Biz C ile yardım için mali destek için Lindback Vakfı, Dr. Alexander Sidorenko ve verimli tartışmalar ve teknik yardım için Elza Chu, ve Profesör Robert Smith&#39;e teşekkür C. elegans deneyleri.

NOT: Aşağıda açıklanan prosedürlerde, laboratuvar güvenlik kurallarına mutlaka uyulmalıdır. Özel öneme sahip yüksek gerilim (&gt; 500 V) ve taşıma kimyasallar ile ilgili güvenliğidir. Mum İs ile İletken Yüzey 1. Kaplama <ol><li> Dikdörtgenler halinde kesilmiş bakır metal (0,5 mm kalınlığında 75 x 43 mm). , Yaklaşık 30 saniye boyunca bakır dağlayıcıda batırılarak her bakır yüzeyin temizliği yaklaşık 20 saniye musluk suyu ile yıkayın ve kağıt ile kurulayın. NOT: Yöntem 1 altında kullanılıyorsa, makinenin içine sığacak şekilde 75 x 25 mm boyutları değiştirin. </li><li> (Yaklaşık 40 mikron kalınlığında) yaklaşık olarak eşit kurum kaplama elde etmek için, 30-45 saniye boyunca bakır tabaka altında yanan parafin mum süpürün. Alev içine ~ 1 cm tabakayı tutun. Kırılgan kurum yüzeyine dokunmayın. </li></ol> 2. Kaplama ile Kurum Tabakasının Korunmasına NOT: is tabakası çok kırılgan olduğunuVe korunması için kaplanabilir. İki basit alternatifleri (yöntemleri 1 ve 2) Burada önerilen, ancak daha sağlam protokoller şu anda geliştirilme aşamasındadır. <ol><li> Yöntem 1 <ol><li> Metal buharlaştırıcı veya püskürtme sistemine örnek yükleyin. Sistemin çalışma prosedürleri izlenerek, bölmeyi tahliye ve kurum katman (150-200 nm) üzerinde altın depozisyonu başlar. Cihazın oda sıcaklığına kadar soğumasını bekleyin. </li><li> Dip kaplama, kimyasal bir bölme içine 10 dakika süre ile (% 95 etanol, ACS / USP olarak% 1 h / h) 1-dodekantiol çözelti içinde metalize tabaka. Daha sonra, 60 ° ye yakın bir açı ile tutucularına, hafifçe ancak etanolün büyük damlacıklar ile yüzeyini yıkamak. Gecede, cihazlar kurumaya bırakın. </li></ol></li><li> Yöntem 2 <ol><li> Taban madde mum alevden sıcakken kimyasal bir kaput, derhal kurum ile kaplanmasından sonra, bir tarafında fluorlu bir miktar sıvı damlalarını bırakmak vesubstrat ve 90 ° yakın bir açıya tabakayı eğin. Daha damlalarını bırakmak ve onları tüm kurum yüzey üzerinde çevirelim. NOT: damlacık bir nokta üzerine düştüğünde, kurum uzakta o bölgeden yıkanmış olur. Mümkün olan fluorlu yayılmış sıvının damlacıklar kadar bildirin. </li><li> Kimyasal bir kaput içerisinde sıcak bir plaka (15 dakika boyunca 160 ° C) üzerindeki alt-tabaka pişirin. </li><li> Alt-tabaka kullanımdan önce gece boyunca oda sıcaklığında bekletin. Süresiz saklayın. </li></ol></li></ol> 3. Üst Elektrotlar Fabrikasyon (Abdelgawad ark uyarlanmıştır. 12) <ol><li> Grafik tasarım yazılımları kullanarak elektrotları çizin. Her bir elektrot 0.3 mm genişliğinde, 2 mm uzunluğunda ve elektrot arasındaki fark 0.3 mm&#39;dir. Rehber (aşağıya bakınız, konnektörüne oturana) arasındaki boşluk 2.3 mm (Şekil 1). </li><li> Monarch formatında (3.87 x 7.5 inç) bir esnek bakır laminat (kalın 35 mikron) Trim. Diğer boyutları kullanın iyazıcıyla uyumlu f. Renkli yazıcının elle besleme tepsisine laminat yükleyin. </li><li> Bakır levha üzerine baskı yaparken, dağlama sırasında baskılı desen koruyan, bakır tabaka üzerine siyah mürekkep yoğun bir tabaka sağlamak için &quot;zengin siyah&quot;, ya da &quot;kayıt siyah&quot; kullanmak için emin olun (detaylar için Abdelgawad ve ark. 12 bakınız) olun . Gecede, tamamen basılı tabaka kurumasını bekleyin. </li><li> Kimyasal bir kaput içinde, (40 ° C) bakır dağlayıcıda 50 ml ile bir beher ısınmak. Beher içinde baskılı laminat Dip ve bu, hafifçe yaklaşık 10 dakika boyunca çözelti içinde sallayın. Dağlama zaman bakır dağlayıcıları çözümüne bağlıdır. Her birkaç dakikada, korozyon kontrol ve desen sağlam olup olmadığını görmek. </li><li> Dikkatle su ile laminat yıkayın ve kimyasal kaput aseton ve etanol ile kaplama çıkarın. Bir kez daha yıkayın ve yavaşça kağıt havlu ile laminat kurulayın. </li><li> Dikkatli bir GLA için elektrotlar ile laminat takmakss slayt (75 x 25 mm kalınlığı ~ 1 mm), çift taraflı bant kullanarak. Hava cepleri kaçının. </li><li> Bant kullanarak elektrotlara perfloroalkoksi PFA bir film takın. Bu damlacık ile elektrotların yanlışlıkla temas önlemek için hizmet eden dolayı kısa devre zararlar üst elektrotlar. </li></ol> 4. (Şekil 2&#39;de devre) elektronik arabirim <ol><li> Evrensel bir devre kartına röleleri ve kapasitörler C lehim. </li><li> Elektronik devreler için bir kaynaksız breadboard üzerinde 10 röle sürücüleri kalanını birleştirin. </li><li> Tel kumanda panosunda bir kanala her röle sürücü girişi. </li><li> Dikkatlice bir bağlantı yerine (Şekil 3) üst elektrotlar oturtun. Tel Şekilde gösterildiği gibi bir üst elektrot her röle sürücü çıkışı. Elektriksel gürültüyü en aza indirmek için, röleleri teller bir çift arasında bir topraklı konnektör temas olduğunu unutmayın. NOT: konnektör t kontrol ayarlanabilir bir platform üzerinde otururüst ve alt (kurum-kaplamalı) alt tabaka arasındaki o mesafe (0.1-0.5 mm). </li><li> Daha sonra 2345, 3456, vb; 0.8 sn, actuate 1234, yani hareket (yönünde 1 elektrot kayması, aynı anda 4 elektrotlara yüksek voltaj (HV) uygulama (yaklaşık 0.8 sn) için zamanlama kontrol etmek için bir programı kullanın ., 0.8 her bir grup için sn ve daha sonra geriye doğru ters yönde çok damlacık hareket de). </li></ol> 5. Damlacık Görselleştirme ve Taşıma <ol><li> CCD kamera ile kombine 96x büyütme montaj - damlacık hareketini kaydetmek için, bir 24X oluşan görselleştirme sistemi kullanırlar. S-video kullanarak kameraya video kaydedici bağlayın. </li><li> C ihtiva eden, 4 ul damlacık Pipet kurum kaplanmış alt-tabakanın altındaki ortam elegans&#39;da. </li><li> ~ Damlacık üzerinde 0.3 mm için üst elektrotlar getirin. Damlacık daha kolay işlem için, beşinci elektrotun altında ortadan yakın olmalıdır. </li><li> Elektronik arayüzü ve yüksek gerilim (500 V RMS) açın ve hareket başlayana kadar damlacık üst elektrot mesafeyi ayarlayın. Üst elektrotlar damlacık dokunmasına izin vermeyin. </li><li> Elektrik darbeleri yanıt cihaz üzerinde başarılı damlacık transferlerin sayısını kaydederek verileri toplayın. Başarılı bir deney, en az 700 damlacık transferi ile karakterize, yani her elektrik nabız sonra bir transferi. </li><li> Damlacık 5-10 darbeleri yanıt artık hareket etmiyor kadar, sürekli veri toplamak. NOT: Yüzey aşağılamak başladığında, hareket yakın damlacık üst elektrotlar getirerek restore edilebilir. </li></ol>

