作者承认（1）从纳米生物医学科学与BK21 PLUS NBM全球研究再生医学中心的檀国大学，并系资金​​支持的重点由NRF，大韩民国，（资助研究中心计划（编号2009-0093829） 2）设施，科学和技术援助的澳大利亚中心显微镜和微量分析在悉尼大学。 HKC感谢澳大利亚研究理事会通过发现项目补助（DP0985367＆DP120102778）的财务支持。世界锦标赛是感谢澳大利亚研究理事会通过联动项目补助（LP120200489，LP110200316）的财务支持。

1，准备胶体探针和原子力显微镜基板<ol><li>为了准备胶体探针，使用由作者以前开发的方法。19 <ol><li>简而言之，使用45°角座贴上无针尖悬臂45°（ 图1A）的特定角度。 </li><li>通过涂抹一薄层的环氧树脂在显微镜载玻片上制备环氧滑动。用干净的抹刀或缓慢的氮气流，以确保环氧树脂加入到显微镜载玻片的层是最小的高度。 </li><li>加盖环氧幻灯片使用一个定制设计的支架（ 图1B）一个40X光学变倍显微镜镜头。然后使用悬臂接近环氧滑动并获取对悬臂少量的环氧树脂。 </li><li>重复上述步骤，还附上感兴趣的单个粒子在悬臂（ 图1C）的顶点。 </li></ol></li><li>通过粘贴胶体面值准备基板的AFM幕进行到使用热塑性胶粘剂安装的原子力显微镜的盖玻片。 <ol><li>热火35毫米的圆形盖玻片至120℃，并涂抹少量的粘合剂盖玻片。高温是必要的，以熔化热塑粘合剂应用。 </li><li>然后冷却，将盖玻片至40℃喷粉胶体粒子上胶前。注:在40℃下的胶被充分地设定，该粒子将不会成为嵌入到胶，但胶是足够粘性的，以确保颗粒将附着在基板上。 </li><li>进一步冷却盖玻片至室温，并用氮气吹干吹掉多余的独立的粒子。 </li><li>与将用于胶体探针测量液体介质洗涤所述基板几次，以确保所有未连接的颗粒从基片上除去。注意:这是重要的，以减少自由流动的颗粒的测量过程中的影响，这可以跨行事悬臂和结果引入误差。 </li></ol></li></ol> 2，安装的胶体探头，对准激光和平衡系统<ol><li>安装盖玻片与胶体颗粒进入底部的液态电池的一半，并确保该O型圈安装正确，以防止任何泄漏。 </li><li>放置的疏水性透明片材上的显微镜载物台上，以防止可能在实验过程中漏出的液体，特别是如果只使用一种液体的细胞进行测定，下半部分，然后将液晶单元上的显微镜载物台上。注意:为了简单起见可以使用一个液晶单元的唯一的下半区，鉴于该系统可以适当地平衡化;提示 - 蒸发改变了测量和影响结果/读取的情况。 </li><li>附加胶体探针的原子力显微镜扫描头和组装到原子力显微镜。随着对原子力显微镜仪器软件，请使用旋钮扫描头使悬臂尖端成为关注的焦点。注意:所有的程序步骤和测量使用的MFP-3D生物原子力显微镜与庇护研究软件完成。 </li><li>为了最大限度地提高强度，对准激光上使用适当的调节旋钮上的扫描头的悬臂的末端。 </li><li>允许系统达到平衡5-10分钟，或直至偏转值稳定。使用该偏转调节旋钮使偏转到零或稍负。 </li><li>当系统在空气中达到平衡，使用原子力显微镜的软件（在主面板窗口中热板），以热计算InvOLS（灵敏度）和胶体探针的弹簧常数。