支持这项研究是由授予约旦第纳尔的国家科学基金会（OCE - 0623475），SPC（OCE - 0623534和0727544），并JHC（OCE - 0727587和奥西- 0623508），由海军研究办公室授予JHC（ N000140810654）。 KK是德文郡基金会提供资金，由伍兹霍尔海洋研究所的博士后学者计划的支持。

<ol><li>要开始此过程中，我们将确保所有SCUVA组件电量充足的电池，录音磁带（高清晰度或高清摄像机），和功能正常。根据流量来衡量，选择1,2摄像头的分辨率和帧速率产生数字粒子图像测速（DPIV）最好的结果。 </li><li>准备使用激光和摄像机防护罩，用干净的毛巾清洁的O型环槽和O形圈或擦拭。传播制造商提供均匀O型环，O型圈润滑脂和更换住房槽。此外，清洁激光和摄像机外壳孔的相机房屋镜头，以防止激光板材变形和标志。 </li><li>检查O型圈密封，放置在一个充满水的浴缸都空外壳。将需要淹没他们置于顶部的外壳，因为外壳的浮空时加权对象。 5至10分钟后，取出从浴缸和毛巾擦干吨的外壳他在外面。检查是否有任何的外壳内的水分。也可以考虑使用压力测试期间一次性的，纸张的湿度带的外壳是否有水分测试后。 </li><li>后外壳通过压力测试，SCUVA组件外壳内。 </li><li>附加高强度放电（HID）灯豆荚摄像机外壳。确保灯都以这样一种方式，他们照亮的面积正前方的摄像头和运营商为导向，不干扰处理及相机控制操作与维护握。 </li><li>在光线较暗的环境，确保正确对齐相安装在激光住房光学镜头，激光束。正确对齐，激光/镜头组合将创建一个垂直的光表是面向垂直相机住房。为了安全起见，用一张纸对温度敏感的板材，以确定激光片方向。 </李&gt; <li>使用SCUVA附件和僵化，伸缩臂，激光住房和摄像机外壳连接到对方。确保外壳牢固地附着的外壳相互尊重，不能旋转。至关重要的是激光片仍然面向垂直相机的整个测量领域。 </li><li>由于SCUVA目前的能力，测量潜水只能在光线不足的场所或夜间进行，以防止激光片自然光的干涉。因此，我们建议入水前等待，直到黄昏或更高版本。 </li><li>入水前，打开相机外壳上。摄像机外壳有一个内置的电子湿度传感器提供水分的情况下摄像机外壳的视觉警告（LED灯闪烁）。仅当相机外壳上的传感器。 </li><li>在水中浸泡SCUVA和重视自己使用的仪器一条线。一旦连接到仪器，释放SCUVA，以确定该设备的浮力特性。根据浮力的特点，将浮力泡沫或铅块一个或两个外壳，以确保中性浮力，防止用水器具的旋转。 </li><li>下一步，交换机上的激光和保持仪器固定。激光定位，从潜水员使用的伸缩臂足够远，以尽量减少测量潜水员诱导流动。任何测量目标附近的潜水员诱导流动引入错误和不供后续分析使用。相机变焦调整，直到实地查看帧的目标和周围流体。 </li><li>虽然保持固定的器具，重点激光负债表上的摄像头，直到颗粒出现急剧和重点。一旦激光片平面的重点是，相机切换到手动对焦模式。这将防止相机领域中出现的任何对象的重新定位查看在测量过程中，导致在激光片模糊的颗粒。 </li><li>要校准SCUVA，地方与激光负债表中已知尺寸的摄像头的视野内的一个对象。几秒钟的记录。潜水后，图像将被从这个视频序列中提取，以确定校准常数转换厘米像素为单位的视场大小。如果操作员随时调整视场大小被重新定位，伸缩臂或在不断变化的潜水相机变焦，步骤12和13将需要重复。 </li><li>开始降工作深度潜水。发现目标后，对环境的散流属性需要确定。如果存在，电流的方向，将决定设备和潜水员在测量过程中的目标定位相对。周围目标的散装流的方向可以推断通过观察气泡从潜水员呼出，并指出它们的横向运动。在除泡沫，少量的荧光染料（即，荧光素）可以释放，以确定当前的方向。由于潜水员产生的流量可以DPIV测量误差的来源，潜水员不应位于上游的目标。此外，激光片应定位电流方向平行，以最大限度地提高粒子的激光片内的停留时间，从而最大限度地减少DPIV错误。但是，如果没有当前或散流目前，潜水员和SCUVA定位相对目标是不受限制的。 </li><li>位置SCUVA，照亮并记录周围流体运动目标。如果试图记录流，围绕一个移动的目标首先预测的目标位置，然后位置SCUVA预测的位置，而余下的一动不动。作为目标，通过移动摄像机的视野，开始录制。如果目标是一动不动，在摄像头帧的目标和周围流体＃x2019;实地查看，并开始录制，而余下的一动不动。经营者应避免在录制视频的旋转和平面运动，因为这些错误的DPIV结果的议案结果。因此，测量期间收集的旋转和平面潜水员议案将不被用于进一步的数据进行分析。 </li><li>一旦视频采集完成后，关闭SCUVA所有元件和激光手臂恢复其缩回位置。从水中取出SCUVA和从手臂分离相机和激光外壳。冲洗或在淡水中浸泡，然后干燥，以防止生锈的设备仪器。一旦干燥的外壳，从外壳移除组件，以及充电和更换电池如果需要另一个潜水。 </li><li>摄像头连接到计算机，并使用了高清视频软件包（即Adobe Premiere Pro或iMovie中）从高清磁带中提取的视频。视频提取后，确定范围视频转换成一系列图像DPIV分析。确保像素长宽比和提取的图像大小相匹配的高清视频设置。 </li><li>这些图像导入到一个DPIV处理程序（即戴维斯或MatPIV）。经过校准常数和图像采集参数，这是从DPIV软件包提示正确的选择，速度场，可以生成从连续的粒子图像。额外的后处理步骤，根据测量的质量和类型，也可应用。 </li></ol>代表性的成果： 当协议是正确的，目标周围的粒子图像锐利，容易分辨。使用SCUVA的摄像头（图1A）和一个DPIV处理软件包，目标周围流（图1B）速度场就地捕获粒子领域将被揭示。向量中的velociTY领域，表明当地流速的大小和方向。如果有足够的视频是收集到的图像提供的时间序列，速度场的时间序列也可确定。 <img src="/files/ftp_upload/2615/2615fig1.jpg" alt="图1"/> 图1 在原位颗粒领域（一）围绕奥里利亚labiata。相应的速度场（B）与指示流动方向和大小的黄色向量。 <img src="/files/ftp_upload/2615/2615fig2.jpg" alt="图2"/> 图2 原位颗粒周围Mastigias SP领域和Solmissus SP（A和B，分别）。 A中的红色箭头表示高反射率的地区，从而导致图像的饱和度，使其难以区分粒子和目标。在B的红色箭头表示裸奔，结果，当流量地区没有足够高的频率采样。

