وقد تم دعم هذا العمل من قبل كلية أوغدن للعلوم والهندسة، بما في ذلك الدعم الداخلي من قسم الكيمياء ومن مكتب البحوث (اللجنة الملكية 13-8032) في جامعة كنتاكي الغربية. وكانت المساعدة من الدكتور جون Andersland في مرفق WKU المجهري (صور SEM) وأستاذ مشارك يان تساو معهد WKU للاحتراق علوم والهندسة (تحليل BET) المركزي لإجراء هذا العمل.

1. إعداد مستحلب <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> مستحلب المحتويات <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> كتلة كمية مناسبة من الملح لإنتاج 10 مل من 0.03-M حل. لالبلاتين (IV) قياس كلوريد 0.101 غرام، لالزنك (II) كلوريد (ZnCl 2) قياس 0.032 غرام، وكلوريد الصوديوم (كلوريد الصوديوم) قياس 0،018 غرام. </li><li style=";text-align:right;direction:rtl"> في أنابيب الاختبار الفردية، ويحل كل الملح في 10 مل من الماء DI. توضع جانبا لاستخدامها لاحقا. </li><li style=";text-align:right;direction:rtl"> استخدام 20 مل، قابل للغلق قارورة زجاجية عن محتويات طوال هذا الإجراء. الفارغة على التوازن في قارورة زجاجية. </li><li style=";text-align:right;direction:rtl"> تزن منتهية الفينيل polydimethylsiloxane بصب ببطء على قضيب ضجة وداخل قارورة زجاجية يستريح على نطاق وركزت. وزن من 1.02 غرام (أي ما يعادل 1.