Name: a versatile automated platform for micro-scale cell stimulation experiments
Uploaded: 2013-08-06T14:00:00
Description: Watch this Scientific Journal Video about A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments at JoVE.com

Forfatterne takker Ronald F. Renzi og Michael S. Bartsch for sine bidrag til design og utvikling av DMF enheter og DMF hub. Denne forskningen var fullt støttet av Laboratory Regi Forskning og utvikling-programmet ved Sandia National Laboratories. Sandia er en multi-program laboratorium administreres og drives av Sandia Corporation, et heleid datterselskap av Lockheed Martin Corporation, for det amerikanske Department of Energy National Nuclear Security Administration under kontrakt DE-AC04-94AL85000.

Denne generelle protokollen er utformet for å støtte anvendelse av plattformen til en lang rekke undersøkelser; aspekter som er spesifikke for den representative studien beskrevet i denne rapport er skilt ut i parentes Fig. 2 illustrerer en representativ studie utført ved å bruke protokollen.. Merk at i protokollen, er alle &quot;instruere&quot; kommandoer automatisert gjennom bruk av forhåndsdefinerte skript. Legg også merke til at trinn 2 kan utføres parallelt med trinn 1 (for eksempel</em...

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Vi har utviklet en enkel og allsidig automatisert plattform for mikro-skala cellekultur og stimulering eksperimenter. Plattformen gjør det mulig for oss å jobbe med små kultur volumer og celle populasjoner (1 - 20 mL og 100 - 2000 celler, per kammer); kultur størrelser kan bli ytterligere redusert gjennom bruk av microcapillaries av mindre diameter. Å jobbe i disse skalaene reduserer kostnadene ved rutinemessige undersøkelser og gjør gjennomførbare studier som krever bruk av edle reagenser og / eller ce...

Studiet av cellene holdt i kultur (in vitro-analyse) har gitt uvurderlig innsikt i de grunnleggende prinsipper og molekylære mekanismer som styrer komplekse biologiske systemer og menneskers helse. Den konvensjonelle metoder for kultur, stimulering, og samling av celler for analyse, som utnytter petriskåler og mikrotiterplatene, ble utformet for studier av store populasjoner av celler (≥ 10 5) i milliliter skala kultur volumer (≥ 0,1 ml). Det er imidlertid mange tilfeller hvor bare begrensede mengder av celler er tilgjengelige (f.eks primære celler), eller små grupper av celler er ønskelig (for eksempel for å redusere celle-til-celle variasjon på tvers av populasjonen), eller de nødvendige reagenser er vanskelig å skaffe eller uoverkommelig dyrt (f.eks renset celle-utskilte faktorer). Slike problemer kan være vellykket behandlet ved å skalere ned kultur størrelse, som har den ekstra fordelen av å redusere forbruket av allereagenser som er nødvendig for in vitro-analyse 1,2. Dessverre konvensjonelt utstyr og metoder støtter ikke presis og reproduserbar manipulering av mikro-skala kulturer og MicroFluidics-baserte automatiserte systemer for tiden tilgjengelig 3-11 er for komplekst og spesialisert for rutinemessig bruk av de fleste laboratorier. I denne rapporten beskriver vi montering og bruk av en enkel og allsidig teknologi plattform for automatisert kultur, stimulering, og gjenvinning av små populasjoner av celler (100 - 2000 celler) i mikro-skala volumer (1-20 ul). Plattformen arkitektur (figur 1) er modulær utforming: et sett med fibronektin-belagt microcapillaries (&quot;celle perfusjon kamre&quot; modul) fungerer som sted for etablering, vedlikehold og stimulering av mikro-skala kulturer, og en digital MicroFluidics (DMF ) 12,13 enhet utstyrt med &quot;overføring&quot; microcapillaries (&quot;sentral hub&quot; modul) 14,15 ruter cellerog reagenser til og fra perfusjon kamre. DMF kan brukeren individuelt rette flere dråper samtidig og til å endre eller endre rekkefølgen på manipulasjoner (dvs. rekonfigurere utvalgets behandling av tog) uten å endre enhetens maskinvare. Sin enorme fleksibilitet er tydelig i sin siste fremvekst som en viktig teknologi i et bredt spekter av applikasjoner, inkludert cellekultur 16,17, enzymanalyser 18,19, immunoanalyser 20,21, DNA-analyse 22,23, protein behandling, 24,25 og klinisk prøve-behandling. 26,27 Vår sentrale nav utnytter den iboende fleksibiliteten til DMF-enheter, og videre forbedrer den gjennom tilsetning av microcapillary grensesnitt, noe som gir mulighet til å gjennomføre en undergruppe av manipulasjoner (f.eks cellekultur) i spesialiserte perifer moduler, snarere enn på DMF enheten selv. Compartmentalization av behandlingen tog på denne måten forenkler også utformingen av plaTForm arkitektur (ikke nødvendig å bygge en DMF enhet som kan utføre alle prosesstrinn) og tilrettelegger sin utvikling som nye funksjoner som kreves (bare integrere nye perifere moduler etter behov). Transport av celler og reagenser innenfor det sentrale navet er drevet av electrowetting kreftene som genereres ved sekvensiell aktivering av elektrodene innenfor DMF-enheten 13,28, transport til, fra og innenfor de perfusjon kamre er drevet av trykkforandringer som genereres av en høy presisjon sprøyte pumpe. Alle disse flytende bevegelser styres via et enkelt elektronisk grensesnitt og automatisert gjennom bruk av forhåndsdefinerte skript. Som et representativt eksempel demonstrerer vi bruk av plattformen for studiet av transkripsjons-fremkalte responser i immunceller ved utfordring med bakterier (figur 2). Gjennomføring av disse eksperimentene på plattformen mulig for oss å jobbe med et lite antall celler (~ 1000 per experimental tilstand), minimere eksperiment-til-eksperiment variasjon, bevare reagenser, og re-direkte hands-on arbeidskraft. Gitt de fordeler som det confers, samt dets tilgjengelighet og fleksibilitet, bør denne plattformen finner anvendelse i en rekke laboratorier og applikasjoner og vise seg særlig nyttig i å tilrettelegge analyse av celler og stimuli som er tilgjengelige bare i begrensede mengder.