<ol>
	<li>Fair, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Digital+microfluidics:+is+a+true+lab-on-a-chip+possible.">Digital microfluidics: is a true lab-on-a-chip possible.</a> Microfluid Nanofluid. 3 (3), 245-281 (2007).</li><li>Gupta, S., Alargova, R. G., Kilpatrick, P. K., Velev, O. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On-Chip+Dielectrophoretic+Coassembly+of+Live+Cells+and+Particles+into+Responsive+Biomaterials.">On-Chip Dielectrophoretic Coassembly of Live Cells and Particles into Responsive Biomaterials.</a> Langmuir. 26 (5), 3441-3452 (2009).</li><li>Shih, S. 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=Dried+blood+spot+analysis+by+digital+microfluidics+coupled+to+nanoelectrospray+ionization+mass+spectrometry.">Dried blood spot analysis by digital microfluidics coupled to nanoelectrospray ionization mass spectrometry.</a> Anal Chem. 84 (8), 3731-3738 (2012).</li><li>Gorbatsova, J., Borissova, M., Kaljurand, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrowetting-on-dielectric+actuation+of+droplets+with+capillary+electrophoretic+zones+for+off-line+mass+spectrometric+analysis.">Electrowetting-on-dielectric actuation of droplets with capillary electrophoretic zones for off-line mass spectrometric analysis.</a> J Chromatogr. 1234, 9-15 (2012).</li><li>Qin, J., Wheeler, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maze+exploration+and+learning+in+C.+elegans.">Maze exploration and learning in C. elegans.</a> Lab Chip. 7 (2), 186-192 (2007).</li><li>Koc, Y., de Mello, A. J., McHale, G., Newton, M. I., Roach, P., Shirtcliffe, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-scale+superhydrophobicity:+suppression+of+protein+adsorption+and+promotion+of+flow-induced+detachment.">Nano-scale superhydrophobicity: suppression of protein adsorption and promotion of flow-induced detachment.</a> Lab Chip. 8 (4), 582-586 (2008).</li><li>Perry, G., Thomy, V., Das, M. 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The authors declare that they have no competing financial interests.

Protokolün en önemli nokta doğrudan damlacıkları hareketli başarı ile ilişkili kurum tabakanın korumasıdır. Kurum katmanı (yukarıdaki yöntem 1) metallenmesi fabrikasyon başarı% 100&#39;e yakın verir. Bununla birlikte, maksimum işletim süresi yaklaşık 10 dakikadır; muhtemelen, damlacık fraksiyonlar metal katmandaki delikler içinden kurum ıslatma edilir. Florlu sıvı ile kurum tabakayla kaplanması kolay ve hızlı bir alternatif olduğunu ve en az kaynak gerektirir, ancak fabrikasyon yüzeylerde...

