可生物降解镁合金血管支架管坯的材料制备及成形研究进展

对可生物降解镁合金血管支架的研究现状进行了综述。镁合金作为新型可降解物材料成为了研究热点,其中血管支架是其最有前景的应用方向之一。镁合金微细管材成形困难及镁合金血管支架腐蚀速率过快,是制约其大规模临床应用的2个主要因素。作者介绍了近期国内外的相关研究,包括改善镁合金力学性能,以及为提高成形极限采取的新成形方法,为提高镁合金耐腐蚀性而采取的各种处理方法等。     

可降解血管支架材料降解行为研究进展

目前可降解血管支架材料包括聚合物、镁合金、铁合金及锌合金,它们的降解特性直接影响其作为血管支架植入后的支撑能力、局部反应和血管修复的预后。聚合物降解时间较易调整、生物相容性较好,但力学性能不足;镁合金的降解存在降解速率快、释氢反应和微环境pH值变化较大的问题;铁合金降解速率太慢;锌合金的降解速率适中,是近年可降解血管内植入材料研究热点。除了材料自身的特性,可降解材料的血管内降解行为还受到环境的离子浓度、酶、pH值和温度等多种因素的影响。综述了目前不同血管内可降解支架材料在模拟体液及动物体内生物降解行为的研究结果,以期为血管内可降解材料研究和产品开发提供参考。     

生物医用可降解锌基合金的研究进展

锌基合金是近几年新兴的一种医用可降解材料,有望应用于心血管支架及骨植入等医疗器械。锌是人体必需的营养元素,具有良好的生物相容性及适宜的体内降解速率,作为可降解合金的基体有很广的应用前景。然而,生物可降解锌基合金的设计、加工、强化及降解机理等研究尚处于起步阶段,还需要做大量的基础研究工作。本文以最终医疗器械产品的理想标准要求为切入点,从生物相容性、力学性能及抗腐蚀性能等方面对近几年医用锌基合金的研究成果进行了综述分析,并展望了其未来的发展方向。     

可生物降解大豆蛋白材料的研究进展

介绍了可生物降解材料的定义和降解机理,阐述了可生物降解大豆蛋白材料的研究概况,从物理改性、化学改性、共混改性三方面对近年来大豆蛋白材料的改性进行了综述,并对其发展前景进行了展望。     

In vivo interaction of cells on poly L-(lactic acid) membranes containing plasticizer

The development of biodegradable materials has lead to renewed interest in the study of their interactions with the host organism in order to make the resulting products appropriate for use as temporary materials in protheses. Poly L-(lactic acid)(PLLA)-based biodegradable devices have been used for several purposes. The physical properties of these materials can be modified by the addition of a plasticizer, such as the triethylcitrate, to provide flexibility and porosity to the implants and enhance control of the polymer degradation time. In this work we examined the biological properties of a PLLA porous membrane containing 7% triethylcitrate, by assessing the process of degradation and the interaction with dermal tissue. Samples of skin obtained from female Wistar rats 2–180 days after implantation with PLLA-based membrane were processed for light microscopy and scanning electron microscopy. The membranes became surrounded by a delicate network of connective tissue which gradually invaded the membrane structure. Polymer degradation began with the appearance of radial fractures in the globular units of the biodegradable membrane, especially by 90 and 180 days after implantation.     

Long-term biodegradation and associated hydrogen evolution of duplex-structured Mg-Li-Al-(RE) alloys and their mechanical properties

