Name: methods development for blood borne macrophage carriage of nanoformulated antiretroviral drugs
Uploaded: 2010-12-09T15:00:00
Duration: 18 min 46 s
Description: Watch this Scientific Journal Video about Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs at JoVE.com

The work was supported by grants 1P01DA028555-01A1, 2R01 NS034239, 2R37 NS36126, P01 NS31492, P20RR 15635, P01MH64570, and P01 NS43985 (to H.E.G.) from the National Institutes of Health. The authors thank Ms. Robin Taylor for critical reading of the manuscript and outstanding graphic and literary support. We would like to thank Steve Grzelak for his wet-milling expertise. We would also like to thank Dr. Han Chen of the University of Nebraska-Lincoln electron microscopy core facility for supplying the scanning and transmission electron microscopy images. Finally, we would like to thank Megan Marquart for her expertise using live confocal microscopy.

<ol>
	<li>Gendelman, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+isolation+and+propagation+of+human+immunodeficiency+virus+on+recombinant+colony-stimulating+factor+1-treated+monocytes.">Efficient isolation and propagation of human immunodeficiency virus on recombinant colony-stimulating factor 1-treated monocytes.</a> J Exp Med. 167 (4), 1428-1441 (1988).</li><li>Dou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+macrophage-based+nanoparticle+platform+for+antiretroviral+drug+delivery.">Development of a macrophage-based nanoparticle platform for antiretroviral drug delivery.</a> Blood. 108 (8), 2827-2835 (2006).</li><li>Dou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+investigations+for+the+morphologic,+pharmacokinetic,+and+anti-retroviral+properties+of+indinavir+nanoparticles+in+human+monocyte-derived+macrophages.">Laboratory investigations for the morphologic, pharmacokinetic, and anti-retroviral properties of indinavir nanoparticles in human monocyte-derived macrophages.</a> Virology. 358, 148-158 (2007).</li><li>Dou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage+delivery+of+nanoformulated+antiretroviral+drug+to+the+brain+in+a+murine+model+of+neuroAIDS.">Macrophage delivery of nanoformulated antiretroviral drug to the brain in a murine model of neuroAIDS.</a> J Immunol. 183 (1), 661-669 (2009).</li><li>Nowacek, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoformulated+Antiretroviral+Drug+Combinations+Extend+Drug+Release+and+Antiretroviral+Responses+in+HIV-1-Infected+Macrophages:+Implications+for+NeuroAIDS+Therapeutics.">Nanoformulated Antiretroviral Drug Combinations Extend Drug Release and Antiretroviral Responses in HIV-1-Infected Macrophages: Implications for NeuroAIDS Therapeutics.</a> J Neuroimmune Pharmacol. , (2010).</li><li>Nowacek, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NanoART+synthesis,+characterization,+uptake,+release+and+toxicology+for+human+monocyte-macrophage+drug+delivery.">NanoART synthesis, characterization, uptake, release and toxicology for human monocyte-macrophage drug delivery.</a> Nanomed. 4 (8), 903-917 (2009).</li><li>Kalter, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+HIV+replication+in+macrophage+colony-stimulating+factor-treated+monocytes.">Enhanced HIV replication in macrophage colony-stimulating factor-treated monocytes.</a> J Immunol. 146 (1), 298-306 (1991).</li></ol>

No conflicts of interest declared.

