non-solvent systems. The material, calcium phosphate granules covered by polymer, was characterised by wide-angle X-ray structural analysis, scanning electron microscopy, infrared spectroscopy and differential scanning calorimetry. Reparation of bone tissue damaged by osteoporosis was investigated in vivo on rats. The method applied enabled production of granules of calcium phosphate-poly-DL-lactide-co- glycolide composite biomaterial of average diameter 150–200 μm. Histological analysis confirmed recuperation of the alveolar bone, which osteoporosis-induced defects were repaired using composite biomaterial. By addition of biostimulative agents, intensity of osteogenesis increases accompanied by the formation of regular, new bone structure.     

金属生物活性复合材料研究

本文叙述了金属羟基磷灰石生物活生复合材料的制作工艺,讨论了ＨＡＰ溶液中浓度对复合材料中ＨＡＰ含量的影响及ＨＡＰ粒子对复全材料内应力的影响,由实验可知,复合材料中羟基磷灰石含量可高达２２％（质量分数）。     

Hydroxyapatite-alginate biocomposite promotes bone mineralization in different length scales in vivo

Tissue engineering is a multidisciplinary research area that aims to develop new techniques and/or biomaterials for medical applications. The objective of the present study was to evaluate the osteogenic potential of a composite of hydroxyapatite and alginate in bone defects with critical sizes, surgically made in the calvaria region of rats. The rats (48 adult males), Rattus norvegicus Wistar, were divided into two groups: control (without composite implantation) and experimental (with composite implantation) and analyzed by optical microscopy at the biological time points 15, 45, 90 and 120 d, and transmission electron microscopy 120 d after the implantation of the biomaterial. It was observed that the biomaterial presented a high degree of fragmentation since the first experimental points studied, and that the fragments were surrounded by new bone after the duration of the project. These areas were studied by analytical transmission electron microscopy using an energy dispersive X-ray spectrometer. Three regions could be distinguished: (1) the biomaterial rich in hydroxyapatite; (2) a thin contiguous region containing phosphorus but without calcium; (3) a region of initial ossification containing mineralizing collagen fibrils with a calcium/phosphorus ratio smaller than the particles of the composite. The intermediate region (without calcium or containing very low amounts of calcium), which just surrounded the composite had not been described in the literature yet, and is probably associated specifically to the biocomposite used. The high performance of the biomaterial observed may be related to the fact that alginate molecules form highly anionic complexes and are capable of adsorbing important factors recognized by integrins from osteoblasts. Regions of fibrotic tissue were also observed mainly in the initial experimental points analyzed. However, it did not significantly influence the final result. In conclusion, the biomaterial presents a great potential for application as bone grafts in the clinical area.     

Characterization and his

Several studies, devoted to the osteogenic potentialities of natural CaCO3 have already been reported. However, it seems questionable if the data obtained from natural calcium carbonates can be extrapolated to a composite biomaterial incorporating coralline material. For these reasons, in the present investigations the structural and crystallographic features of the biomaterial (Biocoral® gel) were thoroughly analyzed prior to implantation, with the aid of X-ray diffraction and electron microscopy. Then, biopsied samples, taken from Biocoral® gel-filled sites, respectively after 7, 8, 9, 12 and 29 mon implantation, were studied with optical and electron microscopy. It could be concluded from the histological analyses of the biopsies, that mineral still remained after long implantation periods. This composite biomaterial may thus be considered for uses in clinical situations where neither incorporation nor dissolution of the implanted biomaterial are essential, i.e. maintenance of edentulous ridge volume. © 1999 Kluwer Academic Publishers     

生物材料对细胞生物学行为的影响

随着细胞生物学、基因工程等研究领域的发展,临床使用的生物医用材料已经由单纯的生物材料制成的植人物,发展成细胞与生物材料的复合物.生物医用材料不仅应具备生物安全性、生物相容性、血液相容性,还应该具有细胞外基质的作用.本文综述了生物材料作为细胞外基质,对细胞粘附、细胞生长及细胞凋亡的影响.     

