这项工作得到了美国国家科学基金会和先进的冷却技术批准号117041PO9621从批准号CBET-0651283。

1。制备纳米二氧化硅的沉积<ol><li>硅微粉干起，准备涂层样本，首先消除了大团聚。 </li><li>用乙醇二氧化硅微粒（直径为200纳米从凝胶Tec的公司购买）（190举证纯）洗净下通风柜与乙醇，直到所有的水分蒸发，留下样品。 </li><li>过筛颗粒通过一系列的金属网格（美国＃100-400）为了打破任何剩余的群。 </li><li>地方颗粒在管式反应器和一个小的磁力搅拌器栏， 如图1所示。颗粒应放在等离子区。 </li><li>放在两法兰，在玻璃管年底和连接到泵管O形圈密封的玻璃反应釜。 </li><li>安装法兰，并用手拧紧螺丝钳的周围围绕不锈钢夹环。 </li></ol> 2。真空系统的制备<ol><li>填充液氮陷阱，然后让表面的陷阱，成为冷。等待5分钟。 </li><li>在起泡添加异丙醇和连接到等离子体反应器。 </li><li>周围放置金属管橡胶O形圈密封起泡和起泡器连接螺母拧紧，直到管的地方变得密封。 </li></ol> 3。等离子体沉积过程<ol><li>放置在水浴温度为34±2°C的起泡</li><li>打开氩气流量控制器和输入设定点为6.00 SCCM。 </li><li>逐渐打开闸阀，玻璃管连接到泵泵工作时。认真执行这一步，因为压力突然下降，可能会导致颗粒流被风吹走。等到压力达到200毫托，然后离开闸阀全开。 </li><li>玻璃管置于磁力搅拌器，并设置速度为100 r下午。 </li><li>周围的管状玻璃反应器的无线电频率，射频发生器连接的铝圈和不锈钢钳连接到地面。 </li><li>匹配网络（埃尼MW-5D），然后切换的电源线和射频发生器电源的开启。设置在整个过程为30 W的功率。 </li><li>后关闭匹配网络的时间（10，20或40分钟），射频信号发生器，交流电源的具体时间。 </li><li>关闭单向阀，然后关闭氩气流量控制器。断开阀鼓泡和反应堆压力逐渐增加，大气。 </li><li>打开夹子，从管的粒子转移到塑料盘使用金属铲。 </li></ol> 4。解散芯材中空粒子的制备<ol><li>置于通风柜的整个过程中添加氢氟酸的样品。 </li><li>氢氟酸是一种极其合作rrosive酸和它的眼睛和皮肤的接触，可能会造成永久性的损害。使用护目镜，面罩和处理高频时穿实验室外套。 </li><li>氢氟酸（Aldrich公司占49％）10毫升与10毫升去离子水混合，并添加到包含包覆颗粒的塑料盘。 </li><li>塑料盘放在磁力搅拌器，并允许为核心，以24小时溶解。 </li><li>一天后，50毫升的去离子水稀释样品和样品离心1小时。丢弃在一个塑料容器在顶部的液体层和传输底层包含的粒子在塑料培养皿。 </li><li>加入50毫升去离子水和旋涡的样品，并再次离心。处置和转移的一个干净的培养皿中的颗粒层的顶层。 </li><li>的粒子用乙醇洗净，风干样品，并转移到一小瓶空心颗粒帽和保持颗粒在干燥器。 </li></ol> 5。甜心的的渗透cterization（核心发行利率） 材料:氯化钾为核心材料<ol><li> 0.001摩尔氯化钾（KCl）溶液混合0.0745克1升去离子水，氯化钾准备。 </li><li>恒定输出雾化器模型3076填充的玻璃瓶，安装瓶盖。 </li><li>连接压缩空气软管膜烘干机，雾化器连接到进气口。然后附加一个过滤器的出口软管，以收集氯化钾纳米粒子。 </li><li>逐渐打开压缩空气阀，并通过膜干燥器让空气流通。允许颗粒积聚在过滤器为5小时。 </li><li>关闭压缩空气阀，并小心地取出过滤器和收集的颗粒。置于干燥器中的粒子之前的涂层工艺。 </li><li>按照协议，2和3以获得氯化钾颗粒均匀涂布。 </li><li>混合涂层氯化钾10毫升去离子WA之三，在一个玻璃小瓶。为了充分混合样品，放入溶液磁力搅拌器，磁力搅拌器离开。在25°C孵育样品</li><li>电导率仪探头（热猎户座模型105）插入小瓶和记录超过30天的电导率。 </li></ol> 6。代表结果我们已经申请了这个过程的核心材料的品种，包括氧化物（二氧化硅），盐（氯化钾）和金属（铝）， 如图2所示。透射电子显微镜已被用来确认径向均匀薄膜，并测量其厚度。我们有成功包覆颗粒范围从37纳米到200纳米的直径（ 图2），但可以用这种方法处理的颗粒大小基本没有限制。壳沉积率大约为1海里/分钟。这相当缓慢的速度，使得它可以控制薄膜的厚度相当准确地通过沉积时间。等离子体聚合壳是一个渗透屏障，作为核心材料可以删除蚀刻或解散的事实证明。 图3显示了仍然硅芯被删除后的空壳。去除的核心是完整​​的和径向均匀性和薄膜的厚度相当高。通过这些薄膜的透气性评估的目的，我们交换为核心的材料氯化钾氯化钾解体以来，可以监视通过离子导电性的解决方案很容易。 图4显示了从核心的氯化钾4个样品的释放厚度不同，20纳米，40纳米，75纳米，95纳米，分别。涂层氯化钾颗粒悬浮在水中，溶液的电导率，为期30天。除了四个样品，未涂布氯化钾颗粒组成的控制也被监控。胶版纸解离氯化钾颗粒绿萼在很短的时间约1分钟。相比之下，氯化钾涂层显示了显着的释放速度较慢。包覆颗粒释放的特点是由最初爆发的第一个小时内的地方，其次要慢得多的版本，需要数天才能完成，取决于薄膜的厚度。 <img alt="图1" src="/files/ftp_upload/4113/4113fig1.jpg" /> 图1。制备纳米粒子，等离子体沉积和空心粒子形成的示意图表示。 <img alt="图2" src="/files/ftp_upload/4113/4113fig2.jpg" /> 图2。涂层的TEM照片（一），（二）与d的二氧化硅微粒= 200纳米（C），D = 37纳米的二氧化硅粒子，（四）与d〜100 nm的铝，及（e）氯化钾颗粒D = 100 nm的<img alt="图3" src="/files/ftp_upload/4113/4113fig3.jpg" /> 图3，TEM后蚀刻（一），（b）与硅芯直径为200 nm，（三）氯化钾的核心空心颗粒的图像。 <img alt="图4" src="/files/ftp_upload/4113/4113fig4.jpg" /> 图4。释放壳厚度的影响。插图图显示了在第一个小时释放。