NanoART are designed to improve HIV-1 therapeutics. We have proposed a monocyte-macrophage based drug delivery system as a first step to develop such technologies for clinical use and as a laboratory testing system for nanoformulated drug development. Our past works have shown that the system is viable for such an application5,6.
In the current report, we have illustrated methods for synthesizing NP of commonly used HIV-1 medications (indinavir, IDV; ritonovir, RTV; efavirenz, EFV and atazanavir, ATV). This was achieved by wet milling, homogenization and ultrasonication. Importantly, our approach allows for modifications of nanoART physical characteristics such as size, shape and charge 5,6. By careful selection of surfactants, one can control the charge of the particle from highly negative to neutral to highly positive. By altering the processing time and intensity, one can control the size and render particles as small as &le; 200 nm or as large as &ge; 3 &mu;m. The shape of the particle can also be controlled, but to a lesser extent than the other physical characteristics. For example, spherical particles can be made via sonication with polymers while multi-sided geometric shapes can be produced via wet milling or homogenization. Wet milling and homogenization produce differently shaped particles, but this process is dependent on the fractionation method and cannot be directly controlled for. These properties of the manufacturing methods can enable researches to easily produce nanoART to exact design specifications. This is vitally important since the physicochemical properties of nanoART have a powerful effect upon both their stability and how they interact with cells. For example, we have shown that nanoART that are approximately 1 &mu;m in size, have a strong positive charge, and have a multisided geometric shape are more rapidly taken up by macrophages, more stable once inside the cells, and released over a longer period of time 6.
A method for testing nanoART was developed that allows for simple screening of the particles' ability to be taken up, retained, and released by macrophages, one of the principle target cells of HIV-1, in addition to their capacity to inhibit viral replication. This allows one to easily differentiate nanoART based on performance and identify those that have the best chance of succeeding in an in vivo model, thus, increasing both the efficiency and speed of developing nanoART for human use.
It has been shown that mouse bone marrow macrophages when loaded ex vivo with nanoART and adoptively transferred by intravenous injection into humanized HIV-1 infected mice can travel to sites of active infection, including the central nervous system, and release drugs for up to 2 weeks to inhibit viral replication2-4. In addition, these nanoART loaded cells were also able to effectively reduce the numbers of virus-infected cells in plasma, lymph nodes, spleen, liver and lung as well as protect CD4+ cells2. These studies, although preliminary, demonstrate that a cell-mediated nanoART delivery system can distribute clinically significant amounts of drug to both blood and infected tissues. Because of the encouraging preliminary results from HIV-1 infected mouse studies, we are currently developing a simian immuno deficiency virus infected macaque model to further test the potential of nanoART for clinical use.