Sıvı ile çalışan cihaz boyut küçültme &quot;lab-on-a-chip&quot; platformlar gelişimi için büyük önem taşımaktadır. Bu doğrultuda, son iki yıl çeşitli uygulamalar ile, Mikroakiskan alanında önemli ilerlemeler kaydedilmiştir. 1-5 kapalı kanallarda (kanal Mikroakiskan) sıvı taşınması ile zıt, DMF elektrotlar diziler üzerinde damlacıklar yönetir. Bu tekniğin en cazip yararları biri sıvıları taşımak üzere hareket edebilen parçaların olmaması ve hareket anında elektrik sinyallerini kapatarak durdurulur. Ancak, damlacık hareket evrensel bir &quot;lab-on-a-chip&quot; platformu için kesinlikle istenmeyen bir özellik, damlacık içeriğine bağlıdır. Proteinler ve diğer analitlerinin içeren damlacıklar kımıldamaz hale, cihaz yüzeylere sopa. Muhtemelen, bu DMF uygulamaların kapsamının genişletilmesi için önemli bir sınırlama olmuştur; 6-8İstenmeyen yüzey tıkanmayı en aza indirmek için alternatifler, potansiyel olarak damlacık içeriğini etkileyebilecek damlacık ya da çevresi ile ilave kimyasal türlerin eklenmesini içerir. Daha önce, bir grup ilave katkı maddeleri (alan-DW cihazlar olmadan), DMF içinde hücreleri ve proteinlerin taşınmasını sağlamak için bir cihaz geliştirdiler. 9 bu damlacık haddeleme çıkaran bir elemanın geometrisine sahip mum is, 10 dayalı bir yüzey birleştirilmesi ile elde edilmiştir ve daha fazla damlacık yüzey etkileşimi azaltmak, damla üstünde yukarı doğru kuvvete yol açar. Bu yaklaşımda, damlacık hareket yüzey ıslaklığı ile ilişkili değildir. 11 Aşağıda tarif edilen ayrıntılı yöntemin amacı, ilave katkı maddesi olmadan proteinleri, hücreleri ve bütün organizmaları içeren damlacıkların taşıma yeteneğine sahip bir DMF cihazı üretmektir. Saha-DW cihazlar damlacık kimyager büyük ölçüde bağımsız çalışan tam kontrollü platformları için önünügelmelidir. Burada, aynı zamanda bu simülasyonlar cihazın çalışması için gerekli yüksek gerilim rağmen gösteren, damlacık boyunca gerilim düşüşü damlacık içinde bioanalytes üzerinde ihmal edilebilir etkilere işaret, uygulanan voltajın bir küçük bir bölümünü oluşturur. Aslında, Caenorhabditis elegans (C. elegans), biyolojide çalışmaların çeşitli için kullanılan bir nematod ile ön testler, gerilimler uygulandığı gibi solucanlar rahatsız yüzmek olduğunu göstermektedir.