<ol>
	<li>Adrian, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Particle-imaging+techniques+for+experimental+fluid+mechanics.">Particle-imaging techniques for experimental fluid mechanics.</a> Ann. Rev. Fluid Mech. 23, 261-304 (1991).</li><li>Willert, C. E., Gharib, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+particle+image+velocimetry.">Digital particle image velocimetry.</a> Exp. Fluids. 10, 181-193 (1991).</li><li>Raffel, M., Willert, C., Wereley, S., Kompenhans, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Particle Image Velocimetry: A Practical Guide. , (2007).</li><li>Agrawal, Y. C., Pottsmith, H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laser+diffraction+particle+sizing+in+STRESS.">Laser diffraction particle sizing in STRESS.</a> Cont. Shelf Res. 14, 1101-1121 (1994).</li><li>Katz, J., Donaghay, P. L., Zhang, J., King, S., Russell, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Submersible+holocamera+for+detection+of+particle+characteristics+and+motions+in+the+ocean.">Submersible holocamera for detection of particle characteristics and motions in the ocean.</a> Deep Sea Res. 46, 1455-1481 (1999).</li><li>Katija, K., Dabiri, J. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+field+measurements+of+aquatic+animal-fluid+interactions+using+a+self-contained+underwater+velocimetry+apparatus+(SCUVA).">In situ field measurements of aquatic animal-fluid interactions using a self-contained underwater velocimetry apparatus (SCUVA).</a> Limnol. Oceanogr.-Meth. 6, 162-171 (2008).</li></ol>