Hydroxyapatite-alginate biocomposite promotes bone mineralization in different length scales in vivo

Tissue engineering is a multidisciplinary research area that aims to develop new techniques and/or biomaterials for medical applications. The objective of the present study was to evaluate the osteogenic potential of a composite of hydroxyapatite and alginate in bone defects with critical sizes, surgically made in the calvaria region of rats. The rats (48 adult males), Rattus norvegicus Wistar, were divided into two groups: control (without composite implantation) and experimental (with composite implantation) and analyzed by optical microscopy at the biological time points 15, 45, 90 and 120 d, and transmission electron microscopy 120 d after the implantation of the biomaterial. It was observed that the biomaterial presented a high degree of fragmentation since the first experimental points studied, and that the fragments were surrounded by new bone after the duration of the project. These areas were studied by analytical transmission electron microscopy using an energy dispersive X-ray spectrometer. Three regions could be distinguished: (1) the biomaterial rich in hydroxyapatite; (2) a thin contiguous region containing phosphorus but without calcium; (3) a region of initial ossification containing mineralizing collagen fibrils with a calcium/phosphorus ratio smaller than the particles of the composite. The intermediate region (without calcium or containing very low amounts of calcium), which just surrounded the composite had not been described in the literature yet, and is probably associated specifically to the biocomposite used. The high performance of the biomaterial observed may be related to the fact that alginate molecules form highly anionic complexes and are capable of adsorbing important factors recognized by integrins from osteoblasts. Regions of fibrotic tissue were also observed mainly in the initial experimental points analyzed. However, it did not significantly influence the final result. In conclusion, the biomaterial presents a great potential for application as bone grafts in the clinical area.     

Fourier-transform infrared spectroscopy study of an organic–mineral composite for bone and dental substitute materials

A new injectable biomaterial for bone and dental surgery is a composite consisting of a polymer as a matrix and bioactive calcium phosphate (CaP) ceramics as fillers. The stability of the polymer is essential in the production of a ready-to-use injectable sterilized biomaterial. The purpose of this study was to detect possible polymer degradation which may have been caused by the interaction with the fillers using Fourier transform infrared spectroscopy. Composites containing CaP fillers (biphasic calcium phosphate, hydroxyapatite and peroxidized hydroxyapatite) and polymer (hydroxypropyl methyl cellulose) were prepared. To investigate the properties of the polymer, the inorganic and organic phases of the composite were separated using several extraction methods. The difficulty in separating the organic (polymer) from the mineral (CaP fillers) phases in the composite investigated in this study suggested the presence of strong interactions between the two phases. Spectra of extracted polymers showed new absorption bands of low intensities and indications that some chemical modifications of the original polymers have occurred. Results also indicated that the filler composition has an effect on the integrity of the polymer.     

In vivo evaluation of a new composite mesh (10% polypropylene/90% poly-<Emphasis Type="SmallCaps">l</Emphasis>-lactic acid) for hernia repair

The increasing use of mesh insertion for groin hernia repair is dashed by a worrying prevalence of chronic pain frequently related as a reaction to the biomaterial implantation. Thus, new biocompatible prosthesis, designed as a composite material associating polypropylene (PP) and long-term absorbable material, are now under development. In the present study, the typical commercially available Prolene mesh has been compared to two new meshes designed with 3-fold less PP, either alone (light PP) or associated with poly-L-lactic acid (PP-PLA) accounting for 90% of the mesh weight. These PP-mesh variants were implanted in an extraperitoneal position within the abdominal wall of 90 rats. Mesh adhesion and size were determined at autopsy 2, 4 and 8 weeks after implantation (10 animals per group) and morphometric parameters of the host tissues by light microscopy. Prolene and light PP-meshes presented intra-corporeal shrinkage and tissue adhesion, both more pronounced with light-PP, whilst PP-PLA meshes were not affected in spite of a strongest fibrosis. In contrast to Prolene and even more with light PP meshes, inflammation and cell-mediated immune responses were reduced without occurrence of angiogenesis or oedema. All these findings advocate together for a better tolerance of this new composite biomaterial, more likely due to a low macrophage response that appeared statistically correlated to the absence of mesh shrinkage and to a decreased adhesion to the tissue. On the basis of these experimental observations, it could be expected that the better tolerance of this composite biomaterial may avoid both long-term pain and recurrence when used as plug in groin hernia repair.     

A review on biodegradable polymeric materials for bone tissue engineering applications

Biodegradable polymer scaffolds have played a significant role in wide range of tissue engineering application such as bone scaffolds since the last decade. The aim of this article is to provide the comprehensive overview of biocompatible and biodegradable polymer materials and composite materials with their advantages and drawbacks in the application of biomaterial scaffolds, furthermore the properties and degradation criteria of the biomaterials are discussed in this review.