<table border="1">
 <tbody>
 <tr>
 <td>Name of Reagent/Material</td>
 <td>Company</td>
 <td>Catalog Number</td>
 <td>Comments</td>
 </tr>
 <tr>
 <td>Prelude Direct Lysis Module</td>
 <td>NuGEN</td>
 <td>1400-24</td>
 <td></td>
 </tr>
 <tr>
 <td>Trypan Blue (0.4% w/v)</td>
 <td>GIBCO</td>
 <td>15250-061</td>
 <td></td>
 </tr>
 <tr>
 <td>Cell Stripper</td>
 <td>Cellgro</td>
 <td>25-056-C1</td>
 <td></td>
 </tr>
 <tr>
 <td>Ovation PicoSL WTA</td>
 <td>NuGEN</td>
 <td>3310-048</td>
 <td></td>
 </tr>
 <tr>
 <td>Agencourt RNAClean XP</td>
 <td>Beckman Coulter Genomics</td>
 <td>A63987</td>
 <td></td>
 </tr>
 <tr>
 <td>pHrodo BioParticles</td>
 <td>Invitrogen</td>
 <td>P35361</td>
 <td></td>
 </tr>
 <tr>
 <td>CCL4 TaqMan qRT-PCR assay</td>
 <td>Applied Biosystems</td>
 <td>Mm00443111_m1</td>
 <td></td>
 </tr>
 <tr>
 <td>CCL5 TaqMan qRT-PCR assay</td>
 <td>Applied Biosystems</td>
 <td>Mm01302428_m1</td>
 <td></td>
 </tr>
 <tr>
 <td>PTGS2 TaqMan qRT-PCR assay</td>
 <td>Applied Biosystems</td>
 <td>Mm00478374_m1</td>
 <td></td>
 </tr>
 <tr>
 <td>TNF TaqMan qRT-PCR assay</td>
 <td>Applied Biosystems</td>
 <td>Mm00443258_m1</td>
 <td></td>
 </tr>
 <tr>
 <td>GAPDH TaqMan qRT-PCR assay</td>
 <td>Applied Biosystems</td>
 <td>Mm99999915_g1</td>
 <td></td>
 </tr>
 <tr>
 <td>Pluronic F127</td>
 <td>Sigma Chemical</td>
 <td>2594628</td>
 <td></td>
 </tr>
 <tr>
 <td>Fluorinert FC-40</td>
 <td>Sigma Chemical</td>
 <td>51142-49-5</td>
 <td></td>
 </tr>
 <tr>
 <td>Parylene C dimer</td>
 <td>Specialty Coating Systems</td>
 <td>28804-46-8</td>
 <td></td>
 </tr>
 <tr>
 <td>Teflon-AF</td>
 <td>DuPont</td>
 <td>AF1600</td>
 <td></td>
 </tr>
 <tr>
 <td>Polyimide tape</td>
 <td>ULINE</td>
 <td>S-11928</td>
 <td></td>
 </tr>
 <tr>
 <td>Indium tin oxide (ITO) coated glass substrates </td>
 <td>Delta Technologies </td>
 <td>CB-40IN-1107</td>
 <td></td>
 </tr>
 <tr>
 <td>DMF hub Teflon-coated fused-silica microcapillaries</td>
 <td>Polymicro Technologies</td>
 <td>TSU100375</td>
 <td></td>
 </tr>
 <tr>
 <td>Perfusion chamber microcapillaries</td>
 <td>Polymicro Technologies</td>
 <td>TSP530700</td>
 <td></td>
 </tr>
 <tr>
 <td>Tubing and microcapillary fittings</td>
 <td>Sandia National Laboratories</td>
 <td>&nbsp;</td>
 <td></td>
 </tr>
 <tr>
 <td>Polycarbonate tubing</td>
 <td>Paradigm Optics</td>
 <td>CTPC100-500-5</td>
 <td></td>
 </tr>
 <tr>
 <td>8-port precision syringe pump equipped with 30 mm (500 &mu;l capacity) syringes</td>
 <td>Hamilton Company</td>
 <td>54848-01</td>
 <td></td>
 </tr>
 <tr>
 <td>Parylene-C vapor deposition instrument</td>
 <td>Specialty Coating Systems</td>
 <td>PDS 2010 Labcoter 2</td>
 <td></td>
 </tr>
 <tr>
 <td>High-voltage function generator</td>
 <td>Trek</td>
 <td>615A-1 615-3</td>
 <td></td>
 </tr>
 <tr>
 <td>MVX10 microscope</td>
 <td>Olympus</td>
 <td></td>
 <td>Optional (facilitates tracking of droplets on DMF hub)</td>
 </tr>
 <tr>
 <td>QIClick digital CCD camera</td>
 <td>QImaging</td>
 <td>QIClick-F-CLR-12</td>
 <td>Optional (facilitates tracking of droplets on DMF hub)</td>
 </tr>
</tbody>
</table>