<ol>
	<li>Xu, X., Asher, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Utilization+of+Monodisperse+Hollow+Polymeric+Particles+in+Photonic+Crystals.">Synthesis and Utilization of Monodisperse Hollow Polymeric Particles in Photonic Crystals.</a> Journal of the American Chemical Society. 126, 7940-7945 (2004).</li><li>Lou, X., Archer, L., Yang, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hollow+Micro-/nanostructures:+Synthesis+and+Applications.">Hollow Micro-/nanostructures: Synthesis and Applications.</a> Advanced Material. 20, (2008).</li><li>Kim, D. J., Kang, J. Y., Kim, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coating+of+TiO2+Thin+Films+on+Particles+by+a+Plasma+Chemical+Vapor+Deposition+Process.">Coating of TiO2 Thin Films on Particles by a Plasma Chemical Vapor Deposition Process.</a> Advanced Powder Technology. 21, 136-140 (2010).</li><li>Marino, E., Huijser, T., Creyghton, Y., van der Heijden, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Coating+of+Copper+Oxide+Nanoparticles+Using+Atmospheric+Pressure+Plasmas.">Synthesis and Coating of Copper Oxide Nanoparticles Using Atmospheric Pressure Plasmas.</a> Surface and Coatings Technology. 201, 9205-9208 (2007).</li><li>Hakim, L., King, D., Zhou, Y., Gump, C., George, S., Weimer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoparticle+Coating+for+Advanced+Optical,+Mechanical+and+Rheological+Properties.">Nanoparticle Coating for Advanced Optical, Mechanical and Rheological Properties.</a> Advanced Functional Materials. 17, 3175-3181 (2007).</li><li>Kim, S. H., Kim, J., Kang, B., Uhm, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superhydrophobic+CFx+Coating+via+In-Line+Atmospheric+RF+Plasma+of+He-CF4-H2.">Superhydrophobic CFx Coating via In-Line Atmospheric RF Plasma of He-CF4-H2.</a> Langmuir. 21, 12213-12217 (2005).</li></ol>

