The publication of this video was supported by My CytoHealth Sdn. Bhd.

NOTE: See the Table of Materials for details about all materials, equipment, and software used in this protocol.
1. Human umbilical cord mesenchymal stem cells and culture
<ol>
	<li>Culture the hUC-MSCs at a seeding density of 5 &#215; 103/cm2 in DMEM, supplemented with 8% Human Platelet Lysate and 1% Pen-Strep. Incubate the cells at 37 &#176;C in 5% CO2. Replace the cell culture medium every 3 days to ensure proper cell growth.</li>
	<li>Expand the cells to passage 5 in T175 flasks for sEV isolation. 
	&#8203;NOTE: Many flasks are needed to harvest a high yield of sEVs (the yield increases with the number of cells).</li>
</ol>
2. Small extracellular vesicle isolation from hUC - MSCs
<ol>
	<li>Replace the culture medium with fresh phenol-red free DMEM supplemented with 1% Pen-Strep [Conditioned medium (CM)] when the culture reaches 70%-80% confluency at passage 5. 
	CAUTION: Use basal media only; avoid FBS and human platelet lysate supplement to avoid contamination by external sEVs.</li>
	<li>After 24 h, centrifuge the CM at 200 &#215; g for 5 min at 4 &#176;C to remove cell debris. Collect and filter the supernatant through a 0.22 &#181;m filter to remove particles larger than 220 nm.</li>
	<li>Fill the centrifugal filter unit with 30 mL of phosphate-buffered saline (PBS) filtered through a 0.2 &#181;m filter. Centrifuge the centrifugal filter unit at 3,500 &#215; g for 5 min at 4 &#176;C.</li>
	<li>Fill the filtered CM into the centrifugal filter unit (each unit&#39;s maximum volume is 70 mL). Centrifuge the CM at 3,500 &#215; g at 4 &#176;C. 
	NOTE: The duration of centrifugation should be monitored from time to time until the solution has reached the surface of the filter.</li>
	<li>Discard the solution in the filtrate solution cup. Reverse centrifuge the sample filter cup with concentrate collection cup at 1,000 x g at 4 &#176;C for 2 min.</li>
	<li>Transfer the concentrated CM back to the centrifugal filter unit. Add 30 mL of filtered PBS into the centrifugal filter unit and centrifuge the unit at 3,500 &#215; g at 4 &#176;C.</li>
	<li>Discard the solution in the filtrate solution cup. Install a concentrate collection cup on the filter unit and reverse-centrifuge at 1,000 &#215; g for 2 min at 4 &#176;C to obtain the purified sEVs.</li>
	<li>Filter the sEVs through a 0.22 &#181;m syringe filter.</li>
	<li>Transfer the samples to new tubes and store them at -80 &#176;C for further analysis.</li>
</ol>
3. Characterization of hUC-MSC-sEVs
<ol>
	<li>Nanoparticle tracking analysis
	<ol>
		<li>Dilute the isolated hUC-MSC-sEVs in filtered PBS to 20-100 particles/frame.</li>
		<li>Introduce 1 mL of the diluted sample into the NTA chamber using 1 mL disposable syringes.</li>
		<li>Set the measurement settings accordingly: adjust the camera level to level 14, determine the detection threshold to include as many particles as possible with the restriction that 10-100 red crosses are counted, and the blue cross count is limited to five.</li>
		<li>For each measurement, record five 1 min videos and analyze them using the NanoSight Software with a detection threshold of five.</li>
		<li>Take measurements in triplicate for each sample.</li>
	</ol>
	</li>
	<li>Western blotting analysis
	<ol>
		<li>Lyse the hUC-MSC-sEVs with ice-cold radioimmunoprecipitation assay (RIPA) lysis buffer, incubate for 30 min at 4 &#176;C, and centrifuge at 200 &#215; g for 5 min at 4 &#176;C. Collect the supernatant.</li>
		<li>Quantify the protein using a Bicinchoninic Acid (BCA) Protein Assay&#160;Kit. Assemble the gel electrophoresis set accordingly and perform gel electrophoresis at 90 V until the protein reaches the stacking gel&#39;s end. Change the voltage to 200 V to separate the proteins until the end of the resolving gel.</li>
		<li>Perform semidry transfer to transfer the proteins from the gel to a polyvinylidene difluoride (PVDF) membrane at 15 V for 1 h.</li>
		<li>Block the PVDF membrane with 3% bovine serum albumin (BSA)/Tris-buffered saline-0.1% v/v Tween 20 (TBS-T) for 1 h on a shaker at room temperature. Incubate the PVDF membrane with primary antibodies as follows: mouse anti-CD 9 monoclonal antibody (1:500), mouse anti-CD 81 monoclonal antibody (1:500), mouse anti-GRP 94 monoclonal mouse anti-TSG 101 monoclonal antibody (1:500) at 4 &#176;C overnight with constant shaking.</li>
		<li>The next day, wash the PVDF membrane 5 x 5 min with TBS-T and further incubate with a secondary antibody: horseradish peroxidase-conjugated mouse IgG kappa binding protein (m-IgG&#954; BP-HRP) (1:5,000) for 1 h with agitation at room temperature.</li>
		<li>Again, wash the PVDF membrane with TBS-T five times, and visualize the membrane in a charge-coupled (CCD) imager using a chemiluminescence detection reagent. Analyze the expression level of the proteins using ImageJ software. First, open the image file in ImageJ (File | Open&#8230;). Enhance the quality of the image by adjusting the brightness and contrast (Image | Adjust | Brightness/Contrast). Adjust the image until the blots are clearly visible, click on the Apply button, and then save the images in TIFF format (File | Save As | TIFF&#8230;).</li>
	</ol>
	</li>
	<li>Transmission electron microscope
	<ol>
		<li>Dilute one part of the hUC-MSC-sEVs sample with four parts of filtered PBS to a total volume of 10 &#181;L and incubate on a carbon-coated copper grid for 15 min.</li>
		<li>Remove excess sample using a laboratory wipe and allow it to air-dry for 3 min.</li>
		<li>Incubate 10 &#181;L of 1% phosphotungstic acid (PTA) solution to stain the sample for 3 min.</li>
		<li>Remove excess 1% PTA solution using a laboratory wipe and allow it to air-dry for 3 min.</li>
		<li>Use the sample for transmission electron microscope imaging. 