Preliminary in vivo tests of two magnesium alloys, i.e. AE21 and WE43, as biodegradable vascular stent materials, have yielded encouraging results. However, their degradation is desired to be prolonged, mechanical stability over a defined time improved and ductility needed for stent expansion enhanced. A search for alternative magnesium alloys that can better meet these clinical requirements is needed. The present research aimed to evaluate the long-term degradation behavior, hydrogen evolution rates and mechanical properties of three lithium-containing magnesium alloys, namely LA92, LAE912 and LAE922 with a duplex crystal structure, in comparison with those of a WE-type alloy. Immersion tests in Hank's balanced salt solution for 600 days showed that the LA92 alloy degraded much less than the LAE912 and the LAE922 alloys. It even outperformed the WE-type alloy after immersion for 94 days. Moreover, unlike the other three alloys investigated, the LA92 alloy displayed a steady hydrogen evolution rate over the whole period of immersion tests. In addition, it possessed an elongation value of 33%, being much higher than the WE-type alloy. Thus, this alloy has a greater potential of meeting the requirements of radially expandable stents in mechanical properties and degradation performance.     

生物可降解脂肪族聚酯在陕西土壤中的降解行为

以西安当地土壤及西安某污水处理厂的活性污泥为降解介质,对生物可降解聚酯聚乳酸(PLA)、聚丁二酸丁二醇酯(PBS)和聚己内酯(PCL)的降解性能进行了研究,并对它们的降解机理进行了初步探讨。根据偏光显微镜和扫描电镜的观察表明,降解后的聚酯膜表面均有明显被侵蚀的痕迹;在陕西当地土壤中,PCL的降解速度最快,PLA次之,PBS最慢。红外光谱表征了这三种聚合物降解前后的化学结构。     

可降解铁基心血管支架材料的研究进展

概述了可降解铁基心血管支架材料的研究历史及现状,介绍了可降解铁基心血管支架的优势及其早期动物实验结果。结果表明,铁基合金是一种非常适宜制作可降解心血管支架的材料,但其存在降解速度过慢的问题。在分析可降解铁基合金的最新研究进展基础上,认为在提高铁基合金的降解速度方面虽然目前已经进行了很多有益的尝试,但是尚无极具意义的结果。同时提出,应在对人体环境下铁基合金的降解行为研究基础上发展新的提高铁基合金降解速度的方法。     

The microscopical characterization of membranes poly (<Emphasis Type="SmallCaps">l</Emphasis>-glycolic-co-lactic acid) with and without added plasticizer: an in vivo study

The development of biodegradable materials has lead to renewed interest in the study of their interactions with the host organism in order to make the resulting products appropriate for use as temporary materials in clinical research, as well as important therapeutic applications. The copolymer poly (l-lactic-co-glycolic acid) or PLGA membranes have been used for several purposes. The physical properties of these materials can be modified by the addition of a plasticizer, such as the triethylcitrate, to provide flexibility and porosity to the implants, and enhance control of the polymer degradation time. Membranes with 7% plasticizer and without plasticizer (triethylcitrate) were compared. Membranes without plasticizer were denser and more compact than those with plasticizer. Two days and 30 days after implantation, the membranes with and without plasticizer showed little degradation. Sixty days and 120 days after implantation, the membranes with 7% plasticizer showed more cell invasion, and tissue adherence, as well as rapid degradation when compared to membranes without plasticizer.     

不同生物质纤维及其添加量对PBAT复合材料结构与性能的影响

目的 将生物质纤维材料芦苇、黄麻和纸浆引入聚己二酸/对苯二甲酸丁二醇酯(PBAT)中,通过高速共混机制备高性能的硬质可生物降解复合材料。方法 研究不同生物质纤维及其添加量对复合材料结构、性能、生物降解性的影响。结果 PBAT/生物质纤维复合材料的弯曲模量和强度得到明显提升。在3种复合材料中,PBAT/纸浆复合材料表现出最佳的力学性能和热稳定性,通过简单混合PBAT和质量分数为60%的纸浆,其弯曲模量、弯曲强度可分别达到(1 055±35)、(12.46±1.10)MPa。降解试验结果表明,复合材料的降解速率显著高于PBAT的降解速率,并且与生物质纤维的吸水性及尺寸有关。结论 经大尺寸生物质纤维填充PBAT得到的硬质可降解复合材料的综合性能优异,为发展绿色可降解硬质包装及包装填充物材料提供了科学思路和技术依据。     

