壳聚糖与神经干细胞生物相容性的研究

目的 探讨生物降解材料壳聚糖与神经干细胞的生物相容性。方法 取SD大鼠胚胎（孕14-16d)大脑皮层组织制成单细胞悬液在无血清培养液中进行培养，获得大量的神经干细胞，再将所获神经干细胞在不同条件下移植接种至壳聚糖膜上联合培养1周，在倒置显微镜下观察神经干细胞生长增殖情况及形态变化，并对其分别进行免疫组化染色，电镜观察，了解壳聚糖对神经干细胞生长，增殖，分化的影响。结果 在无血清联合培养条件下，神经干细胞仍然维持其原有的干细胞特性；在含血清的培养液中，神经干细胞能分化成多种形态的神经细胞，并且在壳聚糖膜上生长良好。结论 壳聚糖与神经干细胞具有良好的生物相容性。     

Neutrophil Oxygen Radical Production by Dialysis Membranes

The ability of different dialysis membranes to activate polymorphonuclearneutrophil oxygen radical production was investigated with chemiluminescence.All the six membranes, namely cuprophan, cellulose acetate,polycarbonate, polysulphone, polyacrilonitrile and polymethylmethacrylatewere able to interact with neutrophils and stimulate their oxygenradical production, the highest responses being seen with polyacrilonitrile,polymethylmethacrylate and polycarbonate. To analyse the roleof complement in this interaction, fresh plasma, heat inactivatedand zymosan-activated plasma were added: with fresh plasma oxygenradical production was stimulated on cuprophan, cellulose acetateand polysulphone, not modified on polycarbonate, and decreasedon polyacrilonitrile and polymethylmethacrylate. With heat-inactivatedplasma, the responses were decreased or abrogated on all themembranes except polycarbonate and polymethylmethacrylate, whereaswith zymosanactivated plasma similar responses to fresh plasmawere observed. In addition, when plasma was used to precoatthe membrane, cuprophan, cellulose acetate and polysulphonedisclosed an enhanced neutrophil oxidative burst, while precoatedpolyacrilonitrile and polymethylmethacrylate were less stimulatorythan uncoated membranes. In contrast the precoating of polycarbonatedid not modify oxygen radical production. These data suggestthat neutrophil activation occurs by direct membrane neutrophilinteraction. Plasmatic factors modulate this interaction butcomplement seems involved on cellulosic and polysulphone membranesonly. Therefore, it appears that oxygen radicals produced fromcontact of neutrophils with the dialysis membrane might playan initial and/or additional role in the events occurring atthe initiation of haemodialysis.     

脱细胞牛心包构建引导骨再生膜的初步研究

目的制备具有良好生物相容性和适宜降解吸收时间的引导骨组织再生（guided bone regeneration，GBR）膜材料。方法采用0．25％Trypsin＋0．5％Triton X-100酶联脱细胞法对新鲜牛心包进行脱细胞处理，将脱细胞牛心包（A组）、甘油保存脱细胞牛心包（B组）、碳化二亚胺[1-ethyl-3-（3-dimethylamino propyl）carbodiimide hydrochloride，EDAC]交联脱细胞牛心包（C组）、甘油保存EDAC交联脱细胞牛心包（D组）4种膜材料分别植入38只SD大鼠背部皮下，不植人材料为E组。于2、4、8和16周分别处死大鼠7、12、12和7只，观察周围组织反应及材料的降解吸收情况。结果4种材料植入动物体内均有不同程度的炎性反应和纤维囊膜形成。术后4周，A组和C组的炎性反应轻微，纤维包膜变薄。A组膜材料吸收替代时间为8周左右，C组吸收替代时间为16周左右；16周时B组和D组材料仍有纤维包膜。结论EDAC交联脱细胞牛心包具有良好的生物相容性和理想的降解性能，在动物体内能顺利被自体组织替代。     

Cora Rotary Pump for Implantable Left Ventricular Assist Device: Biomaterial Aspects