		NOTE: Refer to Figure 1 for the summarized schematic experiment steps.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Th&#233;ry, 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=Minimal+information+for+studies+of+extracellular+vesicles+2018+(MISEV2018):+a+position+statement+of+the+International+Society+for+Extracellular+Vesicles+and+update+of+the+MISEV2014+guidelines.">Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines.</a> Journal of Extracellular Vesicles. 7 (1), 1535750 (2018).</li><li>Jayabalan, 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=Cross+talk+between+adipose+tissue+and+placenta+in+obese+and+gestational+diabetes+mellitus+pregnancies+via+exosomes.">Cross talk between adipose tissue and placenta in obese and gestational diabetes mellitus pregnancies via exosomes.</a> Frontiers in Endocrinology. 8, 239 (2017).</li><li>Li, T., 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=Exosomes+derived+from+human+umbilical+cord+mesenchymal+stem+cells+alleviate+liver+fibrosis.">Exosomes derived from human umbilical cord mesenchymal stem cells alleviate liver fibrosis.</a> Stem Cells and Development. 22 (6), 845-854 (2013).</li><li>Wang, 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=Mesenchymal+stromal+cell-derived+small+extracellular+vesicles+induce+ischemic+neuroprotection+by+modulating+leukocytes+and+specifically+neutrophils.">Mesenchymal stromal cell-derived small extracellular vesicles induce ischemic neuroprotection by modulating leukocytes and specifically neutrophils.</a> Stroke. 51 (6), 1825-1834 (2020).</li><li>Wei, Y., 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=MSC-derived+sEVs+enhance+patency+and+inhibit+calcification+of+synthetic+vascular+grafts+by+immunomodulation+in+a+rat+model+of+hyperlipidemia.">MSC-derived sEVs enhance patency and inhibit calcification of synthetic vascular grafts by immunomodulation in a rat model of hyperlipidemia.</a> Biomaterials. 204, 13-24 (2019).</li><li>Liu, W., 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=MSC-derived+small+extracellular+vesicles+overexpressing+miR-20a+promoted+the+osteointegration+of+porous+titanium+alloy+by+enhancing+osteogenesis+via+targeting+BAMBI.">MSC-derived small extracellular vesicles overexpressing miR-20a promoted the osteointegration of porous titanium alloy by enhancing osteogenesis via targeting BAMBI.</a> Stem Cell Research and Therapy. 12 (1), 1-16 (2021).</li><li>Li, F. X. 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=The+role+of+mesenchymal+stromal+cells-derived+small+extracellular+vesicles+in+diabetes+and+its+chronic+complications.">The role of mesenchymal stromal cells-derived small extracellular vesicles in diabetes and its chronic complications.</a> Frontiers in Endocrinology. 12, 1741 (2021).</li><li>Jayabalan, 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=.">.</a> Frontiers in Endocrinology. 8, (2017).</li><li>Wei, Y., 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> Biomaterials. 204, 13-24 (2019).</li><li>Du, W., 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=Enhanced+proangiogenic+potential+of+mesenchymal+stem+cell-derived+exosomes+stimulated+by+a+nitric+oxide+releasing+polymer.">Enhanced proangiogenic potential of mesenchymal stem cell-derived exosomes stimulated by a nitric oxide releasing polymer.</a> Biomaterials. 133, 70-81 (2017).</li><li>Li, P., Kaslan, M., Lee, S. H., Yao, J., Gao, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+in+exosome+isolation+techniques.">Progress in exosome isolation techniques.</a> Theranostics. 7 (3), 789-804 (2017).</li><li>Nicolas, R. H., Goodwin, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+extracellular+vesicles,+their+origin,+composition,+purpose,+and+methods+for+exosome+isolation+and+analysis.">Overview of extracellular vesicles, their origin, composition, purpose, and methods for exosome isolation and analysis.</a> Cells. 8 (7), 727 (2019).</li><li>Kowal, 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=Proteomic+comparison+defines+novel+markers+to+characterize+heterogeneous+populations+of+extracellular+vesicle+subtypes.">Proteomic comparison defines novel markers to characterize heterogeneous populations of extracellular vesicle subtypes.</a> Proceedings of the National Academy of Sciences of the United States of America. 113 (8), 968-977 (2016).</li><li>Zeringer, E., Barta, T., Li, M., Vlassov, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+for+isolation+of+exosomes.">Strategies for isolation of exosomes.</a> Cold Spring Harbor Protocol. 2015 (4), 319-323 (2015).</li><li>K&#305;rba&#351;, O. K., 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=Optimized+isolation+of+extracellular+vesicles+from+various+organic+sources+using+aqueous+two-phase+system.">Optimized isolation of extracellular vesicles from various organic sources using aqueous two-phase system.</a> Scientific Reports. 9 (1), 1-11 (2019).</li><li>Ev, B., Ms, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+exosomes,+naturally-equipped+nanocarriers,+for+drug+delivery.">Using exosomes, naturally-equipped nanocarriers, for drug delivery.</a> Journal of Controlled Release: Official Journal of the Controlled Release Society. 219, 396-405 (2015).</li><li>Dragovic, R. A., 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=Isolation+of+syncytiotrophoblast+microvesicles+and+exosomes+and+their+characterisation+by+multicolour+flow+cytometry+and+fluorescence+Nanoparticle+Tracking+Analysis.">Isolation of syncytiotrophoblast microvesicles and exosomes and their characterisation by multicolour flow cytometry and fluorescence Nanoparticle Tracking Analysis.</a> Methods. 87, 64-74 (2015).</li><li>Tan, K. 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=Benchtop+isolation+and+characterisation+of+small+extracellular+vesicles+from+human+mesenchymal+stem+cells.">Benchtop isolation and characterisation of small extracellular vesicles from human mesenchymal stem cells.</a> Molecular Biotechnology. 63 (9), 780-791 (2021).</li></ol>