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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>nanoART Manufacture</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Indinavir sulfate</td>
<td>Reagent</td>
<td>Longshem Co., Shanghai, China</td>
<td>Cas # 157810-81-6</td>
<td>&nbsp;</td>
<tr>
<td>Ritonavir</td>
<td>Reagent</td>
<td>China Shengda Pharmaceutical Company, China</td>
<td>Cas # 155213-67-5</td>
<td>&nbsp;</td>
<tr>
<td>Atazanavir sulfate</td>
<td>Reagent</td>
<td>Gyma Laboratories of America INC</td>
<td>Cas # 198904-31-3</td>
<td>&nbsp;</td>
<tr>
<td>Effavirenz</td>
<td>Reagent</td>
<td>Hetero Labs LTD, India</td>
<td>Cas # 154598-52-4</td>
<td>&nbsp;</td>
<tr>
<td>PVA</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>P 8136</td>
<td>&nbsp;</td>
<tr>
<td>SDS</td>
<td>Reagent</td>
<td>Bio-Rad</td>
<td>161-0301</td>
<td>&nbsp;</td>
<tr>
<td>Sucrose</td>
<td>Reagent</td>
<td>Fluka Analytical </td>
<td>84097</td>
<td>&nbsp;</td>
<tr>
<td>P188</td>
<td>Reagent</td>
<td>Sigma Life Science</td>
<td>P 1300</td>
<td>&nbsp;</td>
<tr>
<td>mPEG 2000-DSPE</td>
<td>Reagent</td>
<td>Genzyme </td>
<td>LP-R4-039</td>
<td>&nbsp;</td>
<tr>
<td>Dotap</td>
<td>Reagent</td>
<td>Avanti Polar Lipid, Inc</td>
<td>890890 P</td>
<td>&nbsp;</td>
<tr>
<td>Hepes</td>
<td>Reagent</td>
<td>Sigma Life Science</td>
<td>83264</td>
<td>&nbsp;</td>
<tr>
<td>PLGA 75:25</td>
<td>Reagent</td>
<td>Sigma Life Science </td>
<td>P1941</td>
<td>&nbsp;</td>
<tr>
<td>Dichloromethane</td>
<td>Reagent</td>
<td>Acros</td>
<td>75-09-2</td>
<td>&nbsp;</td>
<tr>
<td>Mannitol</td>
<td>Reagent</td>
<td>Sigma Aldrich</td>
<td>M9546</td>
<td>&nbsp;</td>
<tr>
<td>CTAB</td>
<td>Reagent</td>
<td>Sigma Aldrich</td>
<td>H 9151</td>
<td>&nbsp;</td>
<tr>
<td>Analytical Balance</td>
<td>Tool</td>
<td>Denver Instrument</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>T-18 Mixer</td>
<td>Tool</td>
<td>IKA T 18 basic Ultra-Turrax </td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Ultra Sonicator</td>
<td>Tool</td>
<td>Cole Parmer</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Wet milling, MicroCer</td>
<td>Tool</td>
<td>Netzsch Fine Particle Technology, LLC</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Homogenizer, EmulsiFlex-C5</td>
<td>Tool</td>
<td>Avestin, Inc.</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Zetapotentiometer</td>
<td>Tool</td>
<td>Malvern Instruments</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Gas Manifold System</td>
<td>Tool</td>
<td>Victor 200 Series </td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>In Vitro Testing</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>DMEM</td>
<td>Reagent</td>
<td>Mediatech</td>
<td>10-013-CV</td>
<td>&nbsp;</td>
<tr>
<td>Gentamicin</td>
<td>Reagent</td>
<td>Invitrogen</td>
<td>15710-064</td>
<td>&nbsp;</td>
<tr>
<td>Ciprofloxin</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>17850</td>
<td>&nbsp;</td>
<tr>
<td>Human MCSF</td>
<td>Reagent</td>
<td>Miltenyi Biotech</td>
<td>130-093-964</td>
<td>&nbsp;</td>
<tr>
<td>Pooled normal human serum</td>
<td>Reagent</td>
<td>Cole-Parmer</td>
<td>WU-88061-68</td>
<td>&nbsp;</td>
<tr>
<td>6-well tissue culture plates</td>
<td>Tool</td>
<td>Corning Life Sciences</td>
<td>3524</td>
<td>&nbsp;</td>
<tr>
<td>Methanol (HPLC Grade)</td>
<td>Reagent</td>
<td>Fisher Scientific</td>
<td>A452SK-4</td>
<td>&nbsp;</td>
<tr>
<td>1.7 ml microcentrifuge tubes</td>
<td>Tool</td>
<td>National Scientific</td>
<td>CN1700GT</td>
<td>&nbsp;</td>
<tr>
<td>Glutaraldehyde solution</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>49632</td>
<td>&nbsp;</td>
<tr>
<td>Osmium tetroxide solution</td>
<td>Reagent</td>
<td>Sigma-Aldrich</td>
<td>75632</td>
<td>&nbsp;</td>
<tr>
<td>Centrifuge 5417R</td>
<td>Tool</td>
<td>Eppendorf</td>
<td>022621807</td>
<td>&nbsp;</td>
<tr>
<td>F-45-30-11 fixed angle rotor</td>
<td>Tool</td>
<td>Eppendorf</td>
<td>022636006</td>
<td>&nbsp;</td>
<tr>
<td>HIV-1ADA</td>
<td>Reagent</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>HIV-1 p24 mouse monoclonal antibody</td>
<td>Reagent</td>
<td>Dako</td>
<td>M0857</td>
<td>&nbsp;</td>
<tr>
<td>Microscope slide cover slips</td>
<td>Tool</td>
<td>Fisher Scientific</td>
<td>12-548-5P</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>
			<div>
			Abbreviations used in the table: IDV: indinavir; RTV: ritonavir; ATV: atazanavir; EFV: effavirenz; PVA: polyvinylalcohol; SDS sodium dodecyl sulfate; P188: poloxamer 188 (also termed Pluronic F68); mPEG 2000-DSPE: methyl-poly(ethylene-glycol)1,2-distearoyl-phosphatidyl-ethanolamine; DOTAP: (1-oleoyl-2-[6-[(7-nitro-2&#150;1,3-benzoxadiazol-4-yl) amino]hexanoyl]-3-trimethylammonium propane); PLGA: poly(lactic-co-glycolic acid); CTAB: cetyltrimethyl ammonium bromide; DMEM: Dulbecco's Modified Eagle Medium; MCSF: Macrophage Colony-Stimulating Factor; HPLC: high-pressure liquid chromatography; HIV-1: Human Immunodeficiency Virus-1 		</div>