没有利益冲突的声明。

在该领域的潜在制约因素是粒子流，这是必要的，以实现数字粒子图像测速（DPIV）的需要。在沿海水域，悬浮颗粒物展品尺寸上的直径10微米和0.002，每毫米3 10之间的浓度的顺序4。更多的研究使用粒子检测确认存在足够的种子颗粒在海水执行DPIV潜水holocamera。 5在公海和沿海海洋潜水，我们发现，粒子密度和大小不进行原位 DPIV的约束。 除了粒子密度和大小，另一个值得关注的相关DPIV测量颗粒物浓度的同质性。 定性，如果审讯窗口内的一个地区的颗粒物浓度大于另一个，速度的大小由D生成PIV技术分析，将偏重的地区，具有较高的粒子浓度。因此，SCUVA测量必须进行颗粒物浓度的变化是最小化。我们发现thatcle浓度在颗粒物浓度的相对恒定的，在潜水员在水柱的中间暂停潜水期间相对恒定的。然而，在海底环境中的粒子领域不均匀由于附近海底的环境或潜​​水员诱导流动的颗粒再悬浮的潜力。必须小心，以尽量减少在底栖环境的测量粒子的破坏。作者的知识，还没有正式的不均匀颗粒浓度场产生的错误分析无论是实验室或野外条件下进行，并应进一步考虑在一个单独的出版物的主题。 有几种不同的问题，应考虑在编制和在使用该协议进行现场试验。在录制过程中，操作指示，保持静止，不要所有飞机和旋转运动。这个要求很简单，在理论上却难以在实践中，这些测量需要先进的潜水技能，得以圆满完成。出平面和旋转运动的错误DPIV数据运算符的结果。然而，在平面议案可以通过使用内部软件纠正。 六是建议几个潜水浮力控制前使用SCUVA，最大限度地提高了测量效率的经营实践。 除了浮力的考虑，经营者应当知道目标的流动方向。流，旅游的平面激光片不会产生可靠的DPIV结果，和经营者应东方SCUVA捕捉到这些流动的最有效。此外，潜水员到目标的相对位置必须selecteð，以尽量减少诱导潜水员在流量测量。潜水员诱导流引入了错误的目标流量，不应作进一步的分析和测量，包括潜水员影响。 在事件目标表面具有高反射率，流体周边地区的目标将受到强烈的照明，使其难以分辨周围的流体（红色箭头，图2A表示地区）附近的单个粒子。可以被添加到过滤器或偏光片的激光或摄像机防护罩，以减少摄像传感器所捕获的激光强度。如果这是不可能的的，由于后勤方面的限制和有限的接入设备，使用内部软件的图像后处理，可以提供足够的校正，从图像中减去靠近目标的像素强度升高。另一个需要考虑的影响DPIV数据的质量是粒子条纹是否存在。如果粒子领域有裸奔的区域（红色箭头，图2B表示），摄像头录制的帧速率太低，解决这些高的速度。通过增加帧速率，可以减少粒子裸奔。然而，这个结果在减少光深远的摄像传感器，使得粒子现场看调光。如果摄像头能够手动设置光圈设置，增加光圈设置，以防止调光的粒子场。确定最佳的设备设置，可能需要多个成功的数据收集前SCUVA潜水。

quantitatively measuring in situ flows using a self-contained underwater velocimetry apparatus (scuva)

