Ce projet a été soutenu par le Centre pour l&#39;Innovation Technologique Deshpande au MIT (RK et JMK) et le prix CAREER de la NSF 0952493 à RK à travers le programme chimique et biologique des séparations. Nous remercions l&#39;Institute for Soldier Nanotechnologies (ISN) et le Laboratoire de technique des microsystèmes (MTL) au MIT pour l&#39;utilisation de leurs installations.

1. HL60 cellules de roulement 1.1. La fabrication des substrats à motifs. <ol><li> En utilisant l&#39;impression par microcontact (μCP) 4-7 pour faire en alternance monocouches auto-assemblées (SAM) de molécules PEG sur les lames de verre recouvert d&#39;or: Fabriquer l&#39;impression microcontact polydiméthylsiloxane (PDMS) timbres qui définit les modèles de récepteur avec angle d&#39;inclinaison de α = 10 ° par une SU-8 processus de moulage. Nettoyer la surface d&#39;or avec une solution piranha (3:1 mélange d&#39;acide sulfurique à 30% de peroxyde d&#39;hydrogène) pendant 20 minutes puis rincer la surface avec de l&#39;eau DI copieuses à 24,5 ° C avant utilisation. Encre du timbre de PDMS avec une solution de PEG 5mM dans l&#39;éthanol. Sécher le timbre dans l&#39;air pendant 20 minutes. Sans forcer, insérez le tampon sur la surface d&#39;or pour 40 secondes et s&#39;assurer qu&#39;il ya un bon contact entre la surface d&#39;or et le timbre. Aucun excès de pression est nécessaire. Rincer la surface avec de l&#39;éthanol et le sécher sous un courant de N 2. </li><li> Incuber le substrat dans la P-sélectine solution (15 ug / ml dans du DPBS) en utilisant une chambre de perfusion (Sciences Electron Microscopy) pour 3 heures à 24,5 ° C le modèle des zones restant avec la P-sélectine. Rincer la surface avec du DPBS copieux. </li><li> Remblai de la surface avec de la BSA (1 mg / ml dans du DPBS) pendant 1 h à bloquer des interactions non spécifiques. Rincer la surface avec du DPBS copieux. </li></ol> 1.2. Cellule roulant Expériences dans une chambre d&#39;écoulement. <ol><li> Débit d&#39;une suspension de cellules HL60 (~ 10 5 cellules / mL) au cours des surfaces texturées dans une chambre d&#39;écoulement rectangulaire (Glycotech, Inc; largeur w = 1,0 cm, longueur = 6 cm, hauteur h = 0,0127 cm) à 24,5 ° C. Utiliser une pompe seringue (instruments de précision mondiale, SP230IW) pour générer le débit de 75 uL / min, avec la contrainte de cisaillement correspondante d&#39;environ 0,5 dyn / cm 2 (~ 0,05 Pa). Calculer la contrainte de cisaillement τ en utilisant l&#39;équation d&#39;écoulement plan de Poiseuille τ = 6μQ/wh 2, où μ est la viscosité cinématique (0,001002 Pa s), Q est le débit volumétrique, w est la largeur de la chambre d&#39;écoulement, et h est la hauteur de la chambre d&#39;écoulement. </li><li> Utiliser un microscope inversé (Nikon TE2000-U) avec une caméra montée (Andor ixon 885) pour enregistrer les interactions cellules HL60 rouler avec de l&#39;adhésif P-sélectine substrats utilisant un 4 × objectif, typiquement à une vitesse de 1 image par seconde pour des durées de 300 s. Effectuer trois expériences indépendantes, pour chaque grandeur contrainte de cisaillement et l&#39;angle d&#39;inclinaison motif. Présenter les données que moyenne et l&#39;écart type des valeurs moyennes obtenues par chaque expérience. </li><li> Analyse des données. Analyser les séquences d&#39;images par une mesure de Matlab (The MathWorks, Inc) programme qui utilise une particule de suivi 8 freeware pour créer des pistes le long des bords de ligne à motifs. Pistes s&#39;étendant jusqu&#39;à la fin de la bande P-sélectine sont choisies et montées avec deux segments de ligne droite - un alignement avec le flux, l&#39;autre aligné avec le bord motif. Ces deux segments sont ensuite utilisés pour calculer la longueur de suivi de pointe, la vitesse de roulement sur le bord, et le laminage de vitesse sur la région plaine. </li></ol> 2. Les résultats représentatifs: <img src="/files/ftp_upload/2640/2640fig1.jpg" alt="Figure 1" /> Figure (A) montre une des images de microscopie converti de la vidéo de HL60 interactions rouler avec de l&#39;adhésif P-sélectine substrats en utilisant un objectif 4x. Régions lumineuses et sombres correspondent à la P-sélectine récepteurs et les régions du PEG, respectivement. Figure (B) montre les traces obtenues en utilisant un programme personnalisé de Matlab. L&#39;angle d&#39;inclinaison pointe était de 10 ° et la contrainte de cisaillement a été de 0,5 dyn / cm 2. La longueur de suivi de pointe, l e, le déplacement, d, et les vitesses de roulement sur ​​le bord et l&#39;intérieur des bandes, V e et V p, respectivement, sont décrits dans la figure (C-1). Figure (C-2) montre les distribution (le nombre de cellules enregistrées) de longueur suivi bord. Encarts montrent la valeur moyenne de l e et la vitesse de roulement sur ​​le bord (V e) et l&#39;intérieur des bandes (V p) à l&#39;angle d&#39;inclinaison α = 10 ° et l&#39;ampleur du stress de cisaillement du fluide autour de 0,5 dyn / cm 2. Les barres d&#39;erreur représentent un écart-type, où n = 3 expériences répétées (3 surfaces répliquer) pour chaque condition.