没有利益冲突的声明。

纳米涂层的最大挑战之一是提供一个兼容的化学涂层与基体1,2之间。这里描述的方法的优点是，它不是特定材料。等离子聚合物表明对各种基材，包括硬质金属（ 图2（c）条 ），硅胶（ 图2（c）），硅或软质材料（如聚合物）优异的附着力，而不需要任何特殊的表面改性3 4,5。该技术具有更大的优势，它不是由核心颗粒大小的限制，并在纳米和微米范围?...

<table border="1"><tbody><tr><td>二氧化硅微粒</td><td> geltech公司</td><td></td><td></td></tr><tr><td>氯化钾（晶体） </td><td>电解二氧化锰化学品公司</td><td></td><td></td></tr><tr><td>异丙醇（99.9％） </td><td> Sigma-Aldrich公司</td><td></td><td></td></tr><tr><td>氢氟酸（48-51％） </td><td>厂商VWR </td><td></td><td></td></tr><tr><td>管道和法兰</td><td>世伟洛克</td><td></td><td> ¼直径1英寸</td></tr><tr><td>粗加工泵</td><td>爱德华兹</td><td></td><td></td></tr><tr><td>液氮陷阱</td><td>及ñ公司的</td><td></td><td></td></tr></tbody></table>

encapsulation and permeability characteristics of plasma polymerized hollow particles

在这个协议中，核壳纳米结构的等离子体增强化学气相沉积合成。我们生产各种固体物质，包括二氧化硅和氯化钾异丙醇等离子体聚合非晶屏障。这种多用途的技术被用来治疗范围从37纳米到1微米大小的纳米粒子和纳米粉体，沉积的薄膜，其厚度可以在任何地方从1纳米到100纳米以上。解散的核心，让我们学习的渗透通过薄膜的速率。在这些实验中，我们确定氯化钾通过阻隔膜的扩散系数涂层氯化钾纳米随后监测包覆颗粒悬浮在水中的离子电导率。在这个过程中的主要兴趣是溶质的封装和缓释。壳的厚度是由我们控制释放速率的独立变量之一。它具有强效率释放，从而增加了六个小时的释放（壳厚度为20 nm）到30天以上的长期释放（壳厚度为95纳米）。释放曲线显示了特有的行为:在前五分钟开始解散后，慢释放所有的核心材料，才最终材料（35％）快速释放出来。

Watch this Scientific Journal Video about Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles at JoVE.com

Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

我们已经用等离子体增强化学气相沉积存入范围从几纳米到几100对各种材料的纳米粒子的纳米薄膜。我们随后蚀刻的核心原料生产空心球壳，其渗透壳的厚度控制。我们描述了这些涂料的透气性小分子，并证明这些障碍可以提供数天的核心材料的缓释。

等离子体聚合空心颗粒的封装和渗透特征

In this protocol, core-shell nanostructures are synthesized by plasma enhanced chemical vapor deposition. We produce an amorphous barrier by plasma ...

encapsulation-permeability-characteristics-plasma-polymerized-hollow

Universidad de Cartagena UDEC

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Permeability of Concrete

SCIENTISTS IN ACTION

10.7K 次观看.  The Pennsylvania State University. 我们已经用等离子体增强化学气相沉积存入范围从几纳米到几100对各种材料的纳米粒子的纳米薄膜。我们随后蚀刻的核心原料生产空心球壳，其渗透壳的厚度控制。我们描述了这些涂料的透气性小分子，并证明这些障碍可以提供数天的核心材料的缓释。

