Gli autori desiderano ringraziare Chris Morrow per l&#39;assistenza tecnica. Il finanziamento è stato fornito dal NIH SBIR (R43) concedere 1R43GM101859-01 (MPI) GRANT10940803.

1. Cella Cultura Preparazione <ol><li> Conservare le scorte di cellule NIH/3T3 in azoto liquido fino al momento dell&#39;uso. </li><li> Preparare completa supporti per cellule NIH/3T3 utilizzando Dulbecco Modified Eagle Medium (DMEM) supplementato con 10% di siero fetale bovino, 10 mM tampone HEPES, 50 unità / ml di penicillina e 50 mg / ml di streptomicina. </li><li> Scongelare cellule per 2-3 minuti in un bagno d&#39;acqua a 37 ° C. </li><li> Risospendere le cellule in 5 ml di mezzo completo e centrifugare a 1500 xg per 3 min. </li><li> Rimuovere il surnatante cellulare senza disturbare il pellet. </li><li> Risospendere le cellule in 5 ml di media e contare le cellule utilizzando un emocitometro. <ol><li> Rimuovere 10 ml di sospensione cellulare e posto in una provetta da 0,5 ml. </li><li> Aggiungere 10 ml di Trypan Blue alla sospensione cellulare e mescolare con la punta della pipetta. </li><li> Pipettare 10 ml di cellule colorate in una camera emocitometro. </li><li> Contare le celle in emocitometro a 10xingrandimento. <ol><li> Contare le cellule vive (piccole palline bianche) per 4 dei 9 grandi piazze. Contare solo le cellule vive che non appaiono blu scuro dalla macchia Trypan Blue. </li><li> Calcolare il numero medio di cellule per piazzale, causando il numero di cellule x 10 4 cellule / ml nel cellule sospensione originale. </li><li> Alveoli ad una densità di 1 x 10 5 cellule / ml con un totale di 5 ml in ciascuna beuta T25. </li></ol></li><li> Cellule di coltura tra il 70% e l&#39;80% di confluenza prima degli esperimenti di inizio. Aggiorna i media ogni 2-3 giorni o secondo necessità. </li></ol></li></ol> 2. Stampa Preparazione della superficie <ol><li> Mark un rettangolo con pennarello sul fondo di una cultura trattati tessuto polistirene (TCTPS) 12 pozzetti la dimensione della testina di stampa (7 mm x 19 mm). </li><li> Pipettare 50 microlitri di siero fetale bovino in area rettangolare e diffonderla sull&#39;intera regione con la punta. </li><li> Lasciare la piastra di Petriin una sterile biosicurezza cappuccio O / N per consentire al posto del siero si asciughi completamente. Queste piastre devono essere preparati non più di due giorni prima dell&#39;uso. </li></ol> 3. Stampa sommerso <ol><li> Lavare la testina di stampa con acqua distillata. <ol><li> Riempire una capsula di Petri 60 mm Con acqua distillata e ancorare la testina di stampa sulla superficie. </li><li> Fluire acqua distillata attraverso ciascuna delle linee per 2 min a 150 ml / min usando una pompa pneumatica. </li><li> Eliminare l&#39;acqua dalla piastra di Petri e riempirlo con acqua pulita. </li><li> Spostare la testina di stampa su e giù in acqua 3 volte. </li></ol></li><li> Ancorare il centro della testa di stampa sul posto siero rivestite in 12 piastra ben pre-preparati. </li><li> Prime la testina di stampa con i media completi pre-riscaldato, 300 ml per canale. </li><li> Stampa cellule sospeso ad una concentrazione di 50.000 cellule / ml sulla superficie e 60 microlitri / min, 100 microlitri per canale. </li><li> Posizionare la testina di stampa, a sinistra ancorata contro ilsuperficie, e il collettore in un incubatore di coltura cellulare impostato a 5% di CO 2 e 37 ° C per 2 h. </li><li> Dopo l&#39;incubazione 2 ore, rimuovere la testina di stampa e posizionare il coperchio sul piatto di coltura. Il momento in cui la testina di stampa rimosso è considerato il punto di tempo 0 ore. </li></ol> 4. Standard di coltura cellulare <ol><li> Aggiungere 1 ml di supporti preriscaldata a una piastra TCTPS 12 pozzetti siero-spotted preparato al punto 2. </li><li> Prelevare 1 ml della sospensione cellulare residua dal passaggio 2 e pipetta in un singolo pozzetto di una 12 pozzetti TCTPS piastra. Ciò produrrà una coltura contenente 50.000 cellule nel piatto. </li><li> Posizionare la piastra di coltura cellulare in un incubatore a 37 ° C per 2 h. </li><li> Dopo l&#39;incubazione 2 hr iniziare il cronometraggio; coerenza tra campioni stampati e di semina, questo è considerato il punto di tempo 0 ore. </li></ol> 5. Culture Visualization <ol><li> Dopo 0, 2, 24, e 48 hr cellule prese da ciascuno dei due metodi described sopra e immagine utilizzando un microscopio invertito standard. <ol><li> Colorare le cellule con ioduro di propidio, una macchia rosso fluorescente che è incorporato solo nel nucleo delle cellule morte. <ol><li> Lavare delicatamente le cellule 3 volte con 1 ml di tampone fosfato isotonico con calcio e magnesio (PBS + +) per rimuovere eventuali detriti. </li><li> Aggiungere 1 ml di pre-riscaldato PBS + + a ciascun recipiente di coltura. </li><li> Aggiungere 1 ml di soluzione di ioduro di propidio magazzino (1 mg / ml) per ogni nave cultura. </li><li> Incubare le cellule colorate con ioduro di propidio a 37 ° C per 10 min. </li></ol></li><li> Immagine le cellule utilizzando un microscopio invertito a 10x e 40x di ingrandimento. </li></ol></li><li> Eliminare le celle in un contenitore a rischio biologico appropriato. </li></ol>