The authors declare no conflicts of interest.

EVs are one of the important subsets of the secretome in MSCs that play a crucial role during normal and pathological processes. However, sEVs, with a size range between 30 to 200 nm, have risen as a potential tool for cell-free therapy in the past decade. Various techniques were developed to isolate sEVs from MSCs. However, differential ultracentrifugation, ultrafiltration, polymer-based precipitation, immunoaffinity capture, and microfluidics-based precipitation possess different advantages and disadvantages<sup class=...

According to MISEV 2018, sEVs are non-replicating lipid bilayer particles with no functional nucleus present, with a size of 30-200 nm1. MSC-derived sEVs contain important signaling molecules that play important roles in tissue regeneration, such as microRNA, cytokines, or proteins. They have increasingly become a research &#34;hotspot&#34; in regenerative medicine and cell-free therapy. Many studies have shown that MSC-derived sEVs are as effective as MSCs in treating different conditions, such as immunomodulation2,3,4,5, enhancing osteogenesis6, diabetes mellitus7,8, or vascular regeneration9,10. As early phase trials progress, three main key issues in relation to the clinical translation of MSCs-EVs have been highlighted: the yield of the EVs, the purity of the EVs (free from cell debris and other biological contaminants such as protein and cytokines), and the integrity of the phospholipid bilayer membrane of the EVs after isolation.
Various methods have been developed to isolate sEVs, exploiting the density, shape, size, and surface protein of the sEVs11. The two most common methods in sEVs isolations are ultracentrifugation-based and ultrafiltration-based techniques.
Ultracentrifugation-based methods are considered gold standard methods in sEVs isolation. Two types of ultracentrifugation techniques that are usually employed are differential ultracentrifugation and density gradient ultracentrifugation. However, ultracentrifugation methods often result in low yield and require expensive equipment for high-speed ultracentrifuge (100,000-200,000 &#215; g)11. Furthermore, ultracentrifugation techniques alone are inefficient in separating EV subtypes (sEVs and large EVs), resulting in an impure sediment layer11. Lastly, density gradient ultracentrifugation could be also time-consuming and require additional precaution steps such as sucrose buffer addition to inhibit the gradient damage during acceleration and deceleration steps12. Hence, ultracentrifugation usually leads to a relatively low yield and is not capable of discriminating between different populations of EVs13, which limits its application for large-scale EV preparation11.
The second method of EV isolation is via ultrafiltration, which is based on size filtration. Ultrafiltration is relatively time- and cost-effective compared to ultracentrifugation, as it does not involve expensive equipment or long processing times14. Hence, ultrafiltration appears to be a more effective isolation technique than both aforementioned ultracentrifugation methods. The isolated products can be more specific based on pore sizes and higher yield15. However, the additional force incurred during the filtration process may result in the deformation or eruption of the EVs16.
The current paper proposed a cost- and time-effective benchtop protocol for isolating MSC-derived sEVs for downstream analysis and therapeutic purposes. The method described in this paper combined a simple filtration method with bench top centrifugation to isolate high-yield and good-quality EVs from hUC-MSCs for downstream analysis, including particle size analysis, biomarker assay, and electron microscopic imaging.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>40% acrylamide</td>
			<td>Nacalai Tesque</td>
			<td>06121-95</td>
			<td>Western blot</td>
		</tr>
		<tr>
			<td>95% ethanol</td>
			<td>Nacalai Tesque</td>
			<td>14710-25</td>
			<td>Disinfectants</td>
		</tr>
		<tr>
			<td>Absolute Methanol</td>
			<td>Chemiz</td>
			<td>45081</td>
			<td>To activate PVDF membrane (Western blot)</td>
		</tr>
		<tr>
			<td>Accutase</td>
			<td>STEMCELL Technologies</td>
			<td>7920</td>
			<td>Cell dissociation enzyme</td>
		</tr>
		<tr>
			<td>ammonium persulfate</td>
			<td>Chemiz</td>
			<td>14475</td>
			<td>catalyse the gel polymerisation (Gel electrophoresis</td>
		</tr>
		<tr>
			<td>anti-CD 81 (B-11)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-166029</td>
			<td>Antibody for sEVs marker</td>
