胶原蛋白/葡甘聚糖共混膜的制备及性能表征

以葡甘聚糖和胶原蛋白为主要原料,甘油、氨水为添加剂通过共混的方法制备胶原蛋白/葡甘聚糖膜.通过红外光谱、X-射线衍射、显微镜对共混膜进行性能表征,同时测定了共混膜的透光率、力学性能、吸水率及水蒸气透过系数.结果表明:葡甘聚糖1.0 g,胶原蛋白0.6 g,甘油0.4 mL,氨水1.0 mL,蒸馏水100 mL为制膜最佳配方,共混膜的力学性能和水蒸气透过系数得到改善,葡甘聚糖和胶原蛋白之间有强烈的相互作用和良好的相容性,作为一种潜在的皮肤组织工程支架将具有良好的应用前景.     

脱细胞羊皮基质的制备与性能检测

目的:制备一种廉价、安全而且来源丰富的生物敷料,以用于烧伤患者微粒皮移植后和削痂后创面的保护。方法:实验于2003-10/2007-03在积水潭医院烧伤研究所完成。①主要材料:健康山羊5只,纯种新西兰大白兔10只;戊二醛猪皮(清华源兴生物制品公司);冷冻保存的人皮(志愿者捐献)。②实验方法:山羊麻醉处死,去毛后取全层皮肤,通过反复冻融、配合超声震荡和洗脱液处理,在保证胶原支架完整情况下去除导致皮肤排斥反应的细胞成分,获得脱细胞羊皮基质,冷冻保存。③实验评估:利用常规病理检查和电子显微镜检查其有无明显细胞碎片残留;细菌真菌培养,测试其机械强度、亲水性和细胞毒性,通过动物埋藏实验确定其组织相容性,并与戊二醛交联的脱细胞猪皮以及冷冻保存的人皮作对照。结果:制备的脱细胞羊皮基质,常规病理检查、免疫组织化学染色、电子显微镜检查均未发现表皮和真皮细胞残留;细菌真菌培养呈阴性;为亲液固体,质感柔软有弹性,含水量、极限抗拉强度、应力-应变量、应力松弛特征、蠕变性等物理性能均与冷冻人皮相似,明显优于戊二醛猪皮;细胞毒性0级,在国家标准允许范围内;植入兔背部脊柱两侧的肌肉组织内后,能够与组织很好的融合,并诱导细胞和血管长入,组织相容性良好。结论:采用冻融法制备的脱细胞羊皮敷料安全、廉价、来源丰富,达到临床手术应用的保护性生物敷料标准。     

乳酸-羟基乙酸共聚物缓释微球的制备、性能及应用

用于制备乳酸-羟基乙酸共聚物缓释微球的方法很多,可根据聚合物和药物的性质进行选择,其中乳化-固化法是目前制备乳酸-羟基乙酸共聚物缓释微球中最常用的方法,适用于在连续相中不溶或难溶的药物,缺点在于使用有机溶剂,不利于保持药物的活性,复乳化时工艺也比较复杂,不适宜进行工业化生产;喷雾干燥技术是一种快速的一步微囊化过程,其条件温和,制得的微球具有粒度分布窄、包封率高等特点,其用于不稳定药物微囊化的大规模生产极具潜力.由于给药初期的突释有可能导致血药浓度接近或超过中毒水平,产生明显的毒副作用.乳酸-羟基乙酸共聚物的分子质量、乳酸-羟基乙酸共聚物的纯度、主药理化性质、微球制备方法及制备参数、微球载药量等均是影响突释程度的具体因素.目前防止突释或降低突释程度的方法主要有改变载体材料结构、适当的微球制备以及萃取、洗涤或加入附加剂等.乳酸-羟基乙酸共聚物微球控释系统具有延长药物释放时间、靶向释放、降低药物毒性和刺激性等特点,存在多种给药途径可肌肉注射、皮下注射、玻璃体内注射、关节腔内给药、植入给药、黏膜给药等.     

乳酸-羟基乙酸共聚物缓释微球的制备工艺与生物学性能

微球(microspheres)是一种生物物理靶向载药制剂,粒径为1～300μm.微球的载体材料按其来源可分为天然高分子材料、半合成高分子材料及合成高分子材料.在合成高分子材料中,通过采用合适的制备工艺和处方,制得的载药微球可在几周或几个月时间内以一定速率释放药物,减少给药次数,增加患者顺应性.对蛋白和多肽类药物,微球是相当理想的载药系统.微球制剂是近年来缓释剂型的研究热点,根据临床需要很多药物正被研究成微球制剂.乳酸-羟基乙酸共聚物[poly(lactic-co-glycolic acid),PLGA]有着优良的安全性、生物相容性和可变的生物降解性,是制备微球的常用基本材料.PLGA缓释微球制剂的制备方法基本上可分为3种:溶剂挥发法、喷雾干燥法、相分离法.溶剂挥发法是常用的制备方法之一,目前PLGA微球作为多肽、蛋白类药物的载体已广泛应用于免疫学、基因治疗、肿瘤治疗、骨缺损修复、眼科等众多医学领域中.     

Bioactive glasses and glass-ceramics

Bioactive materials are designed to induce a specific biological activity; in most cases the desired biological activity is one that will give strong bonding to bone. A range of materials has been assessed as being capable of bonding to bone, but this paper is solely concerned with bioactive glasses and glass-ceramics. Firstly, the structure and processing of glasses and glass-ceramics are described, as a basic knowledge is essential for the understanding of the development and properties of the bioactive materials. The effect of composition and structure on the bioactivity is then discussed, and it will be shown that bioactivity is associated with the formation of an apatite layer on the surface of the implant. A survey of mechanical performance demonstrates that the structure and mechanical properties of glass-ceramics depend upon whether the processing involves casting or sintering and that the strength and toughness of glass-ceramics are superior to those of glasses. Attempts to further improve the mechanical performance by the use of non-monolithic components, i.e. bioactive coatings on metal substrates and glass and glass-ceramic matrix composites, are also reviewed and are shown to have varying degrees of success. Finally, some miscellaneous applications, namely bioactive bone cements and bone fillers, are briefly covered.     