海洋学，生态学，生物学，流体力学等不同领域的研究提供实证数据的能力，直接测量流体环境中速度场是必要的。实地测量引入实际的挑战，如环境条件下，动物的空房情况，并现场兼容测量技术的需要。为了避免这些挑战，科学家们通常使用受控的实验室环境，研究动物流体相互作用。但是，它是合理的问题，是否可以推断从实验室测量自然的行为（即，在外地发生）。因此， 在原位定量流量测量需要准确地描述动物在自然环境中游泳。 我们设计了一个自成体系，独立于任何表面的连接的便携设备，操作，并能提供定量测量流场surrounding一个动物。一个自成体系的水下测速装置（SCUVA），这种仪器，可以由一个单潜水员在深度40米由于增加了复杂性的野外条件下，额外的考虑和准备的固有的需要相比，实验室测量。这些考虑因素包括，但不仅限于，运营商的议案，预测游泳的目标，现有的自然悬浮微粒，和利益的流动相对SCUVA方向的位置。以下协议的目的是，以解决这些共同的领域的挑战，并最大限度地提高测量成功。

Watch this Scientific Journal Video about Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus SCUVA at JoVE.com

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus SCUVA

此协议提供了有关如何使用一个自包含水下测速仪（SCUVA），这是量化原位动物产生的流动设计的说明。此外，这个协议解决了野战条件所带来的挑战，包括运营商的议案，预测动物的位置，方向和SCUVA。

定量测量原位流动，使用一个自包含的水下测速仪（SCUVA）

The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as ...

quantitatively-measuring-situ-flows-using-self-contained-underwater

Research

JoVE Journal

Bioengineering

Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

12.9K 次观看.  Woods Hole Oceanographic Institution. 此协议提供了有关如何使用一个自包含水下测速仪（SCUVA），这是量化原位动物产生的流动设计的说明。此外，这个协议解决了野战条件所带来的挑战，包括运营商的议案，预测动物的位置，方向和SCUVA。

视频: Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus SCUVA

Electrospinning Fundamentals: Optimizing Solution and Apparatus Parameters

Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. Electrospinning is a process in which a charged polymer jet is collected on a grounded collector; a rapidly rotating collector results in aligned nanofibers while stationary collectors result in randomly oriented fiber mats. The polymer jet is formed when an applied electrostatic charge overcomes the surface tension of the solution. There is a minimum concentration for a given polymer, termed the critical entanglement concentration, below which a stable jet cannot be achieved and no nanofibers will form - although nanoparticles may be achieved (electrospray). A stable jet has two domains, a streaming segment and a whipping segment. While the whipping jet is usually invisible to the naked eye, the streaming segment is often visible under appropriate lighting conditions. Observing the length, thickness, consistency and movement of the stream is useful to predict the alignment and morphology of the nanofibers being formed. A short, non-uniform, inconsistent, and/or oscillating stream is indicative of a variety of problems, including poor fiber alignment, beading, splattering, and curlicue or wavy patterns. The stream can be optimized by adjusting the composition of the solution and the configuration of the electrospinning apparatus, thus optimizing the alignment and morphology of the fibers being produced. In this protocol, we present a procedure for setting up a basic electrospinning apparatus, empirically approximating the critical entanglement concentration of a polymer solution and optimizing the electrospinning process. In addition, we discuss some common problems and troubleshooting techniques.

Electrospinning techniques can create a variety of nanofibrous scaffolds for tissue engineering or other applications. We describe here a procedure to optimize the parameters of the electrospinning solution and apparatus to obtain fibers with the desired morphology and alignment. Common problems and troubleshooting techniques are also presented.

静电基础：优化解决方案和设备参数

Electrospun nanofiber scaffolds have been shown to accelerate the maturation, improve the growth, and direct the migration of cells in vitro. ...

