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1. Mica e diapositive Preparazione <ol><li> Luogo No. 1 ½ (0,17 mm) coprioggetto in colorazione rack. </li><li> Ultrasuoni per 30 min a 2% di detergente a 60 ° C. </li><li> Lavare 20 volte con acqua deionizzata. </li><li> Estrarre i vetrini con pinze e asciugare con aria compressa o azoto. </li><li> Tagliare foglio di mica in 10 x 10 mm pezzi quadrati utilizzando forbici o lama di rasoio. </li><li> Tagliare ogni pezzo mica in 2-3 foglioline sottili con lama di rasoio. NOTA: Questa fase richiede l&#39;uso di lama affilata. </li></ol> 2. Montaggio Mica e della Camera di montaggio <ol><li> Pulire vetrino microscopico con etanolo. </li><li> Colla foglio di mica tagliati nel passaggio da 1,6 a vetrino con adesivo ottico. Adesivo a bassa viscosità si consiglia di diffondere meglio la goccia e incollare la mica. </li><li> Cure sotto la lampada UV, 10 min. NOTA: Adhesive è curata da luce UV con massimo di assorbimento nell&#39;intervallo di 350 a 380 nm e l&#39;energia raccomandato required per la piena guarigione è di 4,5 J / cm 2. Tuttavia, diverse fonti di luce possono essere utilizzati per questo passo (vedi materiali forniti dal fornitore adesivo). </li><li> Esporre una superficie di mica pulito rimuovendo i primi strati con nastro adesivo. </li><li> Mettere piccola goccia (~ 20 micron) di adesivo ottico sulla superficie di mica. NOTA: In questo passaggio, si consiglia l&#39;adesivo ad alta viscosità con un basso livello di autofluorescenza. La nostra esperienza ha dimostrato che l&#39;utilizzo di combinazione di basso (punto 2.2) e adesivi ad alta viscosità aumenta in modo significativo l&#39;efficacia di mica splitting (fase 2.7). </li><li> Posizionare delicatamente coprioggetto appena pulita sulla goccia di colla, evitando bolle d&#39;aria, lasciare riposare per 1 min. </li><li> Cure sotto la lampada UV, 10 min. NOTA: dopo questa fase, il sandwich di vetrino, mica e coprioggetto può essere conservato per un periodo relativamente lungo di tempo (fino a poche settimane). Procedere alla fase successiva appena prima l&#39;attuale preparazione SLB, per assicurarsi che la superficie di mica è fresco. NOTA: Adesivo è curata da luce UV con il massimo assorbimento nel range di 350 a 380nm e l&#39;energia consigliata necessario per la piena guarigione è 4.5J/cm 2. Tuttavia, diverse fonti di luce possono essere utilizzati per questo passo (vedi materiali forniti dal fornitore adesivo). </li><li> Utilizzando un taglierino, smontare delicatamente il vetrino dal vetrino lato, come mostrato nel video. Nella maggior parte dei casi, uno strato sottile e piatto di mica rimarrà attaccato alla coprioggetto. Mica attaccato al vetrino può essere riutilizzato (ripetere dal punto 2.4). </li><li> Controllare la qualità della superficie a occhio nudo o sotto un microscopio da dissezione, per assicurarsi che strato mica è ancora incollato al coprioggetto e non è stato rimosso completamente durante la divisione nel passaggio 2.8. Fare un piccolo graffio con una pinza o dissezione ago aiuterà a distinguere tra l&#39;adesivo che ha una consistenza diversa da rivelabile mica. </li><li> Rimuovere la guarnizione di gomma da un ml flacone tappo 1.5 e incollare il tappo a testa in giù alla superficie con otticaadesivo o smalto, e la cura con la lampada UV, o lasciare asciugare 10 minuti, rispettivamente. NOTA: Se il campione è pronto per simultanea ottico (TIRFM o confocale) con imaging AFM, un ml flacone tappo 1.5 potrebbe essere troppo piccolo per montare la testa AFM sul palco microscopio. In tal caso, il tappo può essere sostituito con qualsiasi plastica O-ring con un diametro più grande, adatto per il montaggio testa AFM. Nel caso in cui l&#39;esperimento richiede la rimozione del tappo senza danneggiare la superficie di mica, grasso al silicone può essere usata al posto della colla o smalto. </li></ol> 3. Supportato doppio strato lipidico (SLB) Formazione <ol><li> Posizionare soluzione liposomi preparata nella camera con la superficie. Il volume minimo richiesto per la formazione SLB è ~ 30 ml. NOTA: Per maggiori dettagli sulla liposomi e la formazione SLB, fare riferimento a protocolli pubblicati, come ad esempio il sacchetto et al, 2014 15.. </li><li> Procedere con la formazione SLB utilizzando il protocollo desiderato. Durante l&#39;incubazione el&#39;imaging, la camera può essere collocato in un calore-blocco o fase di microscopio riscaldata per mantenere la temperatura necessaria per mantenere i lipidi in uso sopra della loro temperatura di fusione. </li></ol>