注意:这种敏感性会暂时使用，直到真正的灵敏度的测量是在测量完成（见第4步）。 <ol><li>选择"校准弹簧常数"或"校准InvOLS"，然后点击"捕获热数据"。 </li><li>一旦一个突出的峰值很明显，停止捕获数据，然后单击放大了主峰。 </li><li>点击"初始化飞度"，其次是"适合热数据"，以获得自动计算弹簧常数或InvOLS值。 </li></ol></li><li>慢慢加入2毫升液体培养基来使用注射器将液体细胞，并确保没有气泡周围的悬臂本。重新对准激光器中，由于介质的折射率现在已经改变，并再次平衡系统允许挠度值，以调整所述偏转回零之前稳定下来。注意:如果环境和液体之间的温差较大存在，平衡将需要更长的时间。 </li></ol> 3，成像和数据采集<ol><li>设置初始扫描大小为20微米，扫描速度为1赫兹，扫描角度90°时，设置点到0.2 V，将获得的样品的扫描。如需要获得重叠跟踪调整增益而折回的曲线。 </li><li>一旦感兴趣的粒子被发现，立刻放大到该粒子限制与获得力量体积测量前基底延伸探针的相互作用。 </li><li>一旦放大，获得单个粒子的单个粒子的或部分的足够的图像。然后切换到部队面板中的软件。把红色位置栏到最高位置，设置强制距离5微米，扫描速率为0.1赫兹，触发通道为none，并进行单测力。确保探头不接触基板。 </li><li>从所获得的单次测量图，计算出虚拟的偏转线通过右键单击图形窗口，并选择"计算虚拟高清线"选项。这将自动计算虚拟偏转，并根据需要在软件中更新值。 </li><li>改变触发通道偏转，并设置触发点到20纳米。将力区ANCE到1微米和根据感兴趣的测力需要调节扫描速度。 </li><li> 2-3进行初步的连续单力测量后手动调整数值的审查小组委员会在偏转逆光杠杆灵敏度（InvOLS）。 <ol><li>进行单测力，然后点击在部队面板的"审阅"按钮，打开了一个法师部队面板。 </li><li>突出显示最近完成的测力。在"轴"的标题确保只有"DeflV"被选中。以"日"使用下拉菜单更改"X轴"输入字段，并单击"制作图表。" </li><li>点击主面板部队的"帕姆"选项卡上，并调整"InvOLS"的值，直到图形的接触区域是完全垂直的。然后填充这个值在"DEFL InvOLS"栏位于下加州60，子选项卡中的强制选项卡位于主主面板窗口上。 </li><li>重复这个2-3次，以确保InvOLS值不显著改变。 </li></ol></li><li>现在，所有的参数都已经设置，确保液体介质水平仍然足够，偏转仍然是稳定的。注意:在这个时候，可以得到单力曲线或力地图。如果停留力的测量需要，驻留选项可强制面板中进行访问。 </li></ol> 4，后调整灵敏度的分析<ol><li>在完成测量数据的收集之后，测量胶体探针的真实感光度。要做到这一点，使用相对大挠度/力与胶体探针在相同的液体培养基中对"无限"硬表面如云母进行测力。实验结束后，获得灵敏度，因为大挠度/力可能会损坏胶体:注意新娘探针制备多孔或脆弱的胶体。 </li><li>接触区域的斜率是所使用的软件，自动计算出的灵敏度（ 图2）。在所有使用该特定胶体探针得到的曲线数据分析使用灵敏度这个真正的价值。 </li></ol>

