这项工作是由一个BU / CIMIT应用医疗保健工程博士前奖学金，扩大参与科研启动资助工程（桥接器）美国国家科学基金会，美国国立卫生研究院（R21EB0094930）。

1。制备纳米乳剂相移（PSNE） <ol><li> DPPC将11毫克和1.68毫克DSPE-PEG2000在氯仿</li><li>蒸除有机溶剂中的玻璃圆底烧瓶中，以形成干燥的脂质膜</li><li> Dessicate的脂质膜过夜</li><li>用5.5毫升的磷酸盐缓冲盐水（PBS）再水合的脂质膜</li><li>热解决方案，在45℃水浴中，直到脂膜溶解，涡旋式定期</li><li>转移脂解到7毫升小瓶</li><li>超声脂质溶液，持续2分钟，在20％的振幅</li><li>划分的解决方案分为两小瓶2.5毫升每（丢弃其余0.5毫升） </li><li>加入2.5毫升PBS每小瓶</li><li>放置每个小瓶中的0℃的冰水浴中</li><li>添加50微升DDFP的每小瓶</li><li>超声每个小瓶在冰 - 水浴中，使用以下的设置：25％的幅度，脉冲模式（10秒，50秒关），60秒的总时间</li><li>风帆ansfer PSNE的解决方案，以20毫升闪烁瓶中</li><li>加入5毫升PBS中，每个小瓶中，得到的在10毫升的最终体积</li><li>组装挤出机制造商提供的以下几个方向<ol><li>用去离子水冲洗每个部分</li><li>不锈钢支承盘放置在中心的过滤器支撑基地</li><li>不锈钢支承盘的顶部上放置不锈钢丝网</li><li>使用镊子，将挤出机漏极光盘膜（有光泽的一面朝上）的不锈钢丝网</li><li>使用镊子，将在挤出机上的漏盘膜过滤器（闪亮的一面朝上） </li><li>小心地将小O形环的过滤器的支持基础之上，将thermobarrel机，挤出机顶</li><li>翼螺母拧紧每一个部分第一，然后完全拧紧翼螺母的手在交替的方式</li><li>挤出机连接到氮气线</li><li>进入前采样口至最优惠的挤出机，移取10 mL去离子水，上限开放，并拧紧排气阀</li><li>慢慢地打开氮气线，以增加压力，迫使样品通过膜，并收集样品出口管</li><li>使用后，以相反的顺序拆卸，冲洗用去离子水在挤出机的部分，并丢弃的膜过滤器和膜漏极光盘</li></ol></li><li>仅适用于100纳米液滴，先决条件PSNE的挤出10倍至200纳米过滤器</li><li>挤出PSNE 16倍到100 nm或200 nm的过滤器，以获得较窄的粒径分布</li></ol> 2。的含PSNE聚丙烯酰胺水凝胶的制备<ol><li>准备24％BSA溶液稀释1.2克BSA粉末在5毫升去离子水</li><li>准备10％的APS溶液，稀0.1克APS粉1 mL去离子水疗设备ŕ </li><li>按以下顺序，混合丙烯酰胺溶液2.1毫升Tris缓冲液，1.2毫升，0.1毫升10％的APS，4.5毫升24％的BSA溶液，和3.6毫升的去离子水的塑料腔室</li><li>加热至40℃，并置于真空中1小时</li><li>加入480μl的PSNE，并充分混合，轻轻摇动的塑料腔。 </li><li>加入12μLTEMED和室放置在12℃水浴2小时</li></ol> 3。代表性的成果甲的组织模仿水凝胶幻影超声实验设置的示意图在图1中所示。这协议导致脂质涂层具有窄的粒径分布的液滴，全氟化碳，在溶液中保持稳定的至少一个星期。用动态光散射（90Plus粒度分析仪，Brookhaven仪器，州Holtsville，NY）测得的粒度分布，在图2中所示的PSNE使用100和200的挤压纳米过滤器。有效直径的PSNE随着时间的推移，使用动态光散射测量，在表1中列出，表明PSNE是稳定的，至少一个星期。 B模式图像PSNE在聚丙烯酰胺水凝胶的蒸发之前和之后的图3中所示。此外，形成的病变HIFU-介导的加热15秒，在聚丙烯酰胺水凝胶，含有白蛋白和PSNE 如图4所示。的非对称形状的病变是一个结果的发生是由于气泡云的存在下，在上述超声波路径prefocal加热。通过减少所发送的声功率可以被最小化，重要的是要注意，prefocal加热和病灶的形成，由于气泡的散射。 <img src="/files/ftp_upload/4308/4308fig1.jpg" alt="图1"/> 组织MIM超声实验的实验装置示意图图1。舔舐水凝胶。 <img src="/files/ftp_upload/4308/4308fig2.jpg" alt="图2"/> 图2。大小分布PSNE挤压通过100nm或200nm的过滤器，使用动态光散射测量。的纵坐标轴的单位是从一定的大小，相对于从该样本的总的散射光强度的粒子的散射光的强度的基础上。 <img src="/files/ftp_upload/4308/4308fig3.jpg" alt="图3"/> 图3，B模式图像（a）在与（b）在PSNE在聚丙烯酰胺水凝胶的汽化。箭头表示震源区的PSNE汽化形成的泡沫云。 <img src="/files/ftp_upload/4308/4308fig4.jpg" alt="图4"/> 图4。的polyacr图像基酰胺水凝胶含白蛋白及PSNE（一）之前和（b）在与高强度聚焦超声汽化和超声波处理，展示作为超声波感应加热的结果的病变的形成。的超声波中心频率为3.3兆赫。的超声波信号包括一个初始的30个循环的，6.4 W脉冲，以蒸发PSNE，紧接着由15秒的连续的超声波在0.77 W. <table border="1"><tbody><tr><td rowspan="2"> 之后的日子里挤出 </td><td colspan="2"> 挤压与200纳米过滤器 </td><td colspan="2"> 挤压与100纳米过滤器 </td></tr><tr><td> 平均直径。 （nm）的 </td><td> 标准。开发。 （nm）的 </td><td> 平均直径。 （nm）的 </td><td> 标准。开发。 （nm）的 </td></tr><tr><td> 1 </td><td> 182.9 </td><td> 4.9 </td><td> 118.0 </td><td> 0.9 </td></tr><tr><td> 7 </td> &lt;TD&gt; 177.7 </td><td> 2.5 </td><td> 124.8 </td><td> 3.1 </td></tr></tbody></table> 表1在挤出用100 nm和200nm的过滤器的一个和后七天的平均直径和标准偏差PSNE。