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Gli autori sono dipendenti e gli azionisti di Wasatch Microfluidics che produce reagenti e / o strumenti utilizzati in questo manoscritto.

La tecnologia di stampa 3D microfluidica qui descritta è l&#39;unica in grado di stampa microfluidically array di celle in un liquido riempito bene, cioè una superficie sommersa. Stampando sulle superfici sommerse, microarray di cellule possono essere prodotti che mantengono il fenotipo cellulare fisiologicamente rilevanti di cellule così come la capacità di multiplex cellule sul fondo di un singolo pozzetto Figura 4. I risultati di questo studio mostrano che microfluidically stampa cellule...

I recenti progressi nel settore farmaceutico hanno portato ad un crescente interesse nell&#39;utilizzo di microarray cellulari nel processo di scoperta della droga per lo screening di farmaci e analisi cytotoxicological 1,2,3. Lo sviluppo di test in vitro in high-throughput e metodi di screening utilizzando microarrays di cellule faciliterebbe lo sviluppo rapido ed efficace di farmaci candidati, così come anticipo la comprensione fondamentale della cella 1,4. L&#39;approccio tradizionale allo screening con celle utilizza piattaforme e piastre convenzionali; tuttavia questo approccio è limitata a causa del costo elevato, produttività limitata, e la limitata capacità di informazioni quantitative sulla funzione delle cellule 1,5. A causa di queste limitazioni, la ricerca nel campo delle tecnologie di microarray cellulare è fiorente per la caratterizzazione molecolare biologica, ingegneria dei tessuti, e la droga lo screening 1,6. I vantaggi di microarrays cellulari includono l&#39;uso campione più piccolo, effetti minimi difenotipo cellulare eterogeneità mascheratura informazioni, e soprattutto la capacità di automatizzare saggi per più applicazioni high-throughput 1,7,8. L&#39;industria farmaceutica utilizza attualmente high-throughput cell-based test di screening con colture monostrato di cellule 2D per lo screening di stupefacenti in pozzetti microtiter 9. Cellule multiplexing in pozzetti di piastre microtiter offre la possibilità di throughput più elevato con opzioni di sperimentazione uniche. Inoltre, le attuali tecnologie di microarray cellulari permettono alle cellule di asciugare in grado di modificare radicalmente il fenotipo delle cellule in vivo 10,11. Per superare questi problemi, la MFCA è stata progettata ed è mostrato in Figura 1. Il disegno dei fluidica MFCA 3D consente la punta della testina di stampa di figura 1 per essere abbassato in un bagno e compresso contro una superficie per formare un sigillo. La punta morbido silicone della testina di stampa si comporta come unguarnizione e forma una guarnizione reversibile. La tecnologia MFCA è in modo unico adatta per interfacciarsi con superfici sommerse, che è richiesto per entrambe le colture cellulari e sistemi fetta dei tessuti, ed è difficile o impossibile con la maggior parte degli altri approcci. Pins o stampa ink-jet non funzionano, e dispositivi microfluidici 2D non sono adatti per la deposizione o l&#39;interfacciamento con grandi array di punti discreti. Inoltre, da miniaturizzazione e localizzare l&#39;esperimento - il microarray cellulare - il MFCA supera i principali problemi connessi con high-throughput a base di cellule test di screening. Il CFM utilizza le reti di canali 3D per ciclo di piccoli campioni di fluido del volume oltre riprese piatte microscopici su una superficie di 12,13. Mediante stampa con flusso, biomolecole, cellule e altri reagenti sono mantenuti in un ambiente liquido durante il processo di stampa, consentendo la stampa di biomolecole e cellule sensibili senza esposizione all&#39;aria, che ostacola le tecniche di stampa cella corrente. E &#39;anche possibile stampare direttamente da materiale grezzo come ibridoma o surnatanti forniti vi è un meccanismo di cattura sulla superficie dell&#39;array. L&#39;obiettivo di questo manoscritto è spiegare in dettaglio la stampa sommersa di due tipi di cellule su una superficie.

