原子力显微镜在膜技术中的应用

在简要介绍原子力显微镜(AFM)的工作原理和特点的基础上,详细阐述了原子力显微镜在三维形貌观测、膜的表面粗糙度、膜的透过通量、成分分析、成膜机理研究和膜表面污染程度等方面的应用,进一步比较原子力显微镜与其他显微分析技术的不同.原子力显微镜在膜技术方面显示了强大的应用能力,由此推动膜技术的迅猛发展.同时,AFM存在一些不足,对于组成复杂的薄膜,不能获得深层次的结构和化学分析.因此,AFM需要研发更多新的分子探针,以实现对薄膜多种组分的识别和成像.     

纳米级阿维菌素胶囊的AFM观察

应用原子力显微镜(AFM)对乳液聚合法制备的纳米级阿维菌素胶囊进行了表面形貌和相位成像的观察.在水溶液的不同稀释浓度下,纳米级阿维菌素胶囊呈现不同的尺寸和形状.AFM的独特优势使之成为观察纳米胶囊的全新手段.     

基于原子力显微术的肿瘤细胞生物物理特性研究

给出原子力显微术(AFM)在活细胞表面超微结构成像和生物力学特性检测的技术方案,概述了AFM在肿瘤细胞生物物理特性研究的最新进展及其重要意义.     

原子力显微镜成像及力谱在生物研究中的应用

原子力显微镜自发明迄今,已被应用于生物研究的各个领域,展示了其广泛的应用前景。本文将主要结合我们及其他研究小组的工作,简要介绍原子力显微镜成像和力谱技术的基本原理,较系统地综述其在生物研究中的应用。所涵盖的生物分子包括核酸、蛋白质、磷脂、多糖、细胞/细菌以及病毒等。最后探讨和展望了该领域的广阔发展前景。     

原子力显微镜探针自动逼近系统设计与应用

设计出一套能独立运作的原子力显微镜(AFM)探针自动逼近系统,可广泛应用于大部分原子力显微扫描系统的独立开发.逼近过程中,通过VB的串口通讯发送指令控制单片机采集AFM微悬臂梁的偏转信号,并传送到计算机进行分析显示,实时监测探针与样品之间的作用力,最终实现探针的自动逼近.该系统可与多种相关原子力显微镜设备组合应用,达到个性化多功能检测的目的.     

近场光学和单分子操纵（综述）

介绍了近场光学显微镜（SNOM）,原子力显微镜（AFM）,扫描隧道显微镜（STM）和光镊（OPTICAL TWEEZERS）等相关技术的原理。这些技术突破了传统显微镜的衍射极限对分辨率的限制,可以对单个分子进行探测和操纵,因此在物理、化学、生物、医学、材料学以及微电子学等方面都有广泛的应用前景。     

石墨烯量子点的合成及其细胞显影应用

采用柠檬酸作为碳源,通过一步热解法大量合成了石墨烯量子点(GQDs).利用透射电子显微镜(TEM)、原子力显微镜(AFM)、傅里叶红外光谱(FT-IR)、元素分析、紫外-可见吸收光谱(UV-Vis)和荧光发射光谱(PL)等测试手段,对所获得GQDs的形貌、结构、组成、表面基团和荧光性质等进行了表征.研究结果表明,该工作合成的GQDs具有良好的形貌与结构,以及优异的光学性能,而且在金属离子检测领域具有很好的应用,特别是对于铁离子(Fe~(3+))具有高效选择性.此外,所合成的GQDs具有很低的细胞毒性,而且在细胞显影中有着优异的效果,表明其在细胞显影领域具有广泛的应用前景.     

原子力显微镜研究蛋白质晶体生长机理及进展

原子力显微镜(AFM)这种能进行微尺度测量的精密仪器是目前研究晶体生长机理最为有效的方法之一,在晶体生长机理研究中起到了重要的作用,尤其是对于蛋白质晶体生长的研究显得更为突出.分别简明地阐述了利用AFM进行蛋白质晶体生长研究的工作原理,以及在这方面已经取得的研究成果,包括二维台阶生长、螺旋位错生长、法向生长、三维成核生长、台阶发展的不对称性、及杜仲抗真菌蛋白(EAFP)和天花粉蛋白(TCS)晶体生长的新进展.论述了利用空间微重力环境进行蛋白质晶体生长及空间蛋白质晶体生长的科研和应用, 指出今后进行蛋白质晶体生长研究的趋势和前景.     