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临床使用高强度聚焦超声（HIFU）热消融肿瘤1为了提高局部加热，并提高热消融在肿瘤中，已经开发了脂质包衣的全氟化碳的液滴可以汽化HIFU。在许多肿瘤的血管异常漏由于其快速增长。2因此，纳米粒子能够穿透窗孔和被动肿瘤内积聚，这个过程被称为增强的渗透性和保持率（EPR）的效果。3它已被证明是在70和200nm之间的纳米粒子最有效地积累在肿瘤。4本报告中?...

<table border="1"><tbody><tr><td> 通用名 </td><td> 生产厂家 </td><td> 猫。数 </td><td> 姓名/说明 </td></tr><tr><td> DPPC </td><td>阿凡提血脂，雪花石膏，AL，USA </td><td> 850355P </td><td> 1,2 - 二棕榈酰-sn-甘油-3 - 磷酸胆碱</td></tr><tr><td> DSPE-PEG2000 </td><td>阿凡提血脂，雪花石膏，AL，USA </td><td> 880120P </td><td> 1,2 - 二硬脂酰-sn-甘油-3 - 磷酸乙醇胺-N-[甲氧基（聚乙二醇）-2000]（铵盐） </td></tr><tr><td> DDFP </td><td> Fluoromed的Round Rock，TX，USA </td><td> CAS号：138495-42-8 </td><td> Dodecafluoropentane（C 5 F 12） </td></tr><tr><td> PBS </td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> P2194 </td><td>磷酸盐缓冲盐水</td></tr><tr><td>氯仿</td><td> Sigma-Aldrich公司，圣。路易斯，MO，USA </td><td> 372978 </td><td>氯仿</td></tr><tr><td>丙烯酰胺</td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> A9926 </td><td> 40％，19:1的丙烯酰胺/双丙烯酰胺 - 丙烯酰胺</td></tr><tr><td> Tris缓冲液</td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> T2694 </td><td> 1M，pH为8，TRIZMA盐酸盐和Trizma碱</td></tr><tr><td> BSA </td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> A3059 </td><td>牛血清白蛋白</td></tr><tr><td> APS </td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> A3678 </td><td>过硫酸铵水溶液</td></tr><tr><td> TEMED </td><td> Sigma-Aldrich公司，圣路易斯，MO，USA </td><td> 87689 </td><td> N，N，N&#39;，N&#39;-四甲基乙二胺</td></tr><tr><td></td><td></td><td></td><td> 设备 </td></tr><tr><td>超声发生器（3毫米尖） </TD&gt; <td>超音速材料公司，新城，CT，USA </td><td>振动细胞</td><td></td></tr><tr><td>水浴</td><td>赛默飞世尔科技，美国马萨诸塞州沃尔瑟姆， </td><td> NESLAB EX-7 </td><td></td></tr><tr><td>挤出机</td><td>北血脂，伯纳比，不列颠哥伦比亚省，加拿大</td><td> LIPEX </td><td></td></tr><tr><td>挤出机过滤器</td><td>美国Whatman公司，新泽西州皮斯卡塔韦， </td><td>核孔＃110605和＃110606 </td><td></td></tr><tr><td>挤出机漏光盘</td><td> Sterlitech公司，肯特，WA，USA </td><td> ＃PETEDD25100 </td><td></td></tr><tr><td>塑胶室</td><td>美国塑胶工业股份有限公司，利马，OH，USA </td><td> ＃55288，1 3/16“×1 3/16”×2 7/16“的</td><td></td></tr></tbody></table>