<ol>
	<li>Karnik, R., Hong, S., Zhang, H., Mei, Y., Anderson, D. G., Karp, J. M., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanomechanical+control+of+cell+rolling+in+two+dimensions+through+surface+Patterning+of+receptors.">Nanomechanical control of cell rolling in two dimensions through surface Patterning of receptors.</a> Nano Lett. 8 (4), 1153-1158 (2008).</li><li>Lee, C. H., Bose, S., Van Vliet, K. J., Karp, J. M., Karnik, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Examining+Lateral+Displacement+of+HL60+Cells+Rolling+on+Asymmetric+P-selectin+Patterns.">Examining Lateral Displacement of HL60 Cells Rolling on Asymmetric P-selectin Patterns.</a> Langmuir. 27 (1), 240-249 (2011).</li><li>Norman, K. E., Moore, K. L., McEver, R. P., Ley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leukocyte+rolling+in-vivo+is+mediated+by+p-selectin+glycoprotein+ligand-1.">Leukocyte rolling in-vivo is mediated by p-selectin glycoprotein ligand-1.</a> Blood. 86 (12), 4417-4421 (1995).</li><li>Bernard, A., Delamarche, E., Schmid, H., Michel, B., Bosshard, H. R., Biebuyck, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Printing+patterns+of+proteins.">Printing patterns of proteins.</a> Langmuir. 14 (9), 2225-2229 (1998).</li><li>James, C. D., Davis, R. C., Kam, L., Craighead, H. G., Isaacson, M., Turner, J. N., Shain, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterned+protein+layers+on+solid+substrates+by+thin+stamp+microcontact+printing.">Patterned protein layers on solid substrates by thin stamp microcontact printing.</a> Langmuir. 14 (4), 741-744 (1998).</li><li>Mrksich, M., Whitesides, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+self-assembled+monolayers+to+understand+the+interactions+of+man-made+surfaces+with+proteins+and+cells.">Using self-assembled monolayers to understand the interactions of man-made surfaces with proteins and cells.</a> Annual Review of Biophysics and Biomolecular Structure. 25, 55-78 (1996).</li><li>Tan, J. L., Tien, J., Chen, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcontact+printing+of+proteins+on+mixed+self-assembled+monolayers.">Microcontact printing of proteins on mixed self-assembled monolayers.</a> Langmuir. 18 (2), 519-523 (2002).</li><li>Lee, D., King, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microcontact+Printing+of+P-Selectin+Increases+the+Rate+of+Neutrophil+Recruitment+Under+Shear+Flow.">Microcontact Printing of P-Selectin Increases the Rate of Neutrophil Recruitment Under Shear Flow.</a> Biotechnology Progress. 24 (5), 1052-1059 .</li><li>Greenberg, A. W., Hammer, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+separation+mediated+by+differential+rolling+adhesion.">Cell separation mediated by differential rolling adhesion.</a> Biotechnol. Bioeng. 73 (2), 111-124 (2001).</li><li>Higuchi, A., Tsukamoto, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+separation+of+hepatocytes+and+fibroblasts+through+surface-modified+polyurethane+membranes.">Cell separation of hepatocytes and fibroblasts through surface-modified polyurethane membranes.</a> J. Biomed. Mater. Res. Part A. 71A (3), 470-479 (2004).</li><li>Alexeev, A., Verberg, R., Balazs, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterned+surfaces+segregate+compliant+microcapsules.">Patterned surfaces segregate compliant microcapsules.</a> Langmuir. 23 (3), 983-987 (2007).</li></ol>

