Name: microfluidic production of lysolipid-containing temperature-sensitive liposomes
Uploaded: 2020-03-03T13:00:00
Description: Watch this Scientific Journal Video about Microfluidic Production of Lysolipid-Containing Temperature-Sensitive Liposomes at JoVE.com

We thank Prostate Cancer UK (CDF-12-002 Fellowship), and the Engineering and Physical Sciences Research Council (EPSRC) (EP/M008657/1) for funding.

1. Equipment setup
<ol>
	<li>Assemble the syringe pumps and SHM as follows.
	<ol>
		<li>Connect the &#34;To Computer&#34; port of the secondary syringe pump (Pump 02, for aqueous solution) to the &#34;To Network&#34; port of the master syringe pump (Pump 01, for ethanol lipid solution) using Pump to Pump network cable (Figure 1, yellow).</li>
		<li>Connect the &#34;To Computer&#34; port of the master pump to the &#34;RS232 Serial&#34; port of the computer using PC to Pump ...

<ol>
	<li>Needham, D., Park, J., Wright, A. M., Tong, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Materials+characterization+of+the+low+temperature+sensitive+liposome+(LTSL):+effects+of+the+lipid+composition+(lysolipid+and+DSPE-PEG2000)+on+the+thermal+transition+and+release+of+doxorubicin.">Materials characterization of the low temperature sensitive liposome (LTSL): effects of the lipid composition (lysolipid and DSPE-PEG2000) on the thermal transition and release of doxorubicin.</a> Faraday Discussions. 161, 515-534 (2013).</li><li>Ickenstein, L. M., Arfvidsson, M. C., Needham, D., Mayer, L. D., Edwards, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disc+formation+in+cholesterol-free+liposomes+during+phase+transition.">Disc formation in cholesterol-free liposomes during phase transition.</a> Biochimica et Biophysica Acta - Biomembranes. 1614 (2), 135-138 (2003).</li><li>Valencia, P. M., Farokhzad, O. C., Karnik, R., 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=Microfluidic+technologies+for+accelerating+the+clinical+translation+of+nanoparticles.">Microfluidic technologies for accelerating the clinical translation of nanoparticles.</a> Nature Nanotechnology. 7 (10), 623-629 (2012).</li><li>Chen, D., 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=Rapid+discovery+of+potent+siRNA-containing+lipid+nanoparticles+enabled+by+controlled+microfluidic+formulation.">Rapid discovery of potent siRNA-containing lipid nanoparticles enabled by controlled microfluidic formulation.</a> Journal of the American Chemical Society. 134 (16), 6948-6951 (2012).</li><li>Forbes, 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=Rapid+and+scale-independent+microfluidic+manufacture+of+liposomes+entrapping+protein+incorporating+in-line+purification+and+at-line+size+monitoring.">Rapid and scale-independent microfluidic manufacture of liposomes entrapping protein incorporating in-line purification and at-line size monitoring.</a> International Journal of Pharmaceutics. 556, 68-81 (2019).</li><li>Dittrich, P. S., Manz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lab-on-a-chip:+microfluidics+in+drug+discovery.">Lab-on-a-chip: microfluidics in drug discovery.</a> Nature Reviews Drug Discovery. 5 (3), 210-218 (2006).</li><li>Capretto, L., Carugo, D., Mazzitelli, S., Nastruzzi, C., Zhang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+and+lab-on-a-chip+preparation+routes+for+organic+nanoparticles+and+vesicular+systems+for+nanomedicine+applications.">Microfluidic and lab-on-a-chip preparation routes for organic nanoparticles and vesicular systems for nanomedicine applications.</a> Advanced Drug Delivery Reviews. 65 (11-12), 1496-1532 (2013).</li><li>Cheung, C. C. L., Al-Jamal, W. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sterically+stabilized+liposomes+production+using+staggered+herringbone+micromixer:+Effect+of+lipid+composition+and+PEG-lipid+content.">Sterically stabilized liposomes production using staggered herringbone micromixer: Effect of lipid composition and PEG-lipid content.</a> International Journal of Pharmaceutics. 566, 687-696 (2019).</li><li>Suh, Y. K., Kang, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+on+Mixing+in+Microfluidics.">Review on Mixing in Microfluidics.</a> Micromachines. 1 (3), 82-111 (2010).</li><li>Jahn, A., Vreeland, W. N., Gaitan, M., Locascio, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled+Vesicle+Self-Assembly+in+Microfluidic+Channels+with+Hydrodynamic+Focusing.">Controlled Vesicle Self-Assembly in Microfluidic Channels with Hydrodynamic Focusing.</a> Journal of the American Chemical Society. 126 (9), 2674-2675 (2004).</li><li>Stroock, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chaotic+Mixer+for+Microchannels.">Chaotic Mixer for Microchannels.</a> Science. 295 (5555), 647-651 (2002).</li><li>Belliveau, N. 