synthesis of phase-shift nanoemulsions with narrow size distributions for acoustic droplet vaporization and bubble-enhanced ultrasound-mediated ablation

高强度聚焦超声（HIFU）是临床上常用的热消融肿瘤。为了提高局部加热和提高热消融在肿瘤中，已经开发了脂质包衣的全氟化碳的液滴可以汽化HIFU。在许多肿瘤的血管由于其快速增长是不正常的漏水，纳米粒子能够渗透开窗和被动积聚在肿瘤。因此，控制液滴的大小，可以导致更好的肿瘤内积累。在这份报告中，稳定的液滴在与窄粒度分布的相移纳米乳（PSNE）的编制说明。 PSNE合成了在全氟化碳液体的存在下，通过超声处理的脂质溶液。一种窄的粒度分布，得到挤出PSNE多次使用与100或200 nm的孔径的过滤器。超过一个7天的期间，使用动态光散射的粒度分布测定。 Polyac在体外实验中，制备含PSNE的​​rylamide水凝胶。 PSNE的水凝胶中的液滴汽化与超声和增强局部加热产生的气泡。汽化PSNE使更多的快速加热，也减少了所需的热消融的超声波强度。因此，PSNE，预计将提高肿瘤热消融治疗中，有可能改善的高强度聚焦超声介导的热消融治疗的治疗效果。

Watch this Scientific Journal Video about Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation at Jo

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

使用高强度聚焦超声增强局部加热和改善热消融在肿瘤相移纳米乳剂（PSNE）的可以被汽化。在这份报告中，描述的窄粒度分布PSNE稳定的编制。此外，超声介导消融汽化PSNE的影响表现在组织模仿幻影。

相移窄粒度分布的纳米乳液的合成声波液滴蒸发和泡增强的超声介导消融

High-intensity  focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To  enhance localized heating and improve thermal ablation in ...

synthesis-phase-shift-nanoemulsions-with-narrow-size-distributions

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11.0K 次观看.  Boston University. 使用高强度聚焦超声增强局部加热和改善热消融在肿瘤相移纳米乳剂（PSNE）的可以被汽化。在这份报告中，描述的窄粒度分布PSNE稳定的编制。此外，超声介导消融汽化PSNE的影响表现在组织模仿幻影。

视频: Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

控制的大小，形状和稳定性超分子聚合物在水

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

科研

工程学

Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing

This paper discusses fluorescent core microcavity-based sensors that can operate in a microfluidic analysis setup. These structures are based on the formation of a fluorescent quantum-dot (QD) coating on the channel surface of a conventional microcapillary. Silicon QDs are especially attractive for this application, owing in part to their negligible toxicity compared to the II-VI and II-VI compound QDs, which are legislatively controlled substances in many countries. While the ensemble emission spectrum is broad and featureless, an Si-QD film on the channel wall of a capillary features a set of sharp, narrow peaks in the fluorescence spectrum, corresponding to the electromagnetic resonances for light trapped within the film. The peak wavelength of these resonances is sensitive to the external medium, thus permitting the device to function as a refractometric sensor in which the QDs never come into physical contact with the analyte. The experimental methods associated with the fabrication of the fluorescent-core microcapillaries are discussed in detail, as well as the analysis methods. Finally, a comparison is made between these structures and the more widely investigated liquid-core optical ring resonators, in terms of microfluidic sensing capabilities.

Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.

