原子力显微镜在生物学中应用的现状与前景

原子力显微镜 (AFM)是一种新型纳米显微技术 ,它拥有分辨率高、样本制作简单、成像时间短等优点 ,非常适合生物标本的观察。本文对原子力显微镜技术的原理进行介绍 ,并综述其在生物学中的应用现状及应用前景     

原子力显微镜在生物医学研究中的应用

原子力显微镜(AFM)具有纳米级成像分辨率、皮牛顿级力分辨率和可在接近生理条件下对生物样品直接表征等独特的优越性,已成为生命科学研究中的重要工具。本文主要从生物大分子成像和生物分子间相互作用力测定两个方面介绍AFM在生物医学领域中应用的新进展。     

应用原子力显微镜观测血小板的黏附

原子力显微镜(Atomic force microscope,AFM)是近年应用于生物医学领域研究的新技术,分辨率可达到纳米层次.血小板黏附在止血血栓过程中起十分重要的作用.本研究以胶原(collagen)为基质建立血小板的黏附模型,利用AFM的tapping mode在液体环境下观测了血小板的黏附、伸展过程.并应用contact mode中的侧向力模式观察了血小板在胶原上的黏附能力.观察结果表明,血小板在黏附过程中可见到伪足伸出、微小粒子的释放、细胞骨架重组.黏附血小板的细胞骨架网络结构可对抗～80nN的侧向力.     

原子力及原子力声显微镜应用于生物学领域的回顾与展望

回顾了显微镜的发展史,着重介绍了原子力显微镜的工作原理,工作模式,成像特点及其在生物学领域的应用.对最新的原子力声显微镜的发展做了展望.     

原子力显微镜及其在生物医药学研究中的应用

本文介绍了原子力显微镜的工作原理及特点,并对其三种工作模式进行了比较,重点介绍了更适用于生物医药研究的敲击式工作模式以及原子力显微镜在生物医药学研究中的应用.     

应用原子力显微镜对内皮细胞的研究

原子力显微镜具有分辨率高、标本不需特别处理、细胞可在生理条件下直接成像、能观察局部的物理特性、能提供生物分子和细胞表面的分子以及亚分子的三维图像、能以纳米尺度的分辨率观察局部形态和物理特性、测量分子间的相互作用力等优点,为研究内皮细胞尤其是在体细胞形态结构上提供了一个很好的工具。     

人免疫球蛋白G的原子力显微镜观察

应用原子力显微镜（ＡｔｏｍｉｃｆｏｒｃｅｍｉｃｒｏｓｓｃｏｐｅＡＦＭ）观察不同浓度人ＩｇＧ样品，当ＩｇＧ浓度为２０μｇ／ｍｌ时，ＩｇＧ分子不易在基底表面分散，大部分ＩｇＧ聚集而形成多聚体，当浓度为０．２５μｇ／ｍｌ或０．１μｇ／ｍｌ时，ＩｇＧ分子基本上能较好的分散，可见ＩｇＧ呈“三个球形”结构。当浓度为０．０２μｇ／ｍｌ时，可看到单个ＩｇＧ分子的球形结构，大小为１６．５５～１８．５ｎｍ。     

丙型肝炎病毒p7膜蛋白的原子力显微镜研究

目的：以丙型肝炎病毒p7蛋白为模型，探讨原子力显微镜在膜蛋白方面的研究。方法：在云母表面准备p7蛋白样品以及将p7合并到磷脂双分子层中，进行扣击模式原子力显微镜的观察。结果：可清晰观察p7蛋白分子离子隧道结构。p7合并到磷脂双分子层中后，始终存在于DOPC液相中，并出现多个蛋白逐渐结合的现象。结论：原子力显微镜能够用于膜蛋白的基本结构特征的观察，同时可了解磷脂双分子层对膜蛋白所产生的影响，为后期细胞表面膜蛋白的原子力显微镜研究打下基础。     

原子力显微镜在Alzheimer病发病机制研究中的应用

原子力显微镜(AFM)是一种新型的纳米显微技术,具有标本制备简单、分辨率高等优点,并能够在生理条件下对生物样品进行观察,成为神经生物学研究的有力工具。β淀粉样蛋白(Aβ)溶解性的转变在Alzheimer病发病机制中起重要作用。国内外大量研究表明,AFM已成功地应用于Aβ纤维化各阶段的研究中,从而使药物治疗干预Aβ纤维化成为可能。我们综述了AFM的原理及其在生物结构研究中的技术要点,举例说明了它在Alzheimer病(AD)发病机制,尤其是在Aβ及Aβ寡聚体研究中的作用。     