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+Synthesis+of+Highly+Potent+Limit-size+Lipid+Nanoparticles+for+In+Vivo+Delivery+of+siRNA.">Microfluidic Synthesis of Highly Potent Limit-size Lipid Nanoparticles for In Vivo Delivery of siRNA.</a> Molecular Therapy - Nucleic Acids. 1 (8), 37 (2012).</li><li>Patra, 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=Under+the+influence+of+alcohol:+The+effect+of+ethanol+and+methanol+on+lipid+bilayers.">Under the influence of alcohol: The effect of ethanol and methanol on lipid bilayers.</a> Biophysical Journal. 90 (4), 1121-1135 (2006).</li><li>Komatsu, H., Rowe, E. S., Rowe, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Cholesterol+on+the+Ethanol-Induced+Interdigitated+Gel+Phase+in+Phosphatidylcholine:+Use+of+Fluorophore+Pyrene-Labeled+Phosphatidylcholine.">Effect of Cholesterol on the Ethanol-Induced Interdigitated Gel Phase in Phosphatidylcholine: Use of Fluorophore Pyrene-Labeled Phosphatidylcholine.</a> Biochemistry. 30 (9), 2463-2470 (1991).</li><li>Lu, J., Hao, Y., Chen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Cholesterol+on+the+in+Lysophosphatidylcholine+Formation+of+an+Interdigitated+Gel+Phase+and+Phosphatidylcholine+Binary.">Effect of Cholesterol on the in Lysophosphatidylcholine Formation of an Interdigitated Gel Phase and Phosphatidylcholine Binary.</a> Journal of Biochemistry. 129 (6), 891-898 (2001).</li><li>Vanegas, J. M., Contreras, M. F., Faller, R., Longo, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+unsaturated+lipid+and+ergosterol+in+ethanol+tolerance+of+model+yeast+biomembranes.">Role of unsaturated lipid and ergosterol in ethanol tolerance of model yeast biomembranes.</a> Biophysical Journal. 102 (3), 507-516 (2012).</li><li>Haran, G., Cohen, R., Bar, L. K., Barenholz, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transmembrane+ammonium+sulfate+gradients+in+liposomes+produce+efficient+and+stable+entrapment+of+amphipathic+weak+bases.">Transmembrane ammonium sulfate gradients in liposomes produce efficient and stable entrapment of amphipathic weak bases.</a> Biochimica et Biophysica Acta (BBA) - Biomembranes. 1151 (2), 201-215 (1993).</li><li>Sadeghi, 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=Influence+of+cholesterol+inclusion+on+the+doxorubicin+release+characteristics+of+lysolipid-based+thermosensitive+liposomes.">Influence of cholesterol inclusion on the doxorubicin release characteristics of lysolipid-based thermosensitive liposomes.</a> International Journal of Pharmaceutics. 548 (2), 778-782 (2018).</li><li>Lawaczeck, R., Kainosho, M., Chan, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+formation+and+annealing+of+structural+defects+in+lipid+bilayer+vesicles.">The formation and annealing of structural defects in lipid bilayer vesicles.</a> Biochimica et Biophysica Acta (BBA) - Biomembranes. 443 (3), 313-330 (1976).</li><li>Komatsu, H., Okada, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol-induced+aggregation+and+fusion+of+small+phosphatidylcholine+liposome:+participation+of+interdigitated+membrane+formation+in+their+processes.">Ethanol-induced aggregation and fusion of small phosphatidylcholine liposome: participation of interdigitated membrane formation in their processes.</a> BBA - Biomembranes. 1235 (2), 270-280 (1995).</li><li>Marsh, D., Bartucci, R., Sportelli, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+membranes+with+grafted+polymers:+physicochemical+aspects.">Lipid membranes with grafted polymers: physicochemical aspects.</a> Biochimica et Biophysica Acta (BBA) - Biomembranes. 1615 (1-2), 33-59 (2003).</li><li>Hood, R. R., Vreeland, W. N., DeVoe, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+remote+loading+for+rapid+single-step+liposomal+drug+preparation.">Microfluidic remote loading for rapid single-step liposomal drug preparation.</a> Lab on a Chip. 14 (17), 3359-3367 (2014).</li><li>Dalwadi, G., Benson, H. A. E., Chen, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+diafiltration+and+tangential+flow+filtration+for+purification+of+nanoparticle+suspensions.">Comparison of diafiltration and tangential flow filtration for purification of nanoparticle suspensions.</a> Pharmaceutical Research. , (2005).</li><li>Roces, C., Kastner, E., Stone, P., Lowry, D., Perrie, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Quantification+and+Validation+of+Lipid+Concentrations+within+Liposomes.">Rapid Quantification and Validation of Lipid Concentrations within Liposomes.</a> Pharmaceutics. 8 (3), 29 (2016).</li><li>Kim, S. -. H., Kim, J. W., Kim, D. -. H., Han, S. -. H., Weitz, 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=Enhanced-throughput+production+of+polymersomes+using+a+parallelized+capillary+microfluidic+device.">Enhanced-throughput production of polymersomes using a parallelized capillary microfluidic device.</a> Microfluidics and Nanofluidics. 14 (3-4), 509-514 (2013).</li></ol>