<ol>
	<li>Giocondi, M. -. 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=Surface+topography+of+membrane+domains.">Surface topography of membrane domains.</a> Biochimica et Biophysica Acta (BBA) - Biomembranes. 1798, 703-718 (2010).</li><li>Garcia-Saez, A. J., Schwille, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface+analysis+of+membrane+dynamics.">Surface analysis of membrane dynamics.</a> Biochim Biophys Acta. 1798, 766-776 (2010).</li><li>Plochberger, B., 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=Cholesterol+slows+down+the+lateral+mobility+of+an+oxidized+phospholipid+in+a+supported+lipid+bilayer.">Cholesterol slows down the lateral mobility of an oxidized phospholipid in a supported lipid bilayer.</a> Langmuir. 26, 17322-17329 (2010).</li><li>El Kirat, K., Morandat, S., Dufr&#234;ne, Y. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanoscale+analysis+of+supported+lipid+bilayers+using+atomic+force+microscopy.">Nanoscale analysis of supported lipid bilayers using atomic force microscopy.</a> Biochimica et Biophysica Acta (BBA) - Biomembranes. 1798, 750-765 (2010).</li><li>Szmodis, A. W., Blanchette, C. D., Longo, M. L., Orme, C. A., Parikh, A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermally+induced+phase+separation+in+supported+bilayers+of+glycosphingolipid+and+phospholipid+mixtures.">Thermally induced phase separation in supported bilayers of glycosphingolipid and phospholipid mixtures.</a> Biointerphases. 5, 120-130 (2010).</li><li>Strulson, M. K., Maurer, 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=Microcontact+printing+for+creation+of+patterned+lipid+bilayers+on+tetraethylene+glycol+self-assembled+monolayers.">Microcontact printing for creation of patterned lipid bilayers on tetraethylene glycol self-assembled monolayers.</a> Langmuir. 27, 12052-12057 (2011).</li><li>Satriano, 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=Plasma+oxidized+polyhydroxymethylsiloxane--a+new+smooth+surface+for+supported+lipid+bilayer+formation.">Plasma oxidized polyhydroxymethylsiloxane--a new smooth surface for supported lipid bilayer formation.</a> Langmuir. 26, 5715-5725 (2010).</li><li>Bag, N., Sankaran, J., Paul, A., Kraut, R. S., Wohland, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calibration+and+limits+of+camera-based+fluorescence+correlation+spectroscopy:+a+supported+lipid+bilayer+study.">Calibration and limits of camera-based fluorescence correlation spectroscopy: a supported lipid bilayer study.</a> Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry. 13, 2784-2794 (2012).</li><li>Singh, S., Keller, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomic+force+microscopy+of+supported+planar+membrane+bilayers.">Atomic force microscopy of supported planar membrane bilayers.</a> Biophysical Journal. 60, 1401-1410 (1991).</li><li>Przybylo, 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=Lipid+Diffusion+in+Giant+Unilamellar+Vesicles+Is+More+than+2+Times+Faster+than+in+Supported+Phospholipid+Bilayers+under+Identical+Conditions.">Lipid Diffusion in Giant Unilamellar Vesicles Is More than 2 Times Faster than in Supported Phospholipid Bilayers under Identical Conditions.</a> Langmuir. 22, 9096-9099 (2006).</li><li>Scomparin, C., Lecuyer, S., Ferreira, M., Charitat, T., Tinland, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+in+supported+lipid+bilayers:+influence+of+substrate+and+preparation+technique+on+the+internal+dynamics.">Diffusion in supported lipid bilayers: influence of substrate and preparation technique on the internal dynamics.</a> Eur Phys J E Soft Matter. 28, 211-220 (2009).</li><li>Oreopoulos, J., Yip, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+scanning+probe+and+total+internal+reflection+fluorescence+microscopy.">Combined scanning probe and total internal reflection fluorescence microscopy.</a> Methods. 46, 2-10 (2008).</li><li>Shaw, J. E., Slade, A., Yip, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+in+situ+total+internal+reflectance+fluorescence/atomic+force+microscopy+studies+of+DPPC/dPOPC+microdomains+in+supported+planar+lipid+bilayers.">Simultaneous in situ total internal reflectance fluorescence/atomic force microscopy studies of DPPC/dPOPC microdomains in supported planar lipid bilayers.</a> J Am Chem Soc. 125, 11838-11839 (2003).</li><li>Skaug, M. J., Faller, R., Longo, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlating+anomalous+diffusion+with+lipid+bilayer+membrane+structure+using+single+molecule+tracking+and+atomic+force+microscopy.">Correlating anomalous diffusion with lipid bilayer membrane structure using single molecule tracking and atomic force microscopy.</a> J Chem Phys. 134, (2011).</li><li>Bag, N., Yap, D. H., Wohland, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+dependence+of+diffusion+in+model+and+live+cell+membranes+characterized+by+imaging+fluorescence+correlation+spectroscopy.">Temperature dependence of diffusion in model and live cell membranes characterized by imaging fluorescence correlation spectroscopy.</a> Biochimica et Biophysica Acta. , (2013).</li><li>Sbalzarini, I. F., Koumoutsakos, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feature+point+tracking+and+trajectory+analysis+for+video+imaging+in+cell+biology.">Feature point tracking and trajectory analysis for video imaging in cell biology.</a> J Struct Biol. 151, 182-195 (2005).</li><li>Linkert, 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=Metadata+matters:+access+to+image+data+in+the+real+world.">Metadata matters: access to image data in the real world.</a> J Cell Biol. 189, 777-782 (2010).</li><li>Schutz, G. J., Schindler, H., Schmidt, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-molecule+microscopy+on+model+membranes+reveals+anomalous+diffusion.">Single-molecule microscopy on model membranes reveals anomalous diffusion.</a> Biophys J. 73, 1073-1080 (1997).</li><li>Matysik, A., Kraut, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TrackArt:+the+user+friendly+interface+for+single+molecule+tracking+data+analysis+and+simulation+applied+to+complex+diffusion+in+mica+supported+lipid+bilayers.">TrackArt: the user friendly interface for single molecule tracking data analysis and simulation applied to complex diffusion in mica supported lipid bilayers.</a> BMC Research Notes. 7, (2014).</li></ol>