<table border="0" cellpadding="0" cellspacing="0" width="571">
	<tbody>
		<tr height="63">
			<td height="63" style="height:63px;width:215px;">Continuous Flow Microspotter</td>
			<td style="width:71px;">Wasatch Microfluidics</td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">NIH/3T3 cells</td>
			<td style="width:71px;">ATCC</td>
			<td style="width:119px;">CRL-1658</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Dubbleco&#39;s Modified Eagle Medium</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">11965-092</td>
			<td>base media for cells</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">HEPES buffer</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">15630-080</td>
			<td>cell media additive (control pH)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Sodium pyruvate</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">11360-070</td>
			<td>cell media additive</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Penicillin-Streptomycin&#160;</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;"></td>
			<td>cell media additive</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Trypan blue</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">15250-061</td>
			<td>stain cell sfor counting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Haemocytometer</td>
			<td style="width:71px;">Fisher</td>
			<td align="right" style="width:119px;">267110</td>
			<td>cell chamber to count cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Nikon Eclipse TS100</td>
			<td style="width:71px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Used to check on cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;">Nikon Eclipse TE2000-U</td>
			<td style="width:71px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Used for collecting images</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">Phosphate Buffered Saline (with calcium and magnesium)</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">14040-133</td>
			<td>rinsing cells before passaging and before staining with PI</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:215px;">TrypLE Express&#160;</td>
			<td style="width:71px;">Invitrogen</td>
			<td style="width:119px;">A12177-01</td>
			<td>used to remove cells from surface</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:215px;"></td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

the submerged printing of cells onto a modified surface using a continuous flow microspotter

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell phenotype after printing, poor organization and distribution of desired cells, and the inability to deliver drugs and/or nutrients to targeted areas in the array. Our 3D microfluidic printing technology is uniquely capable of sealing and printing arrays of cells onto submerged surfaces in an automated and multiplexed manner. The design of the microfluidic cell array (MFCA) 3D fluidics enables the printhead tip to be lowered into a liquid-filled well or dish and compressed against a surface to form a seal. The soft silicone tip of the printhead behaves like a gasket and is able to form a reversible seal by applying pressure or backing away. Other cells printing technologies such as pin or ink-jet printers are unable to print in submerged applications. Submerged surface printing is essential to maintain phenotypes of cells and to monitor these cells on a surface without disturbing the material surface characteristics. By printing onto submerged surfaces, cell microarrays are produced that allow for drug screening and cytotoxicity assessment in a multitude of areas including cancer, diabetes, inflammation, infections, and cardiovascular disease.