		</tr>
		<tr>
			<td>anti-TSG 101 (C-2)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-7964</td>
			<td>Antibody for sEVs marker</td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Nacalai Tesque</td>
			<td>00653-31</td>
			<td>PVDF membrane blocking</td>
		</tr>
		<tr>
			<td>bromophenol blue</td>
			<td>Nacalai Tesque</td>
			<td>05808-61</td>
			<td>electrophoretic color marker</td>
		</tr>
		<tr>
			<td>Centricon Plus-70 (100 kDa NMWL)</td>
			<td>Millipore</td>
			<td>UFC710008</td>
			<td>sEVs isolation</td>
		</tr>
		<tr>
			<td>ChemiLumi One L</td>
			<td>Nacalai Tesque</td>
			<td>7880</td>
			<td>chemiluminescence detection reagent</td>
		</tr>
		<tr>
			<td>CryoStor Freezing Media</td>
			<td>Sigma-Aldrich</td>
			<td>C3124-100ML</td>
			<td>Cell cryopreserve</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s modified Eagle&#8217;s medium</td>
			<td>Nacalai Tesque</td>
			<td>08458-45</td>
			<td>Cell culture media</td>
		</tr>
		<tr>
			<td>ExcelBand Enhanced 3-color High Range Protein Marker</td>
			<td>SMOBIO</td>
			<td>PM2610</td>
			<td>Protein molecular weight markers</td>
		</tr>
		<tr>
			<td>Extra thick blotting paper</td>
			<td>ATTO</td>
			<td></td>
			<td>buffer reservior (Western blot)</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Merck</td>
			<td>G5516</td>
			<td>Chemicals for western blot</td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>1st Base</td>
			<td>BIO-2085-500g</td>
			<td>Chemicals for buffer (Western Blot)</td>
		</tr>
		<tr>
			<td>horseradish peroxidase-conjugated mouse IgG kappa binding protein (m-IgG&#954;BP-HRP)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-516102</td>
			<td>Secondary antibody (Western Blot)</td>
		</tr>
		<tr>
			<td>Human Wharton&#8217;s Jelly derived Mesenchymal Stem Cells (MSCs)</td>
			<td>Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, The National University Malaysia</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>mouse antibodies anti-CD 9 (C-4)</td>
			<td>Santa Cruz Biotechnology</td>
			<td>&#160;sc-13118</td>
			<td>Antibody for sEVs marker</td>
		</tr>
		<tr>
			<td>Nanosight NS300 equipped with a CMOS camera, a 20 &#215; objective lens, a blue laser module (488&#8201;nm), and NTA software v3.2</td>
			<td>Malvern Panalytical, UK</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>paraformaldehyde</td>
			<td>Nacalai Tesque</td>
			<td>02890-45</td>
			<td>Sample Fixation during TEM</td>
		</tr>
		<tr>
			<td>penicillin&#8211;streptomycin</td>
			<td>Nacalai Tesque</td>
			<td>26253-84</td>
			<td>Antibiotic for media</td>
		</tr>
		<tr>
			<td>phenylmethylsulfonyl fluoride</td>
			<td>Nacalai Tesque</td>
			<td>27327-81</td>
			<td>Inhibit proteases in the sEVs samples after adding lysis buffer</td>
		</tr>
		<tr>
			<td>phosphate-buffered saline</td>
			<td>Gibco</td>
			<td>10010023</td>
			<td>Washing, sample dilution</td>
		</tr>
		<tr>
			<td>polyvinylidene fluoride (PVDF) membrane with 
			0.45 mm pore size</td>
			<td>ATTO</td>
			<td></td>
			<td>To hold protein during protein transfer (Western blot)</td>
		</tr>
		<tr>
			<td>protease inhibitor cocktail</td>
			<td>Nacalai Tesque</td>
			<td>25955-11</td>
			<td>Inhibit proteases in the sEVs samples after adding lysis buffer</td>
		</tr>
		<tr>
			<td>Protein Assay Bicinchoninate Kit</td>
			<td>Nacalai Tesque</td>
			<td>06385-00</td>
			<td>Protein measurement</td>
		</tr>
		<tr>
			<td>sample buffer solution with 2-ME</td>
			<td>Nacalai Tesque</td>
			<td>30566-22</td>
			<td>Reducing agent for western blot</td>
		</tr>
		<tr>
			<td>sodium chloride</td>
			<td>Nacalai Tesque</td>
			<td>15266-64</td>
			<td>Chemicals for western blot</td>
		</tr>
		<tr>
			<td>sodium dodecyl sulfate</td>
			<td>Nacalai Tesque</td>
			<td>31606-62</td>
			<td>ionic surfactant during gel electrophoresis</td>
		</tr>
		<tr>
			<td>Tecnai G2 F20 S-TWIN transmission electron microscope</td>
			<td>FEI, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>tetramethylethylenediamine</td>
			<td>Nacalai Tesque</td>
			<td>33401-72</td>
			<td>chemicals to prepare gel</td>
		</tr>
		<tr>
			<td>tris-base</td>
			<td>1st Base</td>
			<td>BIO-1400-500g</td>
			<td>Chemicals for buffer (Western Blot)</td>
		</tr>
		<tr>
			<td>&#160;Tween 20</td>
			<td>GeneTex</td>
			<td>GTX30962</td>
			<td>Chemicals for western blot</td>
		</tr>
		<tr>
			<td>UVP (Ultra Vision Product) CCD imager</td>
			<td></td>
			<td></td>
			<td>CCD imager for western blot signal detection</td>
		</tr>
	</tbody>
</table>

