纳米羟基磷灰石/胶原复合材料制备方法研究

研究了在脱钙骨基质内原位沉积纳米羟基磷灰石的电化学方法,探讨了影响沉积的实验因素和条件.并利用红外光谱和X衍射表征无机相的组成,透射电子显微镜观测晶体的形态和尺寸,光学显微镜观察无机相分布,灰化法测定无机成分含量.结果表明,电化学方法可以制备出纳米羟基磷灰石/胶原复合材料,其无机成分为53 9±3.2%,并且无机相的组成、分布、性质与自然骨非常一致,是纳米复合材料.     

生物硬组织材料羟基磷灰石--从天然到人工合成

回顾哺乳动物体硬组织材料无机组成羟基磷灰石的结构部分,综述了以羟基磷灰石为中心的种种生物材料．以及通过组织工程活化的羟基磷灰石与高分子复合材料代表硬组织修复材料的发展方向。     

羟基磷灰石水泥的体外生物学安全性试验

羟基磷灰石水泥(HAC)是新型的羟基磷灰石类人工骨材料。1991年得到美国食品与药物管理局(FDA)的批准,在临床试用,用于颅骨缺损的填充治疗。华东理工大学最近研制出类似的HAC。我们用它的生理盐水浸出液对其进行了生物学安全性试验,包括细胞培养毒性试验、全身注射毒性试验、Ames试验、微核试验及UDS试验。结果表明HAC的浸出液对培养细胞的生长无抑制作用,对体细胞的遗传物质(染色体、DNA)无致突变作用。上述结果提示我们,HAC用于人体是安全的。     

羟基磷灰石在自体牙移植术中的临床应用：附30例报告

本文报告３０例在自体牙移植术中,应用羟基磷灰石填充于受牙牙槽窝内,经过１－３年的随访观察,结果表明,羟基磷灰石在牙移植术中有促进和引导牙槽骨的形成和在 与牙根面形成紧密的骨粘合,使供牙得到良好固位和恢复咀功能,成功率达９３％以上。     

羟基磷灰石/胶原类骨仿生复合材料的制备方法及机理

天然骨除了含有羟基磷灰石无机成分外,还有胶原、糖蛋白等少量的有机成分,这种混杂结构使骨具有独特性能。因此模拟天然骨的形成机制,采用仿生的方法制备羟基磷灰石／胶原类骨材料以再生骨的生物学和力学性能势在必行。本就制备羟基磷灰石／胶原类骨仿生复合材料的方法及体外模拟天然骨生物矿化和材料自组装的形成机制进行了综述。     

羟基磷灰石／聚乳酸及其共聚物复合生物材料

阐述了羟基磷灰石、聚乳酸和聚乙醇酸各自的结构性能特点;总结了两者通过复合有望得到具有良好力学性能、生物相容性、骨传导性的可降解羟基磷灰石／聚乳酸复合生物材料;最后展望了这类复合生物材料的发展方向。     

PGDE交联纳米羟基磷灰石/丝素蛋白复合材料

由纳米羟基磷灰石(HA)与丝素蛋白(SF)复合而成的新型生物复合材料,具有优良的生物相容性,已被研究用作骨移植及填充材料,但其由丝素蛋白分子内交联导致的较差的力学性能,限制了该复合材料的应用。本研究中,采用一种名为聚乙二醇二缩水甘油醚(PGDE)的交联剂对复合材料中的丝素蛋白进行改性。该改性的复合材料经过一系列的检测,结果显示交联剂PGDE可以提高丝素蛋白的结晶性,复合材料HA/SF的抗压强度提高了100%,且该交联剂并没有影响复合材料的生物相容性。     

猪骨羟基磷灰石的结构稳定性

在不同酸碱条件下对猪骨处理,利用转靶Ｘ射线衍射（ＸＲＤ）、红外吸收（ＩＲ）、差热分析（ＤＴＡ）分别对猪骨的物相和微结构进行了分析,并与纯的羟基磷灰石（ＨＡ）进行了比较,研究了猪骨中纳米羟基磷灰石的结构稳定性。实验表明猪骨在弱酸弱碱溶液中羟基磷灰石相是稳定的,但晶粒尺寸、结晶度和非晶含量有所变化。６００°Ｃ的高温处理,可改善其结晶度,这对开发新的骨移植材料有重要意义     

国产羟基磷灰石纯化单克隆抗体的探讨

据文献报道,用羟基磷灰石(HA)柱层析纯化单克隆抗体(MAb)具有简便快速、低成本、高效以及适用于各类和亚类免疫球蛋白等优点。国内近年来已有一些实验室开展这方面的工作,但迄今所见文献中所采用的HA材料均系美国Bio-Rad公司的产品,尚未见采用国产HA纯化MAb的报道。我们以市售国产HA制成层析柱,对本室研制的抗促卵     

羟基磷在石水泥的体外生物学安全性试验

羟基磷灰石水泥是新型的羟基磷灰石类 工骨材料。１９９１年得到美国食品与药物管理局的批准,在临床试用,用于颅骨缺损的填充治疗。华东理工大学最后研制了类似的ＨＡＣ。我们用它的生理盐水浸出液对其进行了生物学安全性试验、包括细胞培养毒性试验,全身注射性试验,Ａｍｅｓ试验,微核试验     

几丁聚糖在组织工程中的应用

支架材料作为组织工程的生物学植入替代物,对细胞移植与引导新组织生长有重要的作用。几丁聚糖可制成无毒性,无刺激性,生物相容性和生物可降解性良好的生物医用材料,在人工皮肤,骨修复材料,手术缝线等方面已广泛应用。本文分析了纯几丁聚糖支架结构和它与其他天然或合成材料复合的支架结构的物理、化学性质及其独特的生物学功能,同时还进一步介绍了其应用的范例并探讨了发展前景。     