Abstract: Our group is developing a left ventricular assist device based on the principle of the Maillard-Wankel rotative compressor: it is a rotary, not centrifugal, pump that produces a pulsatile flow. Stringent requirements have been defined for construction materials. They must be light, yet sufficiently hard and rigid, and able to be machined with high precision. The friction coefficient must be low and the wear resistance high. The materials must be chemically inert and not deformable. Also, the materials must be biocompatible, and the blood contacting surface must be hemocompatible. We assessed the materials in terms of physiochemistry, mechanics, and tribology to select the best for hemocompatibility (determined by studies of protein adsorption: platelet, leukocyte, and red cell retention: and hemolysis, among other measurements) and biocompatibility (determined by measurement of complement activation and toxicity, among other criteria). Of the materials tested, for short- and middle-term assistance, we chose titanium alloy (Ti₆AI₄V) and alumina ceramic (Al₂O₃) and for long-term and permanent use, composite materials (TiN coating on graphite). We saw that the polishing process of the substrate must be improved. For the future, the best coating material would be diamond-like carbon (DLC) or crystalline diamond coating.     

小肠粘膜下层的制备及细胞相容性的实验研究

目的了解猪小肠粘膜下层(SIS)的细胞相容性,探讨用SIS为生长载体复合骨髓基质干细胞(BMSCs)构筑组织工程骨的可能性。方法用物理和化学方法处理猪小肠粘膜下层,将兔骨髓基质干细胞与SIS进行体外复合培养,分别进行组织学、相差显微镜和扫描电镜观察。结果经物理和化学处理的SIS纯度高,孔隙多,胶原纤维未受损;BMSCs在SIS材料上生长、粘附、增殖,并能长入材料的孔隙内,分泌大量的细胞外基质成分。结论SIS的细胞相容性良好,不影响BMSCs的形态,对细胞生长和功能表达无抑制作用,可以用作骨组织工程的支架材料。     

几丁糖-聚乳酸复合生物材料神经导管的预构

目的:神经导管修复周围神经损伤,作为一种新的周围神经损伤修复方法显示出广阔的应用前景.本实验将几丁糖、聚乳酸两种材料结合,试图研制出一种理化性质、生物相容性俱佳的神经导管材料.材料和方法:第一部分:几丁糖-聚乳酸复合生物材料的研制及其物理性能测试.将2%几丁糖与0.5%聚乳酸以不同的比例化合反应后制成导管.力学实验检测不同比例制成导管的强度和韧性,根据实验结果选择最佳比例,并进一步测定该复合材料的其它物理性能.第二部分:几丁糖-聚乳酸复合生物材料的生物相容性检测.用细胞增殖度实验评价新材料的细胞毒性.用最大剂量法豚鼠致敏实验测试新材料致敏性.结果:2%几丁糖与0.5%聚乳酸以5∶1(体积比)比例混合反应制成的新材料,其各项物理性能符合制备神经导管要求.在细胞毒性实验中,复合材料浸提液培养2天后及5天后,细胞相对增殖度(RGR)为83.67%,96.41%.致敏实验显示新复合材料浸提液致敏率为0级.实验证明新复合材料无细胞毒性、无致敏性.结论:几丁糖、聚乳酸通过适当比例结合制作的复合生物材料具有良的物理性能及生物相容性,符合制备神经导管的理化要求.     

Développement d’un hydrogel autodurcissant in vivo, en perspective d’un usage biomédicalA new self-hardening gel in prospect of biomedical use

Since 1995, an injectable bone substitute is developed in our laboratory, it is based on a mix of an hydrogel (hydroxypropyl methylcellulose at 3%: cellulose ether) and biphasic calcium phosphate granules (MBCP^® : 60% hydroxyapatite, 40% β-tri calcium phosphate). This first generation of injectable bone substitute is a non-self-hardening past, nevertheless it owns a great osteoconductor potential. But it shows a tendency to the discharge by its initial composition, and involved limited clinical applications. An evolution of this product is presented in this article: the modification is generated by a new self-hardening hydrogel. This hydrogel is a cellulose ether grafted by silane and diluted in an aqueous solution at basic pH. Also it will be presented the general synthesis of this cellulose derivate, the dissolution condition and the self hardening principle in function of the pH and the temperature. As to conclude by preliminary tests, the biocompatibility in vivo and in vitro of the self-hardening hydrogel mixed with biphasic calcium phosphate granules will be studied.     