a simple benchtop filtration method to isolate small extracellular vesicles from human mesenchymal stem cells

The ultracentrifugation-based process is considered the common method for small extracellular vesicles (sEVs) isolation. However, the yield from this isolation method is relatively lower, and these methods are inefficient in separating sEV subtypes. This study demonstrates a simple benchtop filtration method to isolate human umbilical cord-derived MSC small extracellular vesicles (hUC-MSC-sEVs), successfully separated by ultrafiltration from the conditioned medium of hUC-MSCs. The size distribution, protein concentration, exosomal markers (CD9, CD81, TSG101), and morphology of the isolated hUC-MSC-sEVs were characterized with nanoparticle tracking analysis, BCA protein assay, western blot, and transmission electron microscope, respectively. The isolated hUC-MSC-sEVs&#39; size was 30-200 nm, with a particle concentration of 7.75 &#215; 1010 particles/mL and a protein concentration of 80 &#181;g/mL. Positive bands for exosomal markers CD9, CD81, and TSG101 were observed. This study showed that hUC-MSC-sEVs were successfully isolated from hUC-MSCs conditioned medium, and characterization showed that the isolated product fulfilled the criteria mentioned by Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV 2018).

Figure 2 shows that hUC-MSC-sEVs have a particle size mode at 53 nm, while other significant peaks of particle size were 96 and 115 nm. The concentration of hUC-MSC-sEVs measured by NTA was 7.75 &#215; 1010 particles/mL. The protein concentration of hUC-MSC-sEVs measured with the BCA assay was approximately 80 &#181;g/mL.
In western blotting analysis, hUC-MSC-sEVs demonstrated positive bands for exosomal markers CD9, CD81, and TSG101, but were negative ...

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A Simple Benchtop Filtration Method to Isolate Small Extracellular Vesicles from Human Mesenchymal Stem Cells

This protocol demonstrates how to isolate human umbilical cord-derived mesenchymal stem cells&#39; small extracellular vesicles (hUC-MSC-sEVs) with a simple lab-scale benchtop setting. The size distribution, protein concentration, sEVs markers, and morphology of isolated hUC-MSC-sEVs are characterized by nanoparticle tracking analysis, BCA protein assay, western blot, and transmission electron microscope, respectively.

The ultracentrifugation-based process is considered the common method for small extracellular vesicles (sEVs) isolation. However, the yield from this ...

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1.4K Views.  Universiti Kebangsaan Malaysia Medical Centre. This protocol demonstrates how to isolate human umbilical cord-derived mesenchymal stem cells' small extracellular vesicles (hUC-MSC-sEVs) with a simple lab-scale benchtop setting. The size distribution, protein concentration, sEVs markers, and morphology of isolated hUC-MSC-sEVs are characterized by nanoparticle tracking analysis, BCA protein assay, western blot, and transmission electron microscope, respectively.