Le cellule NIH/3T3 linea cellulare di fibroblasti sono stati stampati o seminate su una superficie immersa. Le cellule sono state coltivate ad una densità di 5 x 10 4 cellule per ml. Le cellule sono state seminate utilizzando tecniche di coltura cellulare tradizionali. Le cellule sono state stampate usando una grande formato, dodici flusso testina cella in cui i canali sono più grandi (~ 500 micron) che l&#39;CFM usato per proteine ​​e altre biomolecole. Le cellule sono state stampate o seminate su una ...

Watch this Scientific Journal Video about The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter at JoVE.com

The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter

This 3D microfluidic printing technology prints arrays of cells onto submerged surfaces. We describe how arrays of cells are delivered microfluidically in 3D flow cells onto submerged surfaces. By printing onto submerged surfaces, cell microarrays were produced that allow for drug screening and cytotoxicity assessment in a multitude of areas.

La stampa Sommerso di celle su una superficie modificata utilizzando un flusso di Microspotter continua

The printing of cells for microarray applications possesses significant challenges including the problem of maintaining physiologically relevant cell ...

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8.6K Views.  Wasatch Microfluidics. This 3D microfluidic printing technology prints arrays of cells onto submerged surfaces. We describe how arrays of cells are delivered microfluidically in 3D flow cells onto submerged surfaces. By printing onto submerged surfaces, cell microarrays were produced that allow for drug screening and cytotoxicity assessment in a multitude of areas.

Video: The Submerged Printing of Cells onto a Modified Surface Using a Continuous Flow Microspotter

Planar and Three-Dimensional Printing of Conductive Inks

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical devices1-3. In this paper, we focus on one- (1D), two- (2D), and three-dimensional (3D) printing of conductive metallic inks in the form of flexible, stretchable, and spanning microelectrodes.
Direct-write assembly4,5 is a 1-to-3D printing technique that enables the fabrication of features ranging from simple lines to complex structures by the deposition of concentrated inks through fine nozzles (~0.1 - 250 &mu;m). This printing method consists of a computer-controlled 3-axis translation stage, an ink reservoir and nozzle, and 10x telescopic lens for visualization. Unlike inkjet printing, a droplet-based process, direct-write assembly involves the extrusion of ink filaments either in- or out-of-plane. The printed filaments typically conform to the nozzle size. Hence, microscale features (&lt; 1 &mu;m) can be patterned and assembled into larger arrays and multidimensional architectures.
In this paper, we first synthesize a highly concentrated silver nanoparticle ink for planar and 3D printing via direct-write assembly. Next, a standard protocol for printing microelectrodes in multidimensional motifs is demonstrated. Finally, applications of printed microelectrodes for electrically small antennas, solar cells, and light-emitting diodes are highlighted.

Planar and three-dimensional printing of conductive metallic inks is described. Our approach provides new avenues for fabricating printed electronic, optoelectronic, and biomedical devices in unusual layouts at the microscale.

Stampa planare e tridimensionale di inchiostri conduttivi

Printed electronics rely on low-cost, large-area fabrication routes to create flexible or multidimensional electronic, optoelectronic, and biomedical ...

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Bioingegneria

Parallel-plate Flow Chamber and Continuous Flow Circuit to Evaluate Endothelial Progenitor Cells under Laminar Flow Shear Stress

