We would like to thank the American Cancer Society, Illinois Division (282802) and the National Science Foundation CBET (1512598) for funding support. We also would like to thank Dr. Dianwen Zhang from the University of Illinois Beckman Institute for microscopy training. Finally, we would like to thank Jared Weddell, Stacie Chen, and Spencer Mamer for insightful discussions.

1. Cleaning the Glass Surface and Preparing Reagents
<ol>
	<li>Place a glass surface in an oxygen plasma machine for 5 min at 50% power to clean it.</li>
	<li>Prepare 2.5 ml 2% reconstituted (3-aminopropyl) triethoxysilane (APTES) solution, by adding 50 &#181;l of APTES and 2.45 ml of ethanol in a conical tube.</li>
</ol>
2. APTES and DSB Functionalization
<ol>
	<li>Add APTES solution to the surfaces. Pipette 150 &#181;l per well for 8 well plates. Pipette 100 &#181;l per well for 24 well plat...

<ol>
	<li>Erdbruegger, U., Haubitz, M., Woywodt, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulating+endothelial+cells:+a+novel+marker+of+endothelial+damage.">Circulating endothelial cells: a novel marker of endothelial damage.</a> Clin. Chim. Acta. 373 (1-2), 17-26 (2006).</li><li>De Spiegelaere, W., Cornillie, P., Van Poucke, M., Peelman, L., Burvenich, C., Van den Broeck, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+mRNA+expression+analysis+in+kidney+glomeruli+using+microdissection+techniques.">Quantitative mRNA expression analysis in kidney glomeruli using microdissection techniques.</a> Histol. Histopathol. 26 (2), 267-275 (2011).</li><li>Chen, S., Guo, X., Imarenezor, O., Imoukhuede, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+VEGFRs,+NRP1,+and+PDGFRs+on+Endothelial+Cells+and+Fibroblasts+Reveals+Serum,+Intra-Family+Ligand,+and+Cross-Family+Ligand+Regulation.">Quantification of VEGFRs, NRP1, and PDGFRs on Endothelial Cells and Fibroblasts Reveals Serum, Intra-Family Ligand, and Cross-Family Ligand Regulation.</a> Cell. Mol. Bioeng. 8 (3), 383-403 (2015).</li><li>Cheung, L. S. 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=Detachment+of+captured+cancer+cells+under+flow+acceleration+in+a+bio-functionalized+microchannel.">Detachment of captured cancer cells under flow acceleration in a bio-functionalized microchannel.</a> Lab Chip. 9 (12), 1721-1731 (2009).</li><li>Privorotskaya, 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+thermal+lysis+of+cells+using+silicon-diamond+microcantilever+heaters.">Rapid thermal lysis of cells using silicon-diamond microcantilever heaters.</a> Lab Chip. 10 (9), 1135-1141 (2010).</li><li>Park, K., Akin, D., Bashir, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrical+capture+and+lysis+of+vaccinia+virus+particles+using+silicon+nano-scale+probe+array.">Electrical capture and lysis of vaccinia virus particles using silicon nano-scale probe array.</a> Biomed. Microdevices. 9 (6), 877-883 (2007).</li><li>Galletti, G., Sung, M., Vahdat, L. <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+breast+cancer+and+gastric+cancer+circulating+tumor+cells+by+use+of+an+anti+HER2-based+microfluidic+device.">Isolation of breast cancer and gastric cancer circulating tumor cells by use of an anti HER2-based microfluidic device.</a> Lab Chip. 14 (1), 147-156 (2014).</li><li>Schudel, B. R., Choi, C. J., Cunningham, B. T., Kenis, P. J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+chip+for+combinatorial+mixing+and+screening+of+assays.">Microfluidic chip for combinatorial mixing and screening of assays.</a> Lab Chip. 9 (12), 1676-1680 (2009).</li><li>Lien, K. Y., Chuang, Y. H., 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+isolation+and+detection+of+cancer+cells+by+utilizing+integrated+microfluidic+systems.">Rapid isolation and detection of cancer cells by utilizing integrated microfluidic systems.</a> Lab Chip. 10 (21), 2875-2886 (2010).</li><li>Stott, S. 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=Isolation+of+circulating+tumor+cells+using+a.">Isolation of circulating tumor cells using a.