methods development for blood borne macrophage carriage of nanoformulated antiretroviral drugs

Nanoformulated drugs can improve pharmacodynamics and bioavailability while serving also to reduce drug toxicities for antiretroviral (ART) medicines. To this end, our laboratory has applied the principles of nanomedicine to simplify ART regimens and as such reduce toxicities while improving compliance and drug pharmacokinetics. Simple and reliable methods for manufacturing nanoformulated ART (nanoART) are shown. Particles of pure drug are encapsulated by a thin layer of surfactant lipid coating and produced by fractionating larger drug crystals into smaller ones by either wet milling or high-pressure homogenization. In an alternative method free drug is suspended in a droplet of a polymer. Herein, drug is dissolved within a polymer then agitated by ultrasonication until individual nanosized droplets are formed. Dynamic light scattering and microscopic examination characterize the physical properties of the particles (particle size, charge and shape). Their biologic properties (cell uptake and retention, cytotoxicity and antiretroviral efficacy) are determined with human monocyte-derived macrophages (MDM). MDM are derived from human peripheral blood monocytes isolated from leukopacks using centrifugal elutriation for purification. Such blood-borne macrophages may be used as cellular transporters for nanoART distribution to human immunodeficiency virus (HIV) infected organs. We posit that the repackaging of clinically available antiretroviral medications into nanoparticles for HIV-1 treatments may improve compliance and positively affect disease outcomes.

Watch this Scientific Journal Video about Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs at JoVE.com

Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs

Nanoparticles of indinavir, ritonavir, efavirenz and atazanavir were manufactured using wet milling, homogenization and ultrasonication. These nanoformulations, collectively termed nanoformulated antiretroviral therapy (nanoART), assessed macrophage-based drug delivery. Monocyte-derived macrophage nanoART uptake, retention and sustained release were determined. These preliminary studies suggest the potential of nanoART for clinical use.

Nanoformulated drugs can improve pharmacodynamics and bioavailability while serving also to reduce drug toxicities for antiretroviral (ART) medicines. To ...