The presented protocol describes the preparation of low temperature-sensitive liposomes (LTSLs) using a staggered herringbone micromixer (SHM). The LTSL10 formulation enables temperature-triggered burst release of doxorubicin within 5 minutes at a clinically attainable hyperthermic temperature of 42 &#176;C. Indocyanine green (ICG) can also be co-loaded for photothermal heating triggered the release of DOX. The method relies on: (i) self-assembly of phospholipids into liposomes under a homogenized solvent environment pro...

LTSL formulation is a clinically relevant liposomal product that has been developed to deliver the chemotherapeutic drug doxorubicin (DOX) and allows efficient burst drug release at clinically attainable mild hyperthermia (T &#8776; 41 &#176;C)1. The LTSL formulation consists of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), the lysolipid 1-stearoyl-2-hydroxy-sn-glycero-3-phosphatidylcholine (MSPC; M stands for &#34;mono&#34;) and PEGylated lipid 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2000). Upon reaching the phase transition temperature (Tm &#8776; 41 &#176;C), the lysolipid and DSPE-PEG2000 together facilitate the formation of membrane pores, resulting in a burst release of the drug2. The preparation of LTSLs primarily uses a bulk top-down approach, namely lipid film hydration and extrusion. It remains challenging to reproducibly prepare large batches with identical properties and in sufficient quantities for clinical applications3.
Microfluidics is an emerging technique for preparing liposomes, offering tunable nanoparticle size, reproducibility, and scalability3. Once the manufacturing parameters are optimized, the throughput could be scaled-up by parallelization, with properties identical to those prepared at bench scale3,4,5. A major advantage of microfluidics over conventional bulk techniques is the ability to handle small liquid volumes with high controllability in space and time through miniaturization, allowing faster optimization, while operating in a continuous and automated manner6. Production of liposomes with microfluidic devices is achieved by a bottom-up nanoprecipitation approach, which is more time and energy efficient because homogenization processes such as extrusion and sonication are unnecessary7. Typically, an organic solution (e.g. ethanol) of lipids (and hydrophobic payload) is mixed with a miscible non-solvent (e.g. water and hydrophilic payload). As the organic solvent mixes with the non-solvent, the solubility for the lipids is reduced. The lipid concentration eventually reaches a critical concentration at which the precipitation process is triggered7. Nanoprecipitates of lipids eventually grow in size and close into a liposome. The main factors governing the size and homogeneity of the liposomes are the ratio between the non-solvent and solvent (i.e. aqueous-to-organic flow rate ratio; FRR) and the homogeneity of the solvent environment during the self-assembly of lipids into liposomes8.
Efficient fluid mixing in microfluidics is therefore essential to the preparation of homogeneous liposomes, and various designs of mixers have been employed in different applications9. Staggered herringbone micromixer (SHM) represents one of the new generations of passive mixers, which enables high throughput (in range of mL/min) with a low dilution factor. This is superior to traditional microfluidic hydrodynamic mixing devices8,10. The SHM has patterned herringbone grooves, which rapidly mix fluids by chaotic advection9,11. The short mixing timescale of SHM (&#60; 5 ms, less than the typical aggregation time scale of 10&#8211;100 ms) allows lipid self-assembly to occur in a homogenous solvent environment, producing nanoparticles with uniform size distribution3,12.
The preparation of LTSLs with microfluidics is, however, not as straightforward compared to conventional liposomal formulations due to the lack of cholesterol8, without which lipid bilayers are susceptible to ethanol-induced interdigitation13,14,15. Until now, the effect of residual ethanol presents during the microfluidic production of liposomes has not been well understood. The majority of the reported formulations are inherently resistant to interdigitation (containing cholesterol or unsaturated lipids)16, which unlike LTSLs are both saturated and cholesterol-free.