</a> PNAS. 107 (35), 18392-18397 (2010).</li><li>Yu, M., Ting, D., Stott, S., Wittner, B., Ozsolak, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA+sequencing+of+pancreatic+circulating+tumour+cells+implicates+WNT+signalling+in+metastasis.">RNA sequencing of pancreatic circulating tumour cells implicates WNT signalling in metastasis.</a> Nature. 487 (7408), 510-513 (2012).</li><li>Sheng, W., Ogunwobi, O., Chen, T., Zhang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=>Capture,+release+and+culture+of+circulating+tumor+cells+from+pancreatic+cancer+patients+using+an+enhanced+mixing+chip.">>Capture, release and culture of circulating tumor cells from pancreatic cancer patients using an enhanced mixing chip.</a> Lab Chip. 14 (1), 89-98 (2014).</li><li>Zheng, X., Cheung, L. S. L., Schroeder, J. A., Jiang, L., Zohar, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-performance+microsystem+for+isolating+circulating+tumor+cells.">A high-performance microsystem for isolating circulating tumor cells.</a> Lab Chip. 11 (19), 3269-3276 (2011).</li><li>Imoukhuede, P. I., Popel, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+and+cell-to-cell+variation+of+vascular+endothelial+growth+factor+receptors.">Quantification and cell-to-cell variation of vascular endothelial growth factor receptors.</a> Exp. Cell Res. 317 (7), 955-965 (2011).</li><li>Imoukhuede, P. I., Popel, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+VEGF+receptors+on+endothelial+cells+in+mouse+skeletal+muscle.">Expression of VEGF receptors on endothelial cells in mouse skeletal muscle.</a> PLoS One. 7 (9), e44791 (2012).</li><li>Ludwig, A., Kretzmer, G., Sch&#252;gerl, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+a+&amp;#34;critical+shear+stress+level&amp;#34;+applied+to+adherent+mammalian+cells.">Determination of a &amp;#34;critical shear stress level&amp;#34; applied to adherent mammalian cells.</a> Enzyme Microb. Technol. 14 (3), 209-213 (1992).</li><li>Ansari, A., Lee-Montiel, F. T., Amos, J., Imoukhuede, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Secondary+anchor+targeted+cell+release.">Secondary anchor targeted cell release.</a> Biotechnol. Bioeng. 112 (11), 2214-2227 (2015).</li><li>Drenan, R. M., Nashmi, R., Imoukhuede, P., Just, H., McKinney, S., Lester, 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=Subcellular+trafficking,+pentameric+assembly,+and+subunit+stoichiometry+of+neuronal+nicotinic+acetylcholine+receptors+containing+fluorescently+labeled+alpha6+and+beta3+subunits.">Subcellular trafficking, pentameric assembly, and subunit stoichiometry of neuronal nicotinic acetylcholine receptors containing fluorescently labeled alpha6 and beta3 subunits.</a> Mol. Pharmacol. 73 (1), 27-41 (2008).</li><li>Imoukhuede, P. I., Dokun, A. O., Annex, B. H., Popel, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial+cell-by-cell+profiling+reveals+temporal+dynamics+of+VEGFR1+and+VEGFR2+membrane-localization+following+murine+hindlimb+ischemia.">Endothelial cell-by-cell profiling reveals temporal dynamics of VEGFR1 and VEGFR2 membrane-localization following murine hindlimb ischemia.</a> Am J Physiol Hear. Circ Physiol. 4 (8), H1085-H1093 (2013).</li><li>van Beijnum, J. R., Rousch, M., Castermans, K., van der Linden, E., Griffioen, A. W. <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+endothelial+cells+from+fresh+tissues.">Isolation of endothelial cells from fresh tissues.</a> Nat. Protoc. 3 (6), 1085-1091 (2008).</li><li>Imoukhuede, P. I., Popel, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+fluorescent+profiling+of+VEGFRs+reveals+tumor+cell+and+endothelial+cell+heterogeneity+in+breast+cancer+xenografts.">Quantitative fluorescent profiling of VEGFRs reveals tumor cell and endothelial cell heterogeneity in breast cancer xenografts.</a> Cancer Med. 3 (2), 225-244 (2014).</li><li>BD Biosciences. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> CD Marker Handbook: Human and Mouse. , (2010).</li><li>Tanzeglock, T., Soos, M., Stephanopoulos, G., Morbidelli, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+mammalian+cell+death+by+simple+shear+and+extensional+flows.">Induction of mammalian cell death by simple shear and extensional flows.</a> Biotechnol. Bioeng. 104 (2), 360-370 (2009).</li><li>Perritt, D., Wong, P., Macpherson, J. L., Henrichsen, K., Symonds, G., Pond, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Processing Blood. , (2014).</li><li>Fukuda, S., Schmid-Sch&#246;nbein, G. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Centrifugation+attenuates+the+fluid+shear+response+of+circulating+leukocytes.">Centrifugation attenuates the fluid shear response of circulating leukocytes.</a> J. Leukoc. Biol. 72 (July), 133-139 (2002).</li><li>dela Paz, N. G., Walshe, T. E., Leach, L. L., Saint-Geniez, M., D'Amore, P. A. <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+shear-stress-induced+VEGF+expression+in+endothelial+cell+survival.">Role of shear-stress-induced VEGF expression in endothelial cell survival.</a> J. Cell Sci. 125 (Pt 4), 831-843 (2012).</li><li>Allard, 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=Tumor+Cells+Circulate+in+the+Peripheral+Blood+of+All+Major+Carcinomas+but+not+in+Healthy+Subjects+or+Patients+With+Nonmalignant+Diseases+Tumor+Cells+Circulate+in+the+Peripheral+Blood+of+All+Major+Carcinomas+but+not+in+Healthy+Subjects+or+Patients+With+Nonmalignant+diseases.&amp;#34.">Tumor Cells Circulate in the Peripheral Blood of All Major Carcinomas but not in Healthy Subjects or Patients With Nonmalignant Diseases Tumor Cells Circulate in the Peripheral Blood of All Major Carcinomas but not in Healthy Subjects or Patients With Nonmalignant diseases.&amp;#34.</a> Clinical Cancer Research. 10, 6897-6904 (2005).</li><li>Nagrath, 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=Isolation+of+rare+circulating+tumour+cells+in+cancer+patients+by+microchip+technology.">Isolation of rare circulating tumour cells in cancer patients by microchip technology.</a> Nature. 450 (7173), 1235-1239 (2007).</li><li>Chen, S., Weddel, J., Gupta, P., Conard, G., Parkin, J., Imoukhuede, P. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=QFlow+Cytometer-Based+Receptoromic+Screening:+A+High-throughput+Quantification+Approach+Informing+Biomarker+Selection+and+Nanosensor.">QFlow Cytometer-Based Receptoromic Screening: A High-throughput Quantification Approach Informing Biomarker Selection and Nanosensor.</a> Submiss. , (2016).</li><li>Vasa, 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=Number+and+migratory+activity+of+circulating+endothelial+progenitor+cells+inversely+correlate+with+risk+factors+for+coronary+artery+disease.">Number and migratory activity of circulating endothelial progenitor cells inversely correlate with risk factors for coronary artery disease.</a> Circ. Res. 89 (1), E1-E7 (2001).</li><li>Hirsch, J. D., Eslamizar, 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=Easily+reversible+desthiobiotin+binding+to+streptavidin,+avidin,+and+other+biotin-binding+proteins:+uses+for+protein+labeling,+detection,+and+isolation.">Easily reversible desthiobiotin binding to streptavidin, avidin, and other biotin-binding proteins: uses for protein labeling, detection, and isolation.</a> Anal. Biochem. 308 (2), 343-357 (2002).</li><li>Wilchek, M., Bayer, E. 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Improvements in cell isolation techniques furthers scientific studies in structure-function relationships in neuroscience18, stem cell programming in regenerative biology, and angiogenic signaling in vascular biology19. Indeed, primary cell culture20 (e.g., HUVECs) in vascular biology is primarily done through the use of cell isolation techniques. Cell isolation was also recently used for quantitative flow (qFlow) cytometry analysis of plasma membrane receptors3,14,15,19,21<...