a versatile automated platform for micro-scale cell stimulation experiments

Studie av celler i kultur (in vitro-analyse) har gitt viktig innsikt i komplekse biologiske systemer. Konvensjonelle metoder og utstyr for in vitro-analyse er godt egnet for å studere av et stort antall celler (≥ 10 5) i milliliter skala volumer (≥ 0,1 ml). Det er imidlertid mange tilfeller hvor det er nødvendig eller ønskelig å skalere ned kultur størrelse for å redusere forbruket av cellene av interesse og / eller reagensene som er nødvendig for deres kultur, stimulering eller prosesseringssystem. Dessverre har konvensjonelle tilnærminger støtter ikke presis og reproduserbar manipulering av mikro-skala kulturer, og de MicroFluidics-baserte automatiserte systemer som er tilgjengelige er for komplekst og spesialisert for rutinemessig bruk av de fleste laboratorier. For å løse dette problemet, har vi utviklet en enkel og allsidig teknologiplattform for automatisert kultur, stimulering, og utvinning av små populasjoner av celler (100 - 2000 celler) i mikro-skala volums (1 - 20 ul). Plattformen består av et sett av fibronektin-belagt microcapillaries (&quot;celle&quot; perfusjon kamre), innen hvilken mikro-skala kulturer er etablert, opprettholdes, og stimuleres, en digital MicroFluidics (DMF)-enhet utstyrt med «overføring» microcapillaries (&quot;sentralt nav &quot;), hvilke ruter celler og reagenser til og fra kamrene, en perfusjon høy presisjon sprøytepumpe, som driver transport av produkter mellom de perfusjon kamre og den sentralt nav, og et elektronisk grensesnitt som gir kontroll over transport av materialer, som er koordineres og automatiseres via forhåndsbestemte skript. Som et eksempel har vi brukt plattformen for å lette studiet av transkripsjons-responser oppnås hos immunceller ved utfordring med bakterier. Bruk av plattformen det mulig for oss å redusere forbruket av celler og reagenser, minimere eksperiment-til-eksperimentet variasjon, og re-direkte hands-on arbeidskraft. Gitt de fordeler som den trygdede, samt dens tilgjengelighet og fleksibilitet, our plattformen skal finne anvendelse i en rekke laboratorier og anvendelsesområder, og vise seg særlig nyttig i å tilrettelegge analyse av celler og stimuli som er tilgjengelige bare i begrensede mengder.