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well quantifiable fluid shear stresses1.
Our flow chamber design and flow circuit (Fig. 1) contains a transparent viewing region that enables testing of cell adhesion and imaging of cell morphology immediately before flow (Fig. 11A, B), at various time points during flow (Fig. 11C), and after flow (Fig. 11D). These experiments are illustrated with human umbilical cord blood-derived endothelial progenitor cells (EPCs) and porcine EPCs2,3.
This method is also applicable to other adherent cell types, e.g. smooth muscle cells (SMCs) or fibroblasts.
The chamber and all parts of the circuit are easily sterilized with steam autoclaving. In contrast to other chambers, e.g. microfluidic chambers, large numbers of cells (&gt; 1 million depending on cell size) can be recovered after the flow experiment under sterile conditions for cell culture or other experiments, e.g. DNA or RNA extraction, or immunohistochemistry (Fig. 11E), or scanning electron microscopy5. The shear stress can be adjusted by varying the flow rate of the perfusate, the fluid viscosity, or the channel height and width. The latter can reduce fluid volume or cell needs while ensuring that one-dimensional flow is maintained. It is not necessary to measure chamber height between experiments, since the chamber height does not depend on the use of gaskets, which greatly increases the ease of multiple experiments. Furthermore, the circuit design easily enables the collection of perfusate samples for analysis and/or quantification of metabolites secreted by cells under fluid shear stress exposure, e.g. nitric oxide (Fig. 12)6.

We are describing a method to subject adherent cells to laminar flow shear stress in a sterile continuous flow circuit. The cells' adhesion, morphology can be studied through the transparent chamber, samples obtained from the circuit for metabolite analysis and cells harvested after shear exposure for future experiments or culture.

Piatti paralleli Camera Flow e circuito a flusso continuo per valutare le cellule progenitrici endoteliali sotto sforzo di taglio a flusso laminare

The overall goal of this method is to describe a technique to subject adherent cells to laminar flow conditions and evaluate their response to well ...

Automated Robotic Dispensing Technique for Surface Guidance and Bioprinting of Cells

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using an automated robotic dispensing system. The particular bioink was selected as it allows cells to sediment towards and sense the features. The dispensing system bioprints viable cells in hydrogel bioinks using a backpressure assisted print head. However, by replacing the print head with a sharpened stylus or scalpel, the dispensing system can also be employed to create topographical cues through surface etching. The stylus movement can be programmed in steps of 10 &#181;m in the X, Y and Z directions. The patterned grooves were able to orientate mesenchymal stem cells, influencing them to adopt an elongated morphology in alignment with the grooves&#39; direction. The patterning could be designed using plotting software in straight lines, concentric circles, and sinusoidal waves. In a subsequent procedure, fibroblasts and mesenchymal stem cells were suspended in a 2% gelatin bioink, for bioprinting in a backpressure driven extrusion printhead. The cell bearing bioink was then printed using the same programmed coordinates used for the etching. The bioprinted cells were able to sense and react to the etched features as demonstrated by their elongated orientation along the direction of the etched grooves.

This protocol describes a bioprinting methodology using an automated robotic depositing system that incorporates etched topographical guidance cues with the precision deposition of a cell bearing hydrogel bioink. The printed cells are directly delivered to the etched features and are able to sense and orientate with them.

Tecnica Automated robotica erogazione di orientamento della superficie e Bioprinting di celle

This manuscript describes the introduction of cell guidance features followed by the direct delivery of cells to these features in a hydrogel bioink using ...

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate flow chambers. Endothelial cells form the inner cellular lining of blood vessels and are chronically exposed to the frictional force of blood flow called shear stress. Under physiological conditions, endothelial cells function in the presence of various shear stress conditions. Thus, the application of shear stress conditions in in vitro models can provide greater insight into endothelial responses in vivo. The parallel-plate flow chamber previously published by Lane et al.9 is adapted to study endothelial gene regulation in the presence and absence of steady (non-pulsatile) laminar flow. Key adaptations in the set-up for laminar flow as presented here include a large, dedicated environment to house concurrent flow circuits, the monitoring of flow rates in real-time, and the inclusion of an exogenous reference RNA for the normalization of quantitative real-time PCR data. To assess multiple treatments/conditions with the application of shear stress, multiple flow circuits and pumps are used simultaneously within the same heated and humidified incubator. The flow rate of each flow circuit is measured continuously in real-time to standardize shear stress conditions throughout the experiments. Because these experiments have multiple conditions, we also use an exogenous reference RNA that is spiked-in at the time of RNA extraction for the normalization of RNA extraction and first-strand cDNA synthesis efficiencies. These steps minimize the variability between samples. This strategy is employed in our pipeline for the gene expression analysis with shear stress experiments using the parallel-plate flow chamber, but parts of this strategy, such as the exogenous reference RNA spike-in, can easily and cost-effectively be used for other applications.