视频: Encapsulation and Permeability Characteristics of Plasma Polymerized Hollow Particles

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

对磷酸增强富集制备高度多孔配位聚合物涂层的孔聚合物石柱的

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

科研

化学

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

制备及个体表征和多载药物理截留聚合物胶束

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

High Throughput Single-cell and Multiple-cell Micro-encapsulation

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement from a bulk fluid environment with applications in high throughput screening, cytometry, and mass spectrometry. We describe a method to not only encapsulate single cells, but to repeatedly capture a set number of cells (here we demonstrate one- and two-cell encapsulation) to study both isolation and the interactions between cells in groups of controlled sizes. By combining drop generation techniques with cell and particle ordering, we demonstrate controlled encapsulation of cell-sized particles for efficient, continuous encapsulation. Using an aqueous particle suspension and immiscible fluorocarbon oil, we generate aqueous drops in oil with a flow focusing nozzle. The aqueous flow rate is sufficiently high to create ordering of particles which reach the nozzle at integer multiple frequencies of the drop generation frequency, encapsulating a controlled number of cells in each drop. For representative results, 9.9 &mu;m polystyrene particles are used as cell surrogates. This study shows a single-particle encapsulation efficiency Pk=1 of 83.7% and a double-particle encapsulation efficiency Pk=2 of 79.5% as compared to their respective Poisson efficiencies of 39.3% and 33.3%, respectively. The effect of consistent cell and particle concentration is demonstrated to be of major importance for efficient encapsulation, and dripping to jetting transitions are also addressed. 
Introduction 
Continuous media aqueous cell suspensions share a common fluid environment which allows cells to interact in parallel and also homogenizes the effects of specific cells in measurements from the media. High-throughput encapsulation of cells into picoliter-scale drops confines the samples to protect drops from cross-contamination, enable a measure of cellular diversity within samples, prevent dilution of reagents and expressed biomarkers, and amplify signals from bioreactor products. Drops also provide the ability to re-merge drops into larger aqueous samples or with other drops for intercellular signaling studies.1,2 The reduction in dilution implies stronger detection signals for higher accuracy measurements as well as the ability to reduce potentially costly sample and reagent volumes.3 Encapsulation of cells in drops has been utilized to improve detection of protein expression,4 antibodies,5,6 enzymes,7 and metabolic activity8 for high throughput screening, and could be used to improve high throughput cytometry.9 Additional studies present applications in bio-electrospraying of cell containing drops for mass spectrometry10 and targeted surface cell coatings.11 Some applications, however, have been limited by the lack of ability to control the number of cells encapsulated in drops. Here we present a method of ordered encapsulation12 which increases the demonstrated encapsulation efficiencies for one and two cells and may be extrapolated for encapsulation of a larger number of cells.
To achieve monodisperse drop generation, microfluidic "flow focusing" enables the creation of controllable-size drops of one fluid (an aqueous cell mixture) within another (a continuous oil phase) by using a nozzle at which the streams converge.13 For a given nozzle geometry, the drop generation frequency f and drop size can be altered by adjusting oil and aqueous flow rates Qoil and Qaq. As the flow rates increase, the flows may transition from drop generation to unstable jetting of aqueous fluid from the nozzle.14 