Som en demonstrasjon av automatiserte plattform, vi brukte den til å gjennomføre en studie der små populasjoner av immunceller ble dyrket i mikro-skala kulturer, utfordret med bakterier, og lysert for off-plattform analyse av pro-inflammatoriske responser (Figur 2 ). Hver av seks celle perfusjon kamre ble sådd med 10 4 immunceller (P388D.1 murine makrofager) resuspendert i 10 mL av vekstmedium. Etter en tilslutning periode (37 ° C i 2 timer) og et medium utve...

Watch this Scientific Journal Video about A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments at JoVE.com

A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments

Vi har utviklet en automatisert cellekultur og avhør plattform for mikro-skala celle stimulering eksperimenter. Plattformen tilbyr enkel, allsidig og presis kontroll i pleie og stimulere små populasjoner av celler, og utvinne lysatene for molekylære analyser. Plattformen er godt egnet til studier som bruker edle celler og / eller reagenser.

En allsidig Automated Plattform for Micro-skala Cell Stimulering Experiments

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in ...

a-versatile-automated-platform-for-micro-scale-cell-stimulation

Research

JoVE Journal

Bioengineering

Organotypic Collagen I Assay: A Malleable Platform to Assess Cell Behaviour in a 3-Dimensional Context

Cell migration is fundamental to many aspects of biology, including development, wound healing, the cellular responses of the immune system, and metastasis of tumor cells. Migration has been studied on glass coverslips in order to make cellular dynamics amenable to investigation by light microscopy. However, it has become clear that many aspects of cell migration depend on features of the local environment including its elasticity, protein composition, and pore size, which are not faithfully represented by rigid two dimensional substrates such as glass and plastic 1. Furthermore, interaction with other cell types, including stromal fibroblasts 2 and immune cells 3, has been shown to play a critical role in promoting the invasion of cancer cells. Investigation at the molecular level has increasingly shown that molecular dynamics, including response to drug treatment, of identical cells are significantly different when compared in vitro and in vivo 4. 
Ideally, it would be best to study cell migration in its naturally occurring context in living organisms, however this is not always possible. Intermediate tissue culture systems, such as cell derived matrix, matrigel, organotypic culture (described here) tissue explants, organoids, and xenografts, are therefore important experimental intermediates. These systems approximate certain aspects of an in vivo environment but are more amenable to experimental manipulation such as use of stably transfected cell lines, drug treatment regimes, long term and high-resolution imaging. Such intermediate systems are especially useful as proving grounds to validate probes and establish parameters required to image the dynamic response of cells and fluorescent reporters prior to undertaking imaging in vivo 5. As such, they can serve an important role in reducing the need for experiments on living animals.

A method is described for the preparation of a 3-dimensional matrix consisting of collagen type I and primary human fibroblasts. This organotypic gel serves as a useful substrate to assess invasive cell migration because it mimics basic features of tissue stroma and is amenable to many forms of microscopy.

Cell migration is fundamental to many aspects of biology, including development, wound healing, the cellular responses of the immune system, and ...

GENPLAT: an Automated Platform for Biomass Enzyme Discovery and Cocktail Optimization