折光传感荧光芯微腔的合成和操作

This paper discusses  fluorescent core microcavity-based sensors that can operate in a microfluidic  analysis setup. These structures are based on the ...

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

制作三维微结构，用牺牲部分汽化过程

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains.

In this video we first describe fabrication and operation procedures of a surface acoustic wave (SAW) acoustic counterflow device. We then demonstrate an experimental setup that allows for both qualitative flow visualization and quantitative analysis of complex flows within the SAW pumping device.

制造，操作和表面声波驱动声逆流微流体流动可视化

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we ...

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The common techniques used for the size analysis are transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). These techniques, however, are not suitable for analyzing the nanocrystal size distribution in a fast, non-destructive and a reliable manner at the same time. Our aim in this work is to demonstrate that size distribution of semiconductor nanocrystals that are subject to size-dependent phonon confinement effects, can be quantitatively estimated in a non-destructive, fast and reliable manner using Raman spectroscopy. Moreover, mixed size distributions can be separately probed, and their respective volumetric ratios can be estimated using this technique. In order to analyze the size distribution, we have formulized an analytical expression of one-particle PCM and projected it onto a generic distribution function that will represent the size distribution of analyzed nanocrystal. As a model experiment, we have analyzed the size distribution of free-standing silicon nanocrystals (Si-NCs) with multi-modal size distributions. The estimated size distributions are in excellent agreement with TEM and PL results, revealing the reliability of our model.

We demonstrate how to determine the size distribution of semiconductor nanocrystals in a quantitative manner using Raman spectroscopy employing an analytically defined multi-particle phonon confinement model. Results obtained are in excellent agreement with the other size analysis techniques like transmission electron microscopy and photoluminescence spectroscopy.

使用拉曼光谱与多颗粒的声子坐月子型号纳米大小分布的特征

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

全套材料常数表征及其温度依赖性的压电材料使用共振超声波谱

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal microfluidic device. W/O microdroplets have recently been used in powerful methods that enable miniaturized chemical experiments. Therefore, developing a versatile method to yield monodisperse W/O microdroplets is needed. We have developed a method for generating monodisperse W/O microdroplets based on a capillary-based centrifugal axisymmetric co-flowing microfluidic device. We succeeded in controlling the size of microdroplets by adjusting the capillary orifice. Our method requires equipment that is easier-to-use than with other microfluidic techniques, requires only a small volume (0.1-1 &#181;l) of sample solution for encapsulation, and enables the production of hundreds of thousands number of W/O microdroplets per second. We expect this method will assist biological studies that require precious biological samples by conserving the volume of the samples for rapid quantitative analysis biochemical and biological studies.

Here, we demonstrate a simple production method for size-controllable, monodisperse, water-in-oil (W/O) microdroplets using a capillary-based centrifugal microfluidic device. This method requires only a small sample volume and enables high-yield production. We expect this method will be useful for rapid biochemical and cellular analyses.

基于毛细管的离心微流体装置单分散微滴的大小可控的形成

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal ...

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.

制造和Acoustofluidic设备的运营支撑体声波驻波的聚焦鞘颗粒

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must ...

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

We present protocols to be used in the measurement of spray droplet size from agricultural nozzles used in both aerial and ground based agrochemical applications. These methods presented were developed to provide consistent and repeatable droplet size data both inter- and intra-laboratory, when using laser diffraction systems.

从农业喷嘴采用激光衍射测量喷雾的雾滴尺寸

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to ...

A Pipette-Tip Based Method for Seeding Cells to Droplet Microfluidic Platforms

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and analyzing cells at the single-cell level by eliminating the influence of external factors on the cellular microenvironment. Encapsulation of cells in droplets is dictated by the Poisson distribution as a function of the number of cells present in each droplet and the average number of cells per volume of droplet. Primary cells, especially immune cells, or clinical specimens can be scarce and loss-less encapsulation of cells remains challenging. In this paper, we present a new methodology that uses pipette-tips to load cells to droplet-based microfluidic devices without the significant loss of cells. With various cell types , we demonstrate efficient cell encapsulation in droplets that closely corresponds to the encapsulation efficiency predicted by the Poisson distribution. Our method ensures loss-less loading of cells to microfluidic platforms and can be easily adapted for downstream single cell analysis, e.g., to decode cellular interactions between different cell types.

This article presents a protocol for seeding scarce population of cells using pipette-tips to droplet microfluidic devices in order to provide higher encapsulation efficiency of cells in droplets.

一种基于管尖的液滴微流化平台种子细胞的方法

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and ...