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Questo protocollo descrive un metodo per preparare superfici mica lisce e sottili per deposizione bistrato lipidico e imaging ad alta risoluzione. La tecnica richiede abilità manuale minimo, limitato soprattutto alla attenta smontaggio del sandwich vetro-mica-vetro (passo 2.8), che è essenziale per ottenere una superficie di mica alta qualità. Controllo della mica appena spaccati è sempre necessaria, a questo punto, poiché è possibile per la mica staccare dall&#39;adesivo ottica senza fende, lasciando aree esposte...

L&#39;obiettivo generale del presente protocollo è quello di mostrare un metodo per preparare le superfici mica per imaging ad alta risoluzione di mica sostenuta lipidi bistrati (SLB) utilizzando la microscopia ottica riflessione interna totale in fluorescenza (TIRFM) o la microscopia confocale, che potrebbe anche essere combinato con forza atomica Microscopy (AFM). SLB sono un modello ampiamente utilizzato per numerosi studi di raggruppamento lipidi, separazione di fase, la dinamica di componenti a doppio strato o loro interazioni con peptidi, proteine ​​o altri composti 1-5. Substrati differenti potrebbero essere utilizzati per la formazione SLB (cioè vetro, mica, biossido di silicio, polimeri) a seconda della natura dello studio 4,6-8. Gli studi di membrana tipiche si basano su tecniche di imaging basata microscopia-, come TIRFM e AFM. Così, per l&#39;imaging TIRFM, una superficie di vetro è una tipica scelta perché il vetro è trasparente. Preparazione del vetro è relativamente facile, e la qualità dei risultati è principalmentedeterminato dalla accurata pulizia prima della deposizione delle vescicole lipidiche superficie. AFM grazie alla sua elevata risoluzione assiale richiede superfici di mica. Mica è un minerale silicato, con quasi perfetta scissione basale. Così, la mica appena spaccati è atomicamente piatta, che permette l&#39;osservazione di membrana dislivelli anche a scala sub-nanometrica 9. Studi di diffusione con metodi quali la spettroscopia di correlazione di fluorescenza (FCS), singola molecola di inseguimento (SMT), e recupero di fluorescenza dopo photobleaching (FRAP) hanno mostrato tuttavia che la dinamica della membrana lipidica dipende fortemente dal tipo di superficie su cui sono depositati, per cui vetro e mica può dare risultati ampiamente variabili 10,11. Queste differenze sono non solo i coefficienti di diffusione delle sonde di membrana, ma anche l&#39;individuazione di popolazioni separate di particelle diffondenti con tassi differenti, e possibilmente la commutazione tra i diversi stati. Così,il confronto diretto dei risultati ottenuti utilizzando tecniche TIRFM e AFM è spesso problematico, a meno che la stessa superficie (in questo caso mica) viene utilizzato. Anche se ci sono alcuni studi in cui TIRFM e imaging AFM doppio strato è stata condotta sulla stessa superficie mica 12,13, mica è usato raramente per la microscopia ottica, soprattutto a causa di problemi di gestione. Preparazione Mica richiede il taglio a mano in foglioline sottili, che sono incollati ad coprioggetto con adesivo ottico 12. Questo metodo richiede tuttavia una certa pratica per ottenere risultati soddisfacenti. Inoltre, le superfici ottenute sono spesso ondulati e di spessore, che li rende difficili da utilizzare con bassa distanza di lavoro, alti lenti apertura numerica. Mica superfici preparate come descritto in questo protocollo sono molto sottili (~ 220 micron, compreso lo spessore vetrino di 170 micron) ed estremamente piatta, evitando di &quot;ondulazione&quot;, che è fondamentale per il successo di imaging ad alta risoluzione. Possono essere utilizzatiper TIRFM o confocale configurazioni. Inoltre, gli stessi campioni possono essere trasferiti AFM, e anche ripreso contemporaneamente TIRFM / confocale e AFM. La combinazione di queste due tecniche consente di correlazione diretta del comportamento diffusione con struttura a membrana a doppio strato 14. Poiché le superfici mica sono appena spaccati, sono pulite e non richiedono molto tempo, scarsamente riproducibile, e le procedure di pulizia potenzialmente pericolosi (protocolli di pulizia di vetro di solito includono sostanze chimiche come soluzione Piranha, acido solforico, idrossido di sodio / potassio). Montaggio di una piccola camera, anche descritto nel protocollo, riduce il volume di vescicole necessari per la formazione bistrato efficace e meno di 50 microlitri. Infine, l&#39;intero processo di assemblaggio superficie non è molto tempo (preparazione richiede meno di 30 minuti), e non richiede un elevato grado di abilità manuale, così come convenzionale scissione mica e incollaggio.