Video: A Simple Benchtop Filtration Method to Isolate Small Extracellular Vesicles from Human Mesenchymal Stem Cells

Small Volume (1-3L) Filtration of Coastal Seawater Samples

The workflow begins with the collection of coastal marine waters for downstream microbial community, nutrient and trace gas analyses. For today s demonstration samples were collected from the deck of the HMS John Strickland operating in Saanich Inlet. This video documents small volume (~1 L) filtration of microbial biomass from the water column. The protocol is an extension of the large volume sampling protocol described earlier, with one major difference: here, there is no pre-filtration step, so all size classes of biomass are collected down to the 0.22 &mu;m filter cut-off. Samples collected this way are ideal for nucleic acid analysis. The set-up, filtration, and clean-up steps each take about 20-30 minutes. If using two peristaltic pumps simultaneously, up to 8 samples may be filtered at the same time. To prevent biofilm formation between sampling trips, all filtration equipment must be rinsed with dilute HCl and deionized water and autoclaved immediately after use.

Small Volume 1-3L Filtration of Coastal Seawater Samples

This video documents small volume (~1 L) filtration of microbial biomass from the water column.

The workflow begins with the collection of coastal marine waters for downstream microbial community, nutrient and trace gas analyses. For today s ...

Implantation of Ferumoxides Labeled Human Mesenchymal Stem Cells in Cartilage Defects

The field of tissue engineering integrates the principles of engineering, cell biology and medicine towards the regeneration of specific cells and functional tissue. Matrix associated stem cell implants (MASI) aim to regenerate cartilage defects due to arthritic or traumatic joint injuries. Adult mesenchymal stem cells (MSCs) have the ability to differentiate into cells of the chondrogenic lineage and have shown promising results for cell-based articular cartilage repair technologies. Autologous MSCs can be isolated from a variety of tissues, can be expanded in cell cultures without losing their differentiation potential, and have demonstrated chondrogenic differentiation in vitro and in vivo1, 2.
In order to provide local retention and viability of transplanted MSCs in cartilage defects, a scaffold is needed, which also supports subsequent differentiation and proliferation. The architecture of the scaffold guides tissue formation and permits the extracellular matrix, produced by the stem cells, to expand. Previous investigations have shown that a 2% agarose scaffold may support the development of stable hyaline cartilage and does not induce immune responses3.
Long term retention of transplanted stem cells in MASI is critical for cartilage regeneration. Labeling of MSCs with iron oxide nanoparticles allows for long-term in vivo tracking with non-invasive MR imaging techniques4.
This presentation will demonstrate techniques for labeling MSCs with iron oxide nanoparticles, the generation of cell-agarose constructs and implantation of these constructs into cartilage defects. The labeled constructs can be tracked non-invasively with MR-Imaging.

Goal of the presentation is to demonstrate a highly reproducible method to generate matrix associated stem cell implants in cartilage defects, which can be visualized with MR imaging. Stem cells are labeled with FDA-approved Ferumoxides, mixed with agarose, implanted into cartilage defects and imaged with a 7T MR scanner.

The field of tissue engineering integrates the principles of engineering, cell biology and medicine towards the regeneration of specific cells and ...

Efficient Derivation of Human Cardiac Precursors and Cardiomyocytes from Pluripotent Human Embryonic Stem Cells with Small Molecule Induction

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based transplantation or by cardiac tissue engineering1-3. Cardiomyocytes become terminally-differentiated soon after birth and lose their ability to proliferate. There is no evidence that stem/progenitor cells derived from other sources, such as the bone marrow or the cord blood, are able to give rise to the contractile heart muscle cells following transplantation into the heart1-3. The need to regenerate or repair the damaged heart muscle has not been met by adult stem cell therapy, either endogenous or via cell delivery1-3. The genetically stable human embryonic stem cells (hESCs) have unlimited expansion ability and unrestricted plasticity, proffering a pluripotent reservoir for in vitro derivation of large supplies of human somatic cells that are restricted to the lineage in need of repair and regeneration4,5. Due to the prevalence of cardiovascular disease worldwide and acute shortage of donor organs, there is intense interest in developing hESC-based therapies as an alternative approach. However, how to channel the wide differentiation potential of pluripotent hESCs efficiently and predictably to a desired phenotype has been a major challenge for both developmental study and clinical translation. Conventional approaches rely on multi-lineage inclination of pluripotent cells through spontaneous germ layer differentiation, resulting in inefficient and uncontrollable lineage-commitment that is often followed by phenotypic heterogeneity and instability, hence, a high risk of tumorigenicity6-8 (see a schematic in Fig. 1A). In addition, undefined foreign/animal biological supplements and/or feeders that have typically been used for the isolation, expansion, and differentiation of hESCs may make direct use of such cell-specialized grafts in patients problematic9-11. To overcome these obstacles, we have resolved the elements of a defined culture system necessary and sufficient for sustaining the epiblast pluripotence of hESCs, serving as a platform for de novo derivation of clinically-suitable hESCs and effectively directing such hESCs uniformly towards clinically-relevant lineages by small molecules12 (see a schematic in Fig. 1B). After screening a variety of small molecules and growth factors, we found that such defined conditions rendered nicotinamide (NAM) sufficient to induce the specification of cardiomesoderm direct from pluripotent hESCs that further progressed to cardioblasts that generated human beating cardiomyocytes with high efficiency (Fig. 2). We defined conditions for induction of cardioblasts direct from pluripotent hESCs without an intervening multi-lineage embryoid body stage, enabling well-controlled efficient derivation of a large supply of human cardiac cells across the spectrum of developmental stages for cell-based therapeutics.

