医疗器械生物学评价现状与趋势(综述)

对医疗器械和生物材料进行有效性和安全性评价是进入临床前的关键环节,同时是医疗器械和生物材料市场及应用能否健康蓬勃发展的关键所在。从细胞和组织水平,利用形态学的检测方法观察材料与机体短期和长期的相互作用关系是以往评价医疗器械和生物材料的主要内容和手段。新型医疗器械和生物材料近年来迅猛发展,器械或材料的组成、形态、植入部位及用途日趋复杂,对器械或材料的评价相应提出了更高的要求。发展快速、特异、系统的评价体系至关重要。体外实验因操作可控性强,影响因素单一,重复性好而得到大力的发展,通过体内一体外实验的相关分析有望部分代替体内实验。近源大动物的开发为医疗器械和生物材料的体内评价更接近人体的真实反应提供了新的契机。近几年来,大量分子生物学的先进检测手段的应用使医疗器械和生物材料的评价向细胞和分子水平迈进。其发展趋势是以“三R(replace refine reduce)”为原则,即发展体外实验,采用灵敏、特异、先进的检测手段;优化并减少实验动物数量,建立器械／材料对分子、细胞、机体相互作用的系统性评价是医疗器械和生物材料评价体系的最终目的。     

生物材料体外评价方法研究进展

引言 在生物材料与人体体液、组织和器官的接触应用中，对材料进行生物学评价是至关重要的。生物学评价通常包括体外和体内两种测试途径。体外实验是将材料或其浸提液在体外环境下与细胞或组织接触，观察材料对细胞数量、形态及分化的影响。体内实验则是将材料直接与动物体接触，观察植入体周围组织反映的状况，这类实验模拟了人体生理环境，与材料的最终应用状况接近。目前，动物体内植入仍是生物材料安全性和有效性评价的主要手段。体内实验也有一定的缺点，如在体内环境中，     

分子生物学在生物材料评价研究中的应用现状

对生物材料进行生物相容性评价是生物材料能否进入临床研究的关键环节。分子生物学理论和技术的发展,给生物材料评价研究提供了新的思维和研究工具,大量分子生物学的先进检测手段的应用使生物材料的评价向细胞和分子水平迈进。建立材料对分子、细胞和机体相互作用的系统性评价是生物材料评价的发展趋势和最终目的。本文就分子生物学在生物材料评价研究中的应用及发展趋势作一综述。     

分子生物学在生物材料评价研究中的应用现状

对生物材料进行生物相容性评价是生物材料能否进入临床研究的关键环节。分子生物学理论和技术的发展，给生物材料评价研究提供了新的思维和研究工具，大量分子生物学的先进检测手段的应用使生物材料的评价向细胞和分子水平迈进。建立材料对分子、细胞和机体相互作用的系统性评价是生物材料评价的发展趋势和最终目的。本就分子生物学在生物材料评价研究中的应用及发展趋势作一综述。     

组织工程研究的新策略-组织诱导性生物材料

长期以来组织工程研究主要手段是原代细胞分离和培养(种子细胞),将细胞种植到支架材料上,在体外静态或动态(生物反应器)培养这种细胞/支架复合物,最后进行体内移植实验或应用。多年来的研究表明,这种手段依赖于自体细胞,耗时,费用昂贵,组织工程产品的生物功能不理想,而且很难实现临床推广应用。近几年生物材料科学家提出了组织诱导性生物材料的新概念。基于对材料的微观孔结构设计、化学修饰和复合生物活性分子,赋予材料诱导组织再生的活性,使组织再生和修复在体内完成。由此产生体内组织工程和组织诱导性生物材料等概念。这正在成为组织工程研究的发展方向。本文在调研最近三年相关论文的基础上,对组织诱导性材料的研究进展进行了简要综述。     

