Name: magnetic levitation coupled with portable imaging and analysis for disease diagnostics
Uploaded: 2017-02-19T15:00:00.000+00:00
Duration: 7 min 42 s
Description: Watch this Scientific Journal Video about Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics at JoVE.com

The authors would like to acknowledge Dr. Matthew Heeney of Boston Children's Hospital/Dana-Farber Cancer Institute and Dr. Farzana Pashankar of Yale-New Haven Hospital for providing sickle cell patient samples. The authors would like to thank Chu H. Yu and Ashwini Joshi for their assistance in testing these samples and compiling the data.
S.T. acknowledges the American Heart Association Scientist Development Grant (15SDG25080056) and the University of Connecticut Research Excellence Program award for financial support of this research. S.K. acknowledges that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship (DGE-1247393).

伦理声明:所有涉及人的血液样本程序是按照制度规定执行。所有协议进行审查和机构审查委员会批准。知情同意书是由所有参与者给出。 1.样品制备镰状细胞病诊断5,8 <ol><li>制备的Hank氏平衡盐溶液（HBSS）一个钆布醇的50mM的溶液。 </li><li>溶解于钆溶液的10mM焦亚硫酸钠。 注意:焦亚硫酸钠是吸入有毒，强烈刺激皮肤和组织。它是与水混合时的腐蚀性酸。它可能会分解时加热至高温以发射硫和钠的有毒氧化物烟雾。 </li><li> 通过获取无论指尖或静脉穿刺血液样本。 <ol><li>用采血装置用干净的一次性采血针抽血。美联社穿孔位点附近帘布层压力和擦拭使用移液管收集血液之前的三至四倍形成血液的液滴;注意不要挤压组织，因为这会导致与组织液样品的污染，"毒奶粉"的手指。 </li><li>另外，使用标准的静脉穿刺14抽血。 注意:如果样本将被储存超过几个小时，收集血液与抗凝剂如EDTA的真空采血管。 </li></ol></li><li>血少于1微升加入100微升钆 - 焦亚硫酸钠溶液中。 </li></ol> 2.样品制备WBC 7术<ol><li>无论是通过指尖或静脉穿刺获得血液样本，如在第1节。 </li><li>可选:红细胞裂解与RBC裂解液。吸管5微升的血液进入RBC裂解缓冲液500微升，在室温下进行3孵育 - 5分钟。 注意:这可以这样做，以确认白细胞的分离群体的悬浮范围。然而，这是没有必要执行此步骤，因为此处呈现的结果表明，红细胞悬浮在比白细胞明显较低位置。 </li><li>稀释全血1:1000在25mM钆在HBSS 注意:如果进行细胞裂解，稀释裂解样品9:1裂解的样品:250mM的钆以获得含有25mM的Gd的试样。 </li></ol> 3.样本使用磁悬浮平台4，5，6，7，8分析<ol><li> 启动磁悬浮装置: <ol><li>对于独立设备，插入该设备，使其电，并将其放置在平坦的水平面上。 </li><li>对于智能手机兼容的版本，推出智能手机应用，并向左滑动输入图像捕捉模式，并放置在平坦的水平面上。 </li></ol></li><li> 对于静态磁悬浮: <ol><li>通过浸渍结束到溶液和使样品通过毛细管作用填充毛细管加载制备的样品成方形玻璃微毛细管。 </li><li>慢慢推一端毛细管到材料与密封管密封结束。 </li><li>插入磁悬浮装置的磁铁之间的毛细管，使得只有1厘米的管保持可见（请参阅图3的说明，样品制备）。 注意:此步骤仍然是既智能电话兼容的和自包含设备相同。 </li><li>等待10分钟而不干扰设备或毛细管。 </li></ol></li><li> 对于流辅助磁悬浮: <ol><li>加载样品到样品管中。 </li><li>连接样品容器和英里之间的进口管crocapillary并连接微细和废物容器之间的出口管道。 </li><li>设置LED亮度和流量参数。 </li></ol></li><li>确保细胞在视野中是可见的，然后按拍摄按钮来拍摄的图像（按钮3的自包含设备和屏幕在智能手机应用底部的照相机按钮上）。 注:如果将USB用来存储图像，创建一个名为"图像"文件夹，并打开装置上之前插入USB。如果不存在驱动器，该设备将图像存储在其内部存储器和后来转移。 注:若干图像可以被捕获并分析了或缩小移动毛细管大约图像捕获之间半厘米，以减少异常的风险。 注意:如果单元中的视场范围内的数太高或太低（如检测和报告在用户界面上），移位毛细管在装置或出或准备另一山mple。 </li><li>取出样品，并根据机构或当地法规丢弃样品。毛细管应设置为尖锐。 </li></ol><img alt="图3" src="/files/ftp_upload/55012/55012fig3.jpg" /> 图3:样品制备和用户界面。 （ 一 ）将样品制备过程涉及穿刺被检者的手指，形成血液的液滴，转印血滴到样品测试溶液，搅拌该样品，并通过毛细作用装载到毛细管，样品插入到磁悬浮设备。 （b）中也显示在设备的屏幕上，这些样品制备步骤，以引导样品制备。 （ 三 ）该装置包括四个按键:一键放大到样本图像，以使用调节旋钮适当调整的重点;一个按钮，以获得一个单一的米easurement（5秒的延迟实施时间让用户插入样品）;时间推移测量（6图像以5秒的间隔拍摄）;和一个按钮，使用后关闭设备。再现时，经许可，从Yenilmez， 等。 8 <a href="http://ecsource.jove.com/files/ftp_upload/55012/55012fig3large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> 4.图像分析4，5，6，7，8 <ol><li>运行包括为合适的样品（细胞分布或细胞类型分离）在设备上的图像分析软件。 注:对于自包含设备，自动进行分析并在图形用户界面上显示。对于智能手机兼容设备，进行分析，进入画廊ND选择所需的视频文件进行分析。 </li><li>观察并记录显示在屏幕上的分析的输出。 注:对于细胞分布分析（如镰状细胞病的诊断），输出将是细胞群体的禁闭的宽度。 注:对于细胞类型的分离（如白细胞识别），输出将与所确定的WBC种群的图像。为了计算每微升的细胞数，由2,000倍乘每图像白细胞的平均数目。例如，如果观察到5的白细胞，这将表明万白细胞/μL。在正常范围内被普遍认为是3500 - 11000白细胞/μL。 </li><li>通过或缩小约半厘米的设备的移动的样品管和捕捉另一图像如上所述待分析重复分析。 注:建议5重复分析 - 6次，每次采样，以避免错误。 </li></ol>

