我们承认L. Brino（IGBMC高内涵筛选设备，伊尔基希，法国）为我们提供了抗Giantin抗体，M. Labouesse实验室。为C.线虫 （IGBMC）和B塞拉芬实验室。对芽殖酵母（IGBMC），E帕卢赫和A.海曼荧光灯HeLa细胞（MPI-CBG，德累斯顿），J·莫斯利（达特茅斯医学院）和JQ吴（俄亥俄州立大学）的裂殖酵母细胞; A.饭店Hoel和F Evenou实验的帮助下，里克C.（IBMC，斯特拉斯堡，法国）的技术的帮助下，和JC JEANNOT（飞秒日，法国）在微细的帮助。这项工作是由来自法国国家科学研究中心，斯特拉斯堡大学，Conectus资金的支持，拉基金会倒拉RECHERCHE MEDICALE和斯特拉斯堡的CI-FRC。

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Y., Bartfai, T., Kim, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+promise+of+single-cell+sequencing.">The promise of single-cell sequencing.</a> Nat Meth. 11, 25-27 (2014).</li><li>Allen, T. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+cell-free+extracts+of+Xenopus+eggs+and+demembranated+sperm+chromatin+for+the+assembly+and+isolation+of+in+vitro-formed+nuclei+for+Western+blotting+and+scanning+electron+microscopy+(SEM).">Generation of cell-free extracts of Xenopus eggs and demembranated sperm chromatin for the assembly and isolation of in vitro-formed nuclei for Western blotting and scanning electron microscopy (SEM).</a> Nat. Protocols. 2, 1173-1179 (2007).</li><li>Robbins, E., Marcus, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitotically+Synchronized+Mammalian+Cells:+a+Simple+Method+for+Obtaining+Large+Populations.">Mitotically Synchronized Mammalian Cells: a Simple Method for Obtaining Large Populations.</a> Science. 144, (1964).</li><li>Whitfield, M. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem-loop+binding+protein,+the+protein+that+binds+the+3&amp;#34;+end+of+histone+mRNA,+is+cell+cycle+regulated+by+both+translational+and+posttranslational+mechanisms.">Stem-loop binding protein, the protein that binds the 3&amp;#34; end of histone mRNA, is cell cycle regulated by both translational and posttranslational mechanisms.</a> Molecular and Cellular Biology. 20, (2000).</li><li>Straight, A. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissecting+Temporal+and+Spatial+Control+of+Cytokinesis+with+a+Myosin+II+Inhibitor.">Dissecting Temporal and Spatial Control of Cytokinesis with a Myosin II Inhibitor.</a> Science. 299, 1743-1747 (2003).</li><li>Tang, J., Erikson, R. L., Liu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Checkpoint+kinase+1+(Chk1)+is+required+for+mitotic+progression+through+negative+regulation+of+polo-like+kinase+1+(Plk1).">Checkpoint kinase 1 (Chk1) is required for mitotic progression through negative regulation of polo-like kinase 1 (Plk1).</a> Proc Natl Acad Sci. 103, 11964-11969 (2006).</li><li>Zahreddine, H., Zhang, H., Diogon, M., Nagamatsu, Y., Labouesse, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CRT-1/Calreticulin+and+the+E3+Ligase+EEL-1/HUWE1+Control+Hemidesmosome+Maturation+in+C.+elegans+Development.">CRT-1/Calreticulin and the E3 Ligase EEL-1/HUWE1 Control Hemidesmosome Maturation in C. elegans Development.</a> Curr Biol. 20, 322-327 (2010).</li><li>Porta-de-la-Riva, M., Fontrodona, L., Villanueva, A., Ceron, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Basic+Caenorhabditis+elegans+Methods:+Synchronization+and+Observation.">Basic Caenorhabditis elegans Methods: Synchronization and Observation.</a> JoVE. , e4019 (2012).</li><li>Saha, S., Pollard, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anillin-related+protein+Mid1p+coordinates+the+assembly+of+the+cytokinetic+contractile+ring+in+fission+yeast.">Anillin-related protein Mid1p coordinates the assembly of the cytokinetic contractile ring in fission yeast.</a> Mol Biol Cell. 23, 3982-3992 (2012).</li><li>Prestwich, G. 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我们什么都没有透露。

