Name: manufacture of concentrated, lipid-based oxygen microbubble emulsions by high shear homogenization and serial concentration
Uploaded: 2014-05-26T14:00:00
Description: Watch this Scientific Journal Video about Manufacture of Concentrated, Lipid-based Oxygen Microbubble Emulsions by High Shear Homogenization and Serial Concentration at JoVE.com

Funding: U.S. Army Medical Research &#38; Materiel Command (USAMRMC) and managed by the Telemedicine &#38; Advanced Technology Research Center.&#160; Shunxi Ji contributed the modification of the syringes as described here.

1. System Set-up
The system consists of a holding and concentrating tank (HCT) fitted with a single stage mixer, an in-line high shear homogenizer, a roller pump to move fluid between the HCT and the homogenizer, and a heat-exchanger (Figure 1).
<ol>
	<li>Place a sterilized, wide-mouthed 4 L glass collection vessel fitted with 2 base ports and 3 side ports beneath the single stage mixer. Lower the mixer head to the mouth of the vessel and ensure a gas-tight fitting using rub...

<ol>
	<li>Lentacker, I., De Smedt, S. C., Sanders, N. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+loaded+microbubble+design+for+ultrasound+triggered+delivery.">Drug loaded microbubble design for ultrasound triggered delivery.</a> Soft Matter. 5 (11), 2161-2170 (2009).</li><li>Ren, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Novel+Ultrasound+Microbubble+Carrying+Gene+and+Tat+Peptide:+Preparation+and+Characterization.">A Novel Ultrasound Microbubble Carrying Gene and Tat Peptide: Preparation and Characterization.</a> Academic Radiology. 16 (12), 1457-1465 (2009).</li><li>Tinkov, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbubbles+as+Ultrasound+Triggered+Drug+Carriers.">Microbubbles as Ultrasound Triggered Drug Carriers.</a> Journal of Pharmaceutical Sciences. 98 (6), 1935-1961 (2009).</li><li>Hernot, S., Klibanov, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbubbles+in+ultrasound-triggered+drug+and+gene+delivery.">Microbubbles in ultrasound-triggered drug and gene delivery.</a> Advanced Drug Delivery Reviews. 60 (10), 1153-1166 (2008).</li><li>Lanza, G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+site-targeted+ultrasonic+contrast+agent+with+broad+biomedical+application.">A novel site-targeted ultrasonic contrast agent with broad biomedical application.</a> Circulation. 94 (12), 3334-3340 (1996).</li><li>Cavalli, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+characterization+of+dextran+nanobubbles+for+oxygen+delivery.">Preparation and characterization of dextran nanobubbles for oxygen delivery.</a> International Journal of Pharmaceutics. 381 (2), 160-165 (2009).</li><li>Kheir, J. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxygen+Gas-Filled+Microparticles+Provide+Intravenous+Oxygen+Delivery.">Oxygen Gas-Filled Microparticles Provide Intravenous Oxygen Delivery.</a> Science Translational Medicine. 4 (140), (2012).</li><li>Lindner, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microvascular+rheology+of+definity+microbubbles+after+intra-arterial+and+intravenous+administration.">Microvascular rheology of definity microbubbles after intra-arterial and intravenous administration.</a> Journal of the American Society of Echocardiography. 15 (5), 396-403 (2002).</li><li>Zhao, Y. Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation,+characterization+and+in+vivo+observation+of+phospholipid-based+gas-filled+microbubbles+containing+hirudin.">Preparation, characterization and in vivo observation of phospholipid-based gas-filled microbubbles containing hirudin.</a> Ultrasound in Medicine and Biology. 31 (9), 1237-1243 (2005).</li><li>Seo, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+Assembly+of+Monodisperse,+Nanoparticle-Incorporated+Perfluorocarbon+Microbubbles+for+Medical+Imaging+and+Therapy.">Microfluidic Assembly of Monodisperse, Nanoparticle-Incorporated Perfluorocarbon Microbubbles for Medical Imaging and Therapy.</a> Langmuir. 26 (17), 13855-13860 (2010).</li><li>Wan, J. D., Stone, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coated+Gas+Bubbles+for+the+Continuous+Synthesis+of+Hollow+Inorganic+Particles.">Coated Gas Bubbles for the Continuous Synthesis of Hollow Inorganic Particles.</a> Langmuir. 28 (1), 37-41 (2012).</li><li>Duncanson, W. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monodisperse+Gas-Filled+Microparticles+from+Reactions+in+Double+Emulsions.">Monodisperse Gas-Filled Microparticles from Reactions in Double Emulsions.</a> Langmuir. 28 (17), 6742-6745 (2012).</li><li>Kendall, M. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scaled-Up+Production+of+Monodisperse,+Dual+Layer+Microbubbles+Using+Multi-Array+Microfluidic+Module+for+Medical+Imaging+and+Drug+Delivery.">Scaled-Up Production of Monodisperse, Dual Layer Microbubbles Using Multi-Array Microfluidic Module for Medical Imaging and Drug Delivery.</a> Bubble Science Engineering and Technology. 4 (1), 12-20 (2012).</li><li>Szijjarto, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+Perfluorocarbon+Gases+on+the+Size+and+Stability+Characteristics+of+Phospholipid-Coated+Microbubbles:+Osmotic+Effect+versus+Interfacial+Film+Stabilization.">Effects of Perfluorocarbon Gases on the Size and Stability Characteristics of Phospholipid-Coated Microbubbles: Osmotic Effect versus Interfacial Film Stabilization.</a> Langmuir. 28 (2), 1182-1189 (2012).</li><li>Rossi, S., Waton, G., Krafft, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipid-Coated+Gas+Bubble+Engineering:+Key+Parameters+for+Size+and+Stability+Control,+as+Determined+by+an+Acoustical+Method.">Phospholipid-Coated Gas Bubble Engineering: Key Parameters for Size and Stability Control, as Determined by an Acoustical Method.</a> Langmuir. 26 (3), 1649-1655 (2010).</li><li>Swanson, E. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phospholipid-Stabilized+Microbubble+Foam+for+Injectable+Oxygen+Delivery.">Phospholipid-Stabilized Microbubble Foam for Injectable Oxygen Delivery.</a> Langmuir. 26 (20), 15726-15729 (2010).</li><li>Kv&#229;le, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+fractionation+of+gas-filled+microspheres+by+flotation.">Size fractionation of gas-filled microspheres by flotation.</a> Separations Technology. 6 (4), 219-226 (1996).</li><li>Dressaire, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interfacial+polygonal+nanopatterning+of+stable+microbubbles.">Interfacial polygonal nanopatterning of stable microbubbles.</a> Science. 320 (5880), 1198-1201 (2008).</li><li>Kheir, J. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bulk+Manufacture+of+Concentrated+Oxygen+Gas-Filled+Microparticles+for+Intravenous+Oxygen+Delivery.">Bulk Manufacture of Concentrated Oxygen Gas-Filled Microparticles for Intravenous Oxygen Delivery.</a> Advanced Healthcare Materials. , (2013).</li></ol>