Here, a workflow for the culture and gene expression analysis of endothelial cells under fluid shear stress is presented. Included is a physical arrangement for simultaneously housing and monitoring multiple flow chambers in a controlled environment and the use of an exogenous reference RNA for quantitative PCR.

Analisi dell'espressione genica di cellule endoteliali esposte per Shear Stress utilizzando più flusso parallelo-piastra Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate ...

An Automated Method to Perform The In Vitro Micronucleus Assay using Multispectral Imaging Flow Cytometry

The in vitro micronucleus (MN) assay is often used to evaluate cytotoxicity and genotoxicity but scoring the assay via manual microscopy is laborious and introduces uncertainty in results due to variability between scorers. To remedy this, automated slide-scanning microscopy as well as conventional flow cytometry methods have been introduced in an attempt to remove scorer bias and improve throughput. However, these methods have their own inherent limitations such as inability to visualize the cytoplasm of the cell and the lack of visual MN verification or image data storage with flow cytometry. Multispectral Imaging Flow Cytometry (MIFC) has the potential to overcome these limitations. MIFC combines the high resolution fluorescent imagery of microscopy with the statistical robustness and speed of conventional flow cytometry. In addition, all collected imagery can be stored in dose-specific files. This paper describes the protocol developed to perform a fully automated version of the MN assay on MIFC. Human lymphoblastoid TK6 cells were enlarged using a hypotonic solution (75 mM KCl), fixed with 4% formalin and the nuclear content was stained with Hoechst 33342. All samples were run in suspension on the MIFC, permitting acquisition of high resolution images of all key events required for the assay (e.g. binucleated cells with and without MN as well as mononucleated and polynucleated cells). Images were automatically identified, categorized and enumerated in the MIFC data analysis software, allowing for automated scoring of both cytotoxicity and genotoxicity. Results demonstrate that using MIFC to perform the in vitro MN assay allows statistically significant increases in MN frequency to be detected at several different levels of cytotoxicity when compared to solvent controls following exposure of TK6 cells to Mitomycin C and Colchicine, and that no significant increases in MN frequency are observed following exposure to Mannitol.

The in vitro micronucleus assay is a well-established method for evaluating genotoxicity and cytotoxicity but scoring the assay using manual microscopy is laborious and suffers from subjectivity and inter-scorer variability. This paper describes the protocol developed to perform a fully automated version of the assay using multispectral imaging flow cytometry.

Un metodo automatizzato per eseguire l'analisi in vitro micronucleoutilizzando la citometria del flusso di imaging multispettrale

The in vitro micronucleus (MN) assay is often used to evaluate cytotoxicity and genotoxicity but scoring the assay via manual microscopy is laborious and ...

Continuous Measurement of Biological Noise in Escherichia Coli Using Time-lapse Microscopy

The protocol developed here offers a tool to enable computer tracking of Escherichia coli division and fluorescent levels over several hours. The process starts by screening for colonies that survive on minimal media, assuming that only Escherichia coli harboring the correct plasmid will be able to thrive in the specific conditions. Since the process of building large genetic circuits, requiring the assembly of many DNA parts, is challenging, circuit components are often distributed between multiple plasmids at different copy numbers requiring the use of several antibiotics. Mutations in the plasmid can destroy transcription of the antibiotic resistance genes and interject with resources management in the cell leading to necrosis. The selected colony is set on a glass-bottom Petri dish and a few focus planes are selected for microscopy tracking in both bright field and fluorescent domains. The protocol maintains the image focus for more than 12 hours under initial conditions that cannot be regulated, creating a few difficulties. For example, dead cells start to accumulate in the lenses' field of focus after a few hours of imaging, which causes toxins to buildup and the signal to blur and decay. Depletion of nutrients introduces new metabolic processes and hinder the desired response of the circuit. The experiment's temperature lowers the effectivity of inducers and antibiotics, which can further damage the reliability of the signal. The minimal media gel shrinks and dries, and as a result the optical focus changes over time. We developed this method to overcome these challenges in Escherichia coli, similar to previous works developing analogous methods for other micro-organisms. In addition, this method offers an algorithm to quantify the total stochastic noise in unaltered and altered cells, finding that the results are consistent with flow analyzer predictions as shown by a similar coefficient of variation (CV).