Current bench-top cell separation approaches (e.g., fluorescence activated cell sorting1, laser capture micro-dissection2, immuno-magnetic bead separation1) can take several hours of preparation and sorting. These large time scales can affect physiological response and expression levels, resulting in analyses that are not representative of the physiological response3. Systems are needed that can rapidly and efficiently isolate specific cell types without disrupting cell-surface receptor-levels in order to improve cell isolation and enrichment for biomedical applications. Therefore, the rationale for our approach is to develop a gentle approach for cell isolation.
The &#34;lab on a chip&#34; concept offers the promise of orders of magnitude quicker (hours-to-minutes) cell isolation, and most frequently involves capturing cells onto a surface and releasing cells or intracellular contents through physical4,5 or chemical methods6. Although these approaches offer a few advantages such as identifying protein7,8 expression, identifying RNA expression9-11, or even providing cells for in vitro culture12,13, many of these techniques cannot be translated to diagnostics such as cell receptor profiling due to their non-physiological environments. Enzymatic lifting agents such as collagenases can also affect these receptor quantities14,15, meaning cell receptor quantification techniques that use these lifting agents will not generate accurate physiological data. Cellular lysis prevents differentiation between the native surface receptors, and those which were previously internalized16. This protocol describes a fast and gentle approach for cell isolation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>(3-Aminopropyl) triethoxysilane (APTES)</td>
			<td>Acros Organics</td>
			<td>919-30-2</td>
			<td>Used to make 2% APTES solution</td>
		</tr>
		<tr>
			<td>Plasma Cleaner Pico</td>
			<td>Diener</td>
			<td>Model 1</td>
			<td>Cleans surfaces and allows for bonding of PDMS to glass</td>
		</tr>
		<tr>
			<td>d-Desthiobiotin (DSB)</td>
			<td>Sigma</td>
			<td>D20655</td>
			<td>Used as the releasing mechanism in the cellular capture surface.</td>
		</tr>
		<tr>
			<td>dimethyl sulfoxide (DMSO)</td>
			<td>British Drug Houses (BDH)</td>
			<td>BDH1115-1LP</td>
			<td>Dissolves the DSB into solution</td>
		</tr>
		<tr>
			<td>1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)</td>
			<td>Thermo-Scientific</td>
			<td>5g: 22980 
			25g: 22981</td>
			<td>Activates Carboxylic Acids and allows binding of proteins to glass surface.</td>
		</tr>
		<tr>
			<td>uncoated 8-well culture slide</td>
			<td>BD Falcon</td>
			<td>Case of 24: 354118 
			Case of 96: 354108</td>
			<td>Used in cellular experiments involving Zeiss fluorescence microscope such as initial capture and release quantification experiments</td>
		</tr>
		<tr>
			<td>Glass bottom 24-well plates</td>
			<td>MatTek</td>
			<td>P24G-0-13-F</td>
			<td>Used in cellular experiments involving the plate reader such as antibody and cellular titration experiments</td>
		</tr>
		<tr>
			<td>Mercaptoethanol</td>
			<td>Science Lab</td>
			<td>60-24-2</td>
			<td>Used to quench reaction between EDC and DSB</td>
		</tr>
		<tr>
			<td>4-Morpholinoethanesulfonic acid hydrate 
			(MES Hydrate 99%)</td>
			<td>Fisher Scientific</td>
			<td>AC172590250</td>
			<td>Used to make 0.1 M MES Buffer for use in EDC reaction</td>
		</tr>
		<tr>
			<td>Precision Oven</td>
			<td>Thermo Scientific</td>
			<td>11-475-153</td>
			<td>Used in curing of PDMS and APTES layer.</td>
		</tr>
		<tr>
			<td>Titramax 1000 Shaker</td>
			<td>Heidolph</td>
			<td>13-889-420</td>
			<td>Used to ensure even distribution of APTES on surfaces.</td>
		</tr>
		<tr>
			<td>1X Streptavidin 5mg 
			[e7105-5mg]</td>
			<td>Proteo Chem</td>
			<td>9013-20-1</td>
			<td>Biotin-binding protein 
			May cause irritation</td>
		</tr>
		<tr>
			<td>5 cm Glass Dish</td>
			<td>Fisher Scientific</td>
			<td>08748A</td>
			<td>Used in HUVEC studies as well as future profiling studies.</td>
		</tr>
		<tr>