聚乳酸类复合材料研究进展

综述了近年来聚乳酸类生物可降解高分子复合材料的研究进展，骨修复作为其主要应用领域，未来聚乳酸类复合材料的研究有两方面值得关注：一方面需要通过无机增强材料（尤其是磷酸盐类无机钙质陶瓷成分）的粒径微细化和有机成分进行“内增强”，提高复合材料的强度，另一方面，需要通过填料的加入，使复合材料进一步功能化，特别是利用填料的碱性或药物作用，减少聚乳酸类基体降解引起的炎症。     

Biodegradable Materials and Green Processing for Green Electronics

There is little question that the “electronic revolution” of the 20th century has impacted almost every aspect of human life. However, the emergence of solid-state electronics as a ubiquitous feature of an advanced modern society is posing new challenges such as the management of electronic waste (e-waste) that will remain through the 21st century. In addition to developing strategies to manage such e-waste, further challenges can be identified concerning the conservation and recycling of scarce elements, reducing the use of toxic materials and solvents in electronics processing, and lowering energy usage during fabrication methods. In response to these issues, the construction of electronic devices from renewable or biodegradable materials that decompose to harmless by-products is becoming a topic of great interest. Such “green” electronic devices need to be fabricated on industrial scale through low-energy and low-cost methods that involve low/non-toxic functional materials or solvents. This review highlights recent advances in the development of biodegradable materials and processing strategies for electronics with an emphasis on areas where green electronic devices show the greatest promise, including solar cells, organic field-effect transistors, light-emitting diodes, and other electronic devices.     

可降解医用高分子材料降解建模研究现状

可降解医用高分子材料降解过程复杂,致其医用研究尚处于＂试错＂阶段。文中就降解医用高分子材料的降解建模研究现状展开讨论,针对建模相对比较成熟的药物缓释系统介绍了机理论模型的非蒙特卡洛模型和蒙特卡洛模型及元胞自动机模型;分析了药物缓释系统、组织工程支架降解建模中建模方法的思路与存在的问题;归纳了当前的建模或从微观或从宏观角...     

聚氨基酸共聚物合成研究进展

聚氨基酸共聚物是一类新型生物降解高分子材料。文中简单综述了聚氨基酸-聚醚嵌段共聚物、聚氨基酸-甲壳素共聚物、聚氨基酸-硅氧烷共聚物和聚氨基酸-聚酯共聚物的合成方法。     

可生物降解的化妆品包装材料研究进展

目的 综述可生物降解的包装材料在化妆品应用方面的研究进展,为生物降解材料的广泛使用提供参考。方法 通过对国内外聚乳酸、聚羟基链烷酸酯、纤维素、壳聚糖等可生物降解包装材料在化妆品中的研究与应用,分析各种材料的性能特点,提出可生物降解的包装材料在化妆品应用方面的未来展望。结果 不同类型的化妆品应根据产品特性选择适宜的可生物降解的包装材料,可生物降解包装材料在化妆品中的应用有待进一步研究和推广。结论 可生物降解材料应用于化妆品包装是未来发展趋势之一,应用纳米技术对材料性能提升具有重要意义。     

果蔬包装用可生物降解材料的制备与应用研究进展

目的 可生物降解材料具有高效和环保的特点,可以减轻传统石油基材料过度使用带来的环境污染问题,总结可生物降解材料及其制备技术的特点为进一步促进其在果蔬包装中的应用提供参考和基础。方法 首先对现有的可生物降解材料进行分类,其次探究其制备方法,然后对近年来可生物降解材料在生鲜果蔬包装中的应用,以及对生鲜果蔬保质期和质量的影响相关的研究进行总结和分析,最后对可生物降解材料的特点和应用前景进行归纳、分析和展望。结果 可生物降解材料具有良好的性能,适当的透气性和透湿性,较高的CO2/O2选择透过性,可大幅度地提高果蔬的货架期。结论 可生物降解材料相较于现有的保鲜包装材料有更好的保鲜效果,高效环保,能减轻不可降解材料对环境造成的污染问题。     