Nous avons décrit un protocole pour examiner les cellules trajectoires roulant sur ​​des récepteurs asymétriques surfaces texturées fabriqué en utilisant deux l&#39;impression par microcontact. Les images de microscopie optique de surface à motifs montrant contraste évident entre le PEG et le P-sélectine zones peuvent être utilisées pour confirmer si d&#39;emboutissage est réussie. Sharp, arêtes droites peut être observé lorsque l&#39;horodatage est bien performé. Dur appuyant sur le timbre...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Human promyelocytic leukemia cells</td>
<td>&nbsp;</td>
<td>ATCC</td>
<td>CCL-240</td>
<td>HL60 cells</td>
</tr>
<tr>
<td>Gold-coated glass slides</td>
<td>&nbsp;</td>
<td>EMF</td>
<td>TA134</td>
<td>Gold slides</td>
</tr>
<tr>
<td>(1-Mercaptoundec-11-yl)tetra(ethylene glycol)</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>674508</td>
<td>PEG</td>
</tr>
<tr>
<td>Recombinant human P-selectin</td>
<td>&nbsp;</td>
<td>R&amp;D Systems Inc.</td>
<td>ADP3-050</td>
<td>P-selectin</td>
</tr>
<tr>
<td>Bovine serum albumin</td>
<td>&nbsp;</td>
<td>Rockland Immunochemicals, Inc.</td>
<td>BSA-50</td>
<td>BSA</td>
</tr>
<tr>
<td>Dulbecco's phosphate buffered saline </td>
<td>&nbsp;</td>
<td>Mediatech Inc.</td>
<td>21-030</td>
<td>DPBS</td>
</tr>
<tr>
<td>Sulfuric acid </td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>339741</td>
<td>&nbsp;</td>
<tr>
<td>Hydrogen peroxide</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>316989</td>
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studying cell rolling trajectories on asymmetric receptor patterns

Déplacement latéral des cellules orthogonales à un flux de circulation en roulant sur ​​les habitudes des récepteurs asymétriques présente une opportunité pour le développement de nouveaux dispositifs pour les sans étiquette séparation et l&#39;analyse des cellules 1. De tels dispositifs peuvent utiliser un déplacement latéral des flux continu de séparation, ou des modèles de récepteur qui modulent l&#39;adhérence de distinguer entre les différents phénotypes cellulaires ou des niveaux d&#39;expression du récepteur. Comprendre la nature des trajectoires de cellules roulant sur les récepteurs des substrats est nécessaire pour l&#39;ingénierie des substrats et la conception de tels dispositifs. Ici, nous démontrons un protocole pour l&#39;étude des trajectoires de cellules de roulement sur ​​les habitudes des récepteurs asymétriques qui soutiennent l&#39;adhésion des cellules de roulement 2. Bien définis, um échelle schémas de P-sélectine récepteurs ont été fabriqués en utilisant l&#39;impression par microcontact sur l&#39;or-lames recouvertes qui ont été incorporées dans une chambre d&#39;écoulement. HL60 cellules exprimant le ligand PSGL-1 3 ont coulé à travers un champ de lignes à motifs et visualisés sur un microscope à champ clair inversée. Les cellules laminés et suivis le long des bords inclinés des motifs, résultant en une déviation latérale. Chaque cellule généralement roulé pour une certaine distance le long des bords motif (définie comme la longueur de suivi de bord), détaché à partir du bord, et rattaché à un modèle en aval. Bien que ce détachement, il est difficile de suivre la trajectoire entière d&#39;une cellule de l&#39;entrée jusqu&#39;à la sortie de la chambre d&#39;écoulement, de traces de particules logiciel a été utilisé pour analyser les trajectoires et le rendement de roulement des cellules pendant le temps où ils se déplacent sur un seul récepteur à motif de ligne. Les trajectoires ont ensuite été examinés afin d&#39;obtenir des distributions de vitesses de roulement et la cellule de longueurs d&#39;arêtes de suivi pour chaque cellule pour des motifs différents. Ce protocole est utile pour quantifier les trajectoires de cellules roulant sur les modèles de récepteur et concernant ces paramètres d&#39;ingénierie tels que l&#39;angle modèle et la contrainte de cisaillement. Ces données seront utiles pour la conception de dispositifs microfluidiques pour sans étiquette de séparation des cellules et l&#39;analyse.