聚羟基丁酸己酸酯及其在组织工程中的应用

绍了羟基丁酸酯-羟基己酸酯共聚物的降解性、亲水性、力学性能、表面形态,改性研究、细胞相容性、降解产物的毒性等性能,并对这种材料在组织工程中的应用现状作了阐述,提出了需要改进研究的方向,指出这种微生物来源的新型生物医药材料在组织工程的应用中将具有极大的潜力。     

Letter: Filamentous bacterial viruses. X. X-ray diffraction studies of the R4-protein mutant

Eukaryotic DNA fragments that are totally denatured by alkali swiftly re-form duplex regions that are several hundred up to several thousand nucleotide pairs in length. A combination of sedimentation and electron microscopic studies demonstrate that they arise by the folding-back of a single linear chain, and not from cross-linking between the two complementary chains. Thus these “hairpin”-like structures must come from inverted repetitions of the type A B C t C′B′A′ that are located at intervals along the chromatid. Electron microscopic studies, reveal no unpaired single-chain regions in the “turn-around” t. The resistance of these hairpins to single-chain specific nucleases indicates that t must only consist of a few nucleotides. Therefore we call these regions in double-chain DNA palindromes, because, given the antiparallel arrangement of the polynucleotide chains, these sequences read the same both backwards and forwards. The thermal stability profile of these hairpins is nearly identical to that of sonicated duplex fragments of comparable length. Since these hairpins have the same average base composition as bulk DNA, the palindromes are nearly perfect. By studying the fraction of DNA retained on hydroxyapatite as a function of chain length, one may determine the distribution of palindromes along the DNA. These experiments are best explained by clusters of palindromes located at intervals of 10 to 80 /gm depending on the species. The presence of such long, well-matched palindromes suggests that the linear double helix may sometimes adopt an alternative configuration, the cruciform, in which mismatches that may occur are eliminated by excision and repair.     

Preparation of a New Radiolabeled Biomaterial and Its Biodistribution in Mice

Biomaterials have attracted more attention from biomedical research in recent years. Yet there are still unmet demands for current biomaterials, such as the reduction of local inflammation of the implantation site. Poly-Propylene Carbonate （PPC）, a polymer with ester bonds on COz backbone, degrades to CO2 and water, which are natural components of human body, yielding less inflammatory response than traditional biomaterials. However, the tensile strength and heat resistance properties of PPC are less ideal. In order to improve the properties of PPC, we have developed a new PPC （M-PPC）, modified by mixing with Poly-3-Hydroxybutyrate （PHB）. Here, we report the biodistribution profiles of PPC and M-PPC, their biocompatibility and toxicity. 125I-radiolabeled PPC and M-PPC were prepared and their biodistribution in Balb/c mice were investigated. Then acute systemic toxicity and haemolysis assays were conducted to study their toxicity and biocompatibility respectively. Results show that M-PPC has a good potential to be used as bone repair materials because it possesses typical biodistribution pattern in major organs, minimal toxicity and good biocompatibility.     

抗菌生物材料的研究进展

生物高分子材料(医用缝合线、导尿管等)及人工器官(心瓣膜、人工肾等)的应用日益广泛,使用过程中引发的细菌性感染导致诸多严重后果,不容忽视。基于感染机理,人们通过对生物材料表面进行不同的改性,如通过阻止细菌黏附达到抗菌效果、通过干扰细菌细胞的组成取得杀菌效果等,研究了不同的抗菌机理。本综述了新型有机高分子抗菌剂的发展,提出对生物相容性良好的聚氨酯、聚砜、聚醚砜等材料进行表面改性,使之具有好的抗菌能力,是未来抗菌生物材料的研究与发展方向。     

Individual study of chromium in the stainless steel implants degradation: An experimental study in mice

To study the accumulation and the histological effects in mice organs caused by hexavalent chromium, one of the corrosion products released from AISI 316L stainless steel implants, mice groups were subcutaneously injected with a metallic solution of chromium during a certain period of time. Similar injections were made with HBSS (Hank's Balanced Salt Solution) in other groups to be used as controls. The levels of chromium found in the liver, kidney and spleen of the control and the treated animals were obtained by atomic absorption spectrometry (AAS) and were compared to those obtained by AdSV (adsorptive stripping voltammetry) to test the accuracy of the results. During the experimental period, the liver and spleen showed a progressive and significant accumulation of chromium whereas in the kidney the significant accumulation found after the first week practically remained unchanged during the four weeks. Apparently, the histological analysis of these tissues did not evidence any relevant morphological alteration induced by the chromium accumulations during the four weeks of treatment.     

重组人源性胶原蛋白的制备及表征

为了获得可实现工业化生产的重组人源性胶原蛋白,根据人I型胶原蛋白Gly-X-Y序列,优选亲水性的Gly-X-Y胶原肽段设计人源性胶原蛋白氨基酸序列及对应的核苷酸序列,利用酶切技术构建pPIC9K-COL表达载体,电转化毕赤酵母获得人源性胶原蛋白毕赤酵母工程菌,并对其进行发酵罐发酵、纯化及鉴定。结果显示,获得表达量达4.5 g/L,纯度大于95%的人源性胶原蛋白,经氨基酸N端测序、分子量测定、氨基酸分析及胶原酶降解试验,确定获得的蛋白与理论的人源性胶原蛋白一级结构一致;同时胶原经冷冻干燥后进行扫描电镜分析及细胞毒性试验,确定人源性胶原蛋白冻干品具有多孔纤维网状结构及优良的细胞相容性,预示其具备作为生物医学材料的潜质。