<table border="0" cellpadding="0" cellspacing="0" width="710">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Name of Material/ Equipment</td>
			<td style="width:135px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Bath Sonicator</td>
			<td style="width:135px;">Fisher Scientific</td>
			<td style="width:119px;">FB15051</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Coverslips 24 x 50mm - No H1.5</td>
			<td style="width:135px;">Marienfeld</td>
			<td style="width:119px;">102222</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">DOPC</td>
			<td style="width:135px;">Avanti Polar Lipids</td>
			<td style="width:119px;">850357</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Hellmanex III (detergent)</td>
			<td style="width:135px;">Hellma Analytics</td>
			<td style="width:119px;">320.003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Mica V-1 Grade</td>
			<td style="width:135px;">SPI Suppliers</td>
			<td style="width:119px;">1872-CA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Optical Adhesive (high viscosity)</td>
			<td style="width:135px;">Norland Products</td>
			<td style="width:119px;">NOA63</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">Optical Adhesive (low viscosity)</td>
			<td style="width:135px;">Norland Products</td>
			<td style="width:119px;">NOA60</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sphingomyelin-ATTO647N</td>
			<td style="width:135px;">AttoTec</td>
			<td>AD 647N-171</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:291px;">UV lamp</td>
			<td style="width:135px;">Synoptics Ltd.</td>
			<td style="width:119px;">GelVue GVM20</td>
			<td>The lamp was set to 100% power</td>
		</tr>
	</tbody>
</table>

preparation of mica supported lipid bilayers for high resolution optical microscopy imaging

Doppi strati lipidici supportati (SLB) sono ampiamente usati come modello per lo studio delle proprietà di membrana (separazione di fase, di clustering, dinamica) e la sua interazione con altri composti, come i farmaci o peptidi. Tuttavia caratteristiche SLB variano a seconda del supporto utilizzato. Tecniche utilizzate comunemente per SLB l&#39;imaging e le misure sono single microscopia a fluorescenza molecola, FCS e microscopia a forza atomica (AFM). Poiché la maggior parte degli studi di imaging ottico sono effettuate su un supporto di vetro, mentre AFM richiede una superficie estremamente piatta (generalmente mica), i risultati di queste tecniche non sono direttamente confrontabili, in quanto le proprietà di carica e di funzionamento di questi materiali influenzano fortemente diffusione. Purtroppo, l&#39;alto livello di destrezza manuale richiesto per il taglio e incollaggio fette sottili di mica al vetrino presenta un ostacolo di utilizzare sistematicamente mica per la preparazione SLB. Sebbene questo sarebbe il metodo di scelta, come mica preparatosuperfici spesso finiscono per essere irregolare (ondulato) e difficile da immagine, soprattutto con la piccola distanza di lavoro, alti lenti apertura numerica. Qui vi presentiamo un metodo semplice e riproducibile per la preparazione di sottili superfici piane mica per la deposizione lipidica delle vescicole e preparazione SLB. Inoltre, la nostra camera di misura richiede solo piccole quantità di vescicole per la formazione SLB. I risultati procedura generale nella produzione efficiente, semplice ed economico di superfici doppio strato lipidico alta qualità che sono direttamente paragonabili a quelli utilizzati negli studi AFM.