methods-development-for-blood-borne-macrophage-carriage

Research

JoVE Journal

Bioengineering

Fluorescence detection methods for microfluidic droplet platforms

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that accompany system miniaturisation. Advantages include the ability to efficiently process nano- to femoto- liter volumes of sample, facile integration of functional components, an intrinsic predisposition towards large-scale multiplexing, enhanced analytical throughput, improved control and reduced instrumental footprints.1
In recent years much interest has focussed on the development of droplet-based (or segmented flow) microfluidic systems and their potential as platforms in high-throughput experimentation.2-4 Here water-in-oil emulsions are made to spontaneously form in microfluidic channels as a result of capillary instabilities between the two immiscible phases. Importantly, microdroplets of precisely defined volumes and compositions can be generated at frequencies of several kHz. Furthermore, by encapsulating reagents of interest within isolated compartments separated by a continuous immiscible phase, both sample cross-talk and dispersion (diffusion- and Taylor-based) can be eliminated, which leads to minimal cross-contamination and the ability to time analytical processes with great accuracy. Additionally, since there is no contact between the contents of the droplets and the channel walls (which are wetted by the continuous phase) absorption and loss of reagents on the channel walls is prevented.
Once droplets of this kind have been generated and processed, it is necessary to extract the required analytical information. In this respect the detection method of choice should be rapid, provide high-sensitivity and low limits of detection, be applicable to a range of molecular species, be non-destructive and be able to be integrated with microfluidic devices in a facile manner. To address this need we have developed a suite of experimental tools and protocols that enable the extraction of large amounts of photophysical information from small-volume environments, and are applicable to the analysis of a wide range of physical, chemical and biological parameters. Herein two examples of these methods are presented and applied to the detection of single cells and the mapping of mixing processes inside picoliter-volume droplets. We report the entire experimental process including microfluidic chip fabrication, the optical setup and the process of droplet generation and detection.

Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that ...

Improved Method for the Preparation of a Human Cell-based, Contact Model of the Blood-Brain Barrier

The blood-brain barrier (BBB) comprises impermeable but adaptable brain capillaries which tightly control the brain environment. Failure of the BBB has been implied in the etiology of many brain pathologies, creating a need for development of human in vitro BBB models to assist in clinically-relevant research. Among the numerous BBB models thus far described, a static (without flow), contact BBB model, where astrocytes and brain endothelial cells (BECs) are cocultured on the opposite sides of a porous membrane, emerged as a simplified yet authentic system to simulate the BBB with high throughput screening capacity. Nevertheless the generation of such model presents few technical challenges. Here, we describe a protocol for preparation of a contact human BBB model utilizing a novel combination of primary human BECs and immortalized human astrocytes. Specifically, we detail an innovative method for cell-seeding on inverted inserts as well as specify insert staining techniques and exemplify how we use our model for BBB-related research.

Establishment of human models of the blood-brain barrier (BBB) can benefit research into brain conditions associated with BBB failure. We describe here an improved technique for preparation of a contact BBB model, which permits coculturing of human astrocytes and brain endothelial cells on the opposite sides of a porous membrane.

The blood-brain barrier (BBB) comprises impermeable but adaptable brain capillaries which tightly control the brain environment. Failure of the BBB has ...

Methods for Characterizing the Co-development of Biofilm and Habitat Heterogeneity

Biofilms are surface-attached microbial communities that have complex structures and produce significant spatial heterogeneities. Biofilm development is strongly regulated by the surrounding flow and nutritional environment. Biofilm growth also increases the heterogeneity of the local microenvironment by generating complex flow fields and solute transport patterns. To investigate the development of heterogeneity in biofilms and interactions between biofilms and their local micro-habitat, we grew mono-species biofilms of Pseudomonas aeruginosa and dual-species biofilms of P. aeruginosa and Escherichia coli under nutritional gradients in a microfluidic flow cell. We provide detailed protocols for creating nutrient gradients within the flow cell and for growing and visualizing biofilm development under these conditions. We also present protocols for a series of optical methods to quantify spatial patterns in biofilm structure, flow distributions over biofilms, and mass transport around and within biofilm colonies. These methods support comprehensive investigations of the co-development of biofilm and habitat heterogeneity.

Biofilms have complex interactions with their surrounding environment. To comprehensively investigate biofilm-environment interactions, we present here a series of methods to create heterogeneous chemical environment for biofilm development, to quantify local flow velocity, and to analyze mass transport in and around biofilm colonies.

Biofilms are surface-attached microbial communities that have complex structures and produce significant spatial heterogeneities. Biofilm development is ...