When the aqueous solution contains suspended particles, particles become encapsulated and isolated from one another at the nozzle. For drop generation using a randomly distributed aqueous cell suspension, the average fraction of drops Dk containing k cells is dictated by Poisson statistics, where Dk = &lambda;k exp(-&lambda;)/(k!) and &lambda; is the average number of cells per drop. The fraction of cells which end up in the "correctly" encapsulated drops is calculated using Pk = (k x Dk)/&Sigma;(k' x Dk'). The subtle difference between the two metrics is that Dk relates to the utilization of aqueous fluid and the amount of drop sorting that must be completed following encapsulation, and Pk relates to the utilization of the cell sample. As an example, one could use a dilute cell suspension (low &lambda;) to encapsulate drops where most drops containing cells would contain just one cell. While the efficiency metric Pk would be high, the majority of drops would be empty (low Dk), thus requiring a sorting mechanism to remove empty drops, also reducing throughput.15
Combining drop generation with inertial ordering provides the ability to encapsulate drops with more predictable numbers of cells per drop and higher throughputs than random encapsulation. Inertial focusing was first discovered by Segre and Silberberg16 and refers to the tendency of finite-sized particles to migrate to lateral equilibrium positions in channel flow. Inertial ordering refers to the tendency of the particles and cells to passively organize into equally spaced, staggered, constant velocity trains. Both focusing and ordering require sufficiently high flow rates (high Reynolds number) and particle sizes (high Particle Reynolds number).17,18 Here, the Reynolds number Re =uDh/&nu; and particle Reynolds number Rep =Re(a/Dh)2, where u is a characteristic flow velocity, Dh [=2wh/(w+h)] is the hydraulic diameter, &nu; is the kinematic viscosity, a is the particle diameter, w is the channel width, and h is the channel height. Empirically, the length required to achieve fully ordered trains decreases as Re and Rep increase. Note that the high Re and Rep requirements (for this study on the order of 5 and 0.5, respectively) may conflict with the need to keep aqueous flow rates low to avoid jetting at the drop generation nozzle. Additionally, high flow rates lead to higher shear stresses on cells, which are not addressed in this protocol. The previous ordered encapsulation study demonstrated that over 90% of singly encapsulated HL60 cells under similar flow conditions to those in this study maintained cell membrane integrity.12 However, the effect of the magnitude and time scales of shear stresses will need to be carefully considered when extrapolating to different cell types and flow parameters. The overlapping of the cell ordering, drop generation, and cell viability aqueous flow rate constraints provides an ideal operational regime for controlled encapsulation of single and multiple cells.
Because very few studies address inter-particle train spacing,19,20 determining the spacing is most easily done empirically and will depend on channel geometry, flow rate, particle size, and particle concentration. Nonetheless, the equal lateral spacing between trains implies that cells arrive at predictable, consistent time intervals. When drop generation occurs at the same rate at which ordered cells arrive at the nozzle, the cells become encapsulated within the drop in a controlled manner. This technique has been utilized to encapsulate single cells with throughputs on the order of 15 kHz,12 a significant improvement over previous studies reporting encapsulation rates on the order of 60-160 Hz.4,15 In the controlled encapsulation work, over 80% of drops contained one and only one cell, a significant efficiency improvement over Poisson (random) statistics, which predicts less than 40% efficiency on average.12
In previous controlled encapsulation work,12 the average number of particles per drop &lambda; was tuned to provide single-cell encapsulation. We hypothesize that through tuning of flow rates, we can efficiently encapsulate any number of cells per drop when &lambda; is equal or close to the number of desired cells per drop. While single-cell encapsulation is valuable in determining individual cell responses from stimuli, multiple-cell encapsulation provides information relating to the interaction of controlled numbers and types of cells. Here we present a protocol, representative results using polystyrene microspheres, and discussion for controlled encapsulation of multiple cells using a passive inertial ordering channel and drop generation nozzle.