Il comportamento diffusione di sonde fluorescenti lipidici in SLB è diverso a seconda del substrato. TIRFM combinata con la tecnica SMT è un metodo utile per la visualizzazione movimenti di particelle ed estraendo i loro coefficienti di diffusione. Segnali singola molecola di una sonda sfingomielina-ATTO647N diffusione in un DOPC (1,2-dioleoyl-sn-glycero-3-fosfocolina) doppio strato supportato su vetro e mica sono mostrate nella figura animata allegata. La superficie mica è stato preparato secondo il protoco...

Watch this Scientific Journal Video about Preparation of Mica Supported Lipid Bilayers for High Resolution Optical Microscopy Imaging at JoVE.com

Preparation of Mica Supported Lipid Bilayers for High Resolution Optical Microscopy Imaging

Vi presentiamo un metodo di preparazione mica supportato doppi strati lipidici per microscopia ad alta risoluzione. Mica è trasparente e piatto su scala atomica, ma raramente usata nell&#39;imaging a causa della difficoltà di manipolazione; nostra preparazione comporta anche deposizione del foglio di mica, e riduce il materiale utilizzato nella preparazione bistrato.

Preparazione di Mica supportati doppi strati lipidici per alta risoluzione microscopia ottica Imaging

Supported lipid bilayers (SLBs) are widely used as a model for studying membrane properties (phase separation, clustering, dynamics) and its interaction ...

preparation-mica-supported-lipid-bilayers-for-high-resolution-optical

Research

JoVE Journal

Bioengineering

13.3K Views.  Nanyang Technological University.  Vi presentiamo un metodo di preparazione mica supportato doppi strati lipidici per microscopia ad alta risoluzione. Mica è trasparente e piatto su scala atomica, ma raramente usata nell'imaging a causa della difficoltà di manipolazione; nostra preparazione comporta anche deposizione del foglio di mica, e riduce il materiale utilizzato nella preparazione bistrato. 

Video: Preparation of Mica Supported Lipid Bilayers for High Resolution Optical Microscopy Imaging

High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging

Many biological and clinical studies require the longitudinal study and analysis of morphology and function with cellular level resolution. Traditionally, multiple experiments are run in parallel, with individual samples removed from the study at sequential time points for evaluation by light microscopy. Several intravital techniques have been developed, with confocal, multiphoton, and second harmonic microscopy all demonstrating their ability to be used for imaging in situ 1. With these systems, however, the required infrastructure is complex and expensive, involving scanning laser systems and complex light sources. Here we present a protocol for the design and assembly of a high-resolution microendoscope which can be built in a day using off-the-shelf components for under US$5,000. The platform offers flexibility in terms of image resolution, field-of-view, and operating wavelength, and we describe how these parameters can be easily modified to meet the specific needs of the end user.
We and others have explored the use of the high-resolution microendoscope (HRME) in in vitro cell culture 2-5, in excised 6 and living animal tissues 2,5, and in human tissues in vivo 2,7. Users have reported the use of several different fluorescent contrast agents, including proflavine 2-4, benzoporphyrin-derivative monoacid ring A (BPD-MA) 5, and fluoroscein 6,7, all of which have received full, or investigational approval from the FDA for use in human subjects. High-resolution microendoscopy, in the form described here, may appeal to a wide range of researchers working in the basic and clinical sciences. The technique offers an effective and economical approach which complements traditional benchtop microscopy, by enabling the user to perform high-resolution, longitudinal imaging in situ.

High-resolution Fiber-optic Microendoscopy for in situ Cellular Imaging

In many biological and clinical situations it is advantageous to study cellular processes as they evolve in their native microenvironment. Here we describe the assembly and use of a low-cost fiber-optic microscope which can provide real time imaging in cell culture, animal studies, and clinical patient studies.

Ad alta risoluzione in fibra ottica per Microendoscopy In situ Cellular Imaging

Many biological and clinical studies require the longitudinal study and analysis of morphology and function with cellular level resolution.  ...