The protocol presented herein uses SHM to prepare LTSLs for temperature triggered-release drug delivery. In the presented method, we ensured the microfluidic-prepared LTSLs are nano-sized (100 nm) and uniform (dispersity &#60; 0.2) by dynamic light scattering (DLS). Furthermore, we encapsulated DOX using the transmembrane ammonium sulfate gradient method (also known as remote loading)17 as a validation of the integrity of the LTSL lipid bilayer. Remote loading of DOX requires the liposome to maintain a pH-gradient in order to achieve high encapsulation efficiency (EE), which is unlikely to happen without an intact lipid bilayer. In this presented method, distinctive from typical microfluidic liposome preparation protocols, an annealing step is required before the ethanol is removed to enable the remote loading capability; i.e. to restore the integrity of the lipid bilayer.
As mentioned previously, hydrophilic and hydrophobic payloads can also be introduced to the initial solutions for the simultaneous encapsulation of payloads during the formation of LTSLs. As a proof-of-concept, indocyanine green (ICG), an FDA-approved near-infrared fluorescent dye, which is also a promising photothermal agent, is introduced to the initial lipid mixture and successfully co-loaded into the LTSLs. An 808 nm laser is used to irradiate the DOX/ICG-loaded LTSLs and successfully induce photothermal heating-triggered burst release of DOX within 5 min.
All the instruments and materials are commercially available, ready-to-use, and without the need for customization. Since all the parameters for formulating LTSLs have been optimized, following this protocol, researchers with no prior knowledge of microfluidics could also prepare the LTSLs, which serves as the basis of a thermosensitive drug delivery system.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)</td>
			<td>Lipoid</td>
			<td>PC 16:0/16:0 (DPPC)</td>
			<td></td>
		</tr>
		<tr>
			<td>1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG2000)</td>
			<td>Lipoid</td>
			<td>PE 18:0/18:0-PEG 2000 
			(MPEG 2000-DSPE)</td>
			<td></td>
		</tr>
		<tr>
			<td>1-stearoyl-2-hydroxy-sn-glycero-3-phosphocholine (MSPC)</td>
			<td>Avanti Polar Lipid</td>
			<td>855775P-500MG</td>
			<td>Distributed by Sigma-Adrich; also known as Lyso 16:0 PC 
			(Not to be confused with 14:0/18:0 PC, which is also termed MSPC)</td>
		</tr>
		<tr>
			<td>4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)</td>
			<td>Sigma-Aldrich</td>
			<td>H3375-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Adapters, Female Luer Lock to 1/4&#34;-28UNF</td>
			<td>IDEX Health &#38; Science</td>
			<td>P-624</td>
			<td>Requires 2 units. For the inlets</td>
		</tr>
		<tr>
			<td>Adapters, Union Assembly, 1/4&#34;-28UNF</td>
			<td>IDEX Health &#38; Science</td>
			<td>P-630</td>
			<td>Requires 2 units. (One unit included 2 nuts and 2 ferrules)</td>
		</tr>
		<tr>
			<td>Ammonium Sulfate ((NH4)2SO4)</td>
			<td>Sigma-Aldrich</td>
			<td>31119-1KG-M</td>
			<td></td>
		</tr>
		<tr>
			<td>Bijou vial</td>
			<td>VWR</td>
			<td>216-0980</td>
			<td>7 mL, clear, polystyrene vial</td>
		</tr>
		<tr>
			<td>Centrifugal Filter Unit</td>
			<td>Sigma-Aldrich</td>
			<td>UFC801008</td>
			<td>10 kDa MWCO, Amicon Ultra-4 Centrifugal Filter Unit</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>ThermoFisher Scientific</td>
			<td>Heraeus Megafuge 8R</td>
			<td>With HIGHConic III Fixed Angle Rotor</td>
		</tr>
		<tr>
			<td>Cuvette</td>
			<td>Fisher Scientific</td>
			<td>11602609</td>
			<td>Disposable polystyrene cuvette, low volume, for DLS measurement</td>
		</tr>
		<tr>
			<td>Dialysis Kit - Pur-A-Lyzer Maxi</td>
			<td>Sigma-Aldrich</td>
			<td>PURX12015-1KT</td>
			<td>12-14 kDa MWCO</td>
		</tr>
		<tr>
			<td>Dimethyl Sulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>34943-1L-M</td>
			<td></td>
		</tr>
		<tr>
			<td>DLS Instrument</td>
			<td>Malvern Panalytical</td>
			<td>Zetasizer Nano ZS90</td>
			<td></td>
		</tr>
		<tr>
			<td>Doxorubicin Hydrochloride (DOX)</td>
			<td>Apollo Scientific</td>
			<td>BID0120</td>
			<td></td>
		</tr>
		<tr>
			<td>DSC Instrument</td>