原子力显微镜在生物学中应用的现状与前景

原于力显微镜(AFM)是一种新型纳米显微技术，它拥有分辨率高、样本制作简单、成像时间短等优点，非常适合生物标本的观察。本文对原子力显微镜技术的原理进行介绍，并综述其在生物学中的应用现状及应用前景。     

原子力显微镜在生命科学中的应用

早在八十年代初期 ,人们已能使用扫描隧道显微镜 (ｓｃａｎｎｉｎｇｔｕｎｎｅｌｉｎｇｍｉｃｒｏｓｃｏｐｅ ,ＳＴＭ)获得原子分辨率的物体表面地形图[1] 。从那时起 ,人们便期待ＳＴＭ能够成为ＤＮＡ测序和获得原子分辨率的蛋白质表面图像工具。虽然以上的这些梦想尚未成为现实 ,然而由此却发展了一系列的扫描探针显微镜(ｓｃａｎｎｉｎｇｐｒｏｂｅｍｉｃｒｏｓｃｏｐｅ ,ＳＰＭ )。其中原子力显微镜 (ａｔｏｍｉｃｆｏｒｃｅｍｉｃｒｏｓｃｏｐｅ ,ＡＦＭ ) [2 ] 的应用更是逐渐从最初的物理学、材料科学与工程领域拓宽到生命科学领域 ,…     

神经元膜抗NMDAr1亚基IgG分子构象的原子力显微镜研究

目的　确定兔抗NMDAr1亚基 (N 甲基 D 天冬氨酸受体Nr1亚基 )IgG分子特征性构象。方法　应用原子力显微镜扫描生理状态下分布在云母表面的兔抗NMDAr1亚基蛋白IgG分子 ,并进行理论计算。结果　IgG分子为 136 .4 ×6 2 .8 × 2 6 .1 椭球形三亚基复合物。结论　原子力显微镜可以在生理状态下直观测定生物大分子纳米尺度介观结构。抗NMDAr1蛋白IgG分子的特征性构象 ,可以做为神经细胞膜表面NMDA受体 (N 甲基 D 天冬氨酸受体 )原子力显微镜观测的原位标记物     

原子力显微镜对海藻酸钠水溶液聚集态结构的研究

利用原子力显微镜(AFM)研究了海藻酸钠水溶液浇铸法制得的薄膜，在临界浓度5％(重量比)呈现出典型的多角形结构，这是溶致液晶的结构特征之一。表征了海藻酸钠水溶液聚集态结构，并对溶致液晶现象的形成机理进行了初步探讨。     

原子力显微镜应用于红细胞病理学检验的初步研究

目的: 初步探讨原子力显微镜在临床病理学检验中的应用前景。方法: 应用原子力显微镜对正常人、肺癌病人和骨髓增生异常综合症等病人血液中的红细胞进行大范围和微观结构的形貌图像与数据的获取和分析。结果: 用原子力显微镜获得了多个红细胞、单个红细胞和细胞膜表面微观结构清晰的形貌图像,发现肺癌病人大多数红细胞呈棘刺状,每个细胞共有10-20个棘刺状突起,大部分突起在细胞的边缘,中央有少量突起。细胞边缘的棘刺比中央的棘刺要宽,但较短,平均宽度约为589.0nm,平均长度约为646.7nm。中央棘刺状突起并非伸向细胞片面外,而是倒伏包埋在细胞中。而骨髓增生异常综合症病人的红细胞呈双凹状,膜表面微观结构观察还发现,骨髓增生异常综合症病人的红细胞膜表面出现许多几十nm到一百多nm大小不等的孔洞。结论: 原子力显微镜可广泛地应用于临床病理学检验。其应用前景包括细胞记数,细胞直径、平均高度、体积、表面积和表面积/体积比等参数的获取和比较,单个细胞的形貌观察,以及细胞膜表面微观结构的观察和比较,等等。     

Imaging and manipulating chromosomes with the atomic force microscope

Polytene chromosomes from the salivary gland cells of Drosophila melanogaster were examined by atomic force microscopy. The atomic force microscope (AFM) was capable of resolving chromosomal features down to the limits of the tip sharpness, about 500 Å for pyramidal-shaped tips. Resolution was increased to 300 Å by using electron beam deposited (EBD) tips with high aspect ratios. This significantly exceeds the resolution obtainable with conventional optical microscopes, but at the cost of compromising the structural integrity of the sample. A reasonable compromise was achieved by using oxide-sharpened tips. In this case high resolution was obtained without sample degradation, but when desired these tips were also capable of sample disintegration with increased scanning force and rate. Thus, oxide-sharpened tips were used to precisely dissect defined chromosomal regions to illustrate their potential use in genetic mapping efforts. This study illustrates the utility of the AFM in the characterization and manipulation of chromosomes and chromosomal DNA.     

