纳米颗粒对细胞膜的作用

纳米颗粒在生物医学领域有着广泛的应用前景。在纳米颗粒与细胞相互作用的研究中,颗粒对细胞膜作用的相关研究,对揭示纳米颗粒的生物效应是至关重要的。纳米颗粒对细胞膜的影响有很多种,主要体现在对细胞膜结构和性质,以及对膜上生物大分子(蛋白质等)功能的影响等方面。这里综述了近年来纳米颗粒对细胞膜作用的相关研究成果,分别从颗粒的自身物理化学性质(尺寸、形状、表面形貌、亲疏水性质、表面电荷、特异性修饰等)、颗粒与细胞作用的环境因素,以及外界能量对颗粒与细胞膜作用的调控三个方面出发,就纳米颗粒作用对细胞膜影响的问题分别进行了分析和总结。     

柔性载药纳米颗粒在毛细血管中输运特性的数值模拟研究

基于柔性纳米颗粒的载药系统由于其诸多优势而具有广泛的应用前景.本文采用格子玻尔兹曼方法和浸入边界法建立了柔性纳米颗粒和红细胞在毛细血管中的三维输运模型,研究了柔性纳米颗粒的迁移机制与特性,并分析了红细胞比容、变形能力及纳米颗粒刚度的影响规律.结果表明,在微血管中柔性纳米颗粒自身有向血管中心迁移的趋势,其径向迁移量随颗粒刚度的增强而减小.红细胞的径向迁移运动及变形,会导致纳米颗粒受排挤而趋向血管壁面的无细胞层;红细胞比容、变形能力及纳米颗粒刚度的增加,能提高纳米颗粒的趋壁率.在混合颗粒输送方案中,颗粒间及颗粒与红细胞间的相互作用使得较低刚度颗粒的趋壁率减小并增加刚度较高颗粒的趋壁率.研究结果对纳米载体药物输送系统的设计具有理论指导意义.     

细胞对纳米材料的胞吞及其胞内定位相关机制的研究进展

纳米材料具有独特的理化性质,其在纳米生物医药技术中得到广泛的研究,有着良好的应用前景。纳米材料的尺寸分布在纳米级。使其入胞途径和转运方式与一般尺寸的物质略有不同。细胞可通过网格蛋白介导胞吞、陷窝小泡介导胞吞、吞噬作用和巨胞饮等胞吞方式摄取纳米颗粒。吞噬的方式及后续的转运和定位受细胞的类型、状态,以及纳米颗粒的理化性质如元素组成、尺寸、形状、电荷、表面修饰等多种因素共同影响。     

调制磁性纳米颗粒提高磁热性能的研究

磁性纳米颗粒具有独特的磁学性质,即在外加交变磁场下因产生磁滞释放热量,使其在生物医学领域,特别是肿瘤磁热疗,获得了广泛应用.到目前为止,磁性纳米颗粒介导的磁热疗成为一种治疗癌症的有效手段,已进入临床三期实验.因此,针对磁性纳米颗粒本身,优化设计尺寸、形貌、组分和表面修饰来提高其磁热性能,进而减小临床应用中的颗粒浓度来最小化毒副作用的研究,对肿瘤治疗及生物医药研究具有十分重要的意义.本综述详述如何优化调制磁性纳米颗粒以提高其磁热性能,为高效、低毒的磁性纳米颗粒的设计提供了指导性的研究方向.     

CD45新型免疫荧光标记与检测方法研究

使用经生物修饰后的荧光纳米颗粒,探索了白细胞共同抗原CD45的新型荧光标记与检测方法。将联吡啶钌配合物[三(2,2-联吡啶)氯化钌,六水]为核,二氧化硅为外壳的荧光纳米颗粒用鼠抗人CD45Pur进行生物修饰后,对人体白细胞进行荧光标记,通过荧光显微镜和流式细胞仪检测标记样品的细胞数目和荧光强度,结果表明,该新型荧光标记方法的灵敏度高,光学稳定性好,可准确有效地识别人体白细胞。     