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Authors Stephanie Knowlton and Savas Tasoglu are founders of and have an equity interest in mBiotics, a startup working to commercialize the magnetic levitation platform described herein for point of care diagnostic solutions. A provisional patent entitled "Magnetic Levitation with On-Board Optical Imaging and Image Analysis for Density-Based Separation, Identification, And Measurement" has been filed with UCONN Case No. 16-027 on the technology described here.

该议定书中的关键步骤 在此过程中的关键因素包括磁体的正确对准。如果磁体成为脱落或在装置内分离超过正常值，这可能会影响结果。为了控制这种故障或其他人在这个过程中，一个密度控制的颗粒，如聚苯乙烯微球，可周期性用于控制随时间的变化。另外，悬浮时间是很重要的，以使细胞以达到平衡。对于红细胞，10分钟是足以允许所有的细胞以达到平衡。然而，要注意的是更小的颗粒?...

这里，我们提出了一个技术平台，它采用加上自动成像和分析磁悬浮来分析患者的细胞的密度分布作为疾病指示器的技术。对于基于密度的术分析这种通用方法最终可应用于一系列疾病的诊断。但是，为了能与床边血糖检测兼容，而在发展中国家使用，该技术必须满足低成本，便携，和可用性要求。该设备和消耗品必须以低成本容易地获得。样品制备必须简单，分析应与用户输入或解释的最低要求是自动的，并且结果应该可以快速恢复。此外，该装置必须是紧凑和便携是在临床设置，以及发展中国家是有用的。因此，我们已开发了一种装置和方法，在点的护理兼容TECHNOL使用磁悬浮术通过耦合自动成像和图像分析来对病人的细胞群的密度分布返回结果。 点护理技术提供了显着的优势超过目前临床实验室测试程序。目前可用的技术是太昂贵的由临床医生所拥有或过于复杂，由医务人员来进行。许多这些步骤需要必须由受过训练的技术人员才能进行劳动密集型的协议。由于这些原因，患者样品如血液或尿液中的医生的办公室，然后转移到一个远程的，集中的测试实验室进行的临床试验，这可能需要几天的时间医师收到测试的结果通常收集。这可能会导致在治疗在某些情况下的过程的延误或并发症，使该试验很昂贵和低效率的（导致保险付款人财政负担），并进一步使许多诊断在低资源设置和发展中国家无法访问。 这里，我们提出加上两者具有嵌入摄像处理（ 图1）和智能电话兼容设备（ 图2）的设备自动成像和分析一个磁悬浮技术。这些磁性基于悬浮装置表示具有潜在一个广泛适用的平台技术被应用到一个范围的不同的医疗诊断应用。磁力的浮力1，2，3:基于两种力量之间的平衡磁悬浮方法的功能。当颗粒悬浮在顺磁介质，并插入到由两个磁体彼此面对，磁力作用在朝向两MAGN之间的中心线的方向上的粒子像磁极产生的磁场<html> ETS。浮力是由比悬浮介质的粒子的相对密度引起的是向上的颗粒比中等密集和向下中的颗粒比周围介质致密的情况下少的情况下。基于这两种力量，颗粒将达到它平衡这两股力量领域的磁悬浮平衡位置;该位置是直接关系到颗粒的密度，以更密集的颗粒小于致密颗粒漂浮在外地较低。成像模块，无论是一个内置的智能手机摄像装置4，5，6或配有放大镜7,8独立的光学元件，被用于可视化粒子的位置。图像处理，或者通过智能手机应用4,5="外部参照"&gt; 6或嵌入处理部7，8，然后处理所捕获的图像，以量化的空间分布，因此，人口密度分布。为了分析大样品（如那些具有每毫升兴趣只有几个颗粒，流动可以直接集成到这种颗粒悬浮在设备和当它们通过所述成像区域（ 图2）进行分析。 <img alt="图1" src="/files/ftp_upload/55012/55012fig1.jpg" /> 图1:自含磁悬浮平台。 （ 一 ）紧凑磁悬浮装置包括磁聚焦组件，成像组件（发光二极管（LED），光学透镜，和一个照相机检测器），和一个处理单元与显示屏幕。 （b）该CRO磁场强度其中，被插入所述样本磁铁之间的区域的β-部分。场强最大的在磁体的表面上，并在它们之间的中心线接近零。 （ 三 ）的粒子，如细胞，磁场经验几个部队内:一个磁力（F M）朝向磁性之间的中心线，与大小不同而不同基于所述粒子的位置;一重力（F G&#39;），它依赖于相对于该悬浮介质的粒子的密度，和一拖力（F D）抵抗粒子运动。再现时，经许可，从Yenilmez， 等。 8 <a href="http://ecsource.jove.com/files/ftp_upload/55012/55012fig1large.jpg" target="_blank">，请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/55012/55012fig2.jpg" /> 图URE 2:智能手机兼容的流辅助磁悬浮平台。 （ 一 - 三 ）前面（a）中 ，一侧（b）和背面（ 三 ）次磁悬浮装置（d）该装置的组成部分包括:1）磁悬浮模块，包括永久磁铁，放大透镜，和LED和光扩散，2）智能手机的情况下，3）电子产品，包括微控制器，泵驱动器和蓝牙接收器，4）微泵座，5）调节孔口，6）废液管夹，7）电池座，8 ）样品架，9）两用底座和盖子。 （ 五 ）流动示意图，示出了通过磁场的样品的泵送。 （ 六 ）磁悬浮模块，显示如何不同密度的颗粒将对齐，因为它们是通过现场泵的横截面;密度较小的颗粒，如颗粒1，将平衡在较高的悬浮高度t汉致密颗粒，如颗粒2转载，经许可，从阿明， 等。 1 <a href="http://ecsource.jove.com/files/ftp_upload/55012/55012fig2large.jpg" target="_blank">，请点击这里查看该图的放大版本。</a> 使用任何样品的在该系统中的最低要求的密度分布分析包括以获得悬浮细胞或颗粒大于约5微米，小于约250微米的尺寸（用于成像和图像处理）及其与相容性的能力在一个顺磁性溶液中的溶液混合，如这里使用的钆布醇。用于疾病诊断，兼容的应用包括那些，其中（i）所关注的细胞固有地具有改变的密度相比健康对照，当他们携带的疾病，（ii）一种密度变化所用的细胞通过加入试剂或部分被诱导替代治疗一个短cubation时间，或（iii）不同类型的细胞在单个样品中的被识别和固有（或通过某些治疗）具有独特特征的密度。 镰状细胞病是一种遗传性疾病引起的血红蛋白，HbS的，在一个人的红血细胞（红细胞）要生产的突变形式，其可以导致间歇性血管闭塞事件和慢性溶血性贫血9。它是使用任一血红蛋白等电聚焦，高效液相色谱（HPLC）分离，或血红蛋白电泳是高度准确的，但必须在临床测试实验室，因为它们是与点 - - 关心设置不兼容进行诊断。溶解性和纸基测试镰状细胞病已经被提出，但一般需要用户的主观解释和确证试验。在这里，我们使用了基于密度的方式来确定镰刀红细胞，从而达到比RB更高的密度CS由人没有镰状细胞病。该机制涉及血红蛋白，HBS的突变形式，这将导致红细胞脱水的镰状细胞病的RBCs脱氧条件10，11，12，13下的聚合。 这种基于密度的方法还可以应用到密度的基础上分开的不同类型的细胞:白血细胞（白细胞）和红细胞7。白细胞通常负责在体内抵抗感染。白细胞术可用于量化这些细胞在血液中的数量，并作为一个有用的诊断工具。白细胞计数高于正常（一般认为每微升更大的超过11,000细胞）可能表明感染，免疫系统疾病，或白血病。白细胞计数低于在正常范围（约3500每μL细胞）可能由自身免疫性疾病或康迪特引起离子的损害骨髓。不像替代技术，这里提出的方法不以鉴定白细胞依赖于红细胞或污渍的裂解。这种基于细胞的试验利用了两种细胞类型的独特固有密度进行分离，作为WBC种群密度已经报道为比如先前使用密度梯度离心2,3计算出的RBC群体的低。 相比在远程位置变质测试，这个测试是快速，简单的样品制备（ 图3），在该装置的分离单元10内- 15分钟，自动成像和分析需要不到1分钟。以这种方式，该装置可迅速地返回结果以更好地告知医疗决定，允许处理被立即施用，以减轻身体和心理痛苦，并减少并发症associ的风险ated与医疗保健的延迟。可以在现场或在临床环境，由于简单的样品制备和自动成像和分析返回以最小的用户输入或解释的结果来执行该技术。因为使用的使用试样分析永久磁铁和使用任一智慧型手机或用于成像和图像处理简单的电子部件的一个简单的方法，相对于一些复杂的测试程序的装置，以及每次测试成本是最小的。

