Il finanziamento per questa ricerca è stato fornito dalla Commissione del New Jersey su Spinal Cord Research (NJCSCR) (a FHK), concedere CSCR14IRG005 (a BLF), NIH concedere R15NS087501 (a CHC), e la Kirby Fondazione FM (ETA).

NOTA: Si prega di consultare tutte le schede di sicurezza materiale pertinente (MSDS) prima dell&#39;uso. Alcune delle sostanze chimiche utilizzate in questo protocollo sono tossici e cancerogeni. Si prega di utilizzare tutte le pratiche di sicurezza adeguati (cappa, cassetto portaoggetti) e dispositivi di protezione individuale (occhiali, guanti, camice da laboratorio, pantaloni a figura intera, scarpe chiuse) quando si usano materiali tossici o acido / base. 1. Realizzazione del Maestro Stampo per Soft litografia mediante fotolitografia <ol><li> Disegnare il layout delle microcanali utilizzando uno strumento di disegno computer-aided design (CAD). </li><li> Stampa il layout su un piatto maschera vuoto utilizzando la maschera laser scrittore. </li><li> Risciacquare un wafer di silicio da 4 pollici con acetone mediante isopropanolo e asciugare con una pistola ad aria azoto per garantire che nessun solvente viene lasciato sul wafer. </li><li> Disidratare wafer mediante cottura su una piastra calda a 200 ° C per 5 min. </li><li> Selezionare un fotoresist negativo progettata per l&#39;altezza desiderata dei microcanali. Fo esempio, utilizzare fotoresist negativo SU-8 50 per ottenere microcanali con un&#39;altezza di 50 micron. </li><li> Lasciare il wafer raffreddare a temperatura ambiente, e quindi allineare il wafer sul mandrino di coater rotazione. </li><li> Dispensare 4 ml (1 mL diametro / pollice della fetta) di fotoresist negativo sul centro della fetta. </li><li> Spin cappotto il wafer con un ciclo di centrifuga in due fasi utilizzando un filatore. Innanzitutto, applicare un ciclo di diffusione di 500 rpm con un&#39;accelerazione di 100 rpm / s per 10 s. Quindi applicare un ciclo di centrifuga di 2000 giri con un&#39;accelerazione di 300 rpm / s 2 per 30 s per ottenere un rivestimento 50 micron di photoresist su un wafer. </li><li> Morbido cuocere il wafer in due fasi su un piatto caldo secondo le istruzioni del produttore. Per un rivestimento 50 micron di photoresist, prima pre-cuocere il wafer a 65 ° C per 6 minuti e poi subito rampa della temperatura della piastra calda per lasciare cuocere il wafer a 95 ° C per 20 min. </li><li> Lasciare il wafer raffreddare a temperatura ambiente e quindi caricare ilwafer sul palco litografia. </li><li> Allineare la maschera sul wafer utilizzando maschera allineatore ed esporre la fetta di luce UV (come da istruzioni del produttore) ad una intensità di 1,5 mW / cm 2 per 146 s per applicare la dose totale UV di 220 mJ / cm 2 necessario per un 50 micron di spessore strato di resina fotosensibile. </li><li> Applicare dopo l&#39;esposizione cuocere al wafer in due fasi su un piatto caldo. Per un rivestimento di 50 micron di photoresist, prima pre-cuocere il wafer a 65 ° C per 1 min e immediatamente rampa della temperatura della piastra calda per lasciare cuocere è a 95 ° C per 5 min. </li><li> Sviluppare il wafer in immergendo il wafer di SU-8 sviluppatore e scuotendo delicatamente fino a quando le caratteristiche diventano chiari sul wafer. Sviluppare il wafer per ~ 6 min per il photoresist spessore 50 micron. </li><li> Risciacquare eccesso sviluppatore con isopropanolo ed etanolo, quindi asciugare il wafer con una pistola ad aria azoto. </li><li> Duro cuocere il wafer di silicio su una piastra calda a 150 ° C per 15 min. </li><li> Posiziona ilwafer in un essiccatore con 25 ml di agente silanizzazione tridecafluoro-1,1,2,2-tetrahydrooctyl-1-triclorosilano. NOTA: L&#39;agente silanizzazione è corrosivo, quindi dovrebbe essere utilizzato in un cappa acido / base, con attrezzature adeguate di protezione individuale (occhiali, guanti, camice, pantaloni a figura intera, chiuso-toe scarpe). </li><li> Applicare il vuoto per 5 minuti ed esporre il wafer ai vapori di silano per 30 minuti senza rilasciare il vuoto. </li><li> Trasferire il wafer in una capsula di Petri opportunamente dimensionato. </li></ol> 2. Realizzazione del Maestro Stampo per Soft litografia con nastro adesivo <ol><li> Disegnare il layout delle microcanali utilizzando uno strumento di disegno CAD e stampare il disegno su carta bianca. </li><li> Pulire un vetrino abbastanza grande per ospitare il disegno con isopropanolo e poi asciugare il vetrino con un fucile ad aria. </li><li> Attaccare il nastro adesivo sul vetrino pulito. Non essere attenti a intrappolare eventuali bolle d&#39;aria. </li><li> Nastro lati della glass scivolare sulla carta con il disegno, con il nastro rivolta verso l&#39;alto. </li><li> Utilizzare un bisturi per tagliare il nastro sul vetrino utilizzando il disegno di carta come riferimento e quindi rimuovere il nastro da aree indesiderate del vetrino. </li><li> Sciacquare il vetrino con isopropanolo e asciugare con un fucile ad aria. Cuocere il vetrino in stufa a 65 ° C per 30 min. </li><li> Delicatamente rotolare sopra il nastro con un rullo di gomma per rimuovere le bolle d&#39;aria e consentire la slitta raffreddare a temperatura ambiente. </li></ol> 3. soft litografia fabbricazione dei dispositivi PDMS <ol><li> Mescolare PDMS elastomero e il suo agente di indurimento in un rapporto di 10: 1 (w: w), agitare la miscela vigorosamente, e