Watch this Scientific Journal Video about Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns at JoVE.com

Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns

Nous décrivons un protocole d&#39;observer et d&#39;analyser les trajectoires de cellules roulant sur des récepteurs asymétriques des substrats. Les données obtenues sont utiles pour l&#39;ingénierie des récepteurs des substrats pour les sans étiquette de séparation des cellules et l&#39;analyse.

Etudier Trajectoires Cellule roulant sur les Patterns récepteur asymétrique

Lateral displacement of cells orthogonal to a flow stream by rolling on asymmetric receptor patterns presents an opportunity for development of new ...

studying-cell-rolling-trajectories-on-asymmetric-receptor-patterns

Research

JoVE Journal

Bioengineering

9.5K vues.  MIT - Massachusetts Institute of Technology. Nous décrivons un protocole d'observer et d'analyser les trajectoires de cellules roulant sur des récepteurs asymétriques des substrats. Les données obtenues sont utiles pour l'ingénierie des récepteurs des substrats pour les sans étiquette de séparation des cellules et l'analyse.

Vidéo: Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns

Microfabrication of Nanoporous Gold Patterns for Cell-material Interaction Studies

Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, biomedical device coatings, and drug delivery tools. Nanoporous gold (np-Au), produced by a nano-scale self-assembly process, is a relatively new material that exhibits large effective surface area, high electrical conductivity, and catalytic activity. These properties have made np-Au an attractive material to scientific community. Most studies on np-Au employ macro-scale specimens and focus on fundamental science of the material and its catalytic and sensor applications. The macro-scale specimens limit np-Au's potential in miniaturized systems, including biomedical devices. In order to address these issues, we initially describe two different methods to micropattern np-Au thin films on rigid substrates. The first method employs manually-produced stencil masks for creating millimeter-scale np-Au patterns, while the second method uses lift-off photolithography to pattern sub-millimeter-scale patterns. As the np-Au thin films are obtained by sputter-deposition process, they are compatible with conventional microfabrication techniques, thereby amenable to facile integration into microsystems. These systems include electrically-addressable biosensor platforms that benefit from high effective surface area, electrical conductivity, and gold-thiol-based surface bioconjugation. We describe cell culture, immunostaining, and image processing techniques to quantify np-Au's interaction with mammalian cells, which is an important performance parameter for some biosensors. We expect that the techniques illustrated here will assist the integration of np-Au in platforms at various length-scales and in numerous applications, including biosensors, energy storage systems, and catalysts.

We report on techniques to micropattern nanoporous gold thin films via stencil printing and photolithography, as well as methods to culture cells on the microfabricated patterns. In addition, we describe image analysis methods to characterize morphology of the material and the cultured cells using scanning electron and fluorescence microscopy techniques.

Microfabrication de Patterns d&#39;or nanoporeux d&#39;études sur l&#39;interaction cellule-matériau

Nanostructured materials with feature sizes in tens of nanometers have enhanced the performance of several technologies, including fuel cells, biosensors, ...

Recherche

Bio-ingénierie

Systematic Analysis of In Vitro Cell Rolling Using a Multi-well Plate Microfluidic System

A major challenge for cell-based therapy is the inability to systemically target a large quantity of viable cells with high efficiency to tissues of interest following intravenous or intraarterial infusion. Consequently, increasing cell homing is currently studied as a strategy to improve cell therapy. Cell rolling on the vascular endothelium is an important step in the process of cell homing and can be probed in-vitro using a parallel plate flow chamber (PPFC). However, this is an extremely tedious, low throughput assay, with poorly controlled flow conditions. Instead, we used a multi-well plate microfluidic system that enables study of cellular rolling properties in a higher throughput under precisely controlled, physiologically relevant shear flow1,2. In this paper, we show how the rolling properties of HL-60 (human promyelocytic leukemia) cells on P- and E-selectin-coated surfaces as well as on cell monolayer-coated surfaces can be readily examined. To better simulate inflammatory conditions, the microfluidic channel surface was coated with endothelial cells (ECs), which were then activated with tumor necrosis factor-&#945; (TNF-&#945;), significantly increasing interactions with HL-60 cells under dynamic conditions. The enhanced throughput and integrated multi-parameter software analysis platform, that permits rapid analysis of parameters such as rolling velocities and rolling path, are important advantages for assessing cell rolling properties in-vitro. Allowing rapid and accurate analysis of engineering approaches designed to impact cell rolling and homing, this platform may help advance exogenous cell-based therapy.