空间诱变致成瘤性减弱的B16细胞株形态学观察

观察动物接种实验致瘤性显著减弱的空间诱变小鼠黑色素瘤B16细胞株的细胞形态、细胞骨架和表面结构与对照细胞株的差异。分别使用激光共聚焦显微镜观察筛选所得阳性细胞株与对照细胞株,以及用荧光素标记的鬼笔环肽染色,观察细胞骨架的异同。应用原子力显微镜(AFM)对筛选所得阳性细胞株和对照细胞株分别成像,观察空间诱变细胞株与对照组细胞株所得图像的差异。激光共聚焦显微镜观察结果显示,从空间诱变细胞株中筛选出的8#细胞株的细胞骨架荧光较对照组增强,细胞骨架纤维比对照组粗大。AFM图像显示,8#细胞株分泌的纤维粘连蛋白的纤维形态和分布与对照组细胞有较大差异,其纤维较为扁平、走行弯曲或呈轻度迂曲状;对照组细胞纤维呈山脊状、放射状,源自细胞伪足部细胞膜。在8#细胞株图像中有少量“孔洞”样结构,而在对照组细胞中未观察到类似结构。     

Cu(110)-O表面NC-AFM探针针尖的纳米指纹识别技术研究

在扫描探针显微镜(SPM)技术(包括原子力显微镜(AFM)、扫描隧道显微镜(STM)以及开尔文力探针显微镜(KPFM)等)中,探针针尖的状态和种类对于研究材料表面的物理、化学性质有着重要的影响.本论文以Cu(110)-O为例,主要研究利用AFM针尖控制技术对Cu(110)-O的不同相位,表面扫描结果及相位形成原因,Cu,O原子的关系以及针尖与表面原子种类识别的形成原因等.针对探针针尖原子种类以及尖锐程度的不同,证实了O原子针尖以及Cu原子针尖作用下对Cu(110)-O表面的Cu,O原子具有化学识别的功能.同时,研究发现针尖状态对材料表面信息识别具有重要影响,并给出了具体的解释和讨论.本研究对AFM表面原子成像、原子种类化学识别具有重要意义.     

Atomic force microscopy in cell biology

The history, characteristic, operation modes and coupling techniques of atomic force microscopy （AFM） are introduced. Then the application in cell biology is reviewed in four aspects： cell immobilization methods, cell imaging, force spectrum study and cell manipulation. And the prospect of AFM application in cell biology is discussed.     

原子力显微镜和扫描隧道显微镜兼容系统的研制

扫描隧道显微镜（ＳＴＭ）和原子力显微镜（ＡＦＭ）由于具有原子量级的分辨率,所以在表面物理,化学,生物学领域得到了越来越广泛的应用。但是,扫描隧道显微镜只能观察导电样品,这就限制了它的应用范围。     

Progress of AFM single-cell and single-molecule morphology imaging

Atomic force microscopy (AFM) can probe single living cells and single native membrane proteins in natural fluid environments with label-free high spatial resolution. It has thus become an important tool for cellular and molecular biology that significantly complements traditional biochemical and biophysical techniques such as optical and electron microscopy and X-ray crystallog-raphy. Imaging surface topography is the primary application of AFM in the life sciences. Since the early 1990s, researchers have used AFM to investigate morphological features of living cells and native membrane proteins with impressive results. Steady improvements in AFM techniques for imaging soft biological samples have greatly expanded its applications. Based on the authors’ own research in AFM imaging of living cell morphologies, a review of sample preparation procedures for single-cell and single-molecule imaging experiments is presented, along with a summary of recent progress in AFM imaging of living cells and native membrane proteins. Finally, the challenges of AFM high-resolution imaging at the single-cell and single-molecule levels are discussed.     

戊二醛对原子力显微镜观测大肠杆菌的影晌

戊二醛作为生物材料的固定剂,在原子力显微镜（AFM）制样中已广泛使用．虽然已有用戊二醛观测大肠杆菌的文献报道,但到目前为止,关于戊二醛在AFM观测大肠杆菌中的作用还缺乏系统研究．首先分析AFM扫描图像的假像,进而探讨戊二醛的浓度和固定时间对AFM图像质量和大肠杆菌表面形貌的影响．结果表明,戊二醛的浓度和固定时间对AFM图像的清晰度、大肠杆菌的微观结构以及细胞的三维尺寸都有着重要影响．在相同固定条件下所扫描的AFM图像与扫描电子显微镜（SEM）图像对比发现,两者的形貌相似,而AFM图像比SEM图像分辨率更高,在定量分析上也更有优势．     

Detecting CD20-Rituximab interaction forces using AFM single-molecule force spectroscopy