quindi degassare la miscela ponendolo in una camera a vuoto fino bolle d&#39;aria vengono visualizzati nella miscela. </li><li> Versare il composto su uno stampo di silicone silanizzata o muffa nastro adesivo in una capsula di Petri per ottenere un ~ 2 spesso strato di PDMS e Degas mm fino a quando tutta l&#39;aria bolle scompaiono. </li><li> Curare il PDMS in un fornoa 65 ° C per 2 h. </li><li> Utilizzare un bisturi per tagliare lo strato PDMS di almeno 5 mm di distanza dalle caratteristiche e poi sbucciate le PDMS curato fuori lo stampo con pinzetta. </li><li> Effettuare un singolo foro di ingresso con una biopsia 1 millimetro punzone ovunque sul microcanali, preferibilmente al termine di una rete di microcanali, come mostrato nella figura 2a e 4b. </li><li> Pulire i PDMS espressi con del nastro adesivo per rimuovere le particelle di polvere adsorbiti sul dispositivo. Sterilizzare il dispositivo microcanali PDMS (PDMS Cast) risciacquando con una soluzione di etanolo al 70% seguita da deionizzata sterile dell&#39;acqua (DI), e esporre a UV per 30 min. </li><li> Tenere il dispositivo PDMS sterile in una capsula di Petri sterile fino al momento dell&#39;uso. </li></ol> 4. substrato Patterning <ol><li> Posizionare il PDMS sterili espressi con una pinzetta su un vetrino di vetro sterile o capsula di Petri e applicare una leggera pressione con la punta delle pinzette. NOTA: Il cast PDMS fa una conforme, ma tenuta reversibili con la glass vetrino o una scatola Petri formando microcanali senza l&#39;uso di alcun adesivo. </li><li> Posizionare una goccia (20 - 40 ml) della soluzione di substrato sull&#39;ingresso copre completamente il foro di immissione. Motivo Poly-D-lisina (PDL) posizionando una goccia 20 ml di PDL in tampone sodio tetraborato in ingresso dei microcanali. </li><li> Mettere la capsula di Petri in un vuoto di ~ 254 mmHgA (equivalente ad alloggiare vuoto in laboratori biologici) per 10 minuti, e osservare l&#39;aria che esce dal canale nella forma di bolle. </li><li> Rilasciare il vuoto e osservare la soluzione di substrato che scorre nel microcanali. </li><li> Incubare il piatto alle condizioni adeguate per il substrato aderenza. Vedere Tabelle 1 e 2 per le condizioni di incubazione (questi variano a seconda del substrato). Per PDL patterning, incubare per 1 ora a 37 ° C. </li><li> sbucciare con cautela il timbro PDMS con una pinzetta sterile e lavare il modello sul vetrino di vetro tre volte con acqua deionizzata. </li&gt; <li> Aggiungere una soluzione 1% di siero albumina bovina (BSA) per capsula di Petri per coprire il piatto o vetro coprioggetto e incubare una notte a 37 ° C. NOTA: Ciò consentirà di ridurre l&#39;aderenza non specifico nelle regioni non rivestiti. </li><li> Aspirare off la soluzione BSA 1% e il substrato modellato è ora pronto per l&#39;uso. </li></ol> 5. Patterning indiretta di celle <ol><li> Preparare la sospensione cellulare in terreno di coltura privo di siero. Il tipo di cellula e densità cellulare sono elencati nella Tabella 1. </li><li> Aggiungere la sospensione cellulare al piatto modellato Petri e sommergere completamente la regione modellata in sospensione cellulare. </li><li> Incubare la piastra di Petri a 37 ° C in un incubatore per 15 minuti per permettere alle cellule di allegare al substrato modellato. </li><li> Aspirare la sospensione cellulare in eccesso dalla piastra di Petri e lavare le cellule fantasia tre volte con tampone fosfato (PBS) mentre delicatamente agitazione per 10 s per rimuovere le cellule senza legami. </li><li> Aggiungere l&#39;unamezzo di coltura ppropriate alle colture cellulari fantasia e incubare le cellule modellata a 37 ° C in un incubatore CO 2. </li></ol> 6. Patterning diretta delle cellule NOTA: Questa tecnica è un&#39;alternativa al patterning cella indiretta descritto nel passaggio 5. Tuttavia, a differenza del passaggio 5, in questa tecnica cellule sono modellati su superfici coltura tissutale con o senza rivestimento substrato. <ol><li> Sterilizzare il dispositivo microfluidico risciacquando con una soluzione di 70% di etanolo seguito da acqua DI. </li><li> Immergere il dispositivo notte in una soluzione di 1% BSA per impedire l&#39;adesione cellulare ai PDMS. </li><li> Essiccare il dispositivo a temperatura ambiente e fissarlo al fondo del piatto Petri coltura di tessuti trattati. </li><li> Preparare la sospensione cellulare in terreni di coltura privo di siero. Il tipo di cellula e densità cellulare sono elencati nella Tabella 2. </li><li> Inserire una gocciolina (4 - 8 ml) della sospensione cellulare, sufficiente a riempire lamicrocanali, sull&#39;ingresso coprendo completamente il foro di immissione. </li><li> Mettere la capsula di Petri in un vuoto per 10 minuti e osservare aria proveniente dal canale in forma di bolle. Il vuoto e osservare la sospensione cellulare scorre nel microcanali. </li><li> Incubare la piastra di Petri in un incubatore per favorire l&#39;adesione delle cellule secondo le condizioni di incubazione (dipende dal tipo di cellula modellata) indicato nella Tabella 2. Aggiungere PBS alla capsula di Petri immergendo il dispositivo PDMS. </li><li> Sbucciare la PDMS con cautela la capsula di Petri con una pinzetta e lavare il modello con PBS. Aggiungere terreni di coltura cellulare per la piastra di Petri e posizionare la coltura cellulare in incubatrice. </li></ol>