Atomic force microscopy of plant chromosomes

Atomic force microscopy has been used to image plant chromosomes from standard preparations without staining or coating. This has enabled the collection of high-resolution three-dimensional data on surface structure. The technique has been further applied to the imaging of C-banded chromosomes revealing structural changes resulting from the banding treatment. The bands were observed as localized areas of high relief.     

Analysis by atomic force microscopy of morphological changes in barley chromosomes during FISH treatment

We employed atomic force microscopy (AFM) to examine structural changes in barley chromosomes during the four steps of standard FISH processes. Rehydration and dehydration with alcohol accompanying RNase treatment increased chromosome arm width and decreased chromosome height about 50%. Subsequent heat denaturation reduced chromosome height further. These three-dimensional structural changes of the chromosomes were substantial, but the FISH signal produced by the hybridization of fluorescent probes was clear when observed by a fluorescence microscope. In higher-magnification images, we observed granular structures considered to represent the chromatin fiber on the surface of the chromosomes in each FISH protocol step. These our results indicate that FISH treatments result in severe damage of the three-dimensional higher-order structures of the chromosomes, although nano-structures, such as nucleosome and chromatin fibers, remain intact and relatively unaffected.     

狂犬病病毒CTN-1v株原子力显微镜观察结果的初步分析

目的 利用原子力显微镜对狂犬病病毒进行观察.方法 超速离心制备狂犬病病毒CTN-1v株,采用磷钨酸负染透射电子显微镜进行观察,在此基础上进行原子力显微镜观察,采用轻敲模式在大气常温下扫描成像.结果 透射电子显微镜观察到狂犬病病毒的典型弹状病毒粒子,透射电镜提供病毒二维图像,可见刺突结构,原子力显微镜则呈现了狂犬病病毒三维图像,且可见病毒表面有凹凸不平的特征和边缘有齿轮状的突起,同时获得表面粗糙度等可以量化指标.两种方法最终得到相似的形态学结果.结论 利用原子力显微镜首次观察到狂犬病病毒的三维形态结构,与透射电镜观察相比,原子力显微镜是一种制样简单、观察直观的新型病毒形态学研究工具.

Abstract：

Objective To explore the application of atomic force microscopy( AFM ) on the research of morphology of the rabies viruses. Methods To prepare the rabies virus CTN-1v strains by ultracentrifugation, and observe it with transmission electron microscopy (TEM) which negatively stained by phosphotungstic acid. Then study the morphology of rabies virus with AFM based on the result of TEM. AFM image applies the tapping mode to rabies virus without any further treatment in air at room temperature. Results The TEM image is two-dimensional image which can be seen the classical bullet-shaped structure,and the spike structure can also be seen. The AFM image showed the rabies virus morphology with three-dimensional image which can shows the characteristics of the virus surface and edge. The rabies virus particle was successfully observed by TEM or AFM methods. Conclusion It's the first time to get the three-dimensional morphological structure of rabies virus by atomic force microscopy, compared with transmission electron microscopy, AFM is a new research tool for viral morphology study with the advantages of simple sample preparing and intuitionistic and visible interface for researchers.     

Visualization of inositol 1,4,5-trisphosphate receptor by atomic force microscopy

Inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R) acts as a ligand-gated channel that mediates neuronal signals by releasing Ca(2+) from the endoplasmic reticulum. The three-dimensional (3D) structure of tetrameric IP(3)R has been demonstrated by using electron microscopy (EM) with static specimens; however, the dynamic aspects of the IP(3)R structure have never been visualized in a native environment. Here we attempt to measure the surface topography of IP(3)R in solution using atomic force microscopy (AFM). AFM revealed large protrusions extending approximately 4.3 nm above a flat membrane prepared from Spodoptera frugiperda (Sf9) cells overexpressing mouse type 1 IP(3)R (Sf9-IP(3)R1). The average diameter of the large protrusions was approximately 32 nm. A specific antibody against a cytosolic epitope close to the IP(3)-binding site enabled us to gold-label the Sf9-IP(3)R1 membrane as confirmed by EM. AFM images of the gold-labeled membrane revealed 7.7-nm high protrusions with a diameter of approximately 30 nm, which should be IP(3)R1-antibody complexes. Authentic IP(3)R1 immuno-purified from mouse cerebella had approximately the same dimensions as those of the IP(3)R-like protrusions on the membrane. Altogether, these results suggest that the large protrusions on the Sf9-IP(3)R1 membrane correspond to the cytosolic domain of IP(3)R1. Our study provides the first 3D representation of individual IP(3)R1 particles in an aqueous solution.