This project was supported by the Deshpande Center for Technological Innovation at MIT (R.K. and J.M.K.) and the NSF CAREER award 0952493 to R.K. through the Chemical and Biological Separations program. We thank the Institute for Soldier Nanotechnologies (ISN) and the Microsystems Technology Laboratory (MTL) at MIT for use of their facilities.

1. HL60 cell rolling
1.1. Fabrication of Patterned Substrates.
<ol>
	<li>Using microcontact printing (&mu;CP)4-7 to make alternating self-assembled monolayers (SAMs) of PEG molecules on the gold-coated glass slides: Fabricate microcontact printing polydimethylsiloxane (PDMS) stamps that defined the receptor patterns with inclination angle of &alpha; = 10&deg; by an SU-8 molding process. Clean the gold surface with piranha solution (3:1 mixture of sulfuric acid to 30% hydrogen peroxide) for 20 minutes and then rinse the surface with copious DI water at 24.5 &deg;C prior to use. Ink the PDMS stamp with 5mM PEG solution in ethanol. Dry the stamp in air for 20 minutes. Gently put the stamp on the gold surface for 40 sec and make sure there is a good contact between the gold surface and the stamp. No excess pressure is required. Rinse the surface with ethanol and dry it under a stream of N2.</li>
	<li>Incubate the substrate within P-selectin solution (15 &mu;g/mL in DPBS) using a perfusion chamber (Electron Microscopy Sciences) for 3 hours at 24.5&deg;C to pattern the remaining areas with P-selectin. Rinse the surface with copious DPBS.</li>
	<li>Backfill the surface with BSA (1 mg/mL in DPBS) for 1 h to block non-specific interactions.&nbsp; Rinse the surface with copious DPBS.</li>
</ol>
1.2. Cell Rolling Experiments in a Flow Chamber.
<ol>
	<li>Flow a suspension of HL60 cells (~105 cells/mL) over the patterned surfaces in a rectangular flow chamber (Glycotech, Inc; width w = 1.0 cm; length = 6 cm; height h = 0.0127 cm) at 24.5&deg;C. Use a syringe pump (World Precision Instruments, SP230IW) to generate flow rate of 75 &mu;L/min, with corresponding shear stress around 0.5 dyn/cm2 (~0.05 Pa). Calculate shear stress &tau; by using the plane Poiseuille flow equation &tau; = 6&mu;Q/wh2, where &mu; is the kinematic viscosity (0.001002 Pa s), Q is volumetric flow rate, w is width of the flow chamber, and h is height of the flow chamber.</li>
	<li>Use an inverted microscope (Nikon TE2000-U) with a mounted camera (Andor iXon 885) to record HL60 cells rolling interactions with adhesive P-selectin substrates using a 4&times; objective, typically at a rate of 1 frame per second for durations of 300 s. Perform three independent experiments, for each shear stress magnitude and pattern inclination angle. Present data as mean and standard deviation of the average values obtained from each experiment.</li>
	<li>Data Analysis. 
	Analyze the image sequences by a customized Matlab (Mathworks, Inc.) program that utilized a particle tracking freeware8 to generate tracks along the patterned line edges. Tracks extending till the end of a P-selectin band are selected and fitted with two straight line segments - one aligned with the flow, the other aligned with the pattern edge. These two segments are then used to calculate the edge tracking length, rolling velocity on the edge, and rolling velocity on the plain region.</li>
</ol>
2. Representative Results:
<img src="/files/ftp_upload/2640/2640fig1.jpg" alt="Figure 1" /> 
Figure (A) shows one of microscope images converted from the video of HL60 rolling interactions with adhesive P-selectin substrates using a 4&times; objective. Bright and dark regions correspond to P-selectin receptor and PEG regions, respectively. Figure (B) shows the tracks obtained using a customized Matlab program. The edge inclination angle was 10&deg; and the shear stress was 0.5 dyn/cm2. The edge tracking length, le, displacement, d, and the rolling velocities on the edge and inside the bands, Ve and Vp, respectively, are described in Figure (C-1). Figure (C-2) shows the distribution (the number of recorded cells) of edge tracking length. Insets show the average value of le and the rolling velocity on the edge (Ve) and inside the bands (Vp) at the inclination angle &alpha; =10&deg; and the fluid shear stress magnitude around 0.5 dyn/cm2. Error bars represent one standard deviation, where n = 3 replicate experiments (3 replicate surfaces) for each 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>

No conflicts of interest declared.

We have described a protocol to examine cell rolling trajectories on asymmetric receptor-patterned surfaces fabricated using microcontact printing2. The optical microscope images of patterned surface showing clear contrast between PEG and P-selectin areas can be used to confirm whether stamping is successful. Sharp, straight edges can be observed when the stamping is performed well. Hard pressing of the stamp may result in stamp deformation which limits the precision of patterns. Wavy edges may be obtained whe...

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		<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>
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studying cell rolling trajectories on asymmetric receptor patterns

Lateral displacement of cells orthogonal to a flow stream by rolling on asymmetric receptor patterns presents an opportunity for development of new devices for label-free separation and analysis of cells1. Such devices may use lateral displacement for continuous-flow separation, or receptor patterns that modulate adhesion to distinguish between different cell phenotypes or levels of receptor expression. Understanding the nature of cell rolling trajectories on receptor-patterned substrates is necessary for engineering of the substrates and design of such devices.
Here, we demonstrate a protocol for studying cell rolling trajectories on asymmetric receptor patterns that support cell rolling adhesion2. Well-defined, &mu;m-scale patterns of P-selectin receptors were fabricated using microcontact printing on gold-coated slides that were incorporated in a flow chamber. HL60 cells expressing the PSGL-1 ligand 3were flowed across a field of patterned lines and visualized on an inverted bright field microscope. The cells rolled and tracked along the inclined edges of the patterns, resulting in lateral deflection1. Each cell typically rolled for a certain distance along the pattern edges (defined as the edge tracking length), detached from the edge, and reattached to a downstream pattern. Although this detachment makes it difficult to track the entire trajectory of a cell from entrance to exit in the flow chamber, particle-tracking software was used to analyze and yield the rolling trajectories of the cells during the time when they were moving on a single receptor-patterned line. The trajectories were then examined to obtain distributions of cell rolling velocities and the edge tracking lengths for each cell for different patterns.
This protocol is useful for quantifying cell rolling trajectories on receptor patterns and relating these to engineering parameters such as pattern angle and shear stress. Such data will be useful for design of microfluidic devices for label-free cell separation and analysis.

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

We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.

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

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9.5K Views.  MIT - Massachusetts Institute of Technology. We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.

Video: 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.

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

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.

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.

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.

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.

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.

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.

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.

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.

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