<table border="0" cellpadding="0" cellspacing="0" width="1230">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Name of Material/ Equipment</td>
			<td style="width:119px;">Company</td>
			<td style="width:161px;">Catalog Number</td>
			<td style="width:720px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Paraffin candle</td>
			<td style="width:119px;"></td>
			<td style="width:161px;"></td>
			<td>Any paraffin candle</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:231px;">Sputtering system</td>
			<td style="width:119px;">Denton Vacuum, Moorestown, NJ</td>
			<td style="width:161px;"></td>
			<td>Sputter coater Desk V HP equipped with an Au target.&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">1-dodecanethiol</td>
			<td style="width:119px;">Sigma-Aldrich</td>
			<td align="right" style="width:161px;">471364</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Teflon</td>
			<td style="width:119px;">Dupont</td>
			<td style="width:161px;">AF-1600</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Fluorinert FC-40</td>
			<td style="width:119px;">Sigma-Aldrich</td>
			<td style="width:161px;">F9755</td>
			<td>Fluorinated liquid: Prepare Teflon-AF resin in Fluorinert FC-40, 1:100 (w/w), to create the hydrophobic coating.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:231px;">Graphic design software -Adobe Illustrator</td>
			<td style="width:119px;">Adobe Systems</td>
			<td style="width:161px;"></td>
			<td>Other softwares might be used as well.</td>
		</tr>
		<tr height="18">
			<td height="18" style="height:18px;width:231px;">Copper laminate</td>
			<td style="width:119px;">Dupont</td>
			<td style="width:161px;">LF9110</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:231px;">Laser Printer</td>
			<td style="width:119px;">Xerox</td>
			<td style="width:161px;">Phaser 6360 or similar</td>
			<td>Check for the compatibility with &#34;rich black&#34; or &#34;registration black&#34; (see text).</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Copper Etchant</td>
			<td style="width:119px;">Transene</td>
			<td style="width:161px;">CE-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Perfluoroalkoxy (PFA) film</td>
			<td style="width:119px;">McMaster-Carr</td>
			<td style="width:161px;">84955K22</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:231px;">Breadboard</td>
			<td style="width:119px;">Allied Electronics</td>
			<td style="width:161px;">70012450 or similar</td>
			<td>Large enough to allow the assemble of 10 drivers.</td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:231px;">Universal circuit board</td>
			<td style="width:119px;">Allied Electronics</td>
			<td style="width:161px;">70219535 or similar</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:231px;">Connector</td>
			<td style="width:119px;">Allied Electronics</td>
			<td style="width:161px;">5145154-8 or similar</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:231px;">Control board and control program (LabView software)</td>
			<td style="width:119px;">National Instruments</td>
			<td style="width:161px;">NI-6229 or similar</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">High-voltage amplifier</td>
			<td style="width:119px;">Trek</td>
			<td style="width:161px;">PZD700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Resistor R 27 k&#8486;, 1/4 W</td>
			<td style="width:119px;">Allied&#160;</td>
			<td align="right" style="width:161px;">2964762</td>
			<td></td>
		</tr>
		<tr height="27">
			<td height="27" style="height:27px;width:231px;">Capacitors C and C1, 100 nF, 60 V</td>
			<td style="width:119px;">Allied&#160;</td>
			<td align="right" style="width:161px;">8817183</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Transistor T, NPN</td>
			<td style="width:119px;">Allied&#160;</td>
			<td align="right" style="width:161px;">9350289</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Diode D, 1N4007</td>
			<td style="width:119px;">Allied&#160;</td>
			<td align="right" style="width:161px;">2660007</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Relay&#160;</td>
			<td style="width:119px;">Allied&#160;</td>
			<td align="right" style="width:161px;">8862527</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:231px;">Visualization system</td>
			<td style="width:119px;">Edmund Optics</td>
			<td style="width:161px;">VZM 200i or similar</td>
			<td>System magnification 24X- 96X. It is combined with a Hitachi KP-D20B 1/2 in CCD Color Camera.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:231px;">Recorder</td>
			<td style="width:119px;">Sony</td>
			<td style="width:161px;">GV-D1000 NTSC or similar</td>
			<td>It is connected to the camera by an S-video cable.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:231px;">Simulations</td>
			<td style="width:119px;">COMSOL Multiphysics</td>
			<td style="width:161px;">V. 4.4</td>
			<td></td>
		</tr>
	</tbody>
</table>

taking advantage of reduced droplet-surface interaction to optimize transport of bioanalytes in digital microfluidics

Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of &#8220;lab-on-a-chip&#8221; platforms. Often, droplet motion relies on the wetting of a surface, directly associated with the application of an electric field; surface interactions, however, make motion dependent on droplet contents, limiting the breadth of applications of the technique.
Some alternatives have been presented to minimize this dependence. However, they rely on the addition of extra chemical species to the droplet or its surroundings, which could potentially interact with droplet moieties. Addressing this challenge, our group recently developed Field-DW devices to allow the transport of cells and proteins in DMF, without extra additives.
Here, the protocol for device fabrication and operation is provided, including the electronic interface for motion control. We also continue the studies with the devices, showing that multicellular, relatively large, model organisms can also be transported, arguably unaffected by the electric fields required for device operation.