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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low-cost+rapid+prototyping+of+flexible+microfluidic+devices+using+a+desktop+digital+craft+cutter.">Low-cost rapid prototyping of flexible microfluidic devices using a desktop digital craft cutter.</a> Lab on a Chip. 10 (3), 384-387 (2010).</li><li>Wang, 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=Self-loading+and+cell+culture+in+one+layer+microfluidic+devices.">Self-loading and cell culture in one layer microfluidic devices.</a> Biomed Microdevices. 11 (3), 679-684 (2009).</li><li>Feng, 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=Survival+of+mammalian+cells+under+high+vacuum+condition+for+ion+bombardment.">Survival of mammalian cells under high vacuum condition for ion bombardment.</a> Cryobiology. 49 (3), 241-249 (2004).</li><li>Haubert, K., Drier, T., Beebe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PDMS+bonding+by+means+of+a+portable,+low-cost+corona+system.">PDMS bonding by means of a portable, low-cost corona system.</a> Lab on a Chip. 6 (12), 1548-1549 (2006).</li><li>Fan, D. -. H., Yuan, S. -. W., Shen, Y. -. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+modification+with+BSA+blocking+based+on+in+situ+synthesized+gold+nanoparticles+in+poly+(dimethylsiloxane)+microchip.">Surface modification with BSA blocking based on in situ synthesized gold nanoparticles in poly (dimethylsiloxane) microchip.</a> Colloids Surf, B. 75 (2), 608-611 (2010).</li><li>Hideshima, S., Sato, R., Inoue, S., Kuroiwa, S., Osaka, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+tumor+marker+in+blood+serum+using+antibody-modified+field+effect+transistor+with+optimized+BSA+blocking.">Detection of tumor marker in blood serum using antibody-modified field effect transistor with optimized BSA blocking.</a> Sens Actuator B-Chem. 161 (1), 146-150 (2012).</li><li>Zheng, 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=High-throughput+immunoassay+through+in-channel+microfluidic+patterning.">High-throughput immunoassay through in-channel microfluidic patterning.</a> Lab on a Chip. 12 (14), 2487-2490 (2012).</li><li>MacLeish, P., Barnstable, C., Townes-Anderson, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+a+monoclonal+antibody+as+a+substrate+for+mature+neurons+in+vitro.">Use of a monoclonal antibody as a substrate for mature neurons in vitro.</a> Procs Nat Acad of Sci. 80 (22), 7014-7018 (1983).</li><li>Suchodolskis, 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=Elastic+properties+of+chemically+modified+baker's+yeast+cells+studied+by+AFM.">Elastic properties of chemically modified baker's yeast cells studied by AFM.</a> Surf Interface Anal. 43 (13), 1636-1640 (2011).</li></ol>

The authors declare no competing financial interests.

Mentre fotolitografia convenzionale è una tecnica ben consolidata per la realizzazione di stampi per litografia soft, attrezzature, materiali e competenze necessarie per utilizzare fotolitografia convenzionale non sono facilmente disponibili al maggior parte dei laboratori. Per i laboratori senza accesso a queste risorse, abbiamo presentato adesivo fabbricazione nastro come un metodo per creare stampi con caratteristiche relativamente semplici per dispositivi microfluidici. Questo metodo permette qualsiasi laboratorio ...