生物材料体内外试验相关性研究--DNA法与肌肉埋植试验的相关性探讨

生物材料在医学领域广泛应用,材料的安全性评价是极其重要的一环。研究生物材料体内外试验方法的相关性,以探求与体内动物试验相关性好的体外评价方法。采用体外DNA法与体内肌肉埋植试验对七种生物材料的组织毒性进行了评定,并应用Spearman秩相关统计方法作相关性分析。结果表明：两种方法有良好相关性。     

生物材料体内外试验相关性研究—— 体外白细胞趋化试验与体内肌肉 埋植试验的相关性探讨

探讨生物材料体内外试验的相关性。对七种生物材料分别以体外白细胞趋化性试验和体内肌肉埋植试验来评价材料的组织毒性。体外试验表明不同毒性材料对白细胞趋化能力有不同程度的影响，而导致机体对异物产生不同的抗炎反应；各期体内试验反映了材料在肌肉组织中不同的炎性反应。经     

超临界流体技术合成的复合型骨替代生物材料:体内外生物学评价

背景:在复合材料内部增加细胞黏附性较好的高分子材料或同骨组织羟基磷灰石成分相似的无机材料,可以改善材料的表面化学结构。过去的十几年,产生和发展了许多合成生物降解支架材料的新技术,虽然超临界流体技术应用在合成支架中时间尚短,但有着其他技术不可比拟的众多优点,目前越发受到学者的重视。目的:以聚乳酸和同种异体骨粉为原材料,通过超临界流体技术合成复合型骨替代生物材料,评价其生物学特性。方法:首先将同种异体皮质骨粉与聚乳酸在超临界二氧化碳作用下合成多孔复合型骨生物替代材料。将材料浸提液与成骨细胞系复合培养,体外观察细胞形态、增殖情况;通过材料浸提液皮内注射实验和材料肌袋内埋入实验,体内观察动物的致敏、组织炎症发生情况。结果与结论:体外大体观察该种复合材料形状、大小、孔隙可控,孔径适中,有较好的硬度,体外实验表明细胞相容性良好,对细胞的增殖无毒副作用;体内实验表明材料植入动物体内未发生致敏反应,组织相容性良好,但无异位成骨作用。说明制备的新型复合骨组织生物材料在细胞学和生物相容性检测上可以满足组织工程支架和骨组织替代的要求,该种合成技术及多孔生物材料有广阔发展前景。     

生物材料体内外试验相关性研究——细胞与软组织毒性

生物材料在医学领域已广泛应用 ,材料的安全性评价是极其重要的一环。研究生物材料体内外试验方法的相关性 ,以探求与体内动物试验相关性好的体外评价方法。采用白细胞趋化试验、流式细胞仪法、MTT比色法等体外方法与大鼠皮下埋植试验、兔肌肉埋植试验等体内方法 ,对七种生物材料的组织毒性进行了评定 ,并应用Spearman秩相关统计方法对体内和体外试验方法作对应进行相关性分析。结果表明 :体外方法均与体内方法有良好相关性。     

生物材料血液相容性体外评价的研究进展

体外实验因其快捷、方便、特点 ,通常被用作生物材料血液相容性评价的初步筛选实验。在体外血液相容性评价中 ,需选用合理的血液与材料接触模型、敏感而又特异的检测指标 ,在整个实验中尽量避免外界非待测材料对血液的激活作用。另外接触时间、接触方式、切变率以及参照材料的选择等均是重要的影响因素。近年来 ,体外评价方法虽已取得很大进展 ,但仍有待于标准化 ,以更有效地评价生物材料的血液相容性。     

分子标记在生物材料分子生物相容性中的应用现状

对生物材料进行生物相容性的评价是进入临床实验前的关键环节.随着分子生物学的迅速发展,研究者已经深入到分子水平对生物材料进行生物相容性的评价,并提出了分子生物相容性的概念.当前,主要任务是借助分子生物学技术,确定更多的分子标记物,以便建立分子生物相容性评价标准,并藉此指导设计出相容性更好的生物材料.     