Daha önce, DMF içinde proteinlerin hareketini sağlamak için alan-DW cihazları kullanılmıştır. Özellikle, sığır serumu albümini (BSA) ile damlacıklar daha önce başka yazarlar tarafından (katkı maddesi olmadan) rapor 2.000 kat daha yüksek bir konsantrasyonda taşınmış olabilir. Bu damlacık ve yüzey arasındaki azaltılmış etkileşim nedeniyle oldu; Şekil 4 (. Bakınız Freire ve ark 9 deneyler hakkında daha fazla bilgi için) floresan etiketli BSA ...

Watch this Scientific Journal Video about Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics at JoVE.com

Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics

The protocol for fabrication and operation of field dewetting devices (Field-DW) is described, as well as the preliminary studies of the effects of electric fields on droplet contents.

Azaltılmış Damlacık-yüzey etkileşiminden yararlanarak Dijital Mikroakiskan içinde Bioanalytes ulaşımı optimize etmek

Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of &#8220;lab-on-a-chip&#8221; ...

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7.8K Görüntüleme.  University of the Sciences. The protocol for fabrication and operation of field dewetting devices (Field-DW) is described, as well as the preliminary studies of the effects of electric fields on droplet contents.

Video: Taking Advantage of Reduced Droplet-surface Interaction to Optimize Transport of Bioanalytes in Digital Microfluidics

Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains.

In this video we first describe fabrication and operation procedures of a surface acoustic wave (SAW) acoustic counterflow device. We then demonstrate an experimental setup that allows for both qualitative flow visualization and quantitative analysis of complex flows within the SAW pumping device.

Yüzey-akustik dalga odaklı Akustik-ters akışlı Mikroakiskan Fabrikasyon, İşletme ve Akış Görselleştirme

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we ...

Mühendislik

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information support1,2,3. In this context, metal nanowires are especially desirable for realizing dense routing networks4. A prerequisite to operate such shared nanowire-based platform relies on our ability to electrically contact individual metal nanowires and efficiently excite surface plasmon polaritons5 in this information support. In this article, we describe a protocol to bring electrical terminals to chemically-synthesized silver nanowires6 randomly distributed on a glass substrate7. The positions of the nanowire ends with respect to predefined landmarks are precisely located using standard optical transmission microscopy before encapsulation in an electron-sensitive resist. Trenches representing the electrode layout are subsequently designed by electron-beam lithography. Metal electrodes are then fabricated by thermally evaporating a Cr/Au layer followed by a chemical lift-off. The contacted silver nanowires are finally transferred to a leakage radiation microscope for surface plasmon excitation and characterization8,9. Surface plasmons are launched in the nanowires by focusing a near infrared laser beam on a diffraction-limited spot overlapping one nanowire extremity5,9. For sufficiently large nanowires, the surface plasmon mode leaks into the glass substrate9,10. This leakage radiation is readily detected, imaged, and analyzed in the different conjugate planes in leakage radiation microscopy9,11. The electrical terminals do not affect the plasmon propagation. However, a current-induced morphological deterioration of the nanowire drastically degrades the flow of surface plasmons. The combination of surface plasmon leakage radiation microscopy with a simultaneous analysis of the nanowire electrical transport characteristics reveals the intrinsic limitations of such plasmonic circuitry.

Silver nanowires can simultaneously transport electrons and optical information in the form of surface plasmons. A procedure is described here to realize such a shared circuitry and the limitations at propagating both information carriers are evaluated.

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information ...

Characterization of Thermal Transport in One-dimensional Solid Materials

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (&#961;cp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses.

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials.

Tek boyutlu Katı Malzemelerin Termal Ulaştırma Karakterizasyonu

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including ...