科研

生物工程

Creating Two-Dimensional Patterned Substrates for Protein and Cell Confinement

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1 While microcontact printing can be employed to directly print a large number of molecules, including proteins,2 DNA,3 and silanes,4 the formation of self-assembled monolayers (SAMs) from long chain alkane thiols on gold provides a simple way to confine proteins and cells to specific patterns containing adhesive and resistant regions. This confinement can be used to control cell morphology and is useful for examining a variety of questions in protein and cell biology. Here, we describe a general method for the creation of well-defined protein patterns for cellular studies.5 This process involves three steps: the production of a patterned master using photolithography, the creation of a PDMS stamp, and microcontact printing of a gold-coated substrate. Once patterned, these cell culture substrates are capable of confining proteins and/or cells (primary cells or cell lines) to the pattern.
The use of self-assembled monolayer chemistry allows for precise control over the patterned protein/cell adhesive regions and non-adhesive regions; this cannot be achieved using direct protein stamping. Hexadecanethiol, the long chain alkane thiol used in the microcontact printing step, produces a hydrophobic surface that readily adsorbs protein from solution. The glycol-terminated thiol, used for backfilling the non-printed regions of the substrate, creates a monolayer that is resistant to protein adsorption and therefore cell growth.6 These thiol monomers produce highly structured monolayers that precisely define regions of the substrate that can support protein adsorption and cell growth. As a result, these substrates are useful for a wide variety of applications from the study of intercellular behavior7 to the creation of microelectronics.8
While other types of monolayer chemistry have been used for cell culture studies, including work from our group using trichlorosilanes to create patterns directly on glass substrates,9 patterned monolayers formed from alkane thiols on gold are straight-forward to prepare. Moreover, the monomers used for monolayer preparation are commercially available, stable, and do not require storage or handling under inert atmosphere. Patterned substrates prepared from alkane thiols can also be recycled and reused several times, maintaining cell confinement.10

Self-assembled monolayers (SAMs) formed from long chain alkane thiols on gold provide well-defined substrates for the formation of protein patterns and cell confinement. Microcontact printing of hexadecanethiol using a polydimethylsiloxane (PDMS) stamp followed by backfilling with a glycol-terminated alkane thiol monomer produces a pattern where protein and cells adsorb only to the stamped hexadecanethiol region.

蛋白质和细胞坐月子创建二维图案衬底

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1  While microcontact printing ...

Micro-particle Image Velocimetry for Velocity Profile Measurements of Micro Blood Flows

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows. The images are cross-correlated to give an accurate velocity profile. A protocol is presented for &mu;PIV measurements of blood flows in microchannels. At the scale of the microcirculation, blood cannot be considered a homogeneous fluid, as it is a suspension of flexible particles suspended in plasma, a Newtonian fluid. Shear rate, maximum velocity, velocity profile shape, and flow rate can be derived from these measurements. Several key parameters such as focal depth, particle concentration, and system compliance, are presented in order to ensure accurate, useful data along with examples and representative results for various hematocrits and flow conditions.

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows which are cross-correlated to give an accurate velocity profile. Shear rate, maximum velocity, velocity profile shape, and flow rate, each of which has clinical applications, can be derived from these measurements.

微观粒子图像测速技术，微血液流动的速度剖面测量

Micro-particle image velocimetry (&mu;PIV) is used to visualize paired images of micro particles seeded in blood flows. The images are cross-correlated to ...

Measuring the Mechanical Properties of Living Cells Using Atomic Force Microscopy

Mechanical properties of cells and extracellular matrix (ECM) play important roles in many biological processes including stem cell differentiation, tumor formation, and wound healing. Changes in stiffness of cells and ECM are often signs of changes in cell physiology or diseases in tissues. Hence, cell stiffness is an index to evaluate the status of cell cultures. Among the multitude of methods applied to measure the stiffness of cells and tissues, micro-indentation using an Atomic Force Microscope (AFM) provides a way to reliably measure the stiffness of living cells. This method has been widely applied to characterize the micro-scale stiffness for a variety of materials ranging from metal surfaces to soft biological tissues and cells. The basic principle of this method is to indent a cell with an AFM tip of selected geometry and measure the applied force from the bending of the AFM cantilever. Fitting the force-indentation curve to the Hertz model for the corresponding tip geometry can give quantitative measurements of material stiffness. This paper demonstrates the procedure to characterize the stiffness of living cells using AFM. Key steps including the process of AFM calibration, force-curve acquisition, and data analysis using a MATLAB routine are demonstrated. Limitations of this method are also discussed.