			<td>14 cm Petri Dish with Cover</td>
			<td>Sigma-Aldrich</td>
			<td>Z717231</td>
			<td>Used to hold samples being functionalized and transport them.</td>
		</tr>
		<tr>
			<td>MCF7-GFP cells</td>
			<td>Cell Biolabs</td>
			<td>AKR211</td>
			<td>Stored in liquid nitrogen</td>
		</tr>
		<tr>
			<td>RAW264.7 
			mouse macrophages</td>
			<td>ATCC</td>
			<td>TIB-71</td>
			<td>Gifted to us from Smith lab at the University of Illinois. Stored in liquid nitrogen</td>
		</tr>
		<tr>
			<td>TrypLE</td>
			<td>Life Technologies</td>
			<td>12605036</td>
			<td>Stored in 100mL at room temperature</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s modified Eagle medium</td>
			<td>Cell Media Facility at School of Chemical Sciences at UIUC</td>
			<td>50003PC</td>
			<td>Supplier: Corning</td>
		</tr>
		<tr>
			<td>Nonessential amino acids</td>
			<td>Cell Media Facility at School of Chemical Sciences at UIUC</td>
			<td>25-025-CI</td>
			<td>Already added into DMEM by facility. 
			Supplier: Corning</td>
		</tr>
		<tr>
			<td>10% fetal bovine serum</td>
			<td>Fisher Scientific</td>
			<td>03-600-511</td>
			<td>Stored in 500mL at &#60; -10&#8304;C</td>
		</tr>
		<tr>
			<td>1% Penicillin&#8211;Streptomycin</td>
			<td>Life Sciences Storeroom at UIUC</td>
			<td>17602e</td>
			<td>Supplier: VWR 
			Stored in 100 ml at 4&#8304;C</td>
		</tr>
		<tr>
			<td>Cell scraper</td>
			<td>Fisher Scientific</td>
			<td>12-565-58</td>
			<td>Small 23cm 50 pack</td>
		</tr>
		<tr>
			<td>Cell Dissociation Solution</td>
			<td>Corning</td>
			<td>MT-25-056CI</td>
			<td>Used to lift cells non-enzymatically for the use in cell experiments</td>
		</tr>
		<tr>
			<td>Hemacytometer</td>
			<td>Hausser</td>
			<td>02-671-54</td>
			<td>Used to count cells for quantification of cell solutions and capture and release effectivity.</td>
		</tr>
		<tr>
			<td>Biotin</td>
			<td>Amresco</td>
			<td>58-85-5</td>
			<td>Used to release cells from surface.</td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Created from Recipe</td>
			<td>N/A</td>
			<td>Used to keep cells alive in suspension as well as wash surfaces of non-specific binding. (Adapted from Cold Spring Harbor Protocols): In 500 mL, use 4 g NaCl, .2 g KCl, .0402 g Na2PO4*7H2O, .03 g KH2PO4 and .5 g Glucose. Add DI water to get to 500 mL, filter, and then refrigerate.</td>
		</tr>
		<tr>
			<td>HLA-ABC Antibody</td>
			<td>BioLegend</td>
			<td>311402</td>
			<td>Antibody used to capture MCF7gfp cells</td>
		</tr>
		<tr>
			<td>hIgG Antibody</td>
			<td>BioLegend</td>
			<td>HP6017</td>
			<td>Antibody used to capture MCF7gfp cells</td>
		</tr>
		<tr>
			<td>MCF7 GFP cells</td>
			<td>Cell Biolabs</td>
			<td>AKR-211</td>
			<td>Luminal Breast Cancer line that has been transfected with green fluorescent protein.</td>
		</tr>
		<tr>
			<td>Assorted Conicals</td>
			<td>Thermo-Scientific</td>
			<td>15mL: 12-565-268</td>
			<td>50/15 mL plastic conicals for storing solutions and aliquots.</td>
		</tr>
		<tr>
			<td>Mini-Tube Rotators (End over End Mixer)</td>
			<td>Fisher Scientific</td>
			<td>05-450-127</td>
			<td>Used to incubate antibody and mix other cellular solutions in order to mix</td>
		</tr>
		<tr>
			<td>Axiovert 200M (Fluorescence Microscope)</td>
			<td>Zeiss</td>
			<td>N/A</td>
			<td>Zeiss Axiovert 200 M inverted florescence microscope.</td>
		</tr>
		<tr>
			<td>Zeba Desalting columns</td>
			<td>Thermo-Scientific</td>
			<td>PI-87770</td>
			<td>Used to purify newly biotinylated antibodies after the use of the Biotinylation Kit. Instructions provided at: http://www.funakoshi.co.jp/data/datasheet/PCC/89894.pdf</td>
		</tr>
		<tr>
			<td>EZ Link Sulfo NHS Low Weight Biotinylation Kit</td>
			<td>Thermo- Scientific</td>
			<td></td>
			<td>Used to biotinylate antibodies to allow them to integrate with the capture surface</td>
		</tr>
		<tr>
			<td>Plate Reader</td>
			<td>BioTek</td>
			<td>Synergy HTX Multimode Reader</td>
			<td>Used to quantitatively measure fluorescent intensity in the titration experiments.</td>
		</tr>
	</tbody>
</table>