Continuous Measurement of Biological Noise in Escherichia Coli Using Time-lapse Microscopy

This work presents a microscopy method that allows live imaging of a single cell of Escherichia coli for analysis and quantification of the stochastic behavior of synthetic gene circuits.

Misurazione continua del rumore biologico in Escherichia Coli utilizzando la microscopia time-lapse

The protocol developed here offers a tool to enable computer tracking of Escherichia coli division and fluorescent levels over several hours. The process ...

The Fabrication and Operation of a Continuous Flow, Micro-Electroporation System with Permeabilization Detection

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is accompanied by high manufacturing costs, which has brought about an interest in using alternative methods for gene delivery. Electroporation is an electro-physical, non-viral approach for the intracellular delivery of genes and other exogenous materials. Upon the application of an electric field, the cell membrane temporarily allows molecular delivery into the cell. Typically, electroporation is performed on the macroscale to process large numbers of cells. However, this approach requires extensive empirical protocol development, which is costly when working with primary and difficult-to-transfect cell types. Lengthy protocol development, coupled with the requirement of large voltages to achieve sufficient electric-field strengths to permeabilize the cells, has led to the development of micro-scale electroporation devices. These micro-electroporation devices are manufactured using common microfabrication techniques and allow for greater experimental control with the potential to maintain high throughput capabilities. This work builds off a microfluidic-electroporation technology capable of detecting the level of cell membrane permeabilization at a single-cell level under continuous flow. However, this technology was limited to 4 cells processed per second, and thus a new approach for increasing the system throughput is proposed and presented here. This new technique, denoted as cell-population-based feedback control, considers the cell permeabilization response to a variety of electroporation pulsing conditions and determines the best-suited electroporation pulse conditions for the cell type under test. A higher-throughput mode is then used, where this 'optimal' pulse is applied to the cell suspension in transit. The steps for fabricating the device, setting up and running the microfluidic experiments, and analyzing the results are presented in detail. Finally, this micro-electroporation technology is demonstrated by delivering a DNA plasmid encoding for green fluorescent protein (GFP) into HEK293 cells.

This protocol describes the microfabrication techniques required to build a lab-on-a-chip, microfluidic electroporation device. The experimental setup performs controlled, single-cell-level transfections in a continuous flow and can be extended to higher throughputs with population-based control. An analysis is provided showcasing the ability to electrically monitor the degree of cell membrane permeabilization in real-time.

La fabbricazione e il funzionamento di un sistema di micro-elettroporazione a flusso continuo con rilevamento di permeabilizzazione

Current therapeutic innovations, such as CAR-T cell therapy, are heavily reliant on viral-mediated gene delivery. Although efficient, this technique is ...

Fabrication of Engineered Vascular Flaps Using 3D Printing Technologies

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create tissues by adding layer upon layer of printable biomaterials, termed bioinks, and cells in an orderly and automatic manner, which allows for creating highly intricate structures that traditional tissue engineering techniques cannot achieve. Thus, 3D bioprinting is an appealing in vitro approach to mimic the native vasculature complex structure, ranging from millimetric vessels to microvascular networks. 
Advances in 3D bioprinting in granular hydrogels enabled the high-resolution extrusion of low-viscosity extracellular matrix-based bioinks. This work presents a combined 3D bioprinting and sacrificial mold-based 3D printing approach for fabricating engineered vascularized tissue flaps. 3D bioprinting of endothelial and support cells using recombinant collagen-methacrylate bioink within a gelatin support bath is utilized for the fabrication of a self-assembled capillary network. This printed microvasculature is assembled around a mesoscale vessel-like porous scaffold, fabricated using a sacrificial 3D printed mold, and is seeded with endothelial cells. 
This assembly induces the endothelium of the mesoscale vessel to anastomose with the surrounding capillary network, establishing a hierarchical vascular network within an engineered tissue flap. The engineered flap is then directly implanted by surgical anastomosis to a rat femoral artery using a cuff technique. The described methods can be expanded for the fabrication of various vascularized tissue flaps for use in reconstruction surgery and vascularization studies.