This paper demonstrates a protocol to characterize the mechanical properties of living cells by means of microindentation using an Atomic Force Microscope (AFM).

使用原子力显微镜测量活细胞的力学性能

Mechanical  properties of cells and extracellular matrix (ECM) play important roles in many  biological processes including stem cell differentiation, ...

In situ TEM of Biological Assemblies in Liquid

Researchers regularly use Transmission Electron Microscopes (TEMs) to examine biological entities and to assess new materials. Here, we describe an additional application for these instruments- viewing viral assemblies in a liquid environment. This exciting and novel method of visualizing biological structures utilizes a recently developed microfluidic-based specimen holder. Our video article demonstrates how to assemble and use a microfluidic holder to image liquid specimens within a TEM. In particular, we use simian rotavirus double-layered particles (DLPs) as our model system. We also describe steps to coat the surface of the liquid chamber with affinity biofilms that tether DLPs to the viewing window. This permits us to image assemblies in a manner that is suitable for 3D structure determination. Thus, we present a first glimpse of subviral particles in a native liquid environment.

In situ TEM of Biological Assemblies in Liquid

Here we describe a procedure to image viral complexes in liquid at nanometer resolution using a transmission electron microscope.

就地 液体生物组件的 TEM

Researchers regularly use Transmission Electron Microscopes (TEMs) to examine biological entities and to assess new materials. Here, we describe an ...

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e.,&#160;gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

AN MRI-compatible&#160;custom-designed laser-based heating apparatus has been developed to provide local heating of subcutaneous tumors in order to activate release of agents from thermosensitive liposomes specifically at the tumor region.

定制设计的基于激光的加热装置顺铂触发释放的热敏脂质体与磁共振成像制导

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect ...

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances (EPS). The EPS serves as a physical and protective scaffold that houses the bacterial cells and consists of a variety of materials that includes proteins, exopolysaccharides and DNA. The composition of the EPS may change, which remodels the mechanic properties of the biofilm to further develop or support alternative biofilm structures, such as streamers, as a response to environmental cues. Despite this, there are little quantitative descriptions on how EPS components contribute to the mechanical properties and function of biofilms. Rheology, the study of the flow of matter, is of particular relevance to biofilms as many biofilms grow in flow conditions and are constantly exposed to shear stress. It also provides measurement and insight on the spreading of the biofilm on a surface. Here, particle-tracking microrheology is used to examine the viscoelasticity and effective crosslinking roles of different matrix components in various parts of the biofilm during development. This approach allows researchers to measure mechanic properties of biofilms at the micro-scale, which might provide useful information for controlling and engineering biofilms.

In Situ Mapping of the Mechanical Properties of Biofilms by Particle-tracking Microrheology

Particle-tracking microrheology investigates the viscoelasticity of materials. Here, the technique is used to determine the viscoelasticity, creep compliance and effective crosslinking roles of different matrix components of a bacterial biofilm. The matrix consists of polymeric substances secreted by the bacteria and its components determine biofilm structure and mechanical properties.

在生物膜的力学性能原位制图粒子追踪Microrheology

Bacterial cells are able to form surface-attached biofilm communities known as biofilms by encasing themselves in extracellular polymeric substances ...

Measuring TCR-pMHC Binding In Situ using a FRET-based Microscopy Assay

T-cells are remarkably specific and effective when recognizing antigens in the form of peptides embedded in MHC molecules (pMHC) on the surface of Antigen Presenting Cells (APCs). This is despite T-cell antigen receptors (TCRs) exerting usually a moderate affinity (&#181;M range) to antigen when binding is measured in vitro1. In view of the molecular and cellular parameters contributing to T-cell antigen sensitivity, a microscopy-based methodology has been developed as a means to monitor TCR-pMHC binding in situ, as it occurs within the synapse of a live T-cell and an artificial and functionalized glass-supported planar lipid bilayer (SLB), which mimics the cell membrane of an Antigen presenting Cell (APC) 2. Measurements are based on F&#246;rster Resonance Energy Transfer (FRET) between a blue- and red-shifted fluorescent dye attached to the TCR and the pMHC. Because the efficiency of FRET is inversely proportional to the sixth power of the inter-dye distance, one can employ FRET signals to visualize synaptic TCR-pMHC binding. The sensitive of the microscopy approach supports detection of single molecule FRET events. This allows to determine the affinity and off-rate of synaptic TCR-pMHC interactions and in turn to interpolate the on-rate of binding. Analogous assays could be applied to measure other receptor-ligand interactions in their native environment.