In ingegneria dei tessuti e biosensori, la capacità di controllare l&#39;organizzazione spaziale delle proteine e cellule su scala micron, è diventato sempre più importante negli ultimi quarant&#39;anni 1, 2, 3. Precise organizzazione spaziale delle proteine e cellule ha permesso ai ricercatori di esaminare l&#39;interazione tra cellule e substrati contenenti tipi simili o diversi di cellule, per guidare la crescita cellulare, e immobilizzare biomolecole per la fabbricazione di biosensori 4, 5, 6, 7, 8, 9. Gli attuali metodi di proteine ​​patterning includono photopatterning e stampa microcontact. Photopatterning utilizza materiale sensibile alla luce, che viene reticolato in seguito all&#39;esposizione ad ultruna viola (UV). Luce UV diretta a un fotomaschera (costituito da aree trasparenti con le regioni più scure per prevenire la trasmissione della luce UV) provoca la reticolazione in regioni specifiche che possono poi essere utilizzati per successivo fissaggio dei biomateriali o celle 10, 11. Mentre questo schema è molto preciso e consente un controllo preciso della topografia della superficie cultura, è limitato a biomolecole sensibili ai raggi UV che possono essere modellati da radiazione UV 12. Stampa microcontact è un altro metodo popolare di patterning proteine specifiche 13, 14. In questo metodo, un silossano (PDMS) timbro poli-dimetil viene trattata con una varietà di reagenti modifica della superficie prima di essere stati immersi in una soluzione del substrato biomolecolare prescelto. E &#39;poi delicatamente pressato su un vetrino di vetro o di altra superficie così &quot;stamping&quot; biomolecole sulla superficie cultura. However, stampaggio è limitata al tipo di materiale che può essere trasferito, nonche la bagnabilità di biomolecole alla superficie del timbro PDMS 15. Patterning diretto delle cellule può essere più difficile e si basa su metodi complessi come substrati commutabili, metodi basati stencil, o patterning con specifiche molecole di adesione cellulare 16, 17. Questi metodi sono limitati nella loro capacità di cellule modello a causa della mancanza di substrati di adesione cellulare compatibili, incompatibilità del processo di lavorare con cellule sensibili biologiche e vincoli, incoerenza nel riprodurre il patterning e complessità della procedura. Ad esempio, con i substrati commutabile, substrati personalizzati devono essere progettati per ogni tipo di cellula, per passare la loro adesione a specifici tipi cellulari senza degradazione per esposizione alla luce UV e calore utilizzato nel processo 17, &lt;<html> class = sup &quot;xref&quot;&gt; 18, 19, 20. metodi di patterning basata Stencil sono versatili nella loro capacità di cellule del modello; Tuttavia, è difficile produrre matrici PDMS a spessori adeguati per l&#39;utilizzo 16, 21. L&#39;iniezione diretta di cellule in canali microfluidica PDMS hanno alcuni vantaggi quali: 1) facilità di fabbricazione di canali microfluidica e 2) di idoneità per molte cellule e substrati diversi. Tuttavia, il problema prevalente di cattura bolla d&#39;aria durante il processo di iniezione a causa della idrofobicità del PDMS senza l&#39;uso di pulizia al plasma, o altri metodi per ridurre bolle d&#39;aria, rende difficile creare costantemente cellule modellata su superfici di vetro o di plastica 21. Questo lavoro si espande su capillare micromolding 22, 23,lass = &quot;xref&quot;&gt; 24, 25, 26 e riporta un metodo per iniettare proteine e cellule sospensioni in microcanali. Il metodo utilizzato qui dimostra la patterning dei substrati ed entrambi patterning diretto e indiretto di specifici tipi cellulari. Questa tecnica supera l&#39;elevata idrofobicità di PDMS ed elimina la presenza di bolle durante l&#39;iniezione del substrato o da cellule sfruttando la permeabilità ai gas di PDMS 27. Questo documento dimostra l&#39;uso della tecnica con diversi substrati diversi e tipi di cellule. L&#39;articolo evidenzia anche la fabbricazione di stampi per la litografia morbido utilizzando la fotolitografia convenzionale nonché una semplice ed adesivo a basso costo metodo nastro utile risorse limitate impostazioni 28, 29.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>CorelDRAW X4 CAD Drawing Tools</td>
			<td>Corel Corporation, Canada</td>
			<td>X4 Version 14.0.0.701</td>
			<td>CAD tool used to draw the layout of the microfluidic device</td>
		</tr>
		<tr>
			<td>Laser Printer HP</td>
			<td>Hewlett Packard, CA</td>
			<td>1739629</td>
			<td>Used to print the layout of microfluidic device for adhesive tape technique</td>
		</tr>
		<tr>
			<td>Bel-Art Dessicator</td>
			<td>Fisher Scientific, MA</td>
			<td>08-594-16B</td>
			<td>Used to degass the PDMS mixture</td>
		</tr>
		<tr>
			<td>Adhesive Scotch Tape</td>
			<td>3M Product, MN</td>
			<td>Tape 600</td>
			<td>Used to fabricate adhesive tape Master</td>
		</tr>
		<tr>
			<td>PDMS Sylgard 184</td>
			<td>Dow Corning, MI</td>
			<td>1064291</td>
			<td>Casting polymer</td>
		</tr>
		<tr>
			<td>Petri Dish</td>
			<td>Fisher Scientific, MA</td>
			<td>08-772-23</td>
			<td>Used to keep the mold to cast with PDMS</td>
		</tr>
		<tr>
			<td>Stainless steel Scalpel (#3) with blade (# 11)</td>
			<td>Feather Safety Razor Co. Ltd. Japan</td>
			<td>2976#11</td>
			<td>Used to cut the PDMS</td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>Ted Pella, CA</td>
			<td>5627-07</td>
			<td>Used to handle the PDMS cast during peeling</td>
		</tr>
		<tr>
			<td>Glass slides</td>
			<td>Fisher Scientific, MA</td>
			<td>12-546-2</td>
			<td>Used as surface to pattern the Substrate</td>
		</tr>
		<tr>
			<td>Glass slides</td>
			<td>Fisher Scientific, MA</td>
			<td>12-544-4</td>
			<td>Used as surface to pattern the Substrate</td>
		</tr>
		<tr>
			<td>Rubber Roller</td>
			<td>Dick Blick Art Materials, IL</td>
			<td>40104-1004</td>
			<td>Used to attach adhesive tape on glass without trapping air bubbles</td>
		</tr>
		<tr>
			<td>Laser Mask Writer</td>
			<td>Heidelberg Instruments, Germany</td>
			<td>DWL66fs</td>
			<td>Used to fabricate quartz mask used in photolithography fabrication process</td>
		</tr>
		<tr>
			<td>EVG Mask Aligner (Photolithography UV exposure tool)</td>
			<td>EV Group, Germany</td>
			<td>EVG 620T(B)</td>
			<td>Used to expose the photoresist to UV light</td>
		</tr>
		<tr>
			<td>Spin Coater Headway</td>
			<td>Headway Research Inc, TX</td>
			<td>PWM32-PS-CB15PL</td>
			<td>Used to spin coat the photoresist on silicon wafer</td>
		</tr>
		<tr>
			<td>Photoresists SU-8 50</td>
			<td>MicroChem, MA</td>
			<td>Y131269</td>
			<td>Negative photoresist used for mold fabrication</td>
		</tr>
		<tr>
			<td>SU-8 Devloper</td>
			<td>MicroChem, MA</td>
			<td>Y020100</td>
			<td>Photoresist developer</td>
		</tr>
		<tr>
			<td>Tridecafluoro-1,1,2,2-Tetrahydrooctyl-1-Trichlorosilane</td>
			<td>UCT Specialties, PA</td>
			<td>T2492-KG</td>
			<td>Coat mold to avoid PDMS adhesion</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Sigma-Aldrich, MO</td>
			<td>190764</td>
			<td>Cleaning Solvent</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Sigma-Aldrich, MO</td>
			<td>24102</td>
			<td>Sterilization Solvent</td>
		</tr>
		<tr>
			<td>Poly-D-Lysine hydrobromide (PDL)</td>
			<td>Sigma-Aldrich, MO</td>
			<td>P0899-10MG</td>
			<td>PDL solution is made at 0.1 mg/mL in Sodium Tetraborate Buffer</td>
		</tr>
		<tr>
			<td>Laminin</td>
			<td>Sigma-Aldrich, MO</td>
			<td>L2020</td>
			<td>Laminin aliquoted into 10 &#181;L aliquots and diluted to 20 &#181;g/&#181;L in PBS prior to use</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Fisher Scientific, MA</td>
			<td>BP1605100</td>
			<td>Cell culture</td>
		</tr>
		<tr>
			<td>C2C12 Myoblast cell lline</td>
			<td>ATCC, VA</td>
			<td>CRL-1722</td>
			<td>Used to demonstrate C2C12 patterning</td>
		</tr>
		<tr>
			<td>PC12 Cell Line</td>
			<td>ATCC, VA</td>
			<td>CRL-1721</td>
			<td>Used to demonstrate PC12 patterning</td>
		</tr>
		<tr>
			<td>Collagen type 1, rat tail</td>
			<td>BD Biosciences</td>
			<td>40236</td>
			<td>Cell culture</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>GIBCO, MA</td>
			<td>11965-084</td>
			<td>Cell culture</td>
		</tr>
		<tr>
			<td>Horse Serum, heat inactivated</td>
			<td>Fisher Scientific, MA</td>
			<td>26050-070</td>
			<td>Cell culture</td>
		</tr>
		<tr>
			<td>Phalloidin-tetramethylrhodamine B isothiocyanate (TRITC)</td>
			<td>Sigma-Aldrich, MO</td>
			<td>P1951</td>
			<td>To label cells</td>
		</tr>
		<tr>
			<td>Calcein-AM live dead cell Assay kit</td>
			<td>Invitrogen, MA</td>
			<td>L-3224</td>
			<td>Cell viability Assay</td>
		</tr>
		<tr>
			<td>Biopsy Hole Punch</td>
			<td>Ted Pella, CA</td>
			<td>15110-10</td>
			<td>Punched hole in PDMS</td>
		</tr>
	</tbody>
</table>