In Vitro Model of Physiological and Pathological Blood Flow with Application to Investigations of Vascular Cell Remodeling

Vascular disease is a common cause of death within the United States. Herein, we present a method to examine the contribution of flow dynamics towards vascular disease pathologies. Unhealthy arteries often present with wall stiffening, scarring, or partial stenosis which may all affect fluid flow rates, and the magnitude of pulsatile flow, or pulsatility index. Replication of various flow conditions is the result of tuning a flow pressure damping chamber downstream of a blood pump. Introduction of air within a closed flow system allows for a compressible medium to absorb pulsatile pressure from the pump, and therefore vary the pulsatility index. The method described herein is simply reproduced, with highly controllable input, and easily measurable results. Some limitations are recreation of the complex physiological pulse waveform, which is only approximated by the system. Endothelial cells, smooth muscle cells, and fibroblasts are affected by the blood flow through the artery. The dynamic component of blood flow is determined by the cardiac output and arterial wall compliance. Vascular cell mechano-transduction of flow dynamics may trigger cytokine release and cross-talk between cell types within the artery. Co-culture of vascular cells is a more accurate picture reflecting cell-cell interaction on the blood vessel wall and vascular response to mechanical signaling. Contribution of flow dynamics, including the cell response to the dynamic and mean (or steady) components of flow, is therefore an important metric in determining disease pathology and treatment efficacy. Through introducing an in vitro co-culture model and pressure damping downstream of blood pump which produces simulated cardiac output, various arterial disease pathologies may be investigated.

In Vitro Model of Physiological and Pathological Blood Flow with Application to Investigations of Vascular Cell Remodeling

This protocol replicates physiological or pathological blood flow in vitro to aid in determining cell response in disease pathologies. By introducing a pressure damping chamber downstream of a blood pump, blood flow across the vasculature can be recapitulated and imposed on a monolayer of vascular endothelium or a mimetic co-culture.

Vascular disease is a common cause of death within the United States. Herein, we present a method to examine the contribution of flow dynamics towards ...

Fully Automated Centrifugal Microfluidic Device for Ultrasensitive Protein Detection from Whole Blood

Enzyme-linked immunosorbent assay (ELISA) is a promising method to detect small amount of proteins in biological samples. The devices providing a platform for reduced sample volume and assay time as well as full automation are required for potential use in point-of-care-diagnostics. Recently, we have demonstrated ultrasensitive detection of serum proteins, C-reactive protein (CRP) and cardiac troponin I (cTnI), utilizing a lab-on-a-disc composed of TiO2 nanofibrous (NF) mats. It showed a large dynamic range with femto molar (fM) detection sensitivity, from a small volume of whole blood in 30 min. The device consists of several components for blood separation, metering, mixing, and washing that are automated for improved sensitivity from low sample volumes. Here, in the video demonstration, we show the experimental protocols and know-how for the fabrication of NFs as well as the disc, their integration and the operation in the following order: processes for preparing TiO2 NF mat; transfer-printing of TiO2 NF mat onto the disc; surface modification for immune-reactions, disc assembly and operation; on-disc detection and representative results for immunoassay. Use of this device enables multiplexed analysis with minimal consumption of samples and reagents. Given the advantages, the device should find use in a wide variety of applications, and prove beneficial in facilitating the analysis of low abundant proteins.

This protocol demonstrates how to achieve femto molar detection sensitivity of proteins in 10 &#181;L of whole blood within 30 min. This can be achieved by using electrospun nanofibrous mats integrated in a lab-on-a-disc, which offers high surface area as well as effective mixing and washing for enhanced signal-to-noise ratio.

Enzyme-linked immunosorbent assay (ELISA) is a promising method to detect small amount of proteins in biological samples. The devices providing a platform ...