<table><tbody><tr><td>Gadavist (Bayer)</td><td>Jefferson Medical and Imaging</td><td>2068062</td><td>Gadavist contains 1M gadobutrol, a chelate of gadolinium. We purchased 2 ml vials with 15/ca.</td></tr><tr><td>Square glass microcapillary tubes</td><td>Vitrocom</td><td>8270</td><td>50 mm length is sufficient</td></tr><tr><td>Sodium metabisulfite</td><td>Sigma-Aldrich</td><td>S9000</td><td>Chemical formula: Na&lt;sub&gt;2&lt;/sub&gt;S&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;</td></tr><tr><td>Leica Microsystems Critoseal tube sealant</td><td>Fisher Scientific</td><td>02-676-20</td><td></td></tr><tr><td>Hank&#039;s Balanced Salt Solution</td><td>Sigma-Aldrich</td><td>H9269&amp;nbsp;SIGMA</td><td></td></tr><tr><td>Trypsin-EDTA</td><td>Sigma-Aldrich</td><td>T4049</td><td>Or other reagent as recommended for the cell type used</td></tr><tr><td>MICROLET 2 Adjustable Lancing Device</td><td>Walgreens</td><td>246567</td><td>Any lancing device is acceptable when used according to biosafety protocols</td></tr><tr><td>Microlet Lancets</td><td>Walgreens</td><td>667474</td><td>Must be dispoable and not reused</td></tr><tr><td>Hausser Bright-Line Phase Hemacytometer</td><td>Fisher Scientific</td><td>02-671-6</td><td>Or any preferred method for cell counting</td></tr><tr><td>ACK Lysing Buffer</td><td>ThermoFisher</td><td>A1049201&amp;nbsp;</td><td></td></tr></tbody></table>