How to Build a Vacuum Spring-transport Package for Spinning Rotor Gauges

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to 1.0 Pa. In this application, the SRGs are frequently transported to laboratories for calibration. Events can occur during transportation that change the rotor surface conditions, thus changing the calibration factor. To assure calibration stability, a spring-transport mechanism is often used to immobilize the rotor and keep it under vacuum during transport. It is also important to transport the spring-transport mechanism using packaging designed to minimize the risk of damage during shipping. In this manuscript, a detailed description is given on how to build a robust spring-transport mechanism and shipping container. Together these form a spring-transport package. The spring-transport package design was tested using drop-tests and the performance was found to be excellent. The present spring-transport mechanism design keeps the rotor immobilized when experiencing shocks of several hundred g (g = 9.8 m/sec2 and is the acceleration due to gravity), while the shipping container assures that the mechanism will not experience shocks greater than about 100 g during common shipping mishaps (as defined by industry standards).

Here we describe how to build a robust spring-transport mechanism for a spinning rotor gauge. This device securely immobilizes the rotor and keeps it under vacuum during transportation. We also describe packaging that minimizes the risk of damage during transport. Tests show our design works for typical shocks during transport.

Nasıl Rotor Gauges Spinning için Vakum İlkbahar-taşıma Paketi kurmak için

The spinning rotor gauge (SRG) is a high-vacuum gauge often used as a secondary or transfer standard for vacuum pressures in the range of 1.0 x 10-4 Pa to ...

Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 &#181;m thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm2 and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 &#176;C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 &#730;C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells.

This paper investigates the suitability of inkjet printing for the manufacturing of dye-sensitized solar cells. A binder-free TiO2 nanoparticle ink was formulated and printed onto a FTO glass substrate. The printed layer was fabricated into a cell with an active area of 0.25 cm2 and an efficiency of 3.5%.

Boya duyarlı güneş pilleri için Titanyum Dioksit Dijital Baskı

Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less ...

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

Ultrasonik yorgunluk gerginlik-sıkıştırma modunda test

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...

Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions

The microstructure of soft matter directly impacts macroscopic rheological properties and can be changed by factors including colloidal rearrangement during previous phase changes and applied shear. To determine the extent of these changes, we have developed a microfluidic device that enables repeated phase transitions induced by exchange of the surrounding fluid and microrheological characterization while limiting shear on the sample. This technique is &#181;2rheology, the combination of microfluidics and microrheology. The microfluidic device is a two-layer design with symmetric inlet streams entering a sample chamber that traps the gel sample in place during fluid exchange. Suction can be applied far away from the sample chamber to pull fluids into the sample chamber. Material rheological properties are characterized using multiple particle tracking microrheology (MPT). In MPT, fluorescent probe particles are embedded into the material and the Brownian motion of the probes is recorded using video microscopy. The movement of the particles is tracked and the mean-squared displacement (MSD) is calculated. The MSD is related to macroscopic rheological properties, using the Generalized Stokes-Einstein Relation. The phase of the material is identified by comparison to the critical relaxation exponent, determined using time-cure superposition. Measurements of a fibrous colloidal gel illustrate the utility of the technique. This gel has a delicate structure that can be irreversibly changed when shear is applied. &#181;2rheology data shows that the material repeatedly equilibrates to the same rheological properties after each phase transition, indicating that phase transitions do not play a role in microstructural changes. To determine the role of shear, samples can be sheared prior to injection into our microfluidic device. &#181;2rheology is a widely applicable technique for the characterization of soft matter enabling the determination of rheological properties of delicate microstructures in a single sample during phase transitions in response to repeated changes in the surrounding environmental conditions.

We demonstrate the fabrication and use of a microfluidic device that enables multiple particle tracking microrheology measurements to study the rheological effects of repeated phase transitions on soft matter.

Havacilik ve Microrheology tekrarlanan faz geçişleri sırasında yumuşak madde Rheological özellikleri belirlemek için birleştirme

The microstructure of soft matter directly impacts macroscopic rheological properties and can be changed by factors including colloidal rearrangement ...