We have established a protocol for induction of cardioblasts direct from pluripotent human embryonic stem cells maintained under defined conditions with small molecules, which enables derivation of a large supply of human cardiac progenitors and functional cardiomyocytes for cardiovascular repair.

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...

Nephrotoxin Microinjection in Zebrafish to Model Acute Kidney Injury

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid decline in renal function and development of the clinical syndrome known as acute kidney injury (AKI). Pharmacological agents used to treat medical circumstances ranging from bacterial infection to cancer, when administered individually or in combination with other drugs, can initiate AKI. Zebrafish are a useful animal model to study the chemical effects on renal function in vivo, as they form an embryonic kidney comprised of nephron functional units that are conserved with higher vertebrates, including humans. Further, zebrafish can be utilized to perform genetic and chemical screens, which provide opportunities to elucidate the cellular and molecular facets of AKI and develop therapeutic strategies such as the identification of nephroprotective molecules. Here, we demonstrate how microinjection into the zebrafish embryo can be utilized as a paradigm for nephrotoxin studies.

Renal injuries incurred from nephrotoxins, which include drugs ranging from antibiotics to chemotherapeutics, can result in complex disorders whose pathogenesis remains incompletely understood. This protocol demonstrates how zebrafish can be used for disease modeling of these conditions, which can be applied to the identification of renoprotective measures.

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid ...

Filtration Isolation of Nucleic Acids:  A Simple and Rapid DNA Extraction Method

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad to extract cellular DNA from whole blood in less than 2 min. The blood specimen is treated with detergent, mixed briefly and applied by pipet to the separation membrane. The lysate wicks into the blotting pad due to capillary action, capturing the genomic DNA on the surface of the separation membrane. The extracted DNA is retained on the membrane during a simple wash step wherein PCR inhibitors are wicked into the absorbent blotting pad. The membrane containing the entrapped DNA is then added to the PCR reaction without further purification. This simple method does not require laboratory equipment and can be easily implemented with inexpensive laboratory supplies. Here we describe a protocol for highly sensitive detection and quantitation of HIV-1 proviral DNA from 100 &#181;l whole blood as a model for early infant diagnosis of HIV that could readily be adapted to other genetic targets.

We describe here a simple and rapid paper-based DNA extraction method of HIV proviral DNA from whole blood detected by quantitative PCR. This protocol can be extended for use in detecting other genetic markers or using alternative amplification methods.

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad ...

Magnetic-Activated Cell Sorting Strategies to Isolate and Purify Synovial Fluid-Derived Mesenchymal Stem Cells from a Rabbit Model

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for cartilage tissue engineering. MSCs from synovial fluid (SF-MSCs) have been considered promising candidates for articular regeneration, and their potential therapeutic benefit has made them an important research topic of late. SF-MSCs from the knee cavity of the New Zealand white rabbit can be employed as an optimized translational model to assess human regenerative medicine. By means of CD90-based magnetic activated cell sorting (MACS) technologies, this protocol successfully obtains rabbit SF-MSCs (rbSF-MSCs) from this rabbit model and further fully demonstrates the MSC phenotype of these cells by inducing them to differentiate to osteoblasts, adipocytes, and chondrocytes. Therefore, this approach can be applied in cell biology research and tissue engineering using simple equipment and procedures.

This article presents a simple and economic protocol for the straightforward isolation and purification of mesenchymal stem cells from New Zealand white rabbit synovial fluid.

Mesenchymal stem cells (MSCs) are the main cell source for cell-based therapy. MSCs from articular cavity synovial fluid could potentially be used for ...