具有生物活性的高导复合支架材料制备表征及其生物相容性

背景：组织工程新材料必须既能支持组织生长,又能激发理想的细胞反应（如血管发生）,而导电性则可促进包括神经在内的组织再生。目的：构建一种新型材料,能将导电性和生物活性有效的结合起来,为组织工程提供一种理想的备选材料。方法：将具有生物活性的透明质酸多糖和导电聚合物聚吡咯进行结合,制备具有生物活性的导电聚合物复合材料。结果与结论：含有透明质酸多糖的聚吡咯/透明质酸双层膜具有光滑的表面形貌和良好的导电性。体外细胞相容性实验显示这种复合材料可显著促进神经轴突的延伸。体内实验显示该复合材料还具有良好的惰性和促血管生成效应,是一种较为理想的组织工程备选材料。     

Transparent glass-ceramics for thermal management application: achievement of optical transparency and high thermal conductivity

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures. Therefore, heat dissipation in glass components often becomes a problem and its applications to the thermal management has been limited to use as a heat insulator. To break this mold and to apply it to fields, e.g., transparent sealing materials, for which low thermal conductive glasses and organic polymers have been conventionally used, we fabricated an MgO-dispersed glass-ceramics in our previous work. It comprises MgO crystal and glass matrix and their reflective indices are matched, leading to optical transparency and improvement in thermal conductivity. Here we investigate the atomic-scale structures in the MgO-dispersed glass-ceramics by nuclear magnetic resonance, etc. and attempt to further improve the thermal conductivity and the transparency. As a result, we show an MgO-dispersed glass-ceramic with a thermal conductivity of 3.3 W (m⁻¹ K⁻¹), corresponding to 300% of that of the glass matrix, high optical transparency, and glass transition. This report highlights that our strategies pave the way for development of novel transparent, functional glass-ceramics.

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures.     

壳低聚糖-海藻酸钠微胶囊的制备与表征

目的:探索了壳低聚糖-海藻酸钠微胶囊的制备方法和工艺条件,分析了微胶囊膜的厚度、机械强度、通透性等性能,对比得出性能最佳的壳低聚糖-海藻酸钠微胶囊.方法:改变壳低聚糖溶液pH值和成膜反应时间来制备微胶囊,用倒置相差显微镜观察并计算膜厚,用回旋式振荡器、AG-10TA万能测试仪对微胶囊膜力学强度进行检测,用牛血清白蛋白做蛋白释放对膜通透性等性能进行检测.结果:壳低聚糖溶液pH值为7时制备的微胶囊膜厚随反应时间的增加而增加.该条件下制备的微胶囊的压缩模量在成膜反应10 min时已达到5.12 kPa,通过回旋式振荡器振荡6 h无一破损.微胶囊的蛋白释放随成膜时间的增加而减小.当成膜反应10 min时,微胶囊的蛋白释放率随盐离子浓度增加而减小.当成膜时间延长后,微胶囊的蛋白释放率随盐离子浓度的增加而增加.结论:用壳低聚糖在溶液pH值为7时制备出的微胶囊力学性能较好.此种微胶囊膜的通透性在较短成膜时间下主要受到膜厚的影响;当成膜时间延长,膜的致密度则成为其主要影响因素.     

壳聚糖管状支架的制备及生物降解性

背景:作者课题组在进行肺组织瓣修补食管缺损实验中,发现硅胶支架和金属支架都不理想,都存在排斥反应和远期并发症,为寻找一种理想的生物型可自行降解支架,将壳聚糖制成管型支架,观察其在生物体内的相容性和降解性,为食管重建提供一种可降解支架.目的:探讨壳聚糖管状支架的制备方法及其生物特性.方法:利用乙酸溶液制备60 g/L的壳聚糖乙酸水溶胶,采用成膜方法制管后用NaOH脱下壳聚糖导管,取内径5 mm管,切成段,长度2 mm,消毒,并将壳聚糖管植入大鼠组织内,分别于不同时间段大体及光镜下观察其生物相容性及体内降解性.结果与结论:壳聚糖导管光滑,韧性好,吸收水分变软,组织生物相容性好,随时间可被组织吸收降解.该方法提供了制备壳聚糖导管的一种新方法,并证实了其组织相容性和生物可降解性.     

Halogen-free instinct flame-retardant waterborne polyurethanes: composition,performance, and application

Ideal halogen-free instinct flame-retardant waterborne polyurethanes have high flame-retardant efficiency, environmental friendliness, fine compatibility, and good thermostability. Phosphorus flame-retardants are currently widely used in halogen-free instinct flame-retardant waterborne polyurethanes (HIFWPU), especially those with phosphorous–nitrogen co-structures. Phosphorous–nitrogen HIFWPU have become a hotspot because their co-structures provide higher flame-retardance as compared to waterborne polyurethanes. This review introduces three main types of HIFWPU based on composition, performance and application. HIFWPU not only have improved flame-retardance but also satisfy the various requirements for functionality. HIFWPU have been widely developed in textile, furniture, automobile, and aerospace applications.

Ideal halogen-free instinct flame-retardant waterborne polyurethanes have high flame-retardant efficiency, environmental friendliness, fine compatibility, and good thermostability.