a versatile method of patterning proteins and cells

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This article describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. This method enables researchers to pattern multiple substrates including fibronectin, collagen, antibodies (Sal-1), poly-D-lysine (PDL), and laminin. Patterning of substrates allows one to indirectly pattern a variety of cells. We have tested C2C12 myoblasts, the PC12 neuronal cell line, embryonic rat cortical neurons, and amphibian retinal neurons. In addition, we demonstrate that this technique can directly pattern fibroblasts in microfluidic channels via brief application of a low vacuum on cell suspensions. The low vacuum does not significantly decrease cell viability as shown by cell viability assays. Modifications are discussed for application of the method to different cell and substrate types. This technique allows researchers to pattern cells and proteins in specific patterns without the need for exotic materials or equipment and can be done in any laboratory with a vacuum.

Questo metodo consente di patterning di proteine ​​e patterning indiretta di cellule utilizzando dead-end canali microfluidica con dimensioni piccole come 10 micron e le attrezzature disponibili in quasi tutti i laboratori biologici una volta lo stampo maestro è fatto. Questa tecnica può essere utilizzata con canali microfluidici PDMS creata usando fotolitografia tradizionali morbido, o con canali microfluidici PDMS creati con nastro adesivo di fabbricazione (Figura 1)</str...

Watch this Scientific Journal Video about A Versatile Method of Patterning Proteins and Cells at JoVE.com

A Versatile Method of Patterning Proteins and Cells

This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

Un metodo versatile di patterning proteine ​​e cellule

Substrate and cell patterning techniques are widely used in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning ...

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JoVE Journal

Bioengineering

9.3K Views.  Rutgers University. This report describes a simple, easy to perform technique, using low pressure vacuum, to fill microfluidic channels with cells and substrates for biological research.

Video: A Versatile Method of Patterning Proteins and Cells

Plasma Lithography Surface Patterning for Creation of Cell Networks

Systematic manipulation of a cell microenvironment with micro- and nanoscale resolution is often required for deciphering various cellular and molecular phenomena. To address this requirement, we have developed a plasma lithography technique to manipulate the cellular microenvironment by creating a patterned surface with feature sizes ranging from 100 nm to millimeters. The goal of this technique is to be able to study, in a controlled way, the behaviors of individual cells as well as groups of cells and their interactions.
This plasma lithography method is based on selective modification of the surface chemistry on a substrate by means of shielding the contact of low-temperature plasma with a physical mold. This selective shielding leaves a chemical pattern which can guide cell attachment and movement. This pattern, or surface template, can then be used to create networks of cells whose structure can mimic that found in nature and produces a controllable environment for experimental investigations. The technique is well suited to studying biological phenomenon as it produces stable surface patterns on transparent polymeric substrates in a biocompatible manner. The surface patterns last for weeks to months and can thus guide interaction with cells for long time periods which facilitates the study of long-term cellular processes, such as differentiation and adaption. The modification to the surface is primarily chemical in nature and thus does not introduce topographical or physical interference for interpretation of results. It also does not involve any harsh or toxic substances to achieve patterning and is compatible for tissue culture. Furthermore, it can be applied to modify various types of polymeric substrates, which due to the ability to tune their properties are ideal for and are widely used in biological applications. The resolution achievable is also beneficial, as isolation of specific processes such as migration, adhesion, or binding allows for discrete, clear observations at the single to multicell level.
This method has been employed to form diverse networks of different cell types for investigations involving migration, signaling, tissue formation, and the behavior and interactions of neurons arraigned in a network.

A versatile plasma lithography technique has been developed to generate stable surface patterns for guiding cellular attachment. This technique can be applied to create cell networks including those that mimic natural tissues and has been used for studying several, distinct cell types.

Plasma Surface Patterning litografia per la creazione di reti di cella

Systematic manipulation of a cell microenvironment with micro- and nanoscale resolution is often required for deciphering various cellular and molecular ...