Combining monodisperse drop generation with inertial ordering of cells and particles, we describe a method to encapsulate a desired number of cells or particles in a single drop at kHz rates. We demonstrate efficiencies twice exceeding those of unordered encapsulation for single- and double-particle drops.

高吞吐量的单细胞和多细胞微胶囊

Microfluidic encapsulation methods have been previously utilized to capture cells in picoliter-scale aqueous, monodisperse drops, providing confinement ...

生物工程

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

纳米粒子 - 聚合物复合材料使用直接荧光成像的先进成分分析

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

工程学

PLGA Nanoparticles Formed by Single- or Double-emulsion with Vitamin E-TPGS

Poly(lactic-co-glycolic acid) (PLGA) is a biocompatible member of the aliphatic polyester family of biodegradable polymers. PLGA has long been a popular choice for drug delivery applications, particularly since it is already FDA-approved for use in humans in the form of resorbable sutures. Hydrophobic and hydrophilic drugs are encapsulated in PLGA particles via single- or double-emulsion. Briefly, the drug is dissolved with polymer or emulsified with polymer in an organic phase that is then emulsified with the aqueous phase. After the solvent has evaporated, particles are washed and collected via centrifugation for lyophilization and long term storage. PLGA degrades slowly via hydrolysis in aqueous environments, and encapsulated agents are released over a period of weeks to months. Although PLGA is a material that possesses many advantages for drug delivery, reproducible formation of nanoparticles can be challenging; considerable variability is introduced by the use of different equipment, reagents batch, and precise method of emulsification. Here, we describe in great detail the formation and characterization of microparticles and nanoparticles formed by single- or double-emulsion using the emulsifying agent vitamin E-TPGS. Particle morphology and size are determined with scanning electron microscopy (SEM). We provide representative SEM images for nanoparticles produced with varying emulsifier concentration, as well as examples of imaging artifacts and failed emulsifications. This protocol can be readily adapted to use alternative emulsifiers (e.g. poly(vinyl alcohol), PVA) or solvents (e.g.&#160;dichloromethane, DCM).

We describe the production and characterization of nanoparticles and microparticles composed of poly(lactic-co-glycolic acid) using vitamin E-TPGS as an emulsifier. By varying formulation parameters such as the concentration of emulsifier, it is possible to produce nanoparticles with mean diameters ranging from 220 nm to&#160;1.98 &#181;m.

Poly(lactic-co-glycolic acid) (PLGA) is a biocompatible member of the aliphatic polyester family of biodegradable polymers. PLGA has long been a popular ...

Preparation of Plasma Membrane Vesicles from Bone Marrow Mesenchymal Stem Cells for Potential Cytoplasm Replacement Therapy

We have previously reported on the generation of plasma membrane vesicles (PMVs) through the mechanical extrusion of mammalian cells. The fusion of PMVs with mitochondrial deficient Rho0 cells restored mitotic activity under normal culture conditions. Atherosclerosis, type 2 diabetes, Alzheimer&#39;s disease, and cancer are age-related diseases that have been reported to be associated with multiple mechanical and functional defects in the cytosol and organelles of a variety of cell types. Bone marrow mesenchymal stem cells (BMSCs) represent a unique cell population from the bone marrow that possess self-renewal capabilities while maintaining their multipotency. The supplementation of senescence cells with young cytoplasm from autologous BMSCs via the fusion of PMVs provides a promising approach to ameliorate or even reverse age-associated phenotypes. This protocol describes how to prepare PMVs from BMSCs via extrusion through a polycarbonate membrane with 3 &#181;m pores, determine the existence of mitochondria and examine the maintenance of membrane potential within PMVs using a confocal microscope, concentrate PMVs by centrifugation, and carry out the in vivo injection of PMVs into the gastrocnemius muscle of mice.

Age-related diseases are associated with multiple defects in components of the cytoplasm. Here, we present a protocol to prepare plasma membrane vesicles from bone marrow mesenchymal stem cells. This technique could potentially be used as a means of cytoplasm replacement therapy to ameliorate or even reverse age-associated phenotypes.

从骨髓间充质干细胞制备血浆膜囊泡用于潜在的细胞质替代治疗

We have previously reported on the generation of plasma membrane vesicles (PMVs) through the mechanical extrusion of mammalian cells. The fusion of PMVs ...

发育生物学

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) and fluorocarbon oil (perfluoro-n-octane, PFO) in aqueous surfactant (sodium dodecylsulfate, SDS) solutions. Since fluorocarbon oils are immiscible with hydrocarbon oils, the two oils are separated. Emulsions are prepared by stirring styrene/PFO/aqueous SDS solution mixtures at 80 &#176;C. The type of emulsions and the morphology of droplets in the emulsions are observed by light microscope and scanning confocal fluorescence microscope. It is found that oil droplets with Janus-type morphologies consisting of mutually immiscible styrene and PFO are formed in aqueous SDS solutions. Polystyrene particles are fabricated by radical polymerization of the ternary mixtures of styrene/PFO/aqueous SDS solution at 80 &#176;C. The morphologies of the polystyrene are confirmed by scanning electron microscopy and scanning transmission electron microscopy observations. These observations show the preparation of hollow polystyrene particles with a single hole on the surface. To our knowledge, this method is a novel strategy using the immiscibility of hydrocarbon and fluorocarbon oils. The hollow particles can also be applied to the preparation of microcapsules.