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The authors declare that they have no competing financial interests.

系统不稳定时液体胶体探针纳米显微目前的几个来源可以很容易地通过适当的平衡过程来缓解。所讨论的不稳定性先前导致错误的结果和力曲线更难以客观分析。如果不稳定的所有来源已趋向和图形相似，在图4所示的仍然存在，另一次测量的参数可以是原因。这是要考虑的重要过程中的胶体探针纳米显微其他测量参数包括在该悬臂啮合并从样品回缩的速度和力测量的触发点。另外，?...

原子力显微镜（AFM）是一种技术，它使定性和定量成像和探测的材料的表面。4-6传统AFM用于表面形貌，形貌和多相位材料的结构的评估。 AFM具有定量评价纳米尺度相互作用，如在空气和液体介质的特定探针和基板之间的电荷，吸引，排斥和粘附力的能力。7,8最初由分级，第四纪和Gerber 9的用途开发的原子力显微镜探测已知的/确定的灵敏度和弹性系数接近和/或扫描样本。由于探针与样品之间的物理相互作用，悬臂接触或接近时偏转，这取决于操作的模式下，该偏转可以被转换为获得本探针和样品之间的样品或测量力的地形。修改的原子力显微镜TECHNI阙，如胶体探针纳米显微，10已允许科学家直接评价存在于感兴趣的胶体系统，两种材料间的纳米相互作用力。 在胶体探针纳米显微，选择的球形颗粒附着到悬臂的先端，取代了传统的圆锥形和棱锥形的提示。球形粒子是理想的，允许与理论模型，如强生，肯德尔，罗伯茨（JKR）11和Derjaguin，朗多，Vervwey，Overbeek（DLVO）12-14理论，并尽量减少表面粗糙度对测量的影响比较。 15这些理论用于定义接触力学和颗粒间力预期的胶体系统中。 DLVO理论结合了有吸引力的范德华力和静电排斥力（由于双电层）来定量解释含水的胶体体系的聚集行为，而歼KR理论结合的接触压力和粘附到模型两个组件之间的弹性接触的效果。一旦适当的探针产生的，它被用来逼近的任何其它材料/颗粒，以评估在两个部件之间的力。使用制造的小费标准之一将是能够测量的尖端和选择的材料之间的相互作用力，但使用一个定制的胶体探针的利益使得目前所研究的系统中存在材料之间的力的测量。可测量相互作用包括:粘合剂，有吸引力，排斥力，电荷和存在于粒子之间甚至静电力16此外，胶体探针技术可以用来探索本颗粒和弹性材料之间的切向力17,18 进行测量，在各种媒体的能力是胶体探针纳米显微的主要优点之一。环境条件，液态间EDIA，或湿度可控的条件下都可以被用来模仿所研究的系统的环境条件。进行测量，在液体环境中的能力，使胶体系统中，它天然存​​在的环境中的研究;因此，能够定量地采集数据是直接翻译的系统在其自然状态。例如，定量吸入器（MDI）中存在粒子的相互作用可以用一个模型液体推进剂具有类似属性的计量吸入器所用的推进剂进行研究。在空气中测得相同的相互作用并不能代表在吸入器系统存在的。此外，液体介质可以被修改来评价水分侵入，二次表面活性剂，或温度上在MDI粒子相互作用的影响。以控制温度的能力，可用于模拟在胶体系统的制造某些步骤以评估温度无论是在制造或存储胶体系统可能对粒子的相互作用产生影响。 可以使用胶体探针来获得测量包括;地形扫描，个人的力量 - 距离曲线，力 - 距离粘连的地图里，住力距离测量。正在使用本文介绍的胶体探针纳米显微方法测量关键参数包括管理单元，最大负荷和分离能量值。管理单元是引力的测量，最大负载的最大附着力的价值​​，以及分离能传达到从接触撤回粒子所需的能量。这些值可以通过瞬时或停留力的测量来测量。两种不同类型的停留测量包括变形和压痕。驻留测量的长度和类型可以专门选择模仿所关心的系统中存在特异性相互作用。一个例子是使用偏转停留 - 持有来评估发展中形成的聚集体分散体胶粘剂债券 - 在希望的弯沉值在接触样品。所形成的粘合剂粘结可以测量作为时间的函数，并且可以提供深入了解再分散后的长期储存的聚集体所需的力。数据可以使用这种方法获得的大量证明了该方法的通用性。

<table><tbody><tr><td>Double-Bubble Epoxy</td><td>Hardman</td><td>4004</td><td></td></tr><tr><td>Veeco Tipless Probes</td><td>Veeco</td><td>NP-O10&amp;nbsp;</td><td></td></tr><tr><td>Porous Particles</td><td>Pearl Therapeutics</td><td></td><td></td></tr><tr><td>Atomic Force Microscope (MFP)</td><td>Asylum&amp;nbsp;</td><td>MFP-3D</td><td></td></tr><tr><td>SPIP Scanning Probe Image Processor Software</td><td>NanoScience&amp;nbsp; Instruments</td><td></td><td></td></tr><tr><td>35 mm Coverslips</td><td>Asylum</td><td>504.003</td><td></td></tr><tr><td>Tempfix</td><td>Ted Pella. Inc.</td><td>16030</td><td></td></tr></tbody></table>

quantitative and qualitative examination of particle-particle interactions using colloidal probe nanoscopy

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate using the Atomic Force Microscope (AFM), can provide key insights into physical interactions present within colloidal systems. Colloidal systems are widely existent in several applications including, pharmaceuticals, foods, paints, paper, soil and minerals, detergents, printing and much more.1-3 Furthermore, colloids can exist in many states such as emulsions, foams and suspensions. Using colloidal probe nanoscopy one can obtain key information on the adhesive properties, binding energies and even gain insight into the physical stability and coagulation kinetics of the colloids present within. Additionally, colloidal probe nanoscopy can be used with biological cells to aid in drug discovery and formulation development. In this paper we describe a method for conducting colloidal probe nanoscopy, discuss key factors that are important to consider during the measurement, and show that both quantitative and qualitative data that can be obtained from such measurements.

液体胶体系统用于多种药物给药系统。用于吸入给药，常见的胶体系统是悬浮加压计量剂量吸入器（pMDI的）。在的pMDI中存在粒子的相互作用配方的物理稳定性，存储和药物输送均匀性起到了至关重要的作用。在这个手稿，多孔基于脂质的颗粒之间的颗粒间力（〜2微米的光学平均粒径）在一个模型中的推进剂（2H，3H-全氟戊烷），在室温下进行了评价，以传达的功能，并且与呈现相关的可能的错?...

Watch this Scientific Journal Video about Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy at JoVE.com

Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy

Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems.

粒子粒子相互作用采用胶体探针纳米显微定量和定性检查

Colloidal Probe Nanoscopy (CPN), the study of the nano-scale interactive forces between a specifically prepared colloidal probe and any chosen substrate ...

quantitative-qualitative-examination-particle-particle-interactions

Research

JoVE Journal

Chemistry

11.0K 次观看.  University of Sydney. Colloidal probe nanoscopy can be used within a variety of fields to gain insight into the physical stability and coagulation kinetics of colloidal systems and aid in drug discovery and formulation sciences using biological systems. The method described within provides a quantitative and qualitative means to study such systems. 

视频: Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy

Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed assembly1-3, drug delivery4, improved hydrocarbon recovery5-7, and flowable electrodes for energy storage8. Suspensions containing fluorescent colloids and non-adsorbing polymers are appealing model systems, as the ratio of the polymer radius of gyration to the particle radius&#160;and concentration of polymer control the range and strength of the interparticle attraction, respectively. By tuning the polymer properties and the volume fraction of the colloids, colloid fluids, fluids of clusters, gels, crystals, and glasses can be obtained9.&#160;Confocal microscopy, a variant of fluorescence microscopy, allows an optically transparent and fluorescent sample to be imaged with high spatial and temporal resolution in three dimensions. In this technique, a small pinhole or slit blocks the emitted fluorescent light from regions of the sample that are outside the focal volume of the microscope optical system. As a result, only a thin section of the sample in the focal plane is imaged. This technique is particularly well suited to probe the structure and dynamics in dense colloidal suspensions at the single-particle scale: the particles are large enough to be resolved using visible light and diffuse slowly enough to be captured at typical scan speeds of commercial confocal systems10. Improvements in scan speeds and analysis algorithms have also enabled quantitative confocal imaging of flowing suspensions11-16,37.&#160;In this paper, we demonstrate confocal microscopy experiments to probe the confined phase behavior and flow properties of colloid-polymer mixtures. We first prepare colloid-polymer mixtures that are density- and refractive-index matched. Next, we report a standard protocol for imaging quiescent dense colloid-polymer mixtures under varying confinement in thin wedge-shaped cells. Finally, we demonstrate a protocol for imaging colloid-polymer mixtures during microchannel flow.

Confocal microscopy is used to image quiescent and flowing colloid-polymer mixtures, which are studied as model systems for attractive suspensions. Image analysis algorithms are used to calculate structural and dynamic metrics for the colloidal particles that measure changes due to geometric confinement.

密闭静态和流动胶体聚合物混合物的共聚焦成像

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed ...

科研

化学

Implementation of a Reference Interferometer for Nanodetection

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing its free spectral range (FSR), the module is put in parallel with a fiber taper-microcavity system and then calibrated through isolating and eliminating random shifts in the laser frequency (i.e. laser jitter noise). To realize the taper-microcavity junction and to maximize the optical power that is transferred to the resonator, a single-mode optical fiber waveguide is pulled. Solutions containing polystyrene nanobeads are then prepared and flown to the microcavity in order to demonstrate the system&#8217;s ability to sense binding to the surface of the microcavity. Data is post-processed via adaptive curve fitting, which allows for high-resolution measurements of the quality factor as well as the plotting of time-dependent parameters, such as resonant wavelength and split frequency shifts. By carefully inspecting steps in the time-domain response and shifting in the frequency-domain response, this instrument can quantify discrete binding events.

A reference interferometer technique, which is designed to remove undesirable laser jitter noise for nanodetection, is utilized for probing an ultra-high quality factor microcavity. Instructions for assembly, setup, and data acquisition are provided, alongside the measurement process for specifying the cavity quality factor.

一个参考干涉仪的Nanodetection实施

A thermally and mechanically stabilized fiber interferometer suited for examining ultra-high quality factor microcavities is fashioned. After assessing ...

工程学

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

原位金属氧化物纳米粒子的核探针检测与单细胞定量研究

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

This protocol describes the operation of a liquid flow specimen holder for scanning transmission electron microscopy of AuNPs in water, as used for the observation of nanoscale dynamic processes.

使用扫描透射电子显微镜研究纳米大小的物体的动态过程中的液体

Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a ...

Plasmonic Trapping and Release of Nanoparticles in a Monitoring Environment

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few can observe immobilized particles. Moreover, a limited number of studies have experimentally measured the exertable forces on the particles. The designs can be classified as the protruding nanodisk type or the suppressed nanohole type. For the latter, microscopic observation is extremely challenging. In this paper, a new plasmonic tweezer system is introduced to monitor particles, both in directions parallel and orthogonal to the symmetric axis of a plasmonic nanohole structure. This feature enables us to observe the movement of each particle near the rim of the nanohole. Furthermore, we can quantitatively estimate the maximal trapping forces using a new fluidic channel.

A microchip fabrication process that incorporates plasmonic tweezers is presented here. The microchip enables the imaging of a trapped particle to measure maximal trapping forces.

电浆捕获和纳米粒子的释放在监控环境

Plasmonic tweezers use surface plasmon polaritons to confine polarizable nanoscale objects. Among the various designs of plasmonic tweezers, only a few ...

Visualizing Diffusional Dynamics of Gold Nanorods on Cell Membrane using Single Nanoparticle Darkfield Microscopy

Analyzing the diffusional dynamics of nanoparticles on cell membrane plays a significant role in better understanding the cellular uptake process and provides a theoretical basis for the rational design of nano-medicine delivery. Single particle tracking (SPT) analysis could probe the position and orientation of individual nanoparticles on cell membrane, and reveal their translational and rotational states. Here, we show how to use traditional dark-field microscopy to monitor the dynamics of gold nanorods (AuNRs) on live cell membrane. We also show how to extract the location and orientation of AuNRs using ImageJ and MATLAB, and how to characterize the diffusive states of AuNRs. Statistical analysis of hundreds of particles show that single AuNRs perform Brownian motion on the surface of U87 MG cell membrane. However, individual long trajectory analysis shows that AuNRs have two distinctly different types of motion states on the membrane, namely long-range transport and limited-area confinement. Our SPT methods can be potentially used to study the surface or intracellular particle diffusion in different biological cells and can become a powerful tool for investigations of complex cellular mechanisms.

Here, we show the use of traditional dark-field microscopy to monitor the dynamics of gold nanorods (AuNRs) on cell membrane. The location and orientation of single AuNRs are detected using ImageJ and MATLAB, and the diffusive states of AuNRs are characterized by single particle tracking analysis.

使用单纳米粒子暗场显微镜可视化细胞膜上金纳米棒的扩散动力学

Analyzing the diffusional dynamics of nanoparticles on cell membrane plays a significant role in better understanding the cellular uptake process and ...

生物化学

Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to &#181;m. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10-4 and 0.5 &#197;-1 by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution. Because of its ability to adjust the intensity and the resolution within wide limits during the experiment, combined with the possibility to equip specific sample environments and ancillary devices, the KWS-2 shows a high versatility in addressing the broad range of structural and morphological studies in the field. Equilibrium structures can be studied in static measurements, while dynamic and kinetic processes can be investigated over time scales between minutes to tens of milliseconds with time-resolved approaches. Typical systems that are investigated with the KWS-2 cover the range from complex, hierarchical systems that exhibit multiple structural levels (e.g., gels, networks, or macro-aggregates) to small and poorly-scattering systems (e.g., single polymers or proteins in solution). The recent upgrade of the detection system, which enables the detection of count rates in the MHz range, opens new opportunities to study even very small biological morphologies in buffer solution with weak scattering signals close to the buffer scattering level at high Q.
In this paper, we provide a protocol to investigate samples with characteristic size levels spanning a wide length scale and exhibiting ordering in the mesoscale structure using KWS-2. We present in detail how to use the multiple working modes that are offered by the instrument and the level of performance that is achieved.

Here, we present a protocol to investigate soft matter and biophysical systems over a wide mesoscopic length scale, from nm to &#181;m that involves the use of the KWS-2 SANS diffractometer at high intensities and an adjustable resolution.

在小角度中子衍射仪KWS-2研究软物质和生物系统在广泛的长度尺度从纳米，微米尺寸

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to &#181;m. ...

生物工程

Nanoscale Characterization of Liquid-Solid Interfaces by Coupling Cryo-Focused Ion Beam Milling with Scanning Electron Microscopy and Spectroscopy

Physical and chemical processes at solid-liquid interfaces play a crucial role in many natural and technological phenomena, including catalysis, solar energy and fuel generation, and electrochemical energy storage. Nanoscale characterization of such interfaces has recently been achieved using cryogenic electron microscopy, thereby providing a new path to advancing our fundamental understanding of interface processes.
This contribution provides a practical guide to mapping the structure and chemistry of solid-liquid interfaces in materials and devices using an integrated cryogenic electron microscopy approach. In this approach, we pair cryogenic sample preparation which allows stabilization of solid-liquid interfaces with cryogenic focused ion beam (cryo-FIB) milling to create cross-sections through these complex buried structures. Cryogenic scanning electron microscopy (cryo-SEM) techniques performed in a dual-beam FIB/SEM enable direct imaging as well as chemical mapping at the nanoscale. We discuss practical challenges, strategies to overcome them, as well as protocols for obtaining optimal results. While we focus in our discussion on interfaces in energy storage devices, the methods outlined are broadly applicable to a range of fields where solid-liquid interface play a key role.

Cryogenic Focused Ion Beam (FIB) and Scanning Electron Microscopy (SEM) techniques can provide key insights into the chemistry and morphology of intact solid-liquid interfaces. Methods for preparing high quality Energy Dispersive X-ray (EDX) spectroscopic maps of such interfaces are detailed, with a focus on energy storage devices.

通过冷冻聚焦离子束铣削与扫描电子显微镜和光谱学耦合，对液固界面进行纳米级表征

Physical and chemical processes at solid-liquid interfaces play a crucial role in many natural and technological phenomena, including catalysis, solar ...

Co-localizing Kelvin Probe Force Microscopy with Other Microscopies and Spectroscopies: Selected Applications in Corrosion Characterization of Alloys

Kelvin probe force microscopy (KPFM), sometimes referred to as surface potential microscopy, is the nanoscale version of the venerable scanning Kelvin probe, both of which measure the Volta potential difference (VPD) between an oscillating probe tip and a sample surface by applying a nulling voltage equal in magnitude but opposite in sign to the tip-sample potential difference. By scanning a conductive KPFM probe over a sample surface, nanoscale variations in surface topography and potential can be mapped, identifying likely anodic and cathodic regions, as well as quantifying the inherent material driving force for galvanic corrosion.
Subsequent co-localization of KPFM Volta potential maps with advanced scanning electron microscopy (SEM) techniques, including back scattered electron (BSE) images, energy dispersive spectroscopy (EDS) elemental composition maps, and electron backscattered diffraction (EBSD) inverse pole figures can provide further insight into structure-property-performance relationships. Here, the results of several studies co-localizing KPFM with SEM on a wide variety of alloys of technological interest are presented, demonstrating the utility of combining these techniques at the nanoscale to elucidate corrosion initiation and propagation.
Important points to consider and potential pitfalls to avoid in such investigations are also highlighted: in particular, probe calibration and the potential confounding effects on the measured VPDs of the testing environment and sample surface, including ambient humidity (i.e., adsorbed water), surface reactions/oxidation, and polishing debris or other contaminants. Additionally, an example is provided of co-localizing a third technique, scanning confocal Raman microscopy, to demonstrate the general applicability and utility of the co-localization method to provide further structural insight beyond that afforded by electron microscopy-based techniques.

Kelvin probe force microscopy (KPFM) measures surface topography and differences in surface potential, while scanning electron microscopy (SEM) and associated spectroscopies can elucidate surface morphology, composition, crystallinity, and crystallographic orientation. Accordingly, the co-localization of SEM with KPFM can provide insight into the effects of nanoscale composition and surface structure on corrosion.

开尔文探针力显微镜与其他显微镜和光谱学共定位:合金腐蚀表征中的选定应用

Kelvin probe force microscopy (KPFM), sometimes referred to as surface potential microscopy, is the nanoscale version of the venerable scanning Kelvin ...

An Innovative Method for Exosome Quantification and Size Measurement

Although the biological importance of exosomes has recently gained an increasing amount of scientific and clinical attention, much is still unknown about their complex pathways, their bioavailability and their diverse functions in health and disease. Current work focuses on the presence and the behavior of exosomes (in vitro as well as in vivo) in the context of different human disorders, especially in the fields of oncology, gynecology and cardiology.
Unfortunately, neither a consensus regarding a gold standard for exosome isolation exists, nor is there an agreement on such a method for their quantitative analysis. As there are many methods for the purification of exosomes and also many possibilities for their quantitative and qualitative analysis, it is difficult to determine a combination of methods for the ideal approach. 
Here, we demonstrate nanoparticle tracking analysis (NTA), a semi-automated method for the characterization of exosomes after isolation from human plasma by ultracentrifugation. The presented results show that this approach for isolation, as well as the determination of the average number and size of exosomes, delivers reproducible and valid data, as confirmed by other methods, such as scanning electron microscopy (SEM).

A method for isolation of exosomes from whole blood and further analysis by nanoparticle tracking using a semi-automatic instrument is presented in this article. The presented technology provides an extremely sensitive method for visualizing and analyzing particles in liquid suspension.

对于外来体定量和尺寸测量新方法研究

Although the biological importance of exosomes has recently gained an increasing amount of scientific and clinical attention, much is still unknown about ...