A High Output Method to Isolate Cerebral Pericytes from Mouse

In recent years, cerebral pericytes have become the focus of extensive research in vascular biology and pathology. The importance of pericytes in blood brain barrier formation and physiology is now demonstrated but its molecular basis remains largely unknown. As the pathophysiological role of cerebral pericytes in neurological disorders is intriguing and of great importance, the in vitro models are not only sufficiently appropriate but also able to incorporate different techniques for these studies. Several methods have been proposed as in vitro models for the extraction of cerebral pericytes, although an antibiotic-free protocol with high output is desirable. Most importantly, a method that has increased output per extraction reduces the usage of more animals.
Here, we propose a simple and efficient method for extracting cerebral pericytes with sufficiently high output. The mouse brain tissue homogenate is mixed with a BSA-dextran solution for the separation of the tissue debris and microvascular pellet. We propose a three-step separation followed by filtration to obtain a microvessel rich filtrate. With this method, the quantity of microvascular fragments obtained from 10 mice is sufficient to seed 9 wells (9.6 cm2 each) of a 6-well plate. Most interestingly with this protocol, the user can obtain 27 pericyte rich wells (9.6 cm2 each) in passage 2. The purity of the pericyte cultures are confirmed with the expression of classical pericyte markers: NG2, PDGFR-&#946; and CD146. This method demonstrates an efficient and feasible in vitro tool for physiological and pathophysiological studies on pericytes.

We present a protocol for the extraction of murine cerebral pericytes. Based on an antibiotic-free enrichment oriented pericyte extraction, this protocol is a valuable tool for in vitro studies providing high purity and high yield, thus decreasing the number of experimental animals used.

In recent years, cerebral pericytes have become the focus of extensive research in vascular biology and pathology. The importance of pericytes in blood ...

Isolation, Characterization, and Therapeutic Application of Extracellular Vesicles from Cultured Human Mesenchymal Stem Cells

Extracellular vesicles (EVs) are heterogeneous membrane nanoparticles released by most cell types, and they are increasingly recognized as physiological regulators of organismal homeostasis and important indicators of pathologies; in the meantime, their immense potential to establish accessible and controllable disease therapeutics is emerging. Mesenchymal stem cells (MSCs) can release large amounts of EVs in culture, which have shown promise to jumpstart effective tissue regeneration and facilitate extensive therapeutic applications with good scalability and reproducibility. There is a growing demand for simple and effective protocols for collecting and applying MSC-EVs. Here, a detailed protocol is provided based on differential centrifugation to isolate and characterize representative EVs from cultured human MSCs, exosomes, and microvesicles for further applications. The adaptability of this method is shown for a series of downstream approaches, such as labeling, local transplantation, and systemic injection. The implementation of this procedure will address the need for simple and reliable MSC-EVs collection and application in translational research.

The present protocol describes the differential centrifugation for isolating and characterizing representative EVs (exosomes and microvesicles) from cultured human MSCs. Further applications of these EVs are also explained in this article.

Extracellular vesicles (EVs) are heterogeneous membrane nanoparticles released by most cell types, and they are increasingly recognized as physiological ...

Enhanced Bacterial Extracellular Vesicles Isolation for Microbiota Multi-Omics

Isolation and Purification of Bacterial Extracellular Vesicles from Human Feces Using Density Gradient Centrifugation

Bacterial extracellular vesicles (BEVs) are nanovesicles derived from bacteria that play an active role in bacteria-bacteria and bacteria-host communication, transferring bioactive molecules such as proteins, lipids, and nucleic acids inherited from the parent bacteria. BEVs derived from the gut microbiota have effects within the gastrointestinal tract and can reach distant organs, resulting in significant implications for physiology and pathology. Theoretical investigations that explore the types, quantities, and roles of BEVs derived from human feces are crucial for understanding the secretion and function of BEVs from the gut microbiota. These investigations also necessitate an improvement in the current strategy for isolating and purifying BEVs.
This study optimized the isolation and purification process of BEVs by establishing two density gradient centrifugation (DGC) modes: Top-down and Bottom-up. The enriched distribution of BEVs was determined in fractions 6 to 8 (F6-F8). The effectiveness of the approach was evaluated based on particle morphology, size, concentration, and protein content. The particle and protein recovery rates were calculated, and the presence of specific markers was analyzed to compare the recovery and purity of the two DGC modes. The results indicated that the Top-down centrifugation mode had lower contamination levels and achieved a recovery rate and purity similar to that of the Bottom-up mode. A centrifugation time of 7 h was sufficient to achieve a fecal BEV concentration of 108/mg.
Apart from feces, this method could be applied to other body fluid types with proper modification according to the differences in components and viscosity. In conclusion, this detailed and reliable protocol would facilitate the standardized isolation and purification of BEVs and thus, lay a foundation for subsequent multi-omics analysis and functional experiments.

Author Spotlight: Accelerating Research on Bacterial Extracellular Vesicles Separation and Heterogeneity 

This study describes a method to isolate and purify bacterial extracellular vesicles (BEVs) enriched from human feces via density gradient centrifugation (DGC), identifies the physical characteristics of BEVs from morphology, particle size, and concentration, and discusses the potential applications of the DGC approach in clinical and scientific research.

Methods Article

A Simple Benchtop Filtration Method to Isolate Small Extracellular Vesicles from Human Mesenchymal Stem Cells