固定云芝漆酶纳米金颗粒修饰金盘电极的制备及其对氧还原反应的生物电催化性能

利用1,6-己二硫醇作为联结剂将纳米金颗粒修饰到金盘电极上,再以L-半胱氨酸为修饰剂使纳米金颗粒功能化并进一步与漆酶充分作用,制备了固定漆酶的纳米金颗粒修饰金盘电极并以循环伏安法测试了其对氧还原的催化性能。实验结果表明:O2在该电极上还原电位约为-0.26 V(vs SCE),氧还原峰电流为3.0 uA(25℃),较文献[7]报导的固酶聚异丙基丙烯酰胺(PNIPAM)水凝胶修饰ITO电极的氧还原催化性能要优。(氧气还原电位:-0.26 V,vs NHE,峰电流:0.47 uA)进一步研究表明:本文制备的修饰电极稳定性好,适于长期使用而且热稳定性优于文献[7]报道的固酶聚异丙基丙烯酰胺水凝胶修饰ITO电极:50℃时在本文制备的纳米金修饰电极上氧还原峰电流仍保持为25℃时修饰电极上氧还原峰电流的40%左右。     

荧光银纳米团簇的生物合成及其在痕量六价铬检测中的应用

[目的]利用季也蒙毕赤酵母ZJC-1合成银纳米团簇并用于痕量Cr(Ⅵ)的检测.[方法]使用经耐银驯化的季也蒙毕赤酵母ZJC-1生物合成荧光银纳米团簇,并对其结构和荧光性能进行了表征,探究Cr(Ⅵ)对银纳米团簇荧光的选择性猝灭作用,建立了银纳米团簇荧光强度与Cr(Ⅵ)浓度的线性关系.同时还考察了体系pH和其他金属离子对C...     

磁性纳米颗粒作为载体在基因转染中的研究进展

磁性纳米颗粒具有很强的结合、浓缩与保护DNA的作用,具有超顺磁性、较高的安全性和低的免疫原性,可以结合大片段DNA,在外加磁场的作用下可实现安全、高效的基因靶向性运输,提高外源基因的转染效率。由于磁性纳米颗粒的独特性质,使得其作为非病毒载体在基因治疗中的应用进展迅速。我们简要介绍磁性纳米材料的特点、种类及结构,磁性纳米基因载体的特点,以及磁性纳米颗粒作为载体在基因转染中的应用情况。     

量子点细胞毒性及其作用机制

纳米粒子(NPS)在工业和研究中的使用急剧增加,因而这种材料面临一个其潜在毒性的问题。不幸的是,对纳米颗粒与纳米/生物界面可能发生的相互作用没有足够的了解。广大科技工作者正在积极寻求日益关注的纳米技术对人类的影响答案。我们将从NPS在生物媒体中的浓度,尺寸大小,电荷,和配位体的稳定性方面来了解纳米粒子的性质和他们在生物环境中对细胞毒所起的作用;并初步探讨已知的机制,量子点可以破坏细胞,包括氧化应激引起的活性氧(ROS)。微小浓度量子点足以造成长期持久的,甚至是跨代的影响。本文讨论了从纳摩尔到皮摩尔浓度的诱导细胞损伤的量子点(QDS)的浓度,这意味着含镉量子点可以发挥表观遗传毒性,纳米基因毒性,重金属基因的毒性。在此为评估包括量子点的在内的纳米毒性的的纳米材料,我们采用量子点作为一个例证,来阐述以科学为基础的发展到纳米毒理学的相关的问题。     

金纳米棒的光学性质及其在生物医学领域的应用

简要介绍金纳米棒的光学性质和合成方法,重点阐述其在生物医学领域研究的最新进展,并对其今后的研究方向进行展望．金纳米棒是一种胶囊状的金纳米颗粒,具有一个横向等离子共振吸收峰和一个纵向等离子共振吸收峰,分别对应其横轴和纵轴两个特征尺寸．通过调节金纳米棒的长径比,纵向等离子共振吸收峰可由可见光区跨越至近红外光区．金纳米棒这一独特的光学性质在生物和化学传感方面有着广泛而重要的应用前景．     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.