副本成形，为了制造"eggcups"使用。的制造过程中不需要清洁室;它是容易和简单，但也有一些实践可能是需要的。具体地，释放PDMS压模是为了生产高品质&#39;eggcups&#39;的一个大的面积中最关键的步骤。由于这个原因，特别小心在这一步骤才能作出。如果这一步失败反复，考虑到优化之前的硅烷化和等离子结合等离子清洗机的参数。硅烷化不足，会导致邮票的PDMS膜粘着强。如果发生此种情况，培养?...

当前在体外基于细胞的测定是二维（2D）。这种构造是不自然的哺乳动物细胞，因此不是生理有关1;细胞显示的形状，大小和异构表型的多样性。当应用于筛选应用，如平面和细胞器的极端的表型（应力纤维，特别是）内的无序分布它们呈现额外严重的局限性。这是在药物测试，在高预算每年花在临床试验尤为重要。当因为在药物筛选的初期阶段人工2D培养条件适用于动物模型大多数这些药物​​虽然失败。另外，通过使用这种方法，具体细胞器无法正常显现，如细胞有丝分裂期间cytokinetic肌动球蛋白环，一般认为是在平面垂直演进到观察平面结构。一些新的二维测定人为了克服上述缺点和重要的见解上细胞骨架组织已经观察到2,3被提出。但是，这些检测仍然存在一个严重的局限性:细胞表现出非常价差表型相反的是， 在体内 ，其中细胞呈现出3D架构观察。与培养法相关的这些文物可能引发非生理功能，如增强的应力纤维1,4,5。 时相比2D环境6,7-三维细胞培养测定提供多个优点。它们是生理上更相关的，并且结果是因此有意义。作为一个例子，嵌在水凝胶细胞显示3D状结构，但它们的形态从一个小区的不同而不同8,9。然而，它们的形态从一个小区到另一个，其中筛选应用复杂不同。另一种策略是嵌入单细胞微制造的腔10,11。然后细胞位置，形状，极性和内部细胞组织可以成为标准化。除了 ​​提供类似3D的架构，细胞，微腔还允许高内涵筛选研究10,12-14;单电池可以订购成微阵列和细胞器和它们的演进可以并行进行观察。这个规律提供了较低的细胞数量和更好的时间/空间分辨率良好的统计数据。有用的化合物是更容易识别可靠。 在这项研究中，我们显示了高内涵筛选应用10,12,13制作和全新的3D般的单细胞培养系统中的应用。该装置由弹性微腔（10 5腔/厘米2），创造&#39;eggcups"（EC）的阵列。在这项工作中的尺寸和EC的总体积进行优​​化，个人NIH3T3细胞和HeLa细胞的典型体积在细胞分裂过程。圆柱形 - - 腔形态被选择为活动进程的可视化的正确东方细胞形状。复制品成型用于图案EC的阵列上附着在玻璃的薄聚二甲基硅氧烷（PDMS）层盖玻片15,16。细胞通过离心在欧盟出台。我们在2D使用相同的细胞相比在这里报告的观察和三维（EC）细胞器（应力纤维，高尔基体和胞核）正常化（平）表面。我们还报告，积极动力过程的观察，如cytokinetic肌动球蛋白环的细胞有丝分裂过程中17封。最后，我们表明与刚性壁，如出芽酵母，裂殖酵母和C的其它系统这种方法的结果线虫胚胎这证实了我们的方法是否适用于广泛的模型系统。 接下来我们提出一个详细而详尽的protocol为了制造和应用三维微细加工的"eggcups"。我们的方法是简单，并不需要一个干净的房间。我们预计，这一新方法将成为药物筛选试验和个性化的医学特别有意思，在更换培养皿。最后，我们的设备将用于癌症18或在基础研究19研究的细胞响应的分布对外部刺激，例如有用。

ordering single cells and single embryos in 3d confinement: a new device for high content screening

生物细胞通常在平面（2D）表面观察。这种条件是不生理和表型和形状是高度可变的。根据在这种环境中的细胞筛选具有因而严重的局限性:细胞器显示极端的表型，细胞形态和尺寸是异质和/或特定的细胞器无法正确显示。此外， 在体内细胞位于3D环境;在这种情况下，细胞表现出不同的表型的，主要是因为它们与组织的周围的细胞外基质相互作用的。为了标准化和产生单个细胞中对基于细胞的测定生理相关的3D环境的次序，我们在这里报告的装置的用于体外三维细胞培养物的微加工和应用。此装置由微腔的2D阵列（通常是10 5的空腔/厘米2）中 ，填充有单细胞或胚胎。细胞POSI化，形状，极性和内部细胞组织变得那么标准化呈现出3D架构。我们使用复制品成型图案的微腔的阵列，&#39;eggcups&#39;，到薄聚二甲基硅氧烷（PDMS）粘附在盖玻片层。腔体上布满了纤维连接蛋白更容易粘附。细胞通过离心插入。填充百分比为每个系统允许高达80％的最优化。细胞和胚胎存活率证实。我们应用此方法对细胞器，如细胞核和高尔基体的可视化，并研究活动进程，如cytokinetic环的细胞有丝分裂期间的关闭。该器件允许cytokinetic闭环和压实表型的高尔基体细胞核对准期间的新功能，如周期性积累和肌球蛋白和肌动蛋白的不均匀性的鉴定。我们的特点的方法哺乳动物细胞，裂殖酵母，芽殖酵母，C.线虫 W¯¯在每种情况下i个具体的适应。最后，该装置的特性使得它特别有趣的药物筛选测定法和个性化的药物。

该&#39;eggcups&#39;（EC）是一种新型的高含量筛选方法，它允许导向细胞和胚胎的可视化在3D环境。此外，某些细胞过程，这是很难在标准2D（平面）培养物来观察，可以通过这种新的方法观察到的。 图1a显示了EC微细加工步骤的概要（参见章节1中的上述协议）。该方法简便，快捷，高效，无需特殊设备的任何要求。 图1b和1c显示了一个大型的图片和"eggcups"分别放...

Watch this Scientific Journal Video about Ordering Single Cells and Single Embryos in 3D Confinement: A New Device for High Content Screening at JoVE.com

Ordering Single Cells and Single Embryos in 3D Confinement: A New Device for High Content Screening

我们报告的设备和新的方法来研究细胞和胚胎。单细胞精确下令微阵列。他们的3D坐月子是朝着在生理条件下遇到的3D环境的一个步骤，并允许细胞器的方向。通过控制细胞的形状，此设置最大限度地减少可变性中的标准试验的报道。

订货单细胞和单胚胎的三维约束:高内涵筛选新设备

Biological cells are usually observed on flat (2D) surfaces. This condition is not physiological, and phenotypes and shapes are highly variable. Screening ...

ordering-single-cells-single-embryos-3d-confinement-new-device-for

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

8.5K 次观看.  Institut de Science et d'Ingénierie Supramoléculaires (ISIS), CNRS and Université de Strasbourg. 我们报告的设备和新的方法来研究细胞和胚胎。单细胞精确下令微阵列。他们的3D坐月子是朝着在生理条件下遇到的3D环境的一个步骤，并允许细胞器的方向。通过控制细胞的形状，此设置最大限度地减少可变性中的标准试验的报道。 

视频: Ordering Single Cells and Single Embryos in 3D Confinement: A New Device for High Content Screening

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 ...

科研

生物工程

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 ...

A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this purpose, the cells are passively trapped in the middle of a microchamber. Upon activation of the control layer, the cell is isolated from the surrounding volume in a small chamber. The surrounding volume can then be exchanged without affecting the isolated cell. However, upon short opening and closing of the chamber, the solution in the chamber can be replaced within a few hundred milliseconds. Due to the reversibility of the chambers, the cells can be exposed to different solutions sequentially in a highly controllable fashion, e.g. for incubation, washing, and finally, cell lysis. The tightly sealed microchambers enable the retention of the lysate, minimize and control the dilution after cell lysis. Since lysis and analysis occur at the same location, high sensitivity is retained because no further dilution or loss of the analytes occurs during transport. The microchamber design therefore enables the reliable and reproducible analysis of very small copy numbers of intracellular molecules (attomoles, zeptomoles) released from individual cells. Furthermore, many microchambers can be arranged in an array format, allowing the analysis of many cells at once, given that suitable optical instruments are used for monitoring. We have already used the platform for proof-of-concept studies to analyze intracellular proteins, enzymes, cofactors and second messengers in either relative or absolute quantifiable manner.

In this article we present a microfluidic chip for single cell analysis. It allows the quantification of intracellular proteins, enzymes, cofactors, and second messengers by means of fluorescent assays or immunoassays.&#160;

一个微流控芯片单细胞的多功能化学分析

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this ...

Nanomanipulation of Single RNA Molecules by Optical Tweezers

A large portion of the human genome is transcribed but not translated. In this post genomic era, regulatory functions of RNA have been shown to be increasingly important. As RNA function often depends on its ability to adopt alternative structures, it is difficult to predict RNA three-dimensional structures directly from sequence. Single-molecule approaches show potentials to solve the problem of RNA structural polymorphism by monitoring molecular structures one molecule at a time. This work presents a method to precisely manipulate the folding and structure of single RNA molecules using optical tweezers. First, methods to synthesize molecules suitable for single-molecule mechanical work are described. Next, various calibration procedures to ensure the proper operations of the optical tweezers are discussed. Next, various experiments are explained. To demonstrate the utility of the technique, results of mechanically unfolding RNA hairpins and a single RNA kissing complex are used as evidence. In these examples, the nanomanipulation technique was used to study folding of each structural domain, including secondary and tertiary, independently. Lastly, the limitations and future applications of the method are discussed.

Optical tweezers have been used to study RNA folding by stretching individual molecules from their 5&#8217; and 3&#8217; ends. Here common procedures are described to synthesize RNA molecules for tweezing, calibration of the instrument, and methods to manipulate single molecules.

单个RNA分子的光镊纳米操作

A large portion of the human genome is transcribed but not translated. In this post genomic era, regulatory functions of RNA have been shown to be ...

Cultivation of Mammalian Cells Using a Single-use Pneumatic Bioreactor System

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized medicine innovations. However, translating these advances into therapeutic applications will require in vitro systems that allow for robust, flexible, and cost effective bioreactor systems. There are several bioreactor systems currently utilized in research and commercial settings; however, many of these systems are not optimal for establishing, expanding, and monitoring the growth of different cell types. The culture parameters most challenging to control in these systems include, minimizing hydrodynamic shear, preventing nutrient gradient formation, establishing uniform culture medium aeration, preventing microbial contamination, and monitoring and adjusting culture conditions in real-time. Using a pneumatic single-use bioreactor system, we demonstrate the assembly and operation of this novel bioreactor for mammalian cells grown on micro-carriers. This bioreactor system eliminates many of the challenges associated with currently available systems by minimizing hydrodynamic shear and nutrient gradient formation, and allowing for uniform culture medium aeration. Moreover, the bioreactor&#8217;s software allows for remote real-time monitoring and adjusting of the bioreactor run parameters. This bioreactor system also has tremendous potential for scale-up of adherent and suspension mammalian cells for production of a variety therapeutic proteins, monoclonal antibodies, stem cells, biosimilars, and vaccines.

Using a pneumatic bioreactor, we demonstrate the assembly, operation, and performance of this single-use bioreactor system for the growth of mammalian cells.

培养哺乳动物细胞使用一次性使用气动生物反应器系统

Recent advances in mammalian, insect, and stem cell cultivation and scale-up have created tremendous opportunities for new therapeutics and personalized ...

A Microfluidic Platform for High-throughput Single-cell Isolation and Culture

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet high-throughput, method to perform single-cell culture experiments. Here, we report a microfluidic chip-based strategy for high-efficiency single-cell isolation (~77%) and demonstrate its capability of performing long-term single-cell culture (up to 7 d) and cellular heterogeneity analysis using clonogenic assay. These applications were demonstrated with KT98 mouse neural stem cells, and A549 and MDA-MB-435 human cancer cells. High single-cell isolation efficiency and long-term culture capability are achieved by using different sizes of microwells on the top and bottom of the microfluidic channel. The small microwell array is designed for precisely isolating single-cells, and the large microwell array is used for single-cell clonal culture in the microfluidic chip. This microfluidic platform constitutes an attractive approach for single-cell culture applications, due to its flexibility of adjustable cell culture spaces for different culture strategies, without decreasing isolation efficiency.

Here, we present a protocol for isolating and culturing single cells with a microfluidic platform, which utilizes a new microwell design concept to allow for high-efficiency single cell isolation and long-term clonal culture.

高通量单细胞的分离和文化的微流体平台

Studying the heterogeneity of single cells is crucial for many biological questions, but is technically difficult. Thus, there is a need for a simple, yet ...

3D Microtissues for Injectable Regenerative Therapy and High-throughput Drug Screening

To upgrade traditional 2D cell culture to 3D cell culture, we have integrated microfabrication with cryogelation technology to produce macroporous microscale cryogels (microcryogels), which can be loaded with a variety of cell types to form 3D microtissues. Herein, we present the protocol to fabricate versatile 3D microtissues and their applications in regenerative therapy and drug screening. Size and shape-controllable microcryogels can be fabricated on an array chip, which can be harvested off-chip as individual cell-loaded carriers for injectable regenerative therapy or be further assembled on-chip into 3D microtissue arrays for high-throughput drug screening. Due to the high elastic nature of these microscale cryogels, the 3D microtissues exhibit great injectability for minimally invasive cell therapy by protecting cells from mechanical shear force during injection. This ensures enhanced cell survival and therapeutic effect in the mouse limb ischemia model. Meanwhile, assembly of 3D microtissue arrays in a standard 384-multi-well format facilitates the use of common laboratory facilities and equipment, enabling high-throughput drug screening on this versatile 3D cell culture platform.

This protocol describes the fabrication of elastic 3D macroporous microcryogels by integrating microfabrication with cryogelation technology. Upon loading with cells, 3D microtissues are generated, which can be readily injected in vivo to facilitate regenerative therapy or assembled into arrays for in vitro high-throughput drug screening.

3D Microtissues 用于可注射再生疗法和高通量药物筛选

To upgrade traditional 2D cell culture to 3D cell culture, we have integrated microfabrication with cryogelation technology to produce macroporous ...

A Protocol for Real-time 3D Single Particle Tracking

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although various RT-3D-SPT methods have been put forward in recent years, tracking high speed 3D diffusing particles at low photon count rates remains a challenge. Moreover, RT-3D-SPT setups are generally complex and difficult to implement, limiting their widespread application to biological problems. This protocol presents a RT-3D-SPT system named 3D Dynamic Photon Localization Tracking (3D-DyPLoT), which can track particles with high diffusive speed (up to 20 &#181;m2/s) at low photon count rates (down to 10 kHz). 3D-DyPLoT employs a 2D electro-optic deflector (2D-EOD) and a tunable acoustic gradient (TAG) lens to drive a single focused laser spot dynamically in 3D. Combined with an optimized position estimation algorithm, 3D-DyPLoT can lock onto single particles with high tracking speed and high localization precision. Owing to the single excitation and single detection path layout, 3D-DyPLoT is robust and easy to set up. This protocol discusses how to build 3D-DyPLoT step by step. First, the optical layout is described. Next, the system is calibrated and optimized by raster scanning a 190 nm fluorescent bead with the piezoelectric nanopositioner. Finally, to demonstrate real-time 3D tracking ability, 110 nm fluorescent beads are tracked in water.

This protocol details the construction and operation of a real-time 3D single particle tracking microscope capable of tracking nanoscale fluorescent probes at high diffusive speeds and low photon count rates.