Systematic Analysis of In Vitro Cell Rolling Using a Multi-well Plate Microfluidic System

This study used a multi-well plate microfluidic system, significantly increasing throughput of cell rolling studies under physiologically relevant shear flow. Given the importance of cell rolling in the multi-step cell homing cascade and the importance of cell homing following systemic delivery of exogenous populations of cells in patients, this system offers potential as a screening platform to improve cell-based therapy.

Analyse systématique des<em&gt; In Vitro</em&gt; Cellule de roulement en utilisant un système microfluidique plaque multi-puits

A major challenge for cell-based therapy is the inability to systemically target a large quantity of viable cells with high efficiency to tissues of ...

Electronic Tongue Generating Continuous Recognition Patterns for Protein Analysis

In current protocol, a combinatorial approach has been developed to simplify the design and production of sensing materials for the construction of electronic tongues (eT) for protein analysis. By mixing a small number of simple and easily accessible molecules with different physicochemical properties, used as building blocks (BBs), in varying and controlled proportions and allowing the mixtures to self-assemble on the gold surface of a prism, an array of combinatorial surfaces featuring appropriate properties for protein sensing was created. In this way, a great number of cross-reactive receptors can be rapidly and efficiently obtained. By combining such an array of combinatorial cross-reactive receptors (CoCRRs) with an optical detection system such as surface plasmon resonance imaging (SPRi), the obtained eT can monitor the binding events in real-time and generate continuous recognition patterns including 2D continuous evolution profile (CEP) and 3D continuous evolution landscape (CEL) for samples in liquid. Such an eT system is efficient for discrimination of common purified proteins.

A novel approach is described for construction of electronic tongue (eT), which greatly simplifies the design and production of sensing materials, and allows the eT to generate continuous evolution profiles and landscapes for samples in liquid. The obtained eT is efficient for common protein analysis such as discrimination.

Langue Electronique Génération Schémas de reconnaissance continue pour l&#39;analyse des protéines

In current protocol, a combinatorial approach has been developed to simplify the design and production of sensing materials for the construction of ...

Fluorescence Biomembrane Force Probe: Concurrent Quantitation of Receptor-ligand Kinetics and Binding-induced Intracellular Signaling on a Single Cell

Membrane receptor-ligand interactions mediate many cellular functions. Binding kinetics and downstream signaling triggered by these molecular interactions are likely affected by the mechanical environment in which binding and signaling take place. A recent study demonstrated that mechanical force can regulate antigen recognition by and triggering of the T-cell receptor (TCR). This was made possible by a new technology we developed and termed fluorescence biomembrane force probe (fBFP), which combines single-molecule force spectroscopy with fluorescence microscopy. Using an ultra-soft human red blood cell as the sensitive force sensor, a high-speed camera and real-time imaging tracking techniques, the fBFP is of ~1 pN (10-12 N), ~3 nm and ~0.5 msec in force, spatial and temporal resolution. With the fBFP, one can precisely measure single receptor-ligand binding kinetics under force regulation and simultaneously image binding-triggered intracellular calcium signaling on a single live cell. This new technology can be used to study other membrane receptor-ligand interaction and signaling in other cells under mechanical regulation.

We describe a technique for concurrently measuring force-regulated single receptor-ligand binding kinetics and real-time imaging of calcium signaling in a single T lymphocyte.

Fluorescence Biomembrane la Force Probe: quantification simultanée de Kinetics récepteur-ligand et induits Reliure-signalisation intracellulaire sur une cellule unique

Membrane receptor-ligand interactions mediate many cellular functions. Binding kinetics and downstream signaling triggered by these molecular interactions ...