The invention of atomic force microscopy(AFM) has provided new technology for measuring specific molecular interaction forces.Using AFM single-molecule force spectroscopy(SMFS) techniques,CD20-Rimximab rupture forces were measured on purified CD20 proteins,Raji cells,and lymphoma patient B cells.Rimximab molecules were linked onto AFM tips using AFM probe functionalization technology,and purified CD20 proteins were attached to mica using substrate functionalization technology.Raji cells(a lymphoma cell line) or lymphoma patient cells were immobilized on a glass substrate via electrostatic adsorption and chemical fixation.The topography of the purified CD20 proteins,Raji cells,and patient lymphoma cells was visualized using AFM imaging and the differences in the rupture forces were analyzed and measured.The results showed that the rupture forces between the CD20 proteins on Raji cells and Rituximab were markedly smaller than those for purified CD20 proteins and CD20 proteins on lymphoma patient B cells.These findings provide an effective experimental method for investigating the mechanisms underlying the variable efficacy of Rituximab.     

Research progress in quantifying the mechanical properties of single living cells using atomic force microscopy

The advent of atomic force microscopy （AFM） provides a powerful tool for investigating the behaviors of single living cells under near physiological conditions. Besides acquiring the images of cellular ultra-microstruc- tures with nanometer resolution, the most remarkable advances are achieved on the use of AFM indenting tech- nique to quantify the mechanical properties of single living ceils. By indenting single living cells with AFM tip, we can obtain the mechanical properties of cells and monitor their dynamic changes during the biological processes （e.g., after the stimulation of drugs）. AFM indentation-based mechan- ical analysis of single cells provides a novel approach to characterize the behaviors of cells from the perspective of biomechanics, considerably complementing the traditional biological experimental methods. Now, AFM indentation technique has been widely used in the life sciences, yielding a large amount of novel information that is meaningful to our understanding of the underlying mechanisms that govern the cellular biological functions. Here, based on the authors＇ own researches on AFM measurement of cellular mechani- cal properties, the principle and method of AFM indentationtechnique was presented, the recent progress of measuring the cellular mechanical properties using AFM was summa- rized, and the challenges of AFM single-cell nanomechani- cal analysis were discussed.     

Mapping CD20 molecules on the lymphoma cell surface using atomic force microscopy

Atomic force microscopy (AFM) was used to locate CD20 molecules on the surface of lymphoma Raji cells. Rituximab (a monoclonal antibody against CD20) molecules were linked onto the AFM tip via a polyethylene glycol (PEG) linker. Raji cells were adsorbed onto glass slides coated with poly-L-lysine. First, the CD20 distribution in a local area of the cell surface was visualized using the AFM lift scan mode. Second, 16 × 16 force curves were obtained from the same cell area to construct the CD20-rituximab binding force map. Finally, free rituximab was added to block the CD20 molecules on the cell surface and the lift phase image and CD20-rituximab force map were obtained again. The experimental results indicated that when the lift height was greater than the length of the PEG linker, no recognition sites were observed in the lift phase image. However, as the lift height decreased to the length of the PEG linker, some recognition sites were observed in the lift phase image and these sites were generally consistent with the pixels in the force map. After blocking, both the recognition sites in the lift phase image and the gray pixels in the binding force map decreased markedly. These results can improve our understanding of the distribution of protein molecules on the cell surface and facilitate further investigations into cellular functions.     

纳米材料在植物细胞生物学研究中的应用

纳米材料已广泛应用于药物载体、生物传感器、成像技术以及基因治疗等研究,相对于动物细胞而言,纳米材料在植物细胞生物学中的应用相对滞后,目前主要集中在量子点探针标记技术和纳米基因载体介导外源基因遗传转化两方面。据此,笔者主要介绍了近年来的量子点合成及功能化等方面的进展,特别对于在植物细胞成像中应用进行了评述。另外还介绍了纳米基因载体的种类和特征,以及在植物完整细胞或原生质体中介导外源基因遗传转化等方面的研究进展。笔者认为已有的纳米材料存在粒径过大或自身的细胞毒性过大,限制了其在植物细胞生物学中的进一步应用,所以针对植物细胞自身特征,设计合成新型的纳米材料将是未来研究的焦点。     

多孔硅的电化学形成及微结构研究

采用自制的电解池用电化学腐蚀方法制备多孔硅，使用正交试验法设计阳极腐蚀参数。使用原子力显微镜研究多孔硅的微结构，分析并讨论了实验参数对多孔硅微结构的影响，确定了最佳制备工艺。