Engineered flaps require an incorporated functional vascular network. In this protocol, we present a method of fabricating a 3D printed tissue flap containing a hierarchical vascular network and its direct microsurgical anastomoses to rat femoral artery.

Fabbricazione di lembi vascolari ingegnerizzati utilizzando tecnologie di stampa 3D

Engineering implantable, functional, thick tissues requires designing a hierarchical vascular network. 3D bioprinting is a technology used to create ...

Automation of the Micronucleus Assay Using Imaging Flow Cytometry and Artificial Intelligence

The micronucleus (MN) assay is used worldwide by regulatory bodies to evaluate chemicals for genetic toxicity. The assay can be performed in two ways: by scoring MN in once-divided, cytokinesis-blocked binucleated cells or fully divided mononucleated cells. Historically, light microscopy has been the gold standard method to score the assay, but it is laborious and subjective. Flow cytometry has been used in recent years to score the assay, but is limited by the inability to visually confirm key aspects of cellular imagery. Imaging flow cytometry (IFC) combines high-throughput image capture and automated image analysis, and has been successfully applied to rapidly acquire imagery of and score all key events in the MN assay. Recently, it has been demonstrated that artificial intelligence (AI) methods based on convolutional neural networks can be used to score MN assay data acquired by IFC. This paper describes all steps to use AI software to create a deep learning model to score all key events and to apply this model to automatically score additional data. Results from the AI deep learning model compare well to manual microscopy, therefore enabling fully automated scoring of the MN assay by combining IFC and AI.

The micronucleus (MN) assay is a well-established test for quantifying DNA damage. However, scoring the assay using conventional techniques such as manual microscopy or feature-based image analysis is laborious and challenging. This paper describes the methodology to develop an artificial intelligence model to score the MN assay using imaging flow cytometry data.

Automazione del test del micronucleo mediante citometria a flusso di imaging e intelligenza artificiale

The micronucleus (MN) assay is used worldwide by regulatory bodies to evaluate chemicals for genetic toxicity. The assay can be performed in two ways: by ...

Caratterizzazione quantitativa delle proprietà del bioink per la stampa DLP continua

Quantitative Characterization of Liquid Photosensitive Bioink Properties for Continuous Digital Light Processing Based Printing

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing parameters of digital light processing (DLP). However, the acquisition of working curves wastes materials and requires high formability of materials, which are not suitable for biomaterials. In addition, the reduction of cell activity due to multiple exposures and the failure of structural formation due to repeated positioning are both unavoidable problems in conventional DLP bioprinting. This work introduces a new method of obtaining the working curve and the improvement process of continuous DLP printing technology based on such a working curve. This method of obtaining the working curve is based on the absorbance and photorheological properties of the biomaterials, which do not depend on the formability of the biomaterials. The continuous DLP printing process, obtained from improving the printing process by analyzing the working curve, increases the printing efficiency more than tenfold and greatly improves the activity and functionality of cells, which is beneficial to the development of tissue engineering.

Autore in primo piano: Caratterizzazione quantitativa delle proprietà dei bioink fotosensibili liquidi per la stampa digitale continua basata sull'elaborazione della luce  

This study uses temperature and material composition to control the yield stress properties of yield stress fluids. The solid-like state of the ink can protect the printing structure, and the liquid-like state can continuously fill the printing position, realizing the digital light processing 3D printing of extremely soft bioinks.

Caratterizzazione quantitativa delle proprietà del bioink fotosensibile liquido per la stampa basata sull'elaborazione continua della luce digitale

Precise printing fabrication of bioinks is a prerequisite for tissue engineering; the Jacobs working curve is the tool to determine the precise printing ...