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Bioingegneria

Soft Lithographic Functionalization and Patterning Oxide-free Silicon and Germanium

The development of hybrid electronic devices relies in large part on the integration of (bio)organic materials and inorganic semiconductors through a stable interface that permits efficient electron transport and protects underlying substrates from oxidative degradation. Group IV semiconductors can be effectively protected with highly-ordered self-assembled monolayers (SAMs) composed of simple alkyl chains that act as impervious barriers to both organic and aqueous solutions. Simple alkyl SAMs, however, are inert and not amenable to traditional patterning techniques. The motivation for immobilizing organic molecular systems on semiconductors is to impart new functionality to the surface that can provide optical, electronic, and mechanical function, as well as chemical and biological activity. 
Microcontact printing (&mu;CP) is a soft-lithographic technique for patterning SAMs on myriad surfaces.1-9 Despite its simplicity and versatility, the approach has been largely limited to noble metal surfaces and has not been well developed for pattern transfer to technologically important substrates such as oxide-free silicon and germanium. Furthermore, because this technique relies on the ink diffusion to transfer pattern from the elastomer to substrate, the resolution of such traditional printing is essentially limited to near 1 &mu;m.10-16
In contrast to traditional printing, inkless &mu;CP patterning relies on a specific reaction between a surface-immobilized substrate and a stamp-bound catalyst. Because the technique does not rely on diffusive SAM formation, it significantly expands the diversity of patternable surfaces. In addition, the inkless technique obviates the feature size limitations imposed by molecular diffusion, facilitating replication of very small (&lt;200 nm) features.17-23 However, up till now, inkless &mu;CP has been mainly used for patterning relatively disordered molecular systems, which do not protect underlying surfaces from degradation.
Here, we report a simple, reliable high-throughput method for patterning passivated silicon and germanium with reactive organic monolayers and demonstrate selective functionalization of the patterned substrates with both small molecules and proteins. The technique utilizes a preformed NHS-reactive bilayered system on oxide-free silicon and germanium. The NHS moiety is hydrolyzed in a pattern-specific manner with a sulfonic acid-modified acrylate stamp to produce chemically distinct patterns of NHS-activated and free carboxylic acids. A significant limitation to the resolution of many &mu;CP techniques is the use of PDMS material which lacks the mechanical rigidity necessary for high fidelity transfer. To alleviate this limitation we utilized a polyurethane acrylate polymer, a relatively rigid material that can be easily functionalized with different organic moieties. Our patterning approach completely protects both silicon and germanium from chemical oxidation, provides precise control over the shape and size of the patterned features, and gives ready access to chemically discriminated patterns that can be further functionalized with both organic and biological molecules. The approach is general and applicable to other technologically-relevant surfaces.

Here we describe a simple method for patterning oxide-free silicon and germanium with reactive organic monolayers and demonstrate functionalization of the patterned substrates with small molecules and proteins. The approach completely protects surfaces from chemical oxidation, provides precise control over feature morphology, and provides ready access to chemically discriminated patterns.

Morbido Funzionalizzazione litografica e Patterning ossido senza silicio e germanio

The development of hybrid electronic devices relies in large part on the integration of (bio)organic materials and inorganic semiconductors through a ...

Visualization of Cortex Organization and Dynamics in Microorganisms, using Total Internal Reflection Fluorescence Microscopy

TIRF microscopy has emerged as a powerful imaging technology to study spatio-temporal dynamics of fluorescent molecules in vitro and in living cells1. The optical phenomenon of total internal reflection occurs when light passes from a medium with high refractive index into a medium with low refractive index at an angle larger than a characteristic critical angle (i.e. closer to being parallel with the boundary). Although all light is reflected back under such conditions, an evanescent wave is created that propagates across and along the boundary, which decays exponentially with distance, and only penetrates sample areas that are 100-200 nm near the interface2. In addition to providing superior axial resolution, the reduced excitation of out of focus fluorophores creates a very high signal to noise ratios and minimizes damaging effects of photobleaching2,3. Being a widefield technique, TIRF also allows faster image acquisition than most scanning based confocal setups.
At first glance, the low penetration depth of TIRF seems to be incompatible with imaging of bacterial and fungal cells, which are often surrounded by thick cell walls. On the contrary, we have found that the cell walls of yeast and bacterial cells actually improve the usability of TIRF and increase the range of observable structures4-8. Many cellular processes can therefore be directly accessed by TIRF in small, single-cell microorganisms, which often offer powerful genetic manipulation techniques. This allows us to perform in vivo biochemistry experiments, where kinetics of protein interactions and activities can be directly assessed in living cells.
We describe here the individual steps required to obtain high quality TIRF images for Saccharomyces cerevisiae or Bacillus subtilis cells. We point out various problems that can affect TIRF visualization of fluorescent probes in cells and illustrate the procedure with several application examples. Finally, we demonstrate how TIRF images can be further improved using established image restoration techniques.

Total Internal Reflection Fluorescence (TIRF) microscopy is a powerful approach to observe structures close to the cell surface at high contrast and temporal resolution. We demonstrate how TIRF can be employed to study protein dynamics at the cortex of cell wall-enclosed bacterial and fungal cells.

Visualizzazione di Cortex Organizzazione e Dynamics in microrganismi, utilizzando Total Internal Reflection Fluorescence Microscopy

TIRF microscopy has emerged as  a powerful imaging technology to study spatio-temporal dynamics of fluorescent molecules  in vitro and in living cells1. ...