The most important steps to creating concentrated, highly oxygenated LOMs include: 1) ensuring that the headspace within the HCT remains fully oxygenated; 2) ensuring that the purity of the lipid excipients is optimal (including storage conditions and use of GMP products); 3) ensuring that the powdered lipids mix completely with the aqueous phase prior to priming the system; and 4) paying close attention to the increase in gas fraction within the HCT to ensure that the volume fraction of gas does not exceed 70%.
<p c...

Microbubbles composed of protein, polymer, and lipid shells have been developed as vectors for drug delivery, gene therapy, and ultrasound contrast agents1-5. Because these therapeutic uses require intravascular microbubble persistence, such microbubbles are commonly filled with inert, high molecular-weight gases such as perfluorocarbons6, which have low solubility in blood and stabilize the bubble3,4.
Recently, lipid-based oxygen microbubbles (LOMs) have been designed to deliver therapeutic doses of oxygen, which may preserve end-organ oxygen delivery and prevent hemodynamic instability during periods of airway obstruction or hypoxemia7. Emulsions designed for intravenous gas delivery require different design features than those used for ultrasound contrast agents or targeted drug delivery. First, because the body consumes large volumes of oxygen gas (~200 ml/min), LOMs must be produced and injected on a large scale. This requires that the manufacturing process be efficient. Second, the manufacturing process should be closed-loop in order to avoid nitrogen contamination through the exposure of LOMs (which should be filled with 100% oxygen) to ambient air. Third, because the purpose of LOMs is intravenous gas delivery, the gas fraction of LOMs should be maximized, recognizing the limitations imposed by emulsion viscosity7. Finally, as with any intravenous injectable, precise control over particle size distribution is essential to avoiding microvascular obstruction8.
There are several established methods for microbubble manufacture. Sonication utilizes high intensity, low-frequency ultrasound applied to the air-fluid interface of an emulsion which includes a surfactant, such as an amphipathic phospholipid, in the presence of a gas headspace to produce microbubbles7,9. This process is controllable by varying ultrasound frequency, power and pulse duration, and the resulting size distribution can be tailored to produce microbubbles of a specific size distribution, though sonication is rarely used in the manufacture of clinically-used microbubbles. Amalgamation is the intense mechanical agitation of a surfactant and gas in a closed system, which is also difficult to scale up to accommodate large volumes2. Droplet-based microfluidics allows precise control of microbubble size distribution10-13. Though traditionally difficult to scale up, multi-channel, high-speed microfluidics have been described which increase microbubble production efficiency13. Microbubbles manufactured using any of these methods may require post-manufacture size-reduction processes, such as centrifugal fractionation14,15 and microbubble flotation16,17.
Another established method for the manufacture of highly stable microbubbles is shear homogenization6, which can result in a stabilizing hexagonal phospholipid pattern on the microbubble surface18. Building on this concept, we describe the incorporation of an in-line high shear homogenizer to create self-assembling LOMs19. In this process, the homogenizer utilizes rapidly rotating blades in close proximity to dual fine mesh emulsor screens, creating high mechanical and hydraulic shear for the creation of microbubbles. Serial concentration of the lipid emulsion through this system yields an increasingly concentrated gas fraction, which can be even further concentrated by centrifugation.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="42">
			<td height="42" style="height:43px;width:239px;">Name of Material/ Equipment</td>
			<td style="width:141px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:405px;">Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)</td>
			<td style="width:141px;">Avanti Polar Lipids</td>
			<td style="width:119px;">770365</td>
			<td>Alternate product: non-GMP from NOF America (Coatsome MC-8080)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Cholesterol</td>
			<td style="width:141px;">Sigma Aldrich</td>
			<td style="width:119px;">C75209</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Plasma-Lyte A</td>
			<td style="width:141px;">VWR</td>
			<td style="width:119px;">80089-818</td>
			<td>Alternatively can use NaCl</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Glass collection vessel</td>
			<td style="width:141px;">Specialty Glass, Inc.</td>
			<td style="width:119px;">Custom</td>
			<td>Contact: Pam Zurbrick - 281-595-2210</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Gas composition (oxygen) monitor</td>
			<td style="width:141px;">Precision Medical</td>
			<td style="width:119px;">PM5900L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">Sarns 8000 roller pump</td>
			<td style="width:141px;">Calicut Medical</td>
			<td style="width:119px;">16407</td>
			<td>Part of a modular perfusion system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">BIOtherm Heat Exchanger</td>
			<td style="width:141px;">Medtronic</td>
			<td style="width:119px;">ECMOtherm-II</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">Verso laboratory in-line mixer</td>
			<td style="width:141px;">Silverson Machines, Inc</td>
			<td style="width:119px;">TH-IL-102-VERSO</td>
			<td>Use multistage workheads and front-end extension with T piece</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">T-piece for Silverson Verso inlet port</td>
			<td style="width:141px;">Process Innovations</td>
			<td style="width:119px;">Custom</td>
			<td>Contact: Brian Leavitt - 508-423-2266</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">L5M-A laboratory mixer</td>
			<td style="width:141px;">Silverson Machines, Inc</td>
			<td style="width:119px;">NC0136483</td>
			<td>Use mesh emulsor screen (fine)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">Rochester-Ochsner toothed forceps</td>
			<td style="width:141px;">Fisher Scientific</td>
			<td style="width:119px;">13-812-18</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">140 mL syringe</td>
			<td style="width:141px;">Kendall Healthcare Monoject&#160;</td>
			<td style="width:119px;">8881114030</td>
			<td>Ensure there is a luer lock.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:239px;">IX71 Inverted light microscope</td>
			<td style="width:141px;">Olympus</td>
			<td style="width:119px;">IX71</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:239px;">Retiga-2000R microscope camera</td>
			<td style="width:141px;">QImaging</td>
			<td style="width:119px;">RET-2000R-F-M-12</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:239px;">Accusizer 780A Autodilution</td>
			<td style="width:141px;">PSS-NICOMP Particle Sizing Systems</td>
			<td style="width:119px;">Out of production</td>
			<td></td>
		</tr>
	</tbody>
</table>

manufacture of concentrated, lipid-based oxygen microbubble emulsions by high shear homogenization and serial concentration