The high cost of enzymes for biomass deconstruction is a major impediment to the economic conversion of lignocellulosic feedstocks to liquid transportation fuels such as ethanol. We have developed an integrated high throughput platform, called GENPLAT, for the discovery and development of novel enzymes and enzyme cocktails for the release of sugars from diverse pretreatment/biomass combinations. GENPLAT comprises four elements: individual pure enzymes, statistical design of experiments, robotic pipeting of biomass slurries and enzymes, and automated colorimeteric determination of released Glc and Xyl. Individual enzymes are produced by expression in Pichia pastoris or Trichoderma reesei, or by chromatographic purification from commercial cocktails or from extracts of novel microorganisms. Simplex lattice (fractional factorial) mixture models are designed using commercial Design of Experiment statistical software. Enzyme mixtures of high complexity are constructed using robotic pipeting into a 96-well format. The measurement of released Glc and Xyl is automated using enzyme-linked colorimetric assays. Optimized enzyme mixtures containing as many as 16 components have been tested on a variety of feedstock and pretreatment combinations.
GENPLAT is adaptable to mixtures of pure enzymes, mixtures of commercial products (e.g., Accellerase 1000 and Novozyme 188), extracts of novel microbes, or combinations thereof. To make and test mixtures of &tilde;10 pure enzymes requires less than 100 &mu;g of each protein and fewer than 100 total reactions, when operated at a final total loading of 15 mg protein/g glucan. We use enzymes from several sources. Enzymes can be purified from natural sources such as fungal cultures (e.g., Aspergillus niger, Cochliobolus carbonum, and Galerina marginata), or they can be made by expression of the encoding genes (obtained from the increasing number of microbial genome sequences) in hosts such as E. coli, Pichia pastoris, or a filamentous fungus such as T. reesei. Proteins can also be purified from commercial enzyme cocktails (e.g., Multifect Xylanase, Novozyme 188). An increasing number of pure enzymes, including glycosyl hydrolases, cell wall-active esterases, proteases, and lyases, are available from commercial sources, e.g., Megazyme, Inc. (www.megazyme.com), NZYTech (www.nzytech.com), and PROZOMIX (www.prozomix.com).
Design-Expert software (Stat-Ease, Inc.) is used to create simplex-lattice designs and to analyze responses (in this case, Glc and Xyl release). Mixtures contain 4-20 components, which can vary in proportion between 0 and 100%. Assay points typically include the extreme vertices with a sufficient number of intervening points to generate a valid model. In the terminology of experimental design, most of our studies are "mixture" experiments, meaning that the sum of all components adds to a total fixed protein loading (expressed as mg/g glucan). The number of mixtures in the simplex-lattice depends on both the number of components in the mixture and the degree of polynomial (quadratic or cubic). For example, a 6-component experiment will entail 63 separate reactions with an augmented special cubic model, which can detect three-way interactions, whereas only 23 individual reactions are necessary with an augmented quadratic model. For mixtures containing more than eight components, a quadratic experimental design is more practical, and in our experience such models are usually statistically valid.
All enzyme loadings are expressed as a percentage of the final total loading (which for our experiments is typically 15 mg protein/g glucan). For "core" enzymes, the lower percentage limit is set to 5%. This limit was derived from our experience in which yields of Glc and/or Xyl were very low if any core enzyme was present at 0%. Poor models result from too many samples showing very low Glc or Xyl yields. Setting a lower limit in turn determines an upper limit. That is, for a six-component experiment, if the lower limit for each single component is set to 5%, then the upper limit of each single component will be 75%. The lower limits of all other enzymes considered as "accessory" are set to 0%. "Core" and "accessory" are somewhat arbitrary designations and will differ depending on the substrate, but in our studies the core enzymes for release of Glc from corn stover comprise the following enzymes from T. reesei: CBH1 (also known as Cel7A), CBH2 (Cel6A), EG1(Cel7B), BG (&beta;-glucosidase), EX3 (endo-&beta;1,4-xylanase, GH10), and BX (&beta;-xylosidase).
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GENPLAT (GLBRC Enzyme Platform) is an automated platform for discovery and optimization of enzyme cocktails for biomass degradation. It can be adapted to multiple feedstocks and mixtures of enzymes containing multiple components.

GENPLAT: en Automated Plattform for Biomasse enzym Discovery og Cocktail Optimization

The high cost of enzymes for biomass deconstruction is a major impediment to the economic conversion of lignocellulosic feedstocks to liquid ...

Cell Squeezing as a Robust, Microfluidic Intracellular Delivery Platform

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This technology has shown potential in addressing previously challenging applications; including, delivery to primary immune cells, cell reprogramming, carbon nanotube, and quantum dot delivery. This vector-free microfluidic platform relies on mechanical disruption of the cell membrane to facilitate cytosolic delivery of the target material. Herein, we describe the detailed method of use for these microfluidic devices including, device assembly, cell preparation, and system operation. This delivery approach requires a brief optimization of device type and operating conditions for previously unreported applications. The provided instructions are generalizable to most cell types and delivery materials as this system does not require specialized buffers or chemical modification/conjugation steps. This work also provides recommendations on how to improve device performance and trouble-shoot potential issues related to clogging, low delivery efficiencies, and cell viability.