A Versatile Automated Platform for Micro-scale Cell Stimulation Experiments

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in vitro analysis are well suited to study of large numbers of cells (&ge;105) in milliliter-scale volumes (&ge;0.1 ml). However, there are many instances in which it is necessary or desirable to scale down culture size to reduce consumption of the cells of interest and/or reagents required for their culture, stimulation, or processing. Unfortunately, conventional approaches do not support precise and reproducible manipulation of micro-scale cultures, and the microfluidics-based automated systems currently available are too complex and specialized for routine use by most laboratories. To address this problem, we have developed a simple and versatile technology platform for automated culture, stimulation, and recovery of small populations of cells (100 - 2,000 cells) in micro-scale volumes (1 - 20 &mu;l). The platform consists of a set of fibronectin-coated microcapillaries ("cell perfusion chambers"), within which micro-scale cultures are established, maintained, and stimulated; a digital microfluidics (DMF) device outfitted with "transfer" microcapillaries ("central hub"), which routes cells and reagents to and from the perfusion chambers; a high-precision syringe pump, which powers transport of materials between the perfusion chambers and the central hub; and an electronic interface that provides control over transport of materials, which is coordinated and automated via pre-determined scripts. As an example, we used the platform to facilitate study of transcriptional responses elicited in immune cells upon challenge with bacteria. Use of the platform enabled us to reduce consumption of cells and reagents, minimize experiment-to-experiment variability, and re-direct hands-on labor. Given the advantages that it confers, as well as its accessibility and versatility, our platform should find use in a wide variety of laboratories and applications, and prove especially useful in facilitating analysis of cells and stimuli that are available in only limited quantities.

We have developed an automated cell culture and interrogation platform for micro-scale cell stimulation experiments. The platform offers simple, versatile, and precise control in cultivating and stimulating small populations of cells, and recovering lysates for molecular analyses. The platform is well suited to studies that use precious cells and/or reagents.

Una piattaforma automatizzata versatile per micro-scala Cellulari esperimenti di stimolazione

Study of cells in culture (in vitro analysis) has provided important insight into complex biological systems. Conventional methods and equipment for in ...

A Microfluidic Chip for the Versatile Chemical Analysis of Single Cells

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this purpose, the cells are passively trapped in the middle of a microchamber. Upon activation of the control layer, the cell is isolated from the surrounding volume in a small chamber. The surrounding volume can then be exchanged without affecting the isolated cell. However, upon short opening and closing of the chamber, the solution in the chamber can be replaced within a few hundred milliseconds. Due to the reversibility of the chambers, the cells can be exposed to different solutions sequentially in a highly controllable fashion, e.g. for incubation, washing, and finally, cell lysis. The tightly sealed microchambers enable the retention of the lysate, minimize and control the dilution after cell lysis. Since lysis and analysis occur at the same location, high sensitivity is retained because no further dilution or loss of the analytes occurs during transport. The microchamber design therefore enables the reliable and reproducible analysis of very small copy numbers of intracellular molecules (attomoles, zeptomoles) released from individual cells. Furthermore, many microchambers can be arranged in an array format, allowing the analysis of many cells at once, given that suitable optical instruments are used for monitoring. We have already used the platform for proof-of-concept studies to analyze intracellular proteins, enzymes, cofactors and second messengers in either relative or absolute quantifiable manner.

In this article we present a microfluidic chip for single cell analysis. It allows the quantification of intracellular proteins, enzymes, cofactors, and second messengers by means of fluorescent assays or immunoassays.&#160;

Un chip microfluidica per la Versatile analisi chimica di singole cellule

We present a microfluidic device that enables the quantitative determination of intracellular biomolecules in multiple single cells in parallel. For this ...

Cell Patterning on Photolithographically Defined 
Parylene-C: SiO2 Substrates

Cell patterning platforms support broad research goals, such as construction of predefined in vitro neuronal networks and the exploration of certain central aspects of cellular physiology. To easily combine cell patterning with Multi-Electrode Arrays (MEAs) and silicon-based &#8216;lab on a chip&#8217; technologies, a microfabrication-compatible protocol is required. We describe a method that utilizes deposition of the polymer parylene-C on SiO2&#160;wafers. Photolithography enables accurate and reliable patterning of parylene-C at micron-level resolution. Subsequent activation by immersion in fetal bovine serum (or another specific activation solution) results in a substrate in which cultured cells adhere to, or are repulsed by, parylene or SiO2 regions respectively. This technique has allowed patterning of a broad range of cell types (including primary murine hippocampal cells, HEK 293 cell line, human neuron-like teratocarcinoma cell line, primary murine cerebellar granule cells, and primary human glioma-derived stem-like cells). Interestingly, however, the platform is not universal; reflecting the importance of cell-specific adhesion molecules. This cell patterning process is cost effective, reliable, and importantly can be incorporated into standard microfabrication (chip manufacturing) protocols, paving the way for integration of microelectronic technology.

Cell Patterning on Photolithographically Defined 
Parylene-C: SiO2 Substrates

This protocol describes a microfabrication-compatible method for cell patterning on SiO2. A predefined parylene-C design is photolithographically printed on SiO2 wafers. Following incubation with serum (or other activation solution) cells adhere specifically to (and grow according to the conformity of) underlying parylene-C, whilst being repulsed by SiO2 regions.

Patterning cellulare su fotolitograficamente Definito parylene-C: SiO<sub&gt; 2</sub&gt; Substrati

Cell patterning platforms support broad research goals, such as construction of predefined in vitro neuronal networks and the exploration of certain ...

Delivery of Proteins, Peptides or Cell-impermeable Small Molecules into Live Cells by Incubation with the Endosomolytic Reagent dfTAT

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the efficiency with which macromolecules penetrate the cytosolic space of cells. Recently, we have circumvented this problem by identifying the reagent dfTAT, a disulfide bond dimer of the peptide TAT labeled with the fluorophore tetramethylrhodamine. We have generated a fluorescently labeled dimer of the prototypical cell-penetrating peptide (CPP) TAT, dfTAT, which penetrates live cells and reaches the cytosolic space of cells with a particularly high efficiency. Cytosolic delivery of dfTAT is achieved in multiple cell lines, including primary cells. Moreover, delivery does not noticeably impact cell viability, proliferation or gene expression. dfTAT can deliver small molecules, peptides, antibodies, biologically active enzymes and a transcription factor. In this report, we describe the protocols involved in dfTAT synthesis and cellular delivery. The manuscript describes how to control the amount of protein delivered to the cytosolic space of cells by varying the amount of protein administered extracellularly. Finally, the current limitations of this new technology and steps involved in validating delivery are discussed. The described protocols should be extremely useful for cell-based assays as well as for the ex vivo manipulation and reprogramming of cells.