Spectroscopic translation of cell-material interactions

The characterization of cellular interactions with a biomaterial surface is important to the development of novel biomaterials. Traditional methods used to characterize processes such as cellular adhesion and differentiation on biomaterials can be time consuming, and destructive, and are not amenable to quantitative assessment in situ. As the development of novel biomaterials shifts towards small-scale, combinatorial, and high throughput approaches, new techniques will be required to rapidly screen and characterize cell/biomaterial interactions. Towards this goal, we assessed the feasibility of using 4-dimensional elastic light-scattering fingerprinting (4D-ELF) to describe the differentiation of human aortic smooth muscle cells (HASMCs), as well as the adhesion, and apoptotic processes of human aortic endothelial cells (HAECs), in a quantitative and non-perturbing manner. HASMC and HAEC were cultured under conditions to induce cell differentiation, attachment, and apoptosis which were evaluated via immunohistochemistry, microscopy, biochemistry, and 4D-ELF. The results show that 4D-ELF detected changes in the size distributions of subcellular organelles and structures that were associated with these specific cellular processes. 4D-ELF is a novel way to assess cell phenotype, strength of adhesion, and the onset of apoptosis on a biomaterial surface and could potentially be used as a rapid and quantitative screening tool to provide a more in-depth understanding of cell/biomaterial interactions.     

丝素蛋白材料对免疫细胞激发作用的研究进展

丝素蛋白是一种源于蚕丝的天然高分子材料,其无毒、无刺激、透氧渗水性好.该材料作为诱导型医用生物材料的应用研究已成为热点课题;与此同时,丝素蛋白材料作为＂异种＂抗原物质进入人体后触发免疫应答的研究也正深入开展.机体的免疫系统具有对＂异己＂物质进行识别和攻击的特性,通过激活免疫细胞,产生免疫效应物质包括效应细胞、抗体及细胞因子等,从而对进入机体的＂异己＂物质进行攻击与清除.就丝素蛋白材料对免疫细胞的激发作用研究作一综述.     

Variable cytocompatibility of six cell lines with photoinitiators used for polymerizing hydrogels and cell encapsulation

The development of biocompatible photopolymerizing polymers for biomedical and tissue engineering applications has the potential to reduce the invasiveness and cost of biomaterial implants designed to repair or augment tissues. However, more information is needed about the cellular toxicity of the compounds and initiators used in these systems. The current study evaluates the cellular toxicity of three ultraviolet sensitive photoinitiators on six different cell populations that are used for engineering numerous tissues. The photoinitiator 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Irgacure 2959) caused minimal toxicity (cell death) over a broad range of mammalian cell types and species. It was also demonstrated that different cell types have variable responses to identical concentrations of the same photoinitiator. While inherent differences in the cell lines may contribute to the variable cytotoxicity, a correlation between cellular proliferation rate (population doubling time) and increased cytotoxicity of the photoinitiator was observed. Cell lines that divided more quickly were more sensitive to photoinitiator-induced cell death. In summary, the photoinitiator Irgacure 2959 is well tolerated by many cell types over a range of mammalian species. Cell photoencapsulation strategies may be optimized to improve cell survival by manipulating proliferation rate.     

不同交联改性牛心包材料的细胞毒性研究

本研究采用培养的人胚肺纤维细胞分析比较戊二醛、环氧１铬交联处理后４％甲醛保存的牛心包材料的细胞毒性。在浸泡前与浸泡１０、２０、３０天的周期中，不同交联处理的牛心包材料与浸出液的细胞增殖抑制指数显示：９１）三种交联剂处理的心包材料均有明显的细胞毒性。（２）随浸泡时期的延长，心包材料与浸出液的细胞毒性逐渐降低。（３）铬交联处理的牛心包材料与浸出液的细胞毒性显著高于其他交联材料。     

A systematic review of animal models used to study nerve regeneration in tissue-engineered scaffolds

Research on biomaterial nerve scaffolds has been carried out for 50 years. Only three materials (collagen, polycaprolactone and polyglycollic acid) have progressed to clinical use. Pre-clinical animal models are critical for testing nerve scaffolds prior to implementation in clinical practice. We have conducted a systematic review of 416 reports in which animal models were used for evaluation of nerve regeneration into synthetic conduits. A valid animal model of nerve regeneration requires it to reproduce the specific processes that take place in regeneration after human peripheral nerve injury. No distinct animal species meets all the requirements for an ideal animal model. Certain models are well suited for understanding regenerative neurobiology while others are better for pre-clinical evaluation of efficacy. The review identified that more than 70 synthetic materials were tested in eight species using 17 different nerves. Nerve gaps ranged from 1 to 90?mm. More than 20 types of assessment methodology were used with no standardization of methods between any of the publications. The review emphasizes the urgent need for standardization or rationalization of animal models and evaluation methods for studying nerve repair.     

人牙周膜细胞在左旋聚乳酸/羟基磷灰石生物材料上的生长观察

目的观察电纺左旋聚乳酸/羟基磷灰石(PLLA/HA)生物材料(简称生物材料)的生物相容性,并以人牙周膜细胞作为种子细胞与生物材料复合培养,探索该生物材料用于人牙周组织再生的可能性。方法用电纺法制备PLLA/HA纤维生物材料;组织块法分离培养人牙周膜细胞,并用免疫组织化学方法鉴定;MTT法评价生物材料的生物相容性;将人牙周膜细胞与生物材料复合培养,用扫描电镜进行观察;将转染人腺病毒介导的绿色荧光蛋白的人牙周膜细胞与生物材料复合培养,用激光扫描共焦显微镜观察。结果成功分离了人牙周膜细胞,波形蛋白染色阳性确定该细胞来源于中胚层;MTT法检测人牙周膜细胞在生物材料上的增殖状况与正常培养基本一致;扫描电镜下可见细胞在生物材料上生长旺盛、充分伸展;激光扫描共焦显微镜下可见人牙周膜细胞沿生物材料呈纤丝生长,表现出一定的三维结构。结论电纺PLLA/HA生物材料具有三维空间网状结构和良好的生物相容性,与人牙周膜细胞复合培养有利于细胞的生长、贴附和增殖,并呈现一定的立体结构,为人牙周组织再生提供了实验依据。     

Strategies and applications for incorporating physical and chemical signal gradients in tissue engineering

From embryonic development to wound repair, concentration gradients of bioactive signaling molecules guide tissue formation and regeneration. Moreover, gradients in cellular and extracellular architecture as well as in mechanical properties are readily apparent in native tissues. Perhaps tissue engineers can take a cue from nature in attempting to regenerate tissues by incorporating gradients into engineering design strategies. Indeed, gradient-based approaches are an emerging trend in tissue engineering, standing in contrast to traditional approaches of homogeneous delivery of cells and/or growth factors using isotropic scaffolds. Gradients in tissue engineering lie at the intersection of three major paradigms in the field-biomimetic, interfacial, and functional tissue engineering-by combining physical (via biomaterial design) and chemical (with growth/differentiation factors and cell adhesion molecules) signal delivery to achieve a continuous transition in both structure and function. This review consolidates several key methodologies to generate gradients, some of which have never been employed in a tissue engineering application, and discusses strategies for incorporating these methods into tissue engineering and implant design. A key finding of this review was that two-dimensional physicochemical gradient substrates, which serve as excellent high-throughput screening tools for optimizing desired biomaterial properties, can be enhanced in the future by transitioning from two dimensions to three dimensions, which would enable studies of cell-protein-biomaterial interactions in a more native tissue-like environment. In addition, biomimetic tissue regeneration via combined delivery of graded physical and chemical signals appears to be a promising strategy for the regeneration of heterogeneous tissues and tissue interfaces. In the future, in vivo applications will shed more light on the performance of gradient-based mechanical integrity and signal delivery strategies compared to traditional tissue engineering approaches.