Solid Lipid Nanoparticles (SLNs) for Intracellular Targeting Applications

Nanoparticle-based delivery vehicles have shown great promise for intracellular targeting applications, providing a mechanism to specifically alter cellular signaling and gene expression. In a previous investigation, the synthesis of ultra-small solid lipid nanoparticles (SLNs) for topical drug delivery and biomarker detection applications was demonstrated. SLNs are a well-studied example of a nanoparticle delivery system that has emerged as a promising drug delivery vehicle. In this study, SLNs were loaded with a fluorescent dye and used as a model to investigate particle-cell interactions. The phase inversion temperature (PIT) method was used for the synthesis of ultra-small populations of biocompatible nanoparticles. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylphenyltetrazolium bromide (MTT) assay was utilized in order to establish appropriate dosing levels prior to the nanoparticle-cell interaction studies. Furthermore, primary human dermal fibroblasts and mouse dendritic cells were exposed to dye-loaded SLN over time and the interactions with respect to toxicity and particle uptake were characterized using fluorescence microscopy and flow cytometry. This study demonstrated that ultra-small SLNs, as a nanoparticle delivery system, are suitable for intracellular targeting of different cell types.

Solid Lipid Nanoparticles SLNs for Intracellular Targeting Applications

In this study, a method for synthesizing ultra-small populations of biocompatible nanoparticles was described, as well as several in vitro methods by which to assess their cellular interactions.

Solide Lipid nanoparticules (SLN) Applications pour le ciblage intracellulaire

Nanoparticle-based delivery vehicles have shown great promise for intracellular targeting applications, providing a mechanism to specifically alter ...

Studying the Stoichiometry of Epidermal Growth Factor Receptor in Intact Cells using Correlative Microscopy

This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative fluorescence microscopy and environmental scanning electron microscopy (ESEM) of whole cells in hydrated state. Fluorescent quantum dots (QDs) were coupled to EGFR via a two-step labeling protocol, providing an efficient and specific protein labeling, while avoiding label-induced clustering of the receptor. Fluorescence microscopy provided overview images of the cellular locations of the EGFR. The scanning transmission electron microscopy (STEM) detector was used to detect the QD labels with nanoscale resolution. The resulting correlative images provide data of the cellular EGFR distribution, and the stoichiometry at the single molecular level in the natural context of the hydrated intact cell. ESEM-STEM images revealed the receptor to be present as monomer, as homodimer, and in small clusters. Labeling with two different QDs, i.e.,&#160;one emitting at 655 nm and at 800 revealed similar characteristic results.

This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative light- and electron microscopy of whole cells in hydrated state. The label contained fluorescent quantum dots. The protocol can be used to study the stoichiometry of EGFR at the single molecule level.

L&#39;étude de la Stœchiométrie Epidermal Growth Factor Receptor dans des cellules intactes en utilisant la microscopie corrélative

This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative fluorescence ...

Human Neural Organoids for Studying Brain Cancer and Neurodegenerative Diseases

The lack of relevant in vitro neural models is an important obstacle on medical progress for neuropathologies. Establishment of relevant cellular models is crucial both to better understand the pathological mechanisms of these diseases and identify new therapeutic targets and strategies. To be pertinent, an in vitro model must reproduce the pathological features of a human disease. However, in the context of neurodegenerative disease, a relevant in vitro model should provide neural cell replacement as a valuable therapeutic opportunity. 
Such a model would not only allow screening of therapeutic molecules but also can be used to optimize neural protocol differentiation [for example, in the context of transplantation in Parkinson's disease (PD)]. This study describes two in vitro protocols of 1) human glioblastoma development within a human neural organoids (NO) and 2) neuron dopaminergic (DA) differentiation generating a three-dimensional (3D) organoid. For this purpose, a well-standardized protocol was established that allows the production of size-calibrated neurospheres derived from human embryonic stem cell (hESC) differentiation. The first model can be used to reveal molecular and cellular events occurring during in glioblastoma development within the neural organoid, while the DA organoid not only represents a suitable source of DA neurons for cell therapy in Parkinson's disease but also can be used for drug testing.

This study introduces and describes protocols to derive two specific human neural organoids&#160;as a relevant and accurate model for studying 1) human glioblastoma development within human neural organoids exclusively in humans and 2) neuron dopaminergic differentiation generating a three-dimensional organoid.

Organoïdes neuronaux humains pour étudier le cancer du cerveau et les maladies neurodégénératives

The lack of relevant in vitro neural models is an important obstacle on medical progress for neuropathologies. Establishment of relevant cellular models ...