Gas-filled microbubbles have been developed as ultrasound contrast and drug delivery agents. Microbubbles can be produced by processing surfactants using sonication, mechanical agitation, microfluidic devices, or homogenization. Recently, lipid-based oxygen microbubbles (LOMs) have been designed to deliver oxygen intravenously during medical emergencies, reversing life-threatening hypoxemia, and preventing subsequent organ injury, cardiac arrest, and death. We present methods for scaled-up production of highly oxygenated microbubbles using a closed-loop high-shear homogenizer. The process can produce 2 L of concentrated LOMs (90% by volume) in 90 min. Resulting bubbles have a mean diameter of ~2 &#956;m, and a rheologic profile consistent with that of blood when diluted to 60 volume %. This technique produces LOMs in high capacity and with high oxygen purity, suggesting that this technique may be useful for translational research labs.

High shear homogenization enables the efficient (i.e. within one afternoon) production of sufficient LOMs for an animal study and does not require technical expertise. Once proficient, up to 2 L of concentrated LOMs can be manufactured in 90 min.
Microbubble size and morphology was assessed by light microscopy and by light obscuration. When a 10 &#956;l sample of LOMs was visualized, spherical LOMs were noted, as well as a relative paucity of lipid debris (Figure 3A)....

Watch this Scientific Journal Video about Manufacture of Concentrated, Lipid-based Oxygen Microbubble Emulsions by High Shear Homogenization and Serial Concentration at JoVE.com

Manufacture of Concentrated, Lipid-based Oxygen Microbubble Emulsions by High Shear Homogenization and Serial Concentration

We describe methods for the manufacture of large volumes of lipid-based oxygen microbubbles (LOMs) designed for intravenous oxygen delivery using high-shear homogenization and serial concentration.

Gas-filled microbubbles have been developed as ultrasound contrast and drug delivery agents. Microbubbles can be produced by processing surfactants using ...

Research

JoVE Journal

Bioengineering

Introduction to the Ultrasound Targeted Microbubble Destruction Technique

In UTMD, bioactive molecules, such as negatively charged plasmid DNA vectors encoding a gene of interest, are added to the cationic shells of lipid ...

Characteristics of Precipitation-formed Polyethylene Glycol Microgels Are Controlled by Molecular Weight of Reactants

This work describes the formation of poly(ethylene glycol) (PEG) microgels via a photopolymerized precipitation reaction. Precipitation reactions offer ...

High-resolution Spatiotemporal Analysis of Receptor Dynamics by Single-molecule Fluorescence Microscopy

Single-molecule microscopy is emerging as a powerful approach to analyze the behavior of signaling molecules, in particular concerning those aspect (e.g., ...

Synthesis of Gold Nanoparticle Integrated Photo-responsive Liposomes and Measurement of Their Microbubble Cavitation upon Pulse Laser Excitation

Photo-responsive nanoparticles (NPs) have received considerable attention because of their potential in providing spatial, temporal, and dosage control ...

Manufacture and Drug Delivery Applications of Silk Nanoparticles

Silk is a promising biopolymer for biomedical and pharmaceutical applications due to its outstanding mechanical properties, biocompatibility and ...

Quantifying Intermembrane Distances with Serial Image Dilations

A recently-described extracellular nanodomain, termed the perinexus, has been implicated in ephaptic coupling, which is an alternative mechanism for ...

Catalytic Scavenging of Plant Reactive Oxygen Species In Vivo by Anionic Cerium Oxide Nanoparticles

Catalytic Scavenging of Plant Reactive Oxygen Species In Vivo by Anionic Cerium Oxide Nanoparticles

Reactive oxygen species (ROS) accumulation is a hallmark of plant abiotic stress response. ROS play&#160;a dual role in plants by acting as signaling ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Characterizing Single-Molecule Conformational Changes Under Shear Flow with Fluorescence Microscopy

Single-molecule behavior under mechanical perturbation has been characterized widely to understand many biological processes. However, methods such as ...

Fabrication of Zero Mode Waveguides for High Concentration Single Molecule Microscopy

In single molecule fluorescence enzymology, background fluorescence from labeled substrates in solution often limits fluorophore concentration to pico- to ...