一种实时3D 单粒子跟踪协议

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although ...

Uptake of New Lipid-coated Nanoparticles Containing Falcarindiol by Human Mesenchymal Stem Cells

Nanoparticles are the focus of an increased interest in drug delivery systems for cancer therapy. Lipid-coated nanoparticles are inspired in structure and size by low-density lipoproteins (LDLs) because cancer cells have an increased need for cholesterol to proliferate, and this has been exploited as a mechanism for delivering anticancer drugs to cancer cells. Moreover, depending on drug chemistry, encapsulating the drug can be advantageous to avoid degradation of the drug during circulation in vivo. Therefore, in this&#160;study, this design is used to fabricate lipid-coated nanoparticles of the anticancer drug falcarindiol, providing a potential new delivery system of falcarindiol in order to stabilize its chemical structure against degradation and improve its uptake by tumors. Falcarindiol nanoparticles, with a phospholipid and cholesterol monolayer encapsulating the purified drug core of the particle, were designed. The lipid monolayer coating consists of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol (Chol), and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE PEG 2000) along with the fluorescent label DiI (molar ratios of 43:50:5:2). The nanoparticles are fabricated using the rapid injection method, which is a fast and simple technique to precipitate nanoparticles by good-solvent for anti-solvent exchange. It consists of a rapid injection of an ethanol solution containing the nanoparticle components into an aqueous phase. The size of the fluorescent nanoparticles is measured using dynamic light scattering (DLS) at 74.1 &#177; 6.7 nm. The uptake of the nanoparticles is tested in human mesenchymal stem cells (hMSCs) and imaged using fluorescence and confocal microscopy. The uptake of the nanoparticles is observed in hMSCs, suggesting the potential for such a stable drug delivery system for falcarindiol.

This article describes the encapsulation of falcarindiol in lipid-coated 74 nm nanoparticles. The cellular uptake of the nanoparticles&#160;by human stem cells into lipid droplets is monitored by fluorescent and confocal imaging. Nanoparticles are fabricated by the rapid injection method of solvent shifting, and their size is measured with the dynamic light scattering technique.

人骨髓间充质干细胞吸收含有法卡林多醇的新型脂质包覆纳米颗粒

Nanoparticles are the focus of an increased interest in drug delivery systems for cancer therapy. Lipid-coated nanoparticles are inspired in structure and ...

Fabrication of Zero Mode Waveguides for High Concentration Single Molecule Microscopy

In single molecule fluorescence enzymology, background fluorescence from labeled substrates in solution often limits fluorophore concentration to pico- to nanomolar ranges, several orders of magnitude less than many physiological ligand concentrations. Optical nanostructures called zero mode waveguides (ZMWs), which are 100&#8722;200 nm in diameter apertures fabricated in a thin conducting metal such as aluminum or gold, allow imaging of individual molecules at micromolar concentrations of fluorophores by confining visible light excitation to zeptoliter effective volumes. However, the need for expensive and specialized nanofabrication equipment has precluded the widespread use of ZMWs. Typically, nanostructures such as ZMWs are obtained by direct writing using electron beam lithography, which is sequential and slow. Here, colloidal, or nanosphere, lithography is used as an alternative strategy to create nanometer-scale masks for waveguide fabrication. This report describes the approach in detail, with practical considerations for each phase. The method allows thousands of aluminum or gold ZMWs to be made in parallel, with final waveguide diameters and depths of 100&#8722;200 nm. Only common lab equipment and a thermal evaporator for metal deposition are required. By making ZMWs more accessible to the biochemical community, this method can facilitate the study of molecular processes at cellular concentrations and rates.

Described here is a nanosphere lithography method for parallel fabrication of zero mode waveguides, which are arrays of nanoapertures in a metal-clad glass microscopy coverslip for single molecule imaging at nano- to micromolar concentrations of fluorophores. The method takes advantage of colloidal crystal self-assembly to create a waveguide template.

为高浓度单分子显微镜制造零模式波导

In single molecule fluorescence enzymology, background fluorescence from labeled substrates in solution often limits fluorophore concentration to pico- to ...