A Macrophage Reporter Cell Assay to Examine Toll-Like Receptor-Mediated NF-kB/AP-1 Signaling on Adsorbed Protein Layers on Polymeric Surfaces

The persistent inflammatory host response to an implanted biomaterial, known as the foreign body reaction, is a significant challenge in the development and implementation of biomedical devices and tissue engineering constructs. Macrophages, an innate immune cell, are key players in the foreign body reaction because they remain at the implant site for the lifetime of the device, and are commonly studied to gain an understanding of this detrimental host response. Many biomaterials researchers have shown that adsorbed protein layers on implanted materials influence macrophage behavior, and subsequently impact the host response. The methods in this paper describe an in vitro model using adsorbed protein layers containing cellular damage molecules on polymer biomaterial surfaces to assess macrophage responses. An NF-&#1082;B/AP-1 reporter macrophage cell line and the associated colorimetric alkaline phosphatase assay were used as a rapid method to indirectly examine NF-&#1082;B/AP-1 transcription factor activity in response to complex adsorbed protein layers containing blood proteins and damage-associated molecular patterns, as a model of the complex adsorbed protein layers formed on biomaterial surfaces in vivo.

This protocol provides researchers with a rapid, indirect method of measuring TLR-dependent NF-&#1082;B/AP-1 transcription factor activity in a murine macrophage cell line in response to a variety of polymeric surfaces and adsorbed protein layers that model the biomaterial implant microenvironment.

The persistent inflammatory host response to an implanted biomaterial, known as the foreign body reaction, is a significant challenge in the development ...

A Human 3D Extracellular Matrix-Adipocyte Culture Model for Studying Matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of cellular function. The ECM plays a particularly important role in adipose tissue function in obesity, and alterations in adipose tissue ECM deposition and composition are associated with metabolic disease in mice and humans. Tractable in vitro models that permit dissection of the roles of the ECM and cells in contributing to global tissue phenotype are sparse. We describe a novel 3D in vitro model of human ECM-adipocyte culture that permits study of the specific roles of the ECM and adipocytes in regulating adipose tissue metabolic phenotype. Human adipose tissue is decellularized to isolate ECM, which is subsequently repopulated with preadipocytes that are then differentiated within the ECM into mature adipocytes. This method creates ECM-adipocyte constructs that are metabolically active and retain characteristics of the tissues and patients from which they are derived. We have used this system to demonstrate disease-specific ECM-adipocyte crosstalk in human adipose tissue. This culture model provides a tool for dissecting the roles of the ECM and adipocytes in contributing to global adipose tissue metabolic phenotype and permits study of the role of the ECM in regulating adipose tissue homeostasis.

We describe a 3D human extracellular matrix-adipocyte in vitro culture system that permits dissection of the roles of the matrix and adipocytes in contributing to adipose tissue metabolic phenotype.

Un modèle de culture matrix-adipocyte extracellulaire humaine 3D pour étudier matrix-Cell Metabolic Crosstalk

The extracellular matrix (ECM) plays a central role in regulating tissue homeostasis, engaging in crosstalk with cells and regulating multiple aspects of ...

In Vitro 3D Cell-Cultured Arterial Models for Studying Vascular Drug Targeting Under Flow

The use of three-dimensional (3D) models of human arteries, which are designed with the correct dimensions and anatomy, enables the proper modeling of various important processes in the cardiovascular system. Recently, although several biological studies have been performed using such 3D models of human arteries, they have not been applied to study vascular targeting. This paper presents a new method to fabricate real-sized, reconstructed human arterial models using a 3D printing technique, line them with human endothelial cells (ECs), and study particle targeting under physiological flow. These models have the advantage of replicating the physiological size and conditions of blood vessels in the human body using low-cost components. This technique may serve as a new platform for studying and understanding drug targeting in the cardiovascular system and may improve the design of new injectable nanomedicines. Moreover, the presented approach may provide significant tools for the study of targeted delivery of different agents for cardiovascular diseases under patient-specific flow and physiological conditions.

In Vitro 3D Cell-Cultured Arterial Models for Studying Vascular Drug Targeting Under Flow

Here, we present a new protocol to study and map the targeted deposition of drug carriers to endothelial cells in fabricated, real-sized, three-dimensional human artery models under physiological flow. The presented method may serve as a new platform for targeting drug carriers within the vascular system.

Modèles artériels 3D cultivés en cellules in vitro pour l’étude du ciblage de médicaments vasculaires sous flux

The use of three-dimensional (3D) models of human arteries, which are designed with the correct dimensions and anatomy, enables the proper modeling of ...