Development of a Multicellular Three-dimensional Organotypic Model of the Human Intestinal Mucosa Grown Under Microgravity

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., flasks or dishes). In fact, it is widely recognized that cells grown in flasks or dishes tend to de-differentiate and lose specialized features of the tissues from which they were derived. Currently, there are mainly two types of 3-D culture systems where the cells are seeded into scaffolds mimicking the native extracellular matrix (ECM): (a) static models and (b) models using bioreactors. The first breakthrough was the static 3-D models. 3-D models using bioreactors such as the rotating-wall-vessel (RWV) bioreactors are a more recent development. The original concept of the RWV bioreactors was developed at NASA&#39;s Johnson Space Center in the early 1990s and is believed to overcome the limitations of static models such as the development of hypoxic, necrotic cores. The RWV bioreactors might circumvent this problem by providing fluid dynamics that allow the efficient diffusion of nutrients and oxygen. These bioreactors consist of a rotator base that serves to support and rotate two different formats of culture vessels that differ by their aeration source type: (1) Slow Turning Lateral Vessels (STLVs) with a co-axial oxygenator in the center, or (2) High Aspect Ratio Vessels (HARVs) with oxygenation via a flat, silicone rubber gas transfer membrane. These vessels allow efficient gas transfer while avoiding bubble formation and consequent turbulence. These conditions result in laminar flow and minimal shear force that models reduced gravity (microgravity) inside the culture vessel. Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa composed of an intestinal epithelial cell line and primary human lymphocytes, endothelial cells and fibroblasts cultured under microgravity provided by the RWV bioreactor.

Cells growing in a three-dimensional (3-D) environment represent a marked improvement over cell cultivation in 2-D environments (e.g., flasks or dishes). Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa cultured under microgravity provided by rotating-wall-vessel (RWV) bioreactors.

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., ...

In Vitro Permeation of FITC-loaded Ferritins Across a Rat Blood-brain Barrier: a Model to Study the Delivery of Nanoformulated Molecules

Brain microvascular endothelial cells, supported by pericytes and astrocytes endfeet, are responsible for the low permeation of large hydrosoluble drugs through the blood-brain barrier (BBB), causing difficulties for effective pharmacological therapies. In recent years, different strategies for promoting brain targeting have aimed to improve drug delivery and activity at this site, including innovative nanosystems for drug delivery across the BBB. In this context, an in vitro approach based on a simplified cellular model of the BBB provides a useful tool to investigate the effect of nanoformulations on the trans-BBB permeation of molecules. This study describes the development of a double-layer BBB, consisting of co-cultured commercially available primary rat brain microvascular endothelial cells and astrocytes. A multiparametric approach for the validation of the model, based on the measurement of the transendothelial electrical resistance and the apparent permeability of a high molecular weight dextran, is also described. As proof of concept for the employment of this BBB model to study the effect of different nanoformulations on the translocation of fluorescent molecules across the barrier, we describe the use of fluorescein isothiocyanate (FITC), loaded into ferritin nanoparticles. The ability of ferritins to improve the trans-BBB permeation of FITC was demonstrated by flux measurements and confocal microscopy analyses. The results suggest this is a useful system for validating nanosystems for delivery of drugs across the BBB.

In Vitro Permeation of FITC-loaded Ferritins Across a Rat Blood-brain Barrier: a Model to Study the Delivery of Nanoformulated Molecules

A method to establish an in vitro model of blood-brain barrier based on a co-culture of rat brain microvascular endothelial cells and astrocytes is described and validated. This system proved to be a valid tool to study the effect of nanoformulation on the trans-barrier permeation of fluorescent molecules.

Brain microvascular endothelial cells, supported by pericytes and astrocytes endfeet, are responsible for the low permeation of large hydrosoluble drugs ...

Two Methods for Decellularization of Plant Tissues for Tissue Engineering Applications

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor biocompatibility, and cost. Plant tissues have favorable characteristics that make them uniquely suited for use as scaffolds, such as high surface area, excellent water transport and retention, interconnected porosity, preexisting vascular networks, and a wide range of mechanical properties. Two successful methods of plant decellularization for tissue engineering applications are described here. The first method is based on detergent baths to remove cellular matter, which is similar to previously established methods used to clear mammalian tissues. The second is a detergent-free method adapted from a protocol that isolates leaf vasculature and involves the use of a heated bleach and salt bath to clear the leaves and stems. Both methods yield scaffolds with comparable mechanical properties and low cellular metabolic impact, thus allowing the user to select the protocol which better suits their intended application.