聚乳酸薄膜材料的阻隔性研究进展

目的综述聚乳酸薄膜材料的优缺点和影响其阻隔性的因素及改性技术,为包装(尤其是食品软包装)行业提供理论基础。方法以聚乳酸薄膜材料为主,总结影响聚乳酸阻隔性的自身原因,从物理改性、复合改性、化学改性和表面涂覆处理等方面进行阐述。结果聚乳酸可生物降解,其制备和降解都不会污染环境,但阻隔性差,必须对其进行改性,各种改性方法均有优劣。结论聚乳酸薄膜材料的改性技术仍存在不足,有待开发和完善一种不牺牲材料的生物相容性、设备简单、成本又低的改性技术。     

Poly‐Lactic‐Acid for coating of endovascular stents: preliminary results in canine experimental av‐fistulae

Poly‐Lactic‐Acid (PLA) was evaluated for coating of vascular endoprostheses in the treatment of experimental arterio‐venous‐fistulae (AVF). Bilateral carotid – external jugular AVF were created in 5 adult dogs. 7 PLA coated nitinol stents were placed via a transfemoral approach covering 5 AVF. The contralateral AVF remained untreated. Angiography was performed immediately after stent placement, at weeks 1 and 3 and at months 3, 6 and 9. All grafts were removed and underwent histologic examination. In 2 cases the occlusion of the AVF was successful, while misplacement occurred in 3 cases. Occlusion of the parent vessel was disclosed in 3 cases. Histologic examination revealed a mild inflammatory reaction with the presence of macrophages. There was no foreign‐body reaction or fragmentation of the arterial vessel wall. PLA, which is a well‐known biodegradable material, showed a good mid‐term biocompatibility. Elastic mismatch of the non‐elastic coating and the self‐expandable nitinol stent caused misplacement. Frequent vessel‐occlusions were probably due to PLA‐filaments fraying into the vessel lumen. Using a different textile structure PLA might be a material suitable for coating endovascular stents.     

Bio-Adaption between Magnesium Alloy Stent and the Blood Vessel:A Review

Biodegradable magnesium(Mg) alloy stents are the most promising next generation of bio-absorbable stents. In this article, we summarized the progresses on the in vitro studies, animal testing and clinical trials of biodegradable Mg alloy stents in the past decades. These exciting findings led us to propose the importance of the concept "bio-adaption" between the Mg alloy stent and the local tissue microenvironment after implantation. The healing responses of stented blood vessel can be generally described in three overlapping phases: inflammation, granulation and remodeling. The ideal bio-adaption of the Mg alloy stent, once implanted into the blood vessel, needs to be a reasonable function of the time and the space/dimension. First, a very slow degeneration of mechanical support is expected in the initial four months in order to provide sufficient mechanical support to the injured vessels. Although it is still arguable whether full mechanical support in stented lesions is mandatory during the first four months after implantation, it would certainly be a safety design parameter and a benchmark for regulatory evaluations based on the fact that there is insufficient human in vivo data available, especially the vessel wall mechanical properties during the healing/remodeling phase. Second, once the Mg alloy stent being degraded, the void space will be filled by the regenerated blood vessel tissues. The degradation of the Mg alloy stent should be 100% completed with no residues, and the degradation products(e.g., ions and hydrogen) will be helpful for the tissue reconstruction of the blood vessel. Toward this target, some future research perspectives are also discussed.     

可降解及可吸收性骨科材料研究进展

本文对用作可降解、可吸收性骨科材料的高分子材料、无机材料和复合材料 ,及聚乳酸、甲壳素和磷酸三钙等材料的性质、用途做了较为详细的阐述。并对可降解吸收骨科材料的发展趋势进行了探讨