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Three-dimensional Optical-resolution Photoacoustic Microscopy

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As the mainstays of in vivo three-dimensional (3-D) optical microscopy, single-/multi-photon fluorescence microscopy and optical coherence tomography (OCT) have demonstrated their extraordinary sensitivities to fluorescence and optical scattering contrasts, respectively. However, the optical absorption contrast of biological tissues, which encodes essential physiological/pathological information, has not yet been assessable. 
The emergence of biomedical photoacoustics has led to a new branch of optical microscopy optical-resolution photoacoustic microscopy (OR-PAM)1, where the optical irradiation is focused to the diffraction limit to achieve cellular1 or even subcellular2 level lateral resolution. As a valuable complement to existing optical microscopy technologies, OR-PAM brings in at least two novelties. First and most importantly, OR-PAM detects optical absorption contrasts with extraordinary sensitivity (i.e., 100%). Combining OR-PAM with fluorescence microscopy3 or with optical-scattering-based OCT4 (or with both) provides comprehensive optical properties of biological tissues. Second, OR-PAM encodes optical absorption into acoustic waves, in contrast to the pure optical processes in fluorescence microscopy and OCT, and provides background-free detection. The acoustic detection in OR-PAM mitigates the impacts of optical scattering on signal degradation and naturally eliminates possible interferences (i.e., crosstalks) between excitation and detection, which is a common problem in fluorescence microscopy due to the overlap between the excitation and fluorescence spectra. 
Unique for optical absorption imaging, OR-PAM has demonstrated broad biomedical applications since its invention, including, but not limited to, neurology5, 6, ophthalmology7, 8, vascular biology9, and dermatology10. In this video, we teach the system configuration and alignment of OR-PAM as well as the experimental procedures for in vivo functional microvascular imaging.

Optical-resolution photoacoustic microscopy (OR-PAM) is an emerging technology capable of imaging optical absorption contrasts in vivo with cellular resolution and sensitivity. Here, we provide a visualized instruction on the experimental protocols of OR-PAM, including system configuration, system alignment, typical in vivo experimental procedures, and functional imaging schemes.

Tridimensionale con risoluzione ottica Microscopia fotoacustico

Optical microscopy, providing valuable insights at the cellular and organelle levels, has been widely recognized as an enabling biomedical technology. As ...

Wideband Optical Detector of Ultrasound for Medical Imaging Applications

Optical sensors of ultrasound are a promising alternative to piezoelectric techniques, as has been recently demonstrated in the field of optoacoustic imaging. In medical applications, one of the major limitations of optical sensing technology is its susceptibility to environmental conditions, e.g. changes in pressure and temperature, which may saturate the detection. Additionally, the clinical environment often imposes stringent limits on the size and robustness of the sensor. In this work, the combination of pulse interferometry and fiber-based optical sensing is demonstrated for ultrasound detection. Pulse interferometry enables robust performance of the readout system in the presence of rapid variations in the environmental conditions, whereas the use of all-fiber technology leads to a mechanically flexible sensing element compatible with highly demanding medical applications such as intravascular imaging. In order to achieve a short sensor length, a pi-phase-shifted fiber Bragg grating is used, which acts as a resonator trapping light over an effective length of 350 &#181;m. To enable high bandwidth, the sensor is used for sideway detection of ultrasound, which is highly beneficial in circumferential imaging geometries such as intravascular imaging. An optoacoustic imaging setup is used to determine the response of the sensor for acoustic point sources at different positions.

Optical detection of ultrasound is impractical in many imaging scenarios because it often requires stable environmental conditions. We demonstrate an optical technique for ultrasound sensing in volatile environments with miniaturization and sensitivity levels appropriate for optoacoustic imaging in restrictive scenarios, e.g. intravascular applications.

Wideband rivelatore ottico di ultrasuono per applicazioni Medical Imaging

Optical sensors of ultrasound are a promising alternative to piezoelectric techniques, as has been recently demonstrated in the field of optoacoustic ...

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

Single-molecule microscopy is emerging as a powerful approach to analyze the behavior of signaling molecules, in particular concerning those aspect (e.g., kinetics, coexistence of different states and populations, transient interactions), which are typically hidden in ensemble measurements, such as those obtained with standard biochemical or microscopy methods. Thus, dynamic events, such as receptor-receptor interactions, can be followed in real time in a living cell with high spatiotemporal resolution. This protocol describes a method based on labeling with small and bright organic fluorophores and total internal reflection fluorescence (TIRF) microscopy to directly visualize single receptors on the surface of living cells. This approach allows one to precisely localize receptors, measure the size of receptor complexes, and capture dynamic events such as transient receptor-receptor interactions. The protocol provides a detailed description of how to perform a single-molecule experiment, including sample preparation, image acquisition and image analysis. As an example, the application of this method to analyze two G-protein-coupled receptors, i.e., &#946;2-adrenergic and &#947;-aminobutyric acid type B (GABAB) receptor, is reported. The protocol can be adapted to other membrane proteins and different cell models, transfection methods and labeling strategies.

This protocol describes how to use total internal reflection fluorescence microscopy to visualize and track single receptors on the surface of living cells and thereby analyze receptor lateral mobility, size of receptor complexes as well as to visualize transient receptor-receptor interactions. This protocol can be extended to other membrane proteins.