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This protocol provides detailed steps on how to use the system for a broad range of applications.

Cell klemme som en robust, Microfluidic Intracellulær Levering Platform

Rapid mechanical deformation of cells has emerged as a promising, vector-free method for intracellular delivery of macromolecules and nanomaterials. This ...

A Novel Stretching Platform for Applications in Cell and Tissue Mechanobiology

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have contributed dramatically to the understanding of basic mechanobiology. These techniques have been extensively used to demonstrate how the onset and progression of various diseases are heavily influenced by mechanical cues. This article presents a multi-functional biaxial stretching (BAXS) platform that can either mechanically stimulate single cells or quantify the mechanical stiffness of tissues. The BAXS platform consists of four voice coil motors that can be controlled independently. Single cells can be cultured on a flexible substrate that can be attached to the motors allowing one to expose the cells to complex, dynamic, and spatially varying strain fields. Conversely, by incorporating a force load cell, one can also quantify the mechanical properties of primary tissues as they are exposed to deformation cycles. In both cases, a proper set of clamps must be designed and mounted to the BAXS platform motors in order to firmly hold the flexible substrate or the tissue of interest. The BAXS platform can be mounted on an inverted microscope to perform simultaneous transmitted light and/or fluorescence imaging to examine the structural or biochemical response of the sample during stretching experiments. This article provides experimental details of the design and usage of the BAXS platform and presents results for single cell and whole tissue studies. The BAXS platform was used to measure the deformation of nuclei in single mouse myoblast cells in response to substrate strain and to measure the stiffness of isolated mouse aortas. The BAXS platform is a versatile tool that can be combined with various optical microscopies in order to provide novel mechanobiological insights at the sub-cellular, cellular and whole tissue levels.

We present in this article a novel stretching platform that can be used to investigate single cell responses to complex anisotropic biaxial mechanical deformation and quantify the mechanical properties of biological tissues.

A Novel Stretching plattform for applikasjoner i celler og vev mechanobiology

Tools that allow the application of mechanical forces to cells and tissues or that can quantify the mechanical properties of biological tissues have ...

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.

En mikrofluid plattform for High-throughput encellede Isolering og kultur

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 ...

Layered Alginate Constructs: A Platform for Co-culture of Heterogeneous Cell Populations

Many load bearing tissues possess structurally and functionally distinct regions, typically accompanied by different cell phenotypes with differential mechanosensing characteristics. Engineering and analysis of these tissue types remain a challenge. Layered hydrogel constructs provide an opportunity for investigating the interactions among multiple cell populations within single constructs. Alginate hydrogels are both biocompatible and allow for easy isolation of cells after experimentation. Here, we describe a method for the development of small sized dual layered alginate hydrogel discs. This process maintains high cell viability of human mesenchymal stem cells during the formation process and these layered discs can withstand unconfined cyclic compression, commonly used for stimulation of hMSCs undergoing chondrogenesis. These layered constructs can potentially be scaled up to include additional levels, and also be used to segregate cell populations initially after layering. This dual layer alginate hydrogel culture platform can be used for many different applications including engineering and analysis of cells of load bearing tissues and co-cultures of other cell types.

Engineering and analysis of load bearing tissues with heterogeneous cell populations are still a challenge. Here, we describe a method for creating bi-layered alginate hydrogel discs as a platform for co-culture of diverse cell populations within one construct.

Lagdelte Alginat konstruksjoner: En plattform for Co-kultur av heterogene cellepopulasjoner

Many load bearing tissues possess structurally and functionally distinct regions, typically accompanied by different cell phenotypes with differential ...

A High-throughput Cell Microarray Platform for Correlative Analysis of Cell Differentiation and Traction Forces

Microfabricated cellular microarrays, which consist of contact-printed combinations of biomolecules on an elastic hydrogel surface, provide a tightly controlled, high-throughput engineered system for measuring the impact of arrayed biochemical signals on cell differentiation. Recent efforts using cell microarrays have demonstrated their utility for combinatorial studies in which many microenvironmental factors are presented in parallel. However, these efforts have focused primarily on investigating the effects of biochemical cues on cell responses. Here, we present a cell microarray platform with tunable material properties for evaluating both cell differentiation by immunofluorescence and biomechanical cell&#8211;substrate interactions by traction force microscopy. To do so, we have developed two different formats utilizing polyacrylamide hydrogels of varying Young&#39;s modulus fabricated on either microscope slides or glass-bottom Petri dishes. We provide best practices and troubleshooting for the fabrication of microarrays on these hydrogel substrates, the subsequent cell culture on microarrays, and the acquisition of data. This platform is well-suited for use in investigations of biological processes for which both biochemical (e.g., extracellular matrix composition) and biophysical (e.g., substrate stiffness) cues may play significant, intersecting roles.