A protocol for the fabrication of hollow polymer particles and microcapsules by radical polymerization using emulsions consisting of styrene, perfluoro-n-octane, and aqueous SDS (sodium dodecylsulfate) solution is presented.

由烃类和氟碳油组成的同液滴的自由基聚合制备空心聚苯乙烯颗粒和微胶囊

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g.&#160;polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed.

A plasma-induced polymerization procedure is described for the surface-initiated polymerization on polymer membranes. Further postmodification of the grafted polymer with photochromic substances is presented with a protocol of conducting permeability measurements of light-responsive membranes.

通过结合表面接枝和修改后的过程光敏感膜的制备

In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is ...

Cellular Encapsulation in 3D Hydrogels for Tissue Engineering 

The 3D encapsulation of cells within hydrogels represents an increasingly important and popular technique for culturing cells and towards the development of constructs for tissue engineering. This environment better mimics what cells observe in vivo, compared to standard tissue culture, due to the tissue-like properties and 3D environment. Synthetic polymeric hydrogels are water-swollen networks that can be designed to be stable or to degrade through hydrolysis or proteolysis as new tissue is deposited by encapsulated cells. A wide variety of polymers have been explored for these applications, such as poly(ethylene glycol) and hyaluronic acid. Most commonly, the polymer is functionalized with reactive groups such as methacrylates or acrylates capable of undergoing crosslinking through various mechanisms. In the past decade, much progress has been made in engineering these microenvironments - e.g., via the physical or pendant covalent incorporation of biochemical cues - to improve viability and direct cellular phenotype, including the differentiation of encapsulated stem cells (Burdick et al.).
The following methods for the 3D encapsulation of cells have been optimized in our and other laboratories to maximize cytocompatibility and minimize the number of hydrogel processing steps. In the following protocols (see Figure 1 for an illustration of the procedure), it is assumed that functionalized polymers capable of undergoing crosslinking are already in hand; excellent reviews of polymer chemistry as applied to the field of tissue engineering may be found elsewhere (Burdick et al.) and these methods are compatible with a range of polymer types. Further, the Michael-type addition (see Lutolf et al.) and light-initiated free radical (see Elisseeff et al.) mechanisms focused on here constitute only a small portion of the reported crosslinking techniques. Mixed mode crosslinking, in which a portion of reactive groups is first consumed by addition crosslinking and followed by a radical mechanism, is another commonly used and powerful paradigm for directing the phenotype of encapsulated cells (Khetan et al., Salinas et al.).

Cellular Encapsulation in 3D Hydrogels for Tissue Engineering

We present protocols for the 3-dimensional (3D) encapsulation of cells within synthetic hydrogels. The encapsulation procedure is outlined for two commonly used methods of crosslinking (michael-type addition and light-initiated free radical mechanisms), as well as a number of techniques for assessing encapsulated cell behavior.

组织工程细胞在三维凝胶封装

The 3D encapsulation of cells within hydrogels represents an increasingly important and popular technique for culturing cells and towards the development ...

生物学

Assembly and Characterization of Polyelectrolyte Complex Micelles

Polyelectrolyte complex micelles (PCMs), core-shell nanoparticles formed by self-assembly of charged polymers in aqueous solution, provide a powerful platform for exploring the physics of polyelectrolyte interactions and also offer a promising solution to the pressing problem of delivering therapeutic oligonucleotides in vivo. Developing predictive structure-property relationships for PCMs has proven difficult, in part due to the presence of strong kinetic traps during nanoparticle self-assembly. This article discusses criteria for choosing polymers for PCM construction and provides protocols based on salt annealing that enable assembly of repeatable, low-polydispersity nanoparticles. We also discuss PCM characterization using light scattering, small-angle X-ray scattering, and electron microscopy.

We provide protocols and representative data for designing, assembling, and characterizing polyelectrolyte complex micelles, core-shell nanoparticles formed by polyelectrolytes and hydrophilic charged-uncharged block copolymers.

聚电解质复合微晶体的组装与特性

Polyelectrolyte complex micelles (PCMs), core-shell nanoparticles formed by self-assembly of charged polymers in aqueous solution, provide a powerful ...