Measuring TCR-pMHC Binding In Situ using a FRET-based Microscopy Assay

This manuscript describes how to conduct (single molecule) F&#246;rster Resonance Energy Transfer (FRET)- based assays to measure the binding dynamics between T-cell antigen receptor (TCR) and antigenic peptide-loaded MHC molecules as they occur within the immunological synapse of a T-cell in contact with a functionalized planar supported lipid bilayer.

测量TCR-的pMHC结合<em&gt;原位</em&gt;使用基于FRET的显微镜分析

T-cells are remarkably specific and effective when recognizing antigens in the form of peptides embedded in MHC molecules (pMHC) on the surface of Antigen ...

Apparatus for Harvesting Tissue Microcolumns

This manuscript describes the production process for a laboratory apparatus, made from off-the-shelf components, that can be used to collect microcolumns of full-thickness skin tissue. The small size of the microcolumns allows donor sites to heal quickly without causing donor site scarring, while harvesting full-thickness tissue enables the incorporation of all cellular and extracellular components of skin tissue, including those associated with deeper dermal regions and the adnexal skin structures, which have yet to be successfully reproduced using conventional tissue engineering techniques. The microcolumns can be applied directly into skin wounds to augment healing, or they can be used as the autologous cell/tissue source for other tissue engineering approaches. The harvesting needles are made by modifying standard hypodermic needles, and they can be used alone for harvesting small amounts of tissue or coupled with a simple suction-based collection system (also made from commonly available laboratory supplies) for high-volume harvesting to facilitate studies in large animal models.

Here we describe a protocol for producing harvesting needles that can be used to collect full-thickness skin tissue without causing donor site scarring. The needles can be combined with a simple collection system to achieve high-volume harvesting.

水样组织的采集装置

This manuscript describes the production process for a laboratory apparatus, made from off-the-shelf components, that can be used to collect microcolumns ...

Meso-Scale Particle Image Velocimetry Studies of Neurovascular Flows In Vitro

Particle image velocimetry (PIV) is used in a wide variety of fields, due to the opportunity it provides for precisely visualizing and quantifying flows across a large spatiotemporal range. However, its implementation typically requires the use of expensive and specialized instrumentation, which limits its broader utility. Moreover, within the field of bioengineering, in vitro flow visualization studies are also often further limited by the high cost of commercially sourced tissue phantoms that recapitulate desired anatomical structures, particularly for those that span the mesoscale regime (i.e., submillimeter to millimeter length scales). Herein, we present a simplified experimental protocol developed to address these limitations, the key elements of which include 1) a relatively low-cost method for fabricating mesoscale tissue phantoms using 3-D printing and silicone casting, and 2) an open-source image analysis and processing framework that reduces the demand upon the instrumentation for measuring mesoscale flows (i.e., velocities up to tens of millimeters/second). Collectively, this lowers the barrier to entry for nonexperts, by leveraging resources already at the disposal of many bioengineering researchers. We demonstratethe applicability of this protocol within the context of neurovascular flow characterization; however, it is expected to be relevant to a broader range of mesoscale applications in bioengineering and beyond.

Meso-Scale Particle Image Velocimetry Studies of Neurovascular Flows In Vitro

Here we present simplified methods for fabricating transparent neurovascular phantoms and characterizing the flow therein. We highlight several important parameters and demonstrate their relationship to field accuracy.

神经血管流动的中尺度粒子图像测速研究

Particle image velocimetry (PIV) is used in a wide variety of fields, due to the opportunity it provides for precisely visualizing and quantifying flows ...