We describe how to deliver proteins and cell-impermeable small molecules into cultured mammalian cells by a simple co-incubation protocol with a reagent that causes endocytic organelles to become leaky.

Consegna di proteine, peptidi o cella-impermeabile piccole molecole in cellule vive mediante incubazione con il reagente Endosomolytic dfTAT

Macromolecular delivery strategies typically utilize the endocytic pathway as a route of cellular entry. However, endosomal entrapment severely limits the ...

Rapid Subtractive Patterning of Live Cell Layers with a Microfluidic Probe

The microfluidic probe (MFP) facilitates performing local chemistry on biological substrates by confining nanoliter volumes of liquids. Using one particular implementation of the MFP, the hierarchical hydrodynamic flow confinement (hHFC), multiple liquids are simultaneously brought in contact with a substrate. Local chemical action and liquid shaping using the hHFC, is exploited to create cell patterns by locally lysing and removing cells. By utilizing the scanning ability of the MFP, user-defined patterns of cell monolayers are created. This protocol enables rapid, real-time and spatially controlled cell patterning, which can allow selective cell-cell and cell-matrix interaction studies.

We present a protocol to perform subtractive patterning of live cell monolayers on a surface. This is achieved by local and selective lysis of adherent cells using a microfluidic probe (MFP). The cell lysate retrieved from local regions can be used for downstream analysis, enabling molecular profiling studies.

Rapid Patterning sottrattiva di strati cellulare dal vivo con una sonda Microfluidic

The microfluidic probe (MFP) facilitates performing local chemistry on biological substrates by confining nanoliter volumes of liquids. Using one ...

Light-mediated Formation and Patterning of Hydrogels for Cell Culture Applications

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In particular, light-mediated click reactions, such as photoinitiated thiol&#8722;ene and thiol&#8722;yne reactions, afford spatiotemporal control over material properties and allow the design of systems with a high degree of user-directed property control. Fabrication and modification of hydrogel-based biomaterials using the precision afforded by light and the versatility offered by these thiol&#8722;X photoclick chemistries are of growing interest, particularly for the culture of cells within well-defined, biomimetic microenvironments. Here, we describe methods for the photoencapsulation of cells and subsequent photopatterning of biochemical cues within hydrogel matrices using versatile and modular building blocks polymerized by a thiol&#8722;ene photoclick reaction. Specifically, an approach is presented for constructing hydrogels from allyloxycarbonyl (Alloc)-functionalized peptide crosslinks and pendant peptide moieties and thiol-functionalized poly(ethylene glycol) (PEG) that rapidly polymerize in the presence of lithium acylphosphinate photoinitiator and cytocompatible doses of long wavelength ultraviolet (UV) light. Facile techniques to visualize photopatterning and quantify the concentration of peptides added are described. Additionally, methods are established for encapsulating cells, specifically human mesenchymal stem cells, and determining their viability and activity. While the formation and initial patterning of thiol-alloc hydrogels are shown here, these techniques broadly may be applied to a number of other light and radical-initiated material systems (e.g., thiol-norbornene, thiol-acrylate) to generate patterned substrates.

We describe a sequential process for light-mediated formation and subsequent biochemical patterning of synthetic hydrogel matrices for three-dimensional cell culture applications. The construction and modification of hydrogels with cytocompatible photoclick chemistry is demonstrated. Additionally, facile techniques to quantify and observe patterns and determine cell viability within these hydrogels are presented.

Formazione Light-mediata ed il modello di idrogel per colture cellulari

Click chemistries have been investigated for use in numerous biomaterials applications, including drug delivery, tissue engineering, and cell culture. In ...

Patterning Bioactive Proteins or Peptides on Hydrogel Using Photochemistry for Biological Applications

There are many biological stimuli that can influence cell behavior and stem cell differentiation. General cell culture approaches rely on soluble factors within the medium to control cell behavior. However, soluble additions cannot mimic certain signaling motifs, such as matrix-bound growth factors, cell-cell signaling, and spatial biochemical cues, which are common influences on cells. Furthermore, biophysical properties of the matrix, such as substrate stiffness, play important roles in cell fate, which is not easily manipulated using conventional cell culturing practices. In this method, we describe a straightforward protocol to provide patterned bioactive proteins on synthetic polyethylene glycol (PEG) hydrogels using photochemistry. This platform allows for the independent control of substrate stiffness and spatial biochemical cues. These hydrogels can achieve a large range of physiologically relevant stiffness values. Additionally, the surfaces of these hydrogels can be photopatterned with bioactive peptides or proteins via thiol-ene click chemistry reactions. These methods have been optimized to retain protein function after surface immobilization. This is a versatile protocol that can be applied to any protein or peptide of interest to create a variety of patterns. Finally, cells seeded onto the surfaces of these bioactive hydrogels can be monitored over time as they respond to spatially specific signals.

In this method, we use photopolymerization and click chemistry techniques to create protein or peptide patterns on the surface of polyethylene glycol (PEG) hydrogels, providing immobilized bioactive signals for the study of cellular responses in vitro.

Patterning bioattivi proteine o peptidi su idrogel utilizzando fotochimica per applicazioni biologiche

There are many biological stimuli that can influence cell behavior and stem cell differentiation. General cell culture approaches rely on soluble factors ...

Un metodo versatile di patterning proteine ​​e cellule

Un metodo versatile di patterning proteine e cellule