a method of targeted cell isolation via glass surface functionalization

One of the limiting factors to the adoption and advancement of personalized medicine is the inability to develop diagnostic tools to probe individual nuances in expression from patient to patient. Current methodologies that try to separate cells to fill this niche result in disruption of physiological expression, making the separation technique useless as a diagnostic tool. In this protocol, we describe the functionalization and optimization of a surface for the cellular capture and release. This functionalized surface integrates biotinylated antibodies with a glass surface functionalized with an aminosilane (APTES), desthiobiotin and streptavidin. Cell release is facilitated through the introduction of biotin, allowing the recollection and purification of cells captured by the surface. This release is done through the targeting of the secondary moiety desthiobiotin, which results in a much more gentle release paradigm. This reduction in harsh reagents and shear forces reduces changes in cellular expression. The functionalized surface captures up to 80% of cells in a single cell mixture and has demonstrated 50% capture in a dual-cell mixture. Applications of this technology to xenografts and cancer separation studies are investigated. Quantification techniques for surface verification such as plate reader and ImageJ analyses are described as well.

Using this protocol we show cell capture (Figure 3A) and cell release (Figure 3C) of MCF7GFP cells as well as live cell controls (Figure 4). We quantified the cell capture as 60% and 80% were released (Figure 3C). When we extended this approach to a mixture of RAW 264.7 macrophages and MCF7GFP cells, 50% of RAW macrophages were captured (Fig. 3D) and 80% of RAW macrophages were release with 20 mM biotin (...

Watch this Scientific Journal Video about A Method of Targeted Cell Isolation via Glass Surface Functionalization at JoVE.com

A Method of Targeted Cell Isolation via Glass Surface Functionalization

This protocol describes customizable surface functionalization of the desthiobiotin, streptavidin, and APTES system in order to isolate specific cell types of interest. In addition, this manuscript covers the applications, optimization, and verification of this process.

One of the limiting factors to the adoption and advancement of personalized medicine is the inability to develop diagnostic tools to probe individual ...