			<td>TA Instruments</td>
			<td>TA Q200 DSC</td>
			<td></td>
		</tr>
		<tr>
			<td>DSC Tzero Hermetic Lids</td>
			<td>TA Instruments</td>
			<td>901684.901</td>
			<td>For DSC measurement</td>
		</tr>
		<tr>
			<td>DSC Tzero Pans</td>
			<td>TA Instruments</td>
			<td>901683.901</td>
			<td>For DSC measurement</td>
		</tr>
		<tr>
			<td>DSC Tzero Sample Press Kit</td>
			<td>TA Instruments</td>
			<td>901600.901</td>
			<td>For DSC measurement</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>VWR</td>
			<td>20821.330</td>
			<td>Absolute, &#8805;99.8%</td>
		</tr>
		<tr>
			<td>FC-808 Fibre Coupled Laser System</td>
			<td>CNI Optoelectronics Tech</td>
			<td>FC-808-8W-181315</td>
			<td>FOC-01-B Fiber Collimator included.</td>
		</tr>
		<tr>
			<td>Ferrule, 1/4&#34;-28UNF to 1/16&#34; OD</td>
			<td>IDEX Health &#38; Science</td>
			<td>P-200</td>
			<td>For the outlet</td>
		</tr>
		<tr>
			<td>Fibre Optic Temperature Probe</td>
			<td>Osensa</td>
			<td>PRB-G40</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Staggered Herringbone Micromixer (SHM)</td>
			<td>Darwin Microfluidics</td>
			<td>Herringbone Mixer - Glass Chip</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating Tape</td>
			<td>Omega</td>
			<td>DHT052020LD</td>
			<td>Can be replaced by other syringe heater such as &#34;HTC&#34; or &#34;SRT series&#34; for slower heating. Manual wiring to a 3-pin plug required for 240V models</td>
		</tr>
		<tr>
			<td>Indocyanine Green</td>
			<td>Adooq</td>
			<td>A10473-100</td>
			<td>Distributed by Bioquote Limited (U.K.)</td>
		</tr>
		<tr>
			<td>Luer-lock Syringe, 5 mL</td>
			<td>VWR</td>
			<td>613-2043</td>
			<td>Hanke Sass Wolf SOFT-JECT 3-piece syringes, O.D. 12.45 mm</td>
		</tr>
		<tr>
			<td>Microplate Reader</td>
			<td>BMG Labtech</td>
			<td>FLUOstar Omega</td>
			<td>Installed with 485 nm (exictation) and 590 nm (emission) filters</td>
		</tr>
		<tr>
			<td>Microplate, 96-well, Black, Flat-bottom</td>
			<td>ThermoFisher Scientific</td>
			<td>611F96BK</td>
			<td>For fluorescence measurement in microplate reader</td>
		</tr>
		<tr>
			<td>Microplate, 96-well, Clear, Flat-bottom</td>
			<td>Grenier</td>
			<td>655101</td>
			<td>For absorbance measurement microplate reader</td>
		</tr>
		<tr>
			<td>Nut, 1/4&#34;-28UNF to 1/16&#34; OD</td>
			<td>IDEX Health &#38; Science</td>
			<td>P-245</td>
			<td>For the outlet</td>
		</tr>
		<tr>
			<td>PC to Pump Network Cable for Aladdin, 7ft</td>
			<td>World Precision Instruments</td>
			<td>NE-PC7</td>
			<td>Optional: Syringe pumps can be operated manually</td>
		</tr>
		<tr>
			<td>Pump control software - SyringePumpPro Software License for 2</td>
			<td>World Precision Instruments</td>
			<td>SYRINGE-PUMP-PRO-02</td>
			<td>Optional: Syringe pumps can be operated manually</td>
		</tr>
		<tr>
			<td>Pump to Pump Network Cable for Aladdin, 7 ft</td>
			<td>World Precision Instruments</td>
			<td>NE-NET7</td>
			<td>Optional: Syringe pumps can be operated manually</td>
		</tr>
		<tr>
			<td>Size exclusion chromatography (SEC) column</td>
			<td>GE Life Science</td>
			<td>17085101</td>
			<td>Sephadex G-25 resin in PD-10 Desalting Columns</td>
		</tr>
		<tr>
			<td>Sodium chloride (NaCl)</td>
			<td>Sigma-Aldrich</td>
			<td>31434-1KG-M</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide (NaOH)</td>
			<td>Sigma-Aldrich</td>
			<td>S5881-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe Pumps &#38; Cable (DUAL-PUMP-NE-1000)</td>
			<td>World Precision Instruments</td>
			<td>ALADDIN2-220/AL1000-220</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermostat Temperature Controller</td>
			<td>Inkbird</td>
			<td>ITC-308</td>
			<td>Can be replaced by other syringe heater kit/thermostat</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>X100-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Tubing, ETFE (1/16&#34; OD)</td>
			<td>IDEX Health &#38; Science</td>
			<td>1516</td>
			<td></td>
		</tr>
		<tr>
			<td>USB To RS-232 Converter</td>
			<td>World Precision Instruments</td>
			<td>CBL-USB-232</td>
			<td>Optional: For computer without RS-232 port</td>
		</tr>
		<tr>
			<td>Water Bath</td>
			<td>Grant Instruments Ltd.</td>
			<td>JB Nova 12</td>
			<td></td>
		</tr>
	</tbody>
</table>