Here we present, and contrast two protocols used to decellularize plant tissues: a detergent-based approach and a detergent-free approach. Both methods leave behind the extracellular matrix of the plant tissues used, which can then be utilized as scaffolds for tissue engineering applications.

The autologous, synthetic, and animal-derived grafts currently used as scaffolds for tissue replacement have limitations due to low availability, poor ...

Nondestructive Monitoring of Degradable Scaffold-Based Tissue-Engineered Blood Vessel Development Using Optical Coherence Tomography

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial bypass. Characterization of the growth dynamics and remodeling process of degradable polymer scaffold-based tissue-engineered blood vessels (TEBVs) with pulsatile stimulation is crucial for vascular tissue engineering. Optical imaging techniques stand out as powerful tools for monitoring vascularization of engineered tissue enabling high-resolution imaging in real-time culture. This paper demonstrates a nondestructive and fast real-time imaging strategy to monitor the growth and remodeling of TEBVs in long-term culture by using optical coherence tomography (OCT). Geometric morphology is evaluated, including vascular remodeling process, wall thickness, and comparison of TEBV thickness in different culture time points and presence of pulsatile stimulation. Finally, OCT provides practical possibilities for real-time observation of the degradation of polymer in the reconstructing tissues under pulsatile stimulation or not and in each vessel segment, by compared with the assessment of polymer degradation using scanning electron microscopic(SEM) and polarized microscope.

A step by step protocol for nondestructive and long-period monitoring the process of vascular remodeling and scaffold degradation in real-time culture of biodegradable polymeric scaffold-based tissue-engineered blood vessels with pulsatile stimulation using optical coherence tomography is described here.

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial ...

Intra-cardiac Side-Firing Light Catheter for Monitoring Cellular Metabolism using Transmural Absorbance Spectroscopy of Perfused Mammalian Hearts

Absorbance spectroscopy of cardiac muscle provides non-destructive assessment of cytosolic and mitochondrial oxygenation via myoglobin and cytochrome absorbance respectively. In addition, numerous aspects of the mitochondrial metabolic status such as membrane potential and substrate entry can also be estimated. To perform cardiac wall transmission optical spectroscopy, a commercially available side-firing optical fiber catheter is placed in the left ventricle of the isolated perfused heart as a light source. Light passing through the heart wall is collected with an external optical fiber to perform optical spectroscopy of the heart in near real- time. The transmission approach avoids numerous surface scattering interference occurring in widely used reflection approaches. Changes in transmural absorbance spectra were deconvolved using a library of chromophore reference spectra, providing quantitative measures of all the known cardiac chromophores simultaneously. This spectral deconvolution approach eliminated intrinsic errors that may result from using common dual wavelength methods applied to overlapping absorbance spectra, as well as provided a quantitative evaluation of the goodness of fit. A custom program was designed for data acquisition and analysis, which permitted the investigator to monitor the metabolic state of the preparation during the experiment. These relatively simple additions to the standard heart perfusion system provide a unique insight into the metabolic state of the heart wall in addition to conventional measures of contraction, perfusion, and substrate/oxygen extraction.

Here we introduce a method for using an intra-ventricle optical catheter in perfused hearts to perform absorbance spectroscopy across the heart wall. The data obtained provides robust information on tissue oxygen tension as well as substrate utilization and membrane potential simultaneously with cardiac performance measures in this ubiquitous preparation.

Absorbance spectroscopy of cardiac muscle provides non-destructive assessment of cytosolic and mitochondrial oxygenation via myoglobin and cytochrome ...