Fabrication of Refractive-index-matched Devices for Biomedical Microfluidics

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices can be implemented as part of a robust platform capable of making simultaneous complementary measurements. The primary challenge created by the combination of these two techniques is the mismatch in refractive index between the materials traditionally used to make microfluidic devices and the aqueous solutions typically used in biomedicine. This mismatch can create optical artifacts near the channel or device edges. One solution is to reduce the refractive index of the material used to fabricate the device by using a fluorinated polymer such as MY133-V2000 whose refractive index is similar to that of water (n = 1.33). Here, the construction of a microfluidic device made out of MY133-V2000 using soft lithography techniques is demonstrated, using O2 plasma in conjunction with an acrylic holder to increase the adhesion between the MY133-V2000 fabricated device and the polydimethylsiloxane (PDMS) substrate. The device is then tested by incubating it filled with cell culture media for 24 h to demonstrate the ability of the device to maintain cell culture conditions during the course of a typical imaging experiment. Finally, quantitative phase microscopy (QPM) is used to measure the distribution of mass within the live adherent cells in the microchannel. This way, the increased precision, enabled by fabricating the device from a low index of refraction polymer such as MY133-V2000 in lieu of traditional soft lithography materials such as PDMS, is demonstrated. Overall, this approach for fabricating microfluidic devices can be readily integrated into existing soft lithography workflows in order to reduce optical artifacts and increase measurement precision.

This protocol describes the fabrication of microfluidic devices from MY133-V2000 to eliminate artifacts that often arise in microchannels due to the mismatching refractive indices between microchannel structures and an aqueous solution. This protocol uses an acrylic holder to compress the encapsulated device, improving adhesion both chemically and mechanically.

Biyomedikal Havacilik için refraktif Dizin eşleşen cihazların imalat

The use of microfluidic devices has emerged as a defining tool for biomedical applications. When combined with modern microscopy techniques, these devices ...

Crack Monitoring in Resonance Fatigue Testing of Welded Specimens Using Digital Image Correlation

A procedure using digital image correlation (DIC) to detect cracks on welded specimens during fatigue tests on resonance testing machines is presented. It is intended as a practical and reproducible procedure to identify macroscopic cracks at an early stage and monitor crack propagation during fatigue tests. It consists of strain field measurements at the weld using DIC. Images are taken at fixed load cycle intervals. Cracks become visible in the computed strain field as elevated strains. This way, the whole width of a small-scale specimen can be monitored to detect where and when a crack initiates. Subsequently, it is possible to monitor the development of the crack length. Because the resulting images are saved, the results are verifiable and comparable. The procedure is limited to cracks initiating at the surface and is intended for fatigue tests under laboratory conditions. By visualizing the crack, the presented procedure allows direct observation of macrocracks from their formation until rupture of the specimen.

Digital image correlation is used in fatigue tests on a resonance testing machine to detect macroscopic cracks and monitor crack propagation in welded specimens. Cracks on the specimen surface become visible as increased strains.

Dijital Görüntü Korelasyonkullanılarak Kaynaklı Örneklerin Rezonans Yorulma Testinde Çatlak İzleme

A procedure using digital image correlation (DIC) to detect cracks on welded specimens during fatigue tests on resonance testing machines is presented. It ...

Automated Delivery of Microfabricated Targets for Intense Laser Irradiation Experiments

Described is an experimental procedure that enables high-power laser irradiation of microfabricated targets. Targets are brought to the laser focus by a closed feedback loop that operates between the target manipulator and a ranging sensor. The target fabrication process is explained in detail. Representative results of MeV-level proton beams generated by irradiation of 600 nm thick gold foils at a rate of 0.2 Hz are given. The method is compared with other replenishable target systems and the prospects of increasing the shot rates to above 10 Hz are discussed.

A protocol is presented for automated irradiation of thin gold foils with high intensity laser pulses. The protocol includes a step-by-step description of the micromachining target fabrication process and a detailed guide for how targets are brought to the laser&#39;s focus at a rate of 0.2 Hz.

Yoğun Lazer Işınlama Deneyleri için Mikrofabrikasi Hedeflerin Otomatik Teslimi

Described is an experimental procedure that enables high-power laser irradiation of microfabricated targets. Targets are brought to the laser focus by a ...