microfluidic production of lysolipid-containing temperature-sensitive liposomes

The presented protocol enables a high-throughput continuous preparation of low temperature-sensitive liposomes (LTSLs), which are capable of loading chemotherapeutic drugs, such as doxorubicin (DOX). To achieve this, an ethanolic lipid mixture and ammonium sulfate solution are injected into a staggered herringbone micromixer (SHM) microfluidic device. The solutions are rapidly mixed by the SHM, providing a homogeneous solvent environment for liposomes self-assembly. Collected liposomes are first annealed, then dialyzed to remove residual ethanol. An ammonium sulfate pH-gradient is established through buffer exchange of the external solution by using size exclusion chromatography. DOX is then remotely loaded into the liposomes with high encapsulation efficiency (&#62; 80%). The liposomes obtained are homogenous in size with Z-average diameter of 100 nm. They are capable of temperature-triggered burst release of encapsulated DOX in the presence of mild hyperthermia (42 &#176;C). Indocyanine green (ICG) can also be co-loaded into the liposomes for near-infrared laser-triggered DOX release. The microfluidic approach ensures high-throughput, reproducible and scalable preparation of LTSLs.

The preparation of LTSLs by microfluidics requires the lipid composition of DPPC/MSPC/DSPE-PEG2000 (80/10/10, molar ratio; LTSL10). Figure 7A (left) shows the appearance of as-prepared LTSL10 from step 2.9, as a clear and non-viscous liquid. LTSL10 formulation is developed from the conventional formulation, LTSL4 (DPPC/MSPC/DSPE-PEG2000, 86/10/4, molar ratio) since LTSL4 forms a gel-like viscous sample, as indicated by t...

Watch this Scientific Journal Video about Microfluidic Production of Lysolipid-Containing Temperature-Sensitive Liposomes at JoVE.com

Microfluidic Production of Lysolipid-Containing Temperature-Sensitive Liposomes

The protocol presents the optimized parameters for preparing thermosensitive liposomes using the staggered herringbone micromixer microfluidics device. This also allows co-encapsulation of doxorubicin and indocyanine green into the liposomes and the photothermal-triggered release of doxorubicin for controlled/triggered drug release.

The presented protocol enables a high-throughput continuous preparation of low temperature-sensitive liposomes (LTSLs), which are capable of loading ...

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JoVE Journal

Bioengineering

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