Ad alta risoluzione Spatiotemporal Analisi del recettore Dynamics per singola molecola di microscopia a fluorescenza

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

Fluorescence-quenching of a Liposomal-encapsulated Near-infrared Fluorophore as a Tool for In Vivo Optical Imaging

Optical imaging offers a wide range of diagnostic modalities and has attracted a lot of interest as a tool for biomedical imaging. Despite the enormous number of imaging techniques currently available and the progress in instrumentation, there is still a need for highly sensitive probes that are suitable for in vivo imaging. One typical problem of available preclinical fluorescent probes is their rapid clearance in vivo, which reduces their imaging sensitivity. To circumvent rapid clearance, increase number of dye molecules at the target site, and thereby reduce background autofluorescence, encapsulation of the near-infrared fluorescent dye, DY-676-COOH in liposomes and verification of its potential for in vivo imaging of inflammation was done. DY-676 is known for its ability to self-quench at high concentrations. We first determined the concentration suitable for self-quenching, and then encapsulated this quenching concentration into the aqueous interior of PEGylated liposomes. To substantiate the quenching and activation potential of the liposomes we use a harsh freezing method which leads to damage of liposomal membranes without affecting the encapsulated dye. The liposomes characterized by a high level of fluorescence quenching were termed Lip-Q. We show by experiments with different cell lines that uptake of Lip-Q is predominantly by phagocytosis which in turn enabled the characterization of its potential as a tool for in vivo imaging of inflammation in mice models. Furthermore, we use a zymosan-induced edema model in mice to substantiate the potential of Lip-Q in optical imaging of inflammation in vivo. Considering possible uptake due to inflammation-induced enhanced permeability and retention (EPR) effect, an always-on liposome formulation with low, non-quenched concentration of DY-676-COOH (termed Lip-dQ) and the free DY-676-COOH were compared with Lip-Q in animal trials.

Fluorescence-quenching of a Liposomal-encapsulated Near-infrared Fluorophore as a Tool for In Vivo Optical Imaging

The use of fluorophores for in vivo imaging can be greatly limited by opsonization, rapid clearance, low detection sensitivity and cytotoxic effects on the host. Encapsulation of fluorophores in liposomes by film hydration and extrusion leads to fluorescence quenching and protection which enables in vivo imaging with high detection sensitivity.

Fluorescenza tempra di un vicino infrarosso Fluoroforo incapsulata all&#39;interno di liposomi come strumento per<em&gt; In Vivo</em&gt; Optical Imaging

Optical imaging offers a wide range of diagnostic modalities and has attracted a lot of interest as a tool for biomedical imaging. Despite the enormous ...

Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers

Atomic force microscopy (AFM) is a versatile, high-resolution imaging technique that allows visualization of biological membranes. It has sufficient magnification to examine membrane substructures and even individual molecules. AFM can act as a force probe to measure interactions and mechanical properties of membranes. Supported lipid bilayers are conventionally used as membrane models in AFM studies. In this protocol, we demonstrate how to prepare supported bilayers and characterize their structure and mechanical properties using AFM. These include bilayer thickness and breakthrough force. 
The information provided by AFM imaging and force spectroscopy help define mechanical and chemical properties of membranes. These properties play an important role in cellular processes such as maintaining cell hemostasis from environmental stress, bringing membrane proteins together, and stabilizing protein complexes.

We describe a protocol for preparation of supported lipid bilayers and its characterization using atomic force microscopy and force spectroscopy.

Atomic Force Microscopy Imaging e Spettroscopia Forza supportati doppi strati lipidici

Atomic force microscopy (AFM) is a versatile, high-resolution imaging technique that allows visualization of biological membranes. It has sufficient ...

Single Molecule Fluorescence Microscopy on Planar Supported Bilayers

In the course of a single decade single molecule microscopy has changed from being a secluded domain shared merely by physicists with a strong background in optics and laser physics to a discipline that is now enjoying vivid attention by life-scientists of all venues 1. This is because single molecule imaging has the unique potential to reveal protein behavior in situ in living cells and uncover cellular organization with unprecedented resolution below the diffraction limit of visible light 2. Glass-supported planar lipid bilayers (SLBs) are a powerful tool to bring cells otherwise growing in suspension in close enough proximity to the glass slide so that they can be readily imaged in noise-reduced Total Internal Reflection illumination mode 3,4. They are very useful to study the protein dynamics in plasma membrane-associated events as diverse as cell-cell contact formation, endocytosis, exocytosis and immune recognition. Simple procedures are presented how to generate highly mobile protein-functionalized SLBs in a reproducible manner, how to determine protein mobility within and how to measure protein densities with the use of single molecule detection. It is shown how to construct a cost-efficient single molecule microscopy system with TIRF illumination capabilities and how to operate it in the experiment.