碳纳米管及其复合材料在生物医学领域的研究进展

碳纳米管是一种新型碳材料，具有特殊的纳米结构和优异的力学、电学和磁学性能，在生物医学领域显示出诱人的潜在应用价值和前景，吸引了越来越多的研究者的关注。本文简要介绍了碳纳米管的基本结构与性能，并对近年来碳纳米管在生物大分子的修饰与特异性识别、细胞体外生长支架、植入性生物医学材料、生物医学传感器以及生物医学微电子器件等方面的研究进展和发展趋势进行了综合评述。     

Proliferation and Osteogenic Differentiation of Mesenchymal Stem Cells Cultured onto Three Different Polymers <Emphasis Type="Italic">In Vitro</Emphasis>

In this study, the osteoinductive and cell-binding properties of three different resorbable polymers were evaluated by human mesenchymal stem cells (MSCs). MSCs were isolated, expanded, and cultivated onto resorbable D,D,L,L-polylactide (PLLA), collagen I/III, and polygalactin-910/polydioxanone (PGPD) scaffolds in vitro. To evaluate the influence of dexamethasone, ascorbic acid, and beta-glycerolphosphate (DAG) on osteoblast differentiation, MSCs were incubated in a DAG-enriched medium. After a 28-day period in vitro, the cellular loaded polymers were digested enzymatically by papain and HCl. The Ca(2+) content of the biomembranes was evaluated by an o-kresolphthalein-complexon reaction via photometer. A PicoGreen assay was performed for dsDNA quantification. Significant differences between the number of adherent MSCs were documented (collagen > PLLA > PGPD). Compared to the initial number of adherent cells, all biomaterials induced a significant decrease in cellular adherence after 28 days in vitro. The presence of DAG-enriched culture medium stimulated the cellular proliferation for PLLA and slightly for PGPD, whereas cell proliferation was inhibited when MSCs were cultivated onto collagen I/III. In comparison with the control groups, all biomaterials (PLLA, PGPD, and collagen I/III) showed a significant increase in local Ca(2+) accumulation under DAG stimulation after 28 days in vitro. Furthermore, collagen I/III and PLLA scaffolds showed osteoinductive properties without DAG stimulation. These results were verified by immunocytochemical stainings against osteoblast-typical markers (osteopontin and alkaline phosphatase) and completed by calcified matrix detection (von Kossa staining). MSCs were identified by CD105 and CD13 antigen expression. Corresponding to an absence of CD34, CD45, and collagen II expression, we found no chondrogenic or hematopoietic cell differentiation. The results indicate significant differences for the proliferation, differentiation, adherence, and Ca(2+) accumulation between the tested polymers in a MSC culture.     

人工髓核材料-聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性研究*

目的评估人工髓核材料聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性。方法根据ISO10993-1标准,采用细胞毒性试验(琼脂扩散法)、皮内刺激试验、Ame's致突变试验、微核试验和体内植入(360天)试验对聚乙烯醇水凝胶/聚乙烯纤维复合物的生物相容性进行评估。结果聚乙烯醇水凝胶/聚乙烯纤维复合物的细胞毒性评分小于Ⅰ级,细胞生长无明显抑制现象,对皮内无刺激作用,Ames致突变试验为阴性,微核出现率为3.48‰,无致突变反应。体内植入符合植入材料生物学评价要求。结论聚乙烯醇水凝胶/聚乙烯纤维复合物具有良好的生物安全性,是一种无毒、对皮肤及肌肉、椎间隙无刺激作用的生物医用材料,在动物体内不引起排异反应,可应用于临床。