The overall goal of this glass surface functionalization process is to allow for the gentle capture and release of cells of interest. This method can help answer key questions in the field of tumor angiogenesis, enabling screening of cell biomarkers that indicate drug resistance. The main advantage of this technique is that it is completely customizable, for virtually any cell type of interest.As long as there is an antibody specific to the cell type, the surface can be adapted for its capture. Though this method can provide insight into cancer angiogenesis, it may also be applied to other diseases as purified samples are necessary for the development of more personalized treatment regimens. We first had the idea for this method when we were trying to develop a reversible release mechanism for capturing cells, using the interaction between desthiobiotin and the adivin family.After cleaning a glass surface in an oxygen plasma machine for five minutes according to the text protocol, prepare 2.5 milliliters of 2%reconstituted 3-Aminopropyl triethoxysilane, or APTES solution, by combining 50 microliters of APTES and 2.45 milliliters of ethanol in a conical tube. Pipette the APTES solution onto the glass surfaces, then cover the surfaces and place them on a platform shaker at room temperature for 50 minutes to evenly distribute the APTES layer. In the meantime, preheat the oven to 55 degrees Celsius for the eight-and 24-well plates, or 90 degrees Celsius for the glass dishes.After removing the plates from the shaker, use ethanol to rinse the glass surfaces according to the text protocol. With 100%nitrogen gas, dry the surfaces. Then place the eight-and 24-well plates in the oven for two hours, or the glass dishes in the oven for one hour.Next, prepare 2.5 milliliters of d-Desthiobiotin, or DSB solution, by mixing 1.5 milligrams per milliliter of DSB in 37.5 microliters of DMSO, and adding five milligrams per milliliter of EDC to 2, 462.5 microliters of 0.1 Molar MES buffer, pH 6. Then combine the two solutions. After 15 minutes, add one microliter of BME to quench the reaction between DSB and EDC.Remove the hot APTES functionalized glass surfaces from the oven, and allow them to cool for five to 10 minutes. Add MES buffer to the glass surfaces to rinse them by holding the pipette at a 70 degree angle so that the tip is not directly pointed at the surface. Then discharge and draw the buffer from a fixed point, such as the corner of the well.Then, use the MES buffer to rinse two more times. Apply DSB solution to the glass surfaces. Transfer them to a damp paper towel inside a Petri dish, cover the dish, and incubate in the fridge for 18 to 24 hours.After the incubation at four degrees Celsius, use PBS to rinse each glass surface three times, as demonstrated earlier in this video. Then, dilute Streptavidin, or SAV stock solution, to 0.4 milligrams per milliliter, and evenly apply it to the glass surfaces so that a thin layer forms. After incubating the glass for 18 to 24 hours, use 150 microliters of PBS to rinse each surface three times.Then wet a paper towel with deionized water, and place it flat in a 14 centimeter Petri dish surrounding the plates to retain moisture in the wells. Cover the Petri dish with the glass surfaces, and place it in a four degrees Celsius biosafety Level 1 fridge until needed. To carry out cell capture, aspirate the medium from T175 flasks of cells.Then use PBS to rinse the cells and aspirate the buffer. Add 10 milliliters of non-enzymatic lifting agent, such as Cell Dissociation Solution, to the flask. Then incubate at 37 degrees Celsius for six minutes.After six minutes, add 10 milliliters of cold HBSS to dilute the lifting agent. Then pipette 20 microliters of the cells and use a hemocytometer to count them. Centrifuge the cell suspension at 500 x g, in four degrees Celsius, for five minutes.And use HBSS to resuspend the cells to one times 10 to the sixth cells per milliliter. Pipette up and down to resuspend the cells in solution, and reduce cellular clumping that may reduce antibody binding. Then, split the cellular suspension into separate control and experimental solutions.Add the biotinylated antibodies to the respective cells solutions and incubate on an end-over-end mixer at four degrees Celsius for 30 minutes. Use 150 microliters of HBSS to wash the functionalized glass in eight-well plates three times, as demonstrated earlier in the video. Add the cell solution to the wells, and incubate on ice on the shaker for 45 minutes.In the meantime, prepare a 20 millimolar solution of biotin in sterile HBSS. Then, after the incubation, gently use 150 microliters of HBSS to rinse the cell solution from the glass. After repeating the rinse two more times, add 150 microliters of the biotin solution to each respective release well, and incubate for 20 minutes to allow the reaction to proceed.Recollect nonspecifically bound cells by using HBSS to wash the cells. Then, proceed to fluorescence imaging and analysis according to the text protocol. Include images of live cells in a flask as a control.In this experiment, MCF7GFP cells were exposed to the functionalized surface. 60%of the cells were captured using the HLA-ABC antibody. Upon exposure to 20 millimolar biotin, 80%of the captured cells were released.As shown here when the MCF7GFP cells were mixed with RAW 264.7 cells, 50%of the RAW macrophages were captured, and the addition of 20 micromolar biotin subsequently released 80%of the captured RAW cells. This figure illustrates that the positive control RAW macrophages exhibit no fluorescence activity. However, the negative control MCF7GFP cells are positive for GFP fluorescence.Because excess antibody can decrease cell capture, the antibody concentration was optimized by titrating from zero to 10, 000 nanograms per milliliter of HLA antibody. The results showed that the ideal antibody concentration was between 100 and 1, 000 nanograms per milliliter. In addition, cell optimization experiments determined that the ideal concentration of cells that can be captured is between one times 10 to the fifth, and one times 10 to the sixth cells, since quantities below that number are lower than the background.Once mastered, this technique can be done in three days, with less than six hours of experimental time, not including the overnight incubations. While attempting this procedure, it's important to remember to collect the cell washes during the experiments, as they can give vital information about the effectiveness of the surface. Following this procedure, other methods like flow cytometry can be performed in order to answer additional questions, like what receptor expression levels the cells of interest may have.After its development, surface functionalization has paved the way for researchers in the field of biomaterials to explore biosafe integration of materials, such as, implants in patients for a variety of diseases and injuries. After watching this video, you should have a good understanding of how to surface functionalize glass surfaces to capture and release cells of interest, allowing for downstream analysis. Don't forget that working with live cells in sodium azide can be extremely hazardous, and precautions such as proper training, PPE, and disposal, should always be taken while performing this procedure.

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Cancer Research

9.3K vistas.  University of Illinois at Urbana-Champaign. The overall goal of this glass surface functionalization process is to allow for the gentle capture and release of cells of interest. This method can help answer key questions in the field of tumor angiogenesis, enabling screening of cell biomarkers that indicate drug resistance. The main advantage of this technique is that it is completely customizable, for virtually any cell type of interest.As long as there is an antibody specific to the cell type, the surface can be adapted for its...