Preparation of protein-functionalized planar glass-supported lipid bilayers, determination of protein mobility within and measurement of protein densities is shown here. A roadmap to building a noise-reduced Total Internal Reflection microscope is outlined, which allows visualizing single bilayer-resident fluorochromes with high spatiotemporal resolution.

Singola molecola microscopia a fluorescenza su Planar bilayers supportati

In the course of a single decade single molecule microscopy has changed from being a secluded domain shared merely by physicists with a strong background ...

Ligand Nano-cluster Arrays in a Supported Lipid Bilayer

Currently there is considerable interest in creating ordered arrays of adhesive protein islands in a sea of passivated surface for cell biological studies. In the past years, it has become increasingly clear that living cells respond, not only to the biochemical nature of the molecules presented to them but also to the way these molecules are presented. Creating protein micro-patterns is therefore now standard in many biology laboratories; nano-patterns are also more accessible. However, in the context of cell-cell interactions, there is a need to pattern not only proteins but also lipid bilayers. Such dual proteo-lipidic patterning has so far not been easily accessible. We offer a facile technique to create protein nano-dots supported on glass and propose a method to backfill the inter-dot space with a supported lipid bilayer (SLB). From photo-bleaching of tracer fluorescent lipids included in the SLB, we demonstrate that the bilayer exhibits considerable in-plane fluidity. Functionalizing the protein dots with fluorescent groups allows us to image them and to show that they are ordered in a regular hexagonal lattice. The typical dot size is about 800 nm and the spacing demonstrated here is 2 microns. These substrates are expected to serve as useful platforms for cell adhesion, migration and mechano-sensing studies.

We present a protocol to functionalize glass with nanometric protein patches surrounded by a fluid lipid bilayer. These substrates are compatible with advanced optical microscopy and are expected to serve as platform for cell adhesion and migration studies.

Array Ligand Nano-cluster in un doppio strato lipidico supportati

Currently there is considerable interest in creating ordered arrays of adhesive protein islands in a sea of passivated surface for cell biological ...

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the optical mean free path (~1 mm in skin) with high resolution. By combining optical absorption contrast with the high spatial resolution of ultrasound in a single modality, this technique can penetrate deep tissues. Photoacoustic microscopy systems can have either a low acoustic resolution and probe deeply or a high optical resolution and probe shallowly. It is challenging to achieve high spatial resolution and large depth penetration with a single system. This work presents an AR-OR-PAM system capable of both high-resolution imaging at shallow depths and low-resolution deep-tissue imaging of the same sample in vivo. A lateral resolution of 4 &#181;m with 1.4 mm imaging depth using optical focusing and a lateral resolution of 45 &#181;m with 7.8 mm imaging depth using acoustic focusing were successfully demonstrated using the combined system. Here,&#160;in vivo&#160;small-animal blood vasculature imaging is performed to demonstrate its biological imaging capability.

Switchable Acoustic and Optical Resolution Photoacoustic Microscopy for In Vivo Small-animal Blood Vasculature Imaging

Here a switchable acoustic resolution (AR) and optical resolution (OR) photoacoustic microscopy (AR-OR-PAM) system capable of both high resolution imaging at shallow depth and low resolution deep tissue imaging on the same sample in vivo is demonstrated.

Microscopio fotoacustico acustico e ottico<em&gt; In Vivo</em&gt; Piccolo animale Blood Imaging di Vasculature

Photoacoustic microscopy (PAM) is a fast-growing invivo imaging modality that combines both optics and ultrasound, providing penetration beyond the ...

High Resolution 3D Imaging of the Human Pancreas Neuro-insular Network

Using traditional histological methods, researchers are hampered in their ability to image whole tissues or organs in large-scale 3D. Histological sections are generally limited to &#60;20 &#181;m as formalin fixed paraffin section on glass slides or &#60;500 &#181;m for free-floating fixed sections. Therefore, extensive efforts are required for serial sectioning and large-scale image reconstruction methods to recreate 3D for samples &#62;500 &#181;m using traditional methods. In addition, light scatters from macromolecules within tissues, particularly lipids, prevents imaging to a depth &#62;150 &#181;m with most confocal microscopes. To reduce light scatter and to allow for deep tissue imaging using simple confocal microscopy, various optical clearing methods have been developed that are relevant for rodent and human tissue samples fixed by immersion. Several methods are related and use protein crosslinking with acrylamide and tissue clearing with sodium dodecyl sulfate (SDS). Other optical clearing techniques used various solvents though each modification had various advantages and disadvantages. Here, an optimized passive optical clearing method is described for studies of the human pancreas innervation and specifically for interrogation of the innervation of human islets.

Here, we present a protocol to image human pancreas sections in three dimensions (3D) using optimized passive clearing methods. This manuscript demonstrates these procedures for passive optical clearing followed by multiple immunofluorescence staining to identify key elements of the autonomic and sensory neural networks innervating human islets.