Cell differentiation is regulated by a host of microenvironmental factors, including both matrix composition and substrate material properties. We describe here a technique utilizing cell microarrays in conjunction with traction force microscopy to evaluate both cell differentiation and biomechanical cell&#8211;substrate interactions as a function of microenvironmental context.

En High-throughput Cell microarray plattform for samsvarende analyse av celledifferensiering og Traction Forces

Microfabricated cellular microarrays, which consist of contact-printed combinations of biomolecules on an elastic hydrogel surface, provide a tightly ...

A Versatile Method of Patterning Proteins and Cells

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.

This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

En allsidig Måte mønster Proteiner og celler

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning ...

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of flexible polymers nor of rigid rods. Underlying filaments remain outstretched due to their non-vanishing backbone stiffness, which is quantified via the persistence length (lp), but they are also subject to strong thermal fluctuations. Their finite bending stiffness leads to unique, non-trivial collective mechanics of bulk networks, enabling the formation of stable scaffolds at low volume fractions while providing large mesh sizes. This underlying principle is prevalent in nature (e.g., in cells or tissues), minimizing the high molecular content and thereby facilitating diffusive or active transport. Due to their biological implications and potential technological applications in biocompatible hydrogels, semiflexible polymers have been subject to considerable study. However, comprehensible investigations remained challenging since they relied on natural polymers, such as actin filaments, which are not freely tunable. Despite these limitations and due to the lack of synthetic, mechanically tunable, and semiflexible polymers, actin filaments were established as the common model system. A major limitation is that the central quantity lp cannot be freely tuned to study its impact on macroscopic bulk structures. This limitation was resolved by employing structurally programmable DNA nanotubes, enabling controlled alteration of the filament stiffness. They are formed through tile-based designs, where a discrete set of partially complementary strands hybridize in a ring structure with a discrete circumference. These rings feature sticky ends, enabling the effective polymerization into filaments several microns in length, and display similar polymerization kinetics as natural biopolymers. Due to their programmable mechanics, these tubes are versatile, novel tools to study the impact of lp on the single-molecule as well as the bulk scale. In contrast to actin filaments, they remain stable over weeks, without notable degeneration, and their handling is comparably straightforward.

Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity.

DNA nanorør som et allsidig verktøy for å studere Semiflexible polymerer

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of ...

A Multilayer Microfluidic Platform for the Conduction of Prolonged Cell-Free Gene Expression

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic regulatory circuits. The analysis of synthetic genetic regulatory networks in vivo is time consuming and suffers from a lack of environmental control, with exogenous synthetic components interacting with host processes resulting in undesired behavior. To overcome these issues, cell-free characterization of novel circuitry is becoming more prevalent. In vitro transcription and translation (IVTT) mixtures allow the regulation of the experimental environment and can be optimized for each unique system. The protocols presented here detail the fabrication of a multilayer microfluidic device that can be utilized to sustain IVTT reactions for prolonged durations. In contrast to batch reactions, where resources are depleted over time and (by-) products accumulate, the use of microfluidic devices allows the replenishment of resources as well as the removal of reaction products. In this manner, the cellular environment is emulated by maintaining an out-of-equilibrium environment in which the dynamic behavior of gene circuits can be investigated over extended periods of time. To fully exploit the multilayer microfluidic device, hardware and software have been integrated to automate the IVTT reactions. By combining IVTT reactions with the microfluidic platform presented here, it becomes possible to comprehensively analyze complex network behaviors, furthering our understanding of the mechanisms that regulate cellular processes.

The fabrication process of a PDMS-based, multilayer, microfluidic device that allows in vitro transcription and translation (IVTT) reactions to be performed over prolonged periods is described. Furthermore, a comprehensive overview of the hardware and software required to automate and maintain these reactions for prolonged durations is provided.

En flerlags Mikrovæskebasert plattform for gjennomføring av langvarig Cell-gratis Gene Expression

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic ...