组织工程材料的表面改性研究及应用：等离子体改性和接枝改性

组织工程材料的表面物理化学性质对材料的组织相容性有着重要影响。因而对材料的表面进行改性，在保持材料物理机械性能的前提下引入可促进细胞黏附和生长的基团或生物活性分子，可显著改善材料的细胞相容性。目前，细胞相容性聚合物的表面改性方法主要有：等离子体改性、接枝改性等方法。文章从等离子体改性、接枝改性等方面论述了组织工程材料的表面改性方法及其在组织工程中的应用。     

血管支架材料表面改性与血管内膜的增生

目的：评价血管材料改性后对血管内皮增生的影响和应用前景。 方法：以“血管支架材料,表面改性,内皮增生,再狭窄,生物相容性”为中文关键词,以“biological vascular scaffold;surface modification; tunica intimal hyperplasia;restenosis;biocompatibility” 为英文关键词,采用计算机检索2008-01/2010-04相关文章。纳入有关与血管支架材料,血管支架材料改性相关的文章,排除重复研究或Meta分析类文章,以30篇为重点分析,讨论血管支架材料改性对血管内皮增生、再狭窄的影响。 结果：支架植入后血管内膜的增生和再狭窄严重影响了其远期疗效,大量的动物实验和临床分析表明,血管支架材料表面改性及载药复合支架能比裸体支架能更有效解决局部慢性炎症反应、内皮功能障碍、抗凝血等问题,显示出良好的安全性和降低冠状动脉再狭窄的有效性。可降解血管组织工程支架的发展将成为新的里程碑,内皮细胞是血管组织工程中最重要的种子细胞,通过种子细胞在体外种植于生物可吸收材料的血管支架上,达到修复创伤、病变和重建功能的目的。 结论：血管支架材料表面改性是目前解决支架植入后抑制内膜增生,防止血栓形成和再狭窄等问题有效方法之一。血管组织工程支架发展前景广阔。 关键词：血管支架材料;表面改性;内皮增生;再狭窄;生物相容性 doi:10.3969/j.issn.1673-8225.2010.25.040     

聚对苯二甲酸乙二醇酯表面接枝改性及其血液相容性的研究进展

背景：聚对苯二甲酸乙二醇酯是一种具有优良的力学性能、化学惰性的聚酯材料,但由于聚合材料的血液相容性不高,因此需对其表面进行修饰,改善其血液相容性。 目的：结合凝血机制简要介绍聚对苯二甲酸乙二醇酯材料表面接枝改性方法及其改性后的血液相容性。 方法：检索1990/2009 PubMed、SDOS及CNKI数据库有关凝血发生机制、抗凝血药物的种类和其对凝血发生的影响以及聚对苯二甲酸乙二醇酯材料本体性质、材料表面接枝的方法及其血液相容性评价等方面的文献。 结果与结论：目前聚对苯二甲酸乙二醇酯表面接枝改性的方法局限性在于表面接枝的分子只能改变材料某种特性,而生物材料在人体内所处环境极为复杂,通过单一的改变材料某些性质很难使材料血液相容性得到根本性的改善。因此从仿生学角度通过接枝特殊分子诱导具有生理活性的血管内皮细胞黏附和生长,构建一种类似于天然血管壁模式的材料表面势必成为未来提高生物材料血液相容性的重要方向。     

人工韧带材料表面修饰及在膝关节交叉韧带重建中的应用

摘要 目的：综述人工韧带表面修饰技术及其在重建膝关节交叉韧带中的效果。 方法：采用电子检索的方式,在万方数据库(http://www.wanfangdata.com.cn/)中检索2000-01/2010-08关于人工韧带表面修饰技术及其在重建膝关节交叉韧带应用方面的文章,关键词为“人工韧带,表面修饰,交叉韧带”。排除重复研究、普通综述或Meta分析类文章,筛选纳入33篇文献进行评价。 结果：生物材料的表面修饰是一项复杂的系统工程,需要兼顾材料学和生物科学的需要,实现理想的表面修饰应该设计表面拓扑结构-特异性识别-亲水/疏水平衡-蛋白质吸附等各个方面。目前所采用的表面修饰技术主要有固定多肽法、固定蛋白质法、激光表面修饰法、辐射接枝法、离子注入法、接枝改性法。研究表明,通过生物材料表面修饰,不仅增进了细胞的黏附,而且促进了细胞的增殖。 结论：人工韧带表面修饰技术在提高人工材料的生物相容性方面取得了显著效果,具有良好的应用前景。 关键词：人工韧带;表面修饰;组织工程;交叉韧带;生物材料 doi:10.3969/j.issn.1673-8225.2010.42.030     

血液相容性抗凝血生物医用高分子材料的制备及其机制

背景: 由于生物医用材料要接触人体内环境,甚至必须植入生物体内,因此要求具有无毒性、优良的生物相容性、高化学稳定性、合适的物理机械性能以及易加工成型性。 目的：从生物惰性材料、生物活性表面和白蛋白的结构及其在抗凝血上的应用几个方面分析血液相容性抗凝血生物医用高分子材料的制备及其机制。 方法：由第一作者检索1969/2010 PubMed数据及万方数据库有关血液相容性抗凝血生物医用高分子材料的制备及其机制等方面的文献。 结果与结论：目前抗凝血材料的制备基本上只是采用单独的生物惰性表面或生物活性表面,虽然都获得了较好效果,但不能长期保持其生物相容性尤其是血液相容性,如果能将惰性表面与活性表面结合起来,使材料同时具备两者的长处,并能充分利用人体血液中的天然组分白蛋白或许会是抗凝血材料的一个发展趋势。今后希望通过采用高生物惰性的PEU和具有生物活性的白蛋白识别因子cibacron blue复合,合成具有优良性质的活性改性物,并以此对聚氨酯进行改性。     

人工皮肤替代物的材料种类及其特征

目的：评价组织工程人工皮肤替代物各种生物材料的性能和应用，寻找适合人体的替代物。 方法：以“组织工程，人工皮肤，支架材料”为中文关键词，“tissue engineering， Artificial skin，intravascular stent” 为英文关键词，采用计算机检索1993-01/2009-10相关文章。纳入与有关生物材料与人工皮肤修复相关的文章；排除重复研究或Meta分析类文章。以26篇文献为主重点进行了讨论组织工程人工皮肤替代物及其性能。 结果：组织工程人工皮肤是应用组织工程技术将体外培养的上皮细胞和成纤维细胞扩增后，接种于具有良好生物相容性的材料上，经体外培养，形成含有与正常皮肤相似的表皮和真皮结构的皮肤替代物。然后将其移植于皮肤创面处，以实现创伤的修复和重建。将两种或两种以上的材料复合在一起，或对生物材料表面进行各种各样的修饰，促进细胞与材料之间的黏附、提高细胞的生物活性、维持生物功能成为目前组织工程生物材料研究的热点。 结论：目前还没有一种人工材料能完全符合组织工程的要求。进一步提高支架材料的微观渗透性和生物活性，促进毛细血管的长入；制备结构仿生支架材料及高活性复合支架材料是今后的研究方向。 关键词：组织工程皮肤材料；人工皮肤；支架材料；皮肤替代物；生物相容性 doi:10.3969/j.issn.1673-8225.2010.29.037     

钙磷多孔陶瓷表面明胶处理及体外细胞相容性

背景：烧结的钙磷多孔陶瓷由于其表面结构致密，在诱导细胞黏附和生长方面仍存在不足。 目的：观察表面明胶处理对钙磷多孔陶瓷细胞相容性的影响。 方法：以羟基磷灰石和磷酸钙为主要原料，采用有机泡沫浸渍工艺制备钙磷多孔陶瓷，然后将多孔陶瓷浸于5%的明胶溶液中进行表面处理。扫描电镜观察处理前后样品的孔隙形貌和表面结构，阿基米德法测试样品的孔隙率，WD-10A型电子万能材料试验机测定压缩强度；将材料与兔骨髓基质干细胞进行体外复合培养，通过MTT实验和扫描电镜观察细胞在材料上的生长情况。 结果与结论：表面明胶处理后，多孔陶瓷的孔壁表面形成了较均匀的明胶涂层，样品的孔隙特征并没有受到显著影响。然而它们的平均压缩强度却从(1.04±0.15) MPa提高到了(5.17±0.17) MPa。扫描电镜观察和MTT实验结果表明，表面涂覆处理前后的多孔材料都具有良好的细胞相容性。与烧结的多孔陶瓷相比，表面明胶处理的样品更能增进细胞在材料表面的早期黏附和增殖。结果表明表面明胶处理在不破坏多孔陶瓷孔隙特征的情况下，不仅提高了钙磷多孔陶瓷的力学性能，而且改善了多孔陶瓷的细胞相容性。 关键词：钙磷多孔陶瓷；明胶；表面处理；细胞相容性；生物材料 doi:10.3969/j.issn.1673-8225.2010.16.011     

人工材料在急性运动骨损伤中的应用与表面修饰

摘要 背景：选择合适的表面修饰材料,有针对性的对基质支架材料进行表面改性和表面修饰,提高材料表面的细胞黏附性以及促进细胞的增生是骨组织工程支架材料研究的重要内容。 目的：概述骨组织工程支架材料的运用情况,支架材料表面修饰材料的运用以及修饰方法或途径。 方法：由第一作者检索1995/2010 PubMed数据及万方数据库文章,选择与组织工程支架材料运用及表面修饰相关的文献。 结果与结论：成骨细胞与支架材料的作用依赖于材料的表面特性、局部形态、表面能或化学能等,这些表面特性决定了细胞怎样吸附到材料表面、细胞的定位以及细胞的功能行为等。因此生物材料的复杂性和细胞-生物材料表面的相互作用决定着进行生物支架材料表面修饰的重要性。理想的表面修饰应该兼顾表面拓扑结构、特异性识别、亲水与疏水平衡、蛋白质吸附等各个方面才能得到功能化的新生组织。目前,应用最多的表面修饰材料是Ⅰ型胶原,未来研究中将多种表面修饰材料进行复合发挥材料的互补作用,以及基因疗法和纳米材料的发展,将成为骨组织工程学领域研究的热点问题。 关键词：骨;支架材料;表面修饰;运动损伤;生物材料 doi:10.3969/j.issn.1673-8225.2011.03.041     

人工韧带表面修饰重建韧带缺损的方法及其效果评价

目的：综述生物材料治疗韧带缺损中表面修饰的主要方法及其效果，为科研工作者提供一定的借鉴。 方法：采用电子检索的方式，在万方数据库(http://www.wanfangdata.com.cn/)中检索2000-01/2010-05关于韧带重建生物材料表面修饰方法与应用效果的研究文章，关键词为“生物材料，表面修饰，人工韧带”。排除重复研究、普通综述或Meta分析类文章，筛选纳入22篇文献进行评价。 结果：目前为了使生物材料在治疗韧带、肌腱等缺损中具有良好的生物相容性和细胞亲和性，要进行生物材料表面改性，通常称为表面修饰。所采用的表面修饰方法主要有固定蛋白质法、固定多肽法、辐射接枝法、离子注入法。研究表明，通过生物材料表面修饰，不仅增进了细胞的黏附，而且促进了细胞的增殖。 结论：生物材料的表面修饰是一个复杂的系统工程，需要兼顾材料科学和生物科学的需要，实现优化。理想的表面修饰应该兼顾表面拓扑结构、特异性识别、亲水/疏水平衡、蛋白质吸附等各个方面才能得到功能化的新生组织。     

壳聚糖-肝素静电自组装多层膜在钛表面进行的生物化修饰**

摘要 背景：基于聚电解质阴阳离子交替组装的静电自组装技术可在温和、简单、易控的条件下实现多种生物大分子在材料表面的固定,已成为生物材料表面设计的重要手段。 目的：利用静电自组装技术将具有生物活性的壳聚糖和肝素固定在钛表面,实现钛表面的氨基多糖生物化修饰,构建一种钛种植体材料的新型生物化表面,以改善钛的细胞相容性。 方法：首先采用NaOH处理钛基材,获得多孔、负电荷的钛表面;然后吸附一层正电荷的聚赖氨酸;最后,多次交替吸附负电荷的肝素和正电荷的壳聚糖,形成以壳聚糖为最外层的多层膜结构。通过漫反射红外光谱扫描电镜和原子力显微镜对多层膜进行表征。并与成骨细胞共培养,观察成骨细胞的黏附、增殖以及分化情况。 结果与结论：红外光谱、原子力显微镜、扫描电镜结果表明肝素-壳聚糖多层膜逐渐形成。此涂层可促进成骨细胞的黏附、增殖和分化。肝素-壳聚糖多层膜有望成为一种新型的生物化钛表面,从而改善钛表面的生物相容性。 关键词：静电自组装;钛;表面改性;壳聚糖;肝素 doi:10.3969/j.issn.1673-8225.2010.21.008     

Tactile sensing of surface features

The tactile recognition of an object held in the hand involves characterizing its surface features. Recent neurophysiological studies point to a number of possible ways in which tactile primary afferents convey information about surface characteristics. The spatial pattern of the afferents that are activated probably underlies the unique recognition of patterns. Measures of afferent response intensity correlate well with overall surface texture and quantitatively encode variations in surface spatial parameters. The temporal patterns of afferent firing provide yet another potential mechanism by which surface features are signaled. Studies of somatosensory cortex have already begun to examine the central processing of these afferent signals, and this remains a fertile field for the future.     

Developmental surface dyslexias

Individuals with surface dyslexia read via grapheme-to-phoneme conversion due to a deficit in the lexical route. A deficit in the lexical route can be caused by impairments at several different loci. In the current study we identify three subtypes of developmental surface dyslexia, each caused by impairment at a different locus on the lexical route, and each showing a different pattern of performance in various tasks. All three subtypes show the classical pattern of reading aloud, with regularizations and difficulty in reading words that have more than a single possible conversion to a phoneme string, but they differ in their performance in lexical decision and homophone comprehension. The first subtype, input surface dyslexia, results from a deficit to the orthographic input lexicon, and entails poor performance in lexical decision and comprehension tasks. The second subtype, orthographic lexicon output surface dyslexia, in which the orthographic input lexicon is accessible but its output to the phonological output lexicon and to the semantic system is impaired, allows normal lexical decision, but causes impaired comprehension of homophones. The third subtype, interlexical surface dyslexia, caused by a selective deficit in the connection between the orthographic input lexicon and the phonological output lexicon but with intact access from the orthographic input lexicon to the semantic system, allows normal performance in lexical decision and comprehension tasks. Seventeen Hebrew-speaking individuals with developmental surface dyslexia aged 10-43 participated in the study, eight of them showed the first pattern, three showed the second pattern, and six displayed the third pattern. Another result of the study pertains to the importance of the lexicality of the result of grapheme-to-phoneme conversion for each target word. Some words, when read via grapheme-to-phoneme conversion, can potentially be read as other words (such as "now" in English, which can be sounded as the word "know"), we term these words potentiophones. The results indicate that potentiophones yield the highest error rate in reading aloud for all the participants with surface dyslexia.     

Innate immunity of the ocular surface

The ocular surface epithelium serves a critical function as the defensive front line of the innate immune system. While the detection of microbes is arguably its most important task, an exaggerated host defense reaction to endogenous bacterial flora may initiate and perpetuate inflammatory mucosal responses. The ability of cells to recognize pathogen-associated molecular patterns (PAMPs) mainly depends on the expression of a family of Toll-like receptors (TLRs). A healthy ocular surface is not inflammatory, even though ocular surface epithelium is in constant contact with bacteria and bacterial products. In this study, we show that human ocular surface epithelial cells, both corneal and conjuctival epithelial cells, respond to viral double-stranded RNA mimic polyI:C to produce pro-inflammatory cytokines through TLR3, while they fail to respond functionally to lipopolysaccharide, a TLR4 ligand. Moreover, human ocular surface epithelium responds to flagellins from ocular pathogenic, but not ocular non-pathogenic bacteria, to produce pro-inflammatory cytokines through TLR5. Thus, ocular surface epithelial cells selectively respond to microbial components and induce limited inflammation; immune-competent cells can recognize microbial components through TLRs and induce the inflammation. The unique innate immune response of the ocular surface epithelium may contribute to its coexistence with commensal bacteria.Inflammatory bowel disease is thought to result from an abnormal response to the gut microbiota. Thus, we also considered the possibility of an association between ocular surface inflammation and a disordered innate immune response. IκBζ is important for TLR signaling, in mice, its knock-out produced severe, spontaneous ocular surface inflammation, the eventual loss of goblet cells, and spontaneous perioral inflammation, suggesting that dysfunction/abnormality of innate immunity can lead to ocular surface inflammation.     

纯钛金属种植体表面活性化的处理方法

摘要：检索pubmed数据库和中国期刊全文数据库文献，然后对资料进行整理，综述分析纯钛金属种植体表面活性化处理方法近年来国内外的进展。文献涉及钛种植体表面活性化处理方法主要有：酸蚀处理法、碱热处理法等化学处理方法，表面涂层、离子注入等物理方法，也有采用高能辐射技术，通过激发电离来调控钛氧化膜的性状，以及钛表面组织工程化等生物方法。目前报道的钛种植体表面改性的方法很多，但尚没有较公认的处理方法，为此探索一种最佳的化学表面活性化处理方法有着极其重要的科学意义。目前认为较简捷又行之有效的表面处理方法是化学处理法     

Recording characteristics of the surface EMG electrodes

Routine motor nerve conduction studies are conducted using surface EMG electrodes. Most techniques of estimating the number of motor units (MUs) are based on surface EMG recordings. Therefore, it is important to assess the uptake area of these electrodes. We recorded surface EMG motor unit action potentials (SMUAPs) from the biceps muscle of normal subjects. The SMUAP amplitude fell from 42 μV for the superficially located MUs (i.e., within 10 mm of skin surface) to 11 μV for the deep MUs (i.e., more than 20 mm from the skin surface). We infer that the pickup radius of the surface electrode is less than 20 mm. The implications of the limited uptake area of the surface electrodes to the analysis of compound muscle action potentials, estimation of the number of MUs, and the surface EMG recordings are discussed. © 1994 John Wiley & Sons, Inc.     

Visualization and measurement of the cortical surface

Much of the human cortical surface is obscured from view by the complex pattern of folds, making the spatial relationship between different surface locations hard to interpret. Methods for viewing large portions of the brain's surface in a single flattened representation are described. The flattened representation preserves several key spatial relationships between regions on the cortical surface. The principles used in the implementations and evaluations of these implementations using artificial test surfaces are provided. Results of applying the methods to structural magnetic resonance measurements of the human brain are also shown. The implementation details are available in the source code, which is freely available on the Internet.     

Brain surface ependymoma

A case of brain surface ependymoma is reported here. A 41‐year‐old woman presented with weakness of the right upper limb. Magnetic resonance imaging revealed a left fronto‐parietal cystic tumor with a calcified mural nodule. Total removal of the tumor was performed. This tumor was located within the surface portion of the fronto‐parietal parenchyma and was sharply demarcated from the surrounding brain tissue, and there was no continuity with the ventricles. Histological examination of this tumor showed monotonous proliferation of tumor cells with moderate cellularity and occasional mitoses, forming true ependymal rosettes and perivascular pseudorosettes with fibrillary background. A clear cell component resembling oligodendroglioma was partly noted. The tumor cells showed positive immunoreaction for glial fibrillary acid protein and vimentin.     

从体表电生理信号中提取希氏束信号的分析系统**

背景：传统的希氏束检测方法是对体表心电信号进行数百次叠加或者经食道检测以及心内导管检测得到,研制从体表心电信号提取希氏束信号不但有利于临床诊断,也有利于动物药物实验。 目的：从体表心电信号中提取希氏束信号,并开发体表希氏束信号分析系统。 方法：以家兔体表心电信号作为待分析信号,以其心内希氏束电图作为对照信号,采用随机共振、小波变换、叠加平均和耦合累加等分析方法,对体表心电信号进行分析。 结果与结论：小波变换后得到的信号,可以从体表心电信号中检测出希氏束信号,但并不是所有希氏束信号都能被识别,心内信号经过小波变换后,个别希氏束信号反而消失。随机共振方法从体表心电中检测出的希氏束信号识别率要高于小波分析方法,随机共振方法与小波分析相同之处是,心内信号经过处理后,个别希氏束信号反而消失。本文提出的耦合叠加算法能够从体表心电信号提取出希氏束信号,与经典叠加方法比较,其优点是希氏束信号明显,叠加次数远远少于经典叠加方法。提示实验采用的随机共振、小波变换、耦合累加等分析方法,能够有效抑制噪声、提取希氏束信号,开发研制的体表希氏束信号分析系统具有较强的实用价值。 关键词：希氏束;随机共振;小波;心电图;数字化医学     

Clinical applications of surface electromyography in neuromuscular disorders.

Surface electromyography (SEMG) is still rarely used in clinical settings for the detection and analysis of myoelectric signals. The electromyographic signal detected on the skin surface includes information from a greater proportion of the muscle of interest than conventional clinical EMG, acquired using needle electrodes. SEMG is therefore more representative than the localised, and thus very selective needle EMG signals currently used. However, both reliability and interpretation of surface EMG need to be questioned. This review looks at the studies concerned with the characterisation of neuromuscular pathologies using EMG parameters. After introducing principles and limitations of surface EMG, an overview of the main results obtained in clinical settings is presented and discussed. There is a particular focus on high spatial resolution surface EMG as it is currently the best compromise between the selectivity of needle EMG and the representative nature of classical SEMG. Several perspectives are proposed that underline the fact that surface EMG is an evolving discipline and should be worthy of a place in routine clinical examinations.     

Planar brain surface reformations for localization of cortical brain lesions

Cortical lesions close to the central region may be difficult to localize on orthogonal MRI slices, especially when space-occupying lesions distort the brain surface relief and obscure anatomical landmarks. The purpose of this study was to evaluate, whether localization can be improved with planar brain surface (Mercator or "pancake") reformations. Three independent MRI readers localized superficial brain lesions of 30 patients on orthogonal MRI slices and on planar brain surface views reformatted from a sagittal 3D T(1)-weighted gradient echo sequence. On orthogonal MRI slices 46% of lesions were considered easy to localize, 37% difficult and 17% could not be localized. Corresponding values for planar brain surface views were 82%, 16% and 2%, respectively. Evaluation of orthogonal MRI slices took 190 min compared to 100 min for planar brain surface views. Thus, planar brain surface reformations are a helpful and time-saving means to localize superficial brain lesions.