magnetic levitation coupled with portable imaging and analysis for disease diagnostics

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for specialized equipment and trained personnel require that many diagnostic tests be performed at remote, centralized clinical laboratories. Magnetic levitation is a simple yet powerful technique and can be applied to levitate cells, which are suspended in a paramagnetic solution and placed in a magnetic field, at a position determined by equilibrium between a magnetic force and a buoyancy force. Here, we present a versatile platform technology designed for point-of-care diagnostics which uses magnetic levitation coupled to microscopic imaging and automated analysis to determine the density distribution of a patient's cells as a useful diagnostic indicator. We present two platforms operating on this principle: (i) a smartphone-compatible version of the technology, where the built-in smartphone camera is used to image cells in the magnetic field and a smartphone application processes the images and to measures the density distribution of the cells and (ii) a self-contained version where a camera board is used to capture images and an embedded processing unit with attached thin-film-transistor (TFT) screen measures and displays the results. Demonstrated applications include: (i) measuring the altered distribution of a cell population with a disease phenotype compared to a healthy phenotype, which is applied to sickle cell disease diagnosis, and (ii) separation of different cell types based on their characteristic densities, which is applied to separate white blood cells from red blood cells for white blood cell cytometry. These applications, as well as future extensions of the essential density-based measurements enabled by this portable, user-friendly platform technology, will significantly enhance disease diagnostic capabilities at the point of care.

为细胞密度分布分析，这是用于镰状细胞疾病的诊断的技术中，其目的是确定细胞群的分布的宽度。患者血细胞无镰状细胞病将在可预见的宽度内被限制。从患者的镰状细胞疾病的细胞将在整个较宽的区域分布，与小区分配一个向下偏斜（参见图4）对于任何特定的应用中，一个阈值可以控制样品的分布宽度与该健康之间设定样品为"健康的"和"积极的疾病<sup cl...

Watch this Scientific Journal Video about Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics at JoVE.com

Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

磁悬浮加上便携式成像与分析诊断疾病

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for ...

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Equilibrium of a Particle

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8.7K 次观看.  University of Connecticut. We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

视频: Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring 

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end organs. The latter include the lung, RES, and brain and are operative during human immunodeficiency virus type one (HIV-1) infection. Macrophage entry into tissues is notable in areas of active HIV-1 replication and sites of inflammation. In order to assess the potential of macrophages as nanocarriers, superparamagnetic iron-oxide and/or drug laden particles coated with surfactants were parenterally injected into HIV-1 encephalitic mice. This was done to quantitatively assess particle and drug biodistribution. Magnetic resonance imaging (MRI) test results were validated by histological coregistration and enhanced image processing. End organ disease as typified by altered brain histology were assessed by MRI. The demonstration of robust migration of nanoformulations into areas of focal encephalitis provides '"proof of concept" for the use of advanced bioimaging techniques to monitor macrophage migration. Importantly, histopathological aberrations in brain correlate with bioimaging parameters making the general utility of MRI in studies of cell distribution in disease feasible. We posit that using such methods can provide a real time index of disease burden and therapeutic efficacy with translational potential to humans.

Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring

Bioimaging methods used to assess cell biodistribution of nanoparticles are applicable for therapeutic and diagnostic monitoring of nanoformulated compounds. The methods described herein are sensitive and specific when assessed by histological coregistration. The methodologies provide a translational pathway from rodent to human applications.

注册生物成像，纳米材料可用于诊断和治疗监测

Nanomedications can be carried by blood borne monocyte-macrophages into the reticuloendothelial system (RES; spleen, liver, lymph nodes) and to end ...

科研

生物工程

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

X-ray fluoroscopy-guided endovascular procedures have several significant limitations, including difficult catheter navigation and use of ionizing radiation, which can potentially be overcome using a magnetically steerable catheter under MR guidance.
	The main goal of this work is to develop a microcatheter whose tip can be remotely controlled using the magnetic field of the MR scanner. This protocol aims to describe the procedures for applying current to the microcoil-tipped microcatheter to produce consistent and controllable deflections.
	A microcoil was fabricated using laser lathe lithography onto a polyimide-tipped endovascular catheter. In vitro testing was performed in a waterbath and vessel phantom under the guidance of a 1.5-T MR system using steady-state free precession (SSFP) sequencing. Various amounts of current were applied to the coils of the microcatheter to produce measureable tip deflections and navigate in vascular phantoms.
	The development of this device provides a platform for future testing and opportunity to revolutionize the endovascular interventional MRI environment.

Current applied to an endovascular microcatheter with microcoil tip made by laser lathe lithography can achieve controllable deflections under magnetic resonance (MR) guidance, which may improve speed and efficacy of navigation of vasculature during various endovascular procedures.

磁力辅助的远程控制微导管尖端偏转根据磁共振成像

X-ray fluoroscopy-guided  endovascular procedures have several significant limitations, including  difficult catheter navigation and use of ionizing ...

Frequency Mixing Magnetic Detection Scanner for Imaging Magnetic Particles in Planar Samples

The setup of a planar Frequency Mixing Magnetic Detection (p-FMMD) scanner for performing Magnetic Particles Imaging (MPI) of flat samples is presented. It consists of two magnetic measurement heads on both sides of the sample mounted on the legs of a u-shaped support. The sample is locally exposed to a magnetic excitation field consisting of two distinct frequencies, a stronger component at about 77 kHz and a weaker field at 61 Hz. The nonlinear magnetization characteristics of superparamagnetic particles give rise to the generation of intermodulation products. A selected sum-frequency component of the high and low frequency magnetic field incident on the magnetically nonlinear particles is recorded by a demodulation electronics. In contrast to a conventional MPI scanner, p-FMMD does not require the application of a strong magnetic field to the whole sample because mixing of the two frequencies occurs locally. Thus, the lateral dimensions of the sample are just limited by the scanning range and the supports. However, the sample height determines the spatial resolution. In the current setup it is limited to 2 mm. As examples, we present two 20 mm &#215; 25 mm p-FMMD images acquired from samples with 1 &#181;m diameter maghemite particles in silanol matrix and with 50 nm magnetite particles in aminosilane matrix. The results show that the novel MPI scanner can be applied for analysis of thin biological samples and for medical diagnostic purposes.

A scanner for imaging magnetic particles in planar samples was developed using the planar frequency mixing magnetic detection technique. The magnetic intermodulation product response from the nonlinear nonhysteretic magnetization of the particles is recorded upon a two-frequency excitation. It can be used to take 2D images of thin biological samples.

混频磁探测仪在平面样品成像磁性微粒

The setup of a planar Frequency Mixing Magnetic Detection (p-FMMD) scanner for performing Magnetic Particles Imaging (MPI) of flat samples is presented. ...

工程学

Remote Magnetic Actuation of Micrometric Probes for in situ 3D Mapping of Bacterial Biofilm Physical Properties

Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in these structures are held together by physical interactions mediated by a network of extracellular polymeric substances. Bacterial biofilms impact many human activities and the understanding of their properties is crucial for a better control of their development &#8212; maintenance or eradication &#8212; depending on their adverse or beneficial outcome. This paper describes a novel methodology aiming to measure in situ the local physical properties of the biofilm that had been, until now, examined only from a macroscopic and homogeneous material perspective. The experiment described here&#160;involves introducing magnetic particles into a growing biofilm to seed local probes that can be remotely actuated without disturbing the structural properties of the biofilm. Dedicated magnetic tweezers were developed to exert a defined force on each particle embedded in the biofilm. The setup is mounted on the stage of a microscope to enable the&#160;recording of time-lapse images of the particle-pulling period. The particle trajectories are then extracted from the pulling sequence and the local viscoelastic parameters are derived from each particle displacement curve, thereby providing the 3D-spatial distribution of the parameters. Gaining insights into the biofilm mechanical profile is essential from an engineer&#39;s point of view for biofilm control purposes but also from a fundamental perspective to clarify the relationship between the architectural properties and the specific biology of these structures.

Remote Magnetic Actuation of Micrometric Probes for in situ 3D Mapping of Bacterial Biofilm Physical Properties

This paper shows an original methodology based on the remote actuation of magnetic particles seeded in a bacterial biofilm and the development of dedicated magnetic tweezers to measure in situ the local mechanical properties of the complex living material built by micro-organisms at interfaces.

测微探针进行远程磁驱动<em&gt;原位</em&gt; 3D细菌生物膜物理性质的映射

Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in ...

Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-&#945; 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-&#945; 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies.

This study demonstrates the successful establishment of magnetic resonance microscopy imaging as a non-invasive tool to assess the cardiac abnormalities in mice affected with autoimmune myocarditis. The data indicate that the technique can be used to monitor the disease-progression in live animals.

心脏异常的实验性自身免疫性心肌炎的无创性评估磁共振成像显微镜在鼠标

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events ...

医学

Magnetic Field Mapping using Off-Axis Electron Holography in the Transmission Electron Microscope

Off-axis electron holography is a powerful technique that involves the formation of an interference pattern in a transmission electron microscope (TEM) by overlapping two parts of an electron wave, one of which has passed through a region of interest on a specimen and the other is a reference wave. The resulting off-axis electron hologram can be analyzed digitally to recover the phase difference between the two parts of the electron wave, which can then be interpreted to provide quantitative information about local variations in electrostatic potential and magnetic induction within and around the specimen. Off-axis electron holograms can be recorded while a specimen is subjected to external stimuli such as elevated or reduced temperature, voltage, or light. The protocol that is presented here describes the practical steps that are required to record, analyze, and interpret off-axis electron holograms, with a primary focus on the measurement of magnetic fields within and around nanoscale materials and devices. Presented here are the steps involved in the recording, analysis, and processing of off-axis electron holograms, as well as the reconstruction and interpretation of phase images and visualization of the results. Also discussed are the need for optimization of the specimen geometry, the electron optical configuration of the microscope, and the electron hologram acquisition parameters, as well as the need for the use of information from multiple holograms to extract the desired magnetic contributions from the recorded signal. The steps are illustrated through a study of specimens of B20-type FeGe, which contain magnetic skyrmions and were prepared with focused ion beams (FIBs). Prospects for the future development of the technique are discussed.

<meta charset="utf8"></head><body>在透射电子显微镜中使用离轴电子全息技术进行磁场映射

Guidelines are presented for recording and interpreting off-axis electron holograms to provide quantitative images of magnetic fields in nanoscale materials and devices in the transmission electron microscope.

在透射电子显微镜中使用离轴电子全息技术进行磁场映射

Off-axis electron holography is a powerful technique that involves the formation of an interference pattern in a transmission electron microscope (TEM) by ...

Rapid Homogeneous Detection of Biological Assays Using Magnetic Modulation Biosensing System

A magnetic modulation biosensing system (MMB) [1,2] rapidly and homogeneously detected biological targets at low concentrations without any washing or separation step. When the IL-8 target was present, a 'sandwich'-based assay attached magnetic beads with IL-8 capture antibody to streptavidin coupled fluorescent protein via the IL-8 target and a biotinylated IL-8 antibody. The magnetic beads are maneuvered into oscillatory motion by applying an alternating magnetic field gradient through two electromagnetic poles. The fluorescent proteins, which are attached to the magnetic beads are condensed into the detection area and their movement in and out of an orthogonal laser beam produces a periodic fluorescent signal that is demodulated using synchronous detection. The magnetic modulation biosensing system was previously used to detect the coding sequences of the non-structural Ibaraki virus protein 3 (NS3) complementary DNA (cDNA) [2]. The techniques that are demonstrated in this work for external manipulation and condensation of particles may be used for other applications, e.g. delivery of magnetically-coupled drugs in-vivo or enhancing the contrast for in-vivo imaging applications.

Magnetic modulation biosensing system is utilized to rapidly, sensitively and simply detect biological assays, such as DNA molecules and proteins.

利用磁调制生物传感系统的生物检测的快速均质检测

A magnetic modulation biosensing system (MMB) [1,2] rapidly and homogeneously detected biological targets at low concentrations without any washing or ...

生物学

Measuring the Influence of Magnetic Vestibular Stimulation on Nystagmus, Self-Motion Perception, and Cognitive Performance in a 7T MRT

Strong magnetic fields induce dizziness, vertigo, and nystagmus due to Lorentz forces acting on the cupula in the semi-circular canals, an effect called magnetic vestibular stimulation (MVS). In this article, we present an experimental setup in a 7T MRT scanner (MRI scanner) that allows the investigation of the influence of strong magnetic fields on nystagmus as well as perceptual and cognitive responses. The strength of MVS is manipulated by altering the head positions of the participants. The orientation of the participants&#39; semicircular canals with respect to the static magnetic field is assessed by combining a 3D magnetometer and 3D constructive interference in steady-state (3D-CISS) images. This approach allows to account for intra- and inter-individual differences in participants&#8217; responses to MVS. In the future, MVS can be useful for clinical research, for example, in the investigation of compensatory processes in vestibular disorders. Furthermore, it could foster insights into the interplay between vestibular information and cognitive processes in terms of spatial cognition and the emergence of self-motion percepts under conflicting sensory information. In fMRI studies, MVS can elicit a possible confounding effect, especially in tasks influenced by vestibular information or in studies comparing vestibular patients with healthy controls.

In this article, we describe the experimental setup, material, and procedures to assess reflexive eye movements, self-motion perception, and cognitive tasks under magnetic vestibular stimulation, as well as the anatomical orientation of the vestibular organs, in a 7 Tesla Magnetic resonance tomography (7T-MRT) scanner.

测量磁前庭刺激对7T MRT眼球震颤、自我运动知觉和认知表现的影响

Strong magnetic fields induce dizziness, vertigo, and nystagmus due to Lorentz forces acting on the cupula in the semi-circular canals, an effect called ...

神经科学

Quantification of Cellular Densities and Antigenic Properties using Magnetic Levitation

The described method was developed based on the principles of magnetic levitation, which separates cells and particles based on their density and magnetic properties. Density is a cell type identifying property, directly related to its metabolic rate, differentiation, and activation status. Magnetic levitation allows a one-step approach to successfully separate, image and characterize circulating blood cells, and to detect anemia, sickle cell disease, and circulating tumor cells based on density and magnetic properties. This approach is also amenable to detecting soluble antigens present in a solution by using sets of low- and high-density beads coated with capture and detection antibodies, respectively. If the antigen is present in solution, it will bridge the two sets&#160;of beads, generating a new bead-bead complex, which will levitate in between the rows of antibody-coated beads. Increased concentration of the target antigen in solution will generate a larger number of bead-bead complexes when compared to lower concentrations of antigen, thus allowing for quantitative measurements of the target antigen. Magnetic levitation is advantageous to other methods due to its decreased sample preparation time and lack of dependance on classical readout methods. The image generated is easily captured and analyzed using a standard microscope or mobile device, such as a smartphone or a tablet.

This paper describes a magnetic levitation-based method that can specifically detect the presence of antigens, either soluble or membrane-bound, by quantifying changes in the levitation height of capture beads with fixed densities.

使用磁悬浮定量细胞密度和抗原特性

The described method was developed based on the principles of magnetic levitation, which separates cells and particles based on their density and magnetic ...

磁悬浮加上便携式成像与分析诊断疾病

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在透射电子显微镜中使用离轴电子全息技术进行磁场映射

在透射电子显微镜中使用离轴电子全息技术进行磁场映射

利用磁调制生物传感系统的生物检测的快速均质检测

测量磁前庭刺激对7T MRT眼球震颤、自我运动知觉和认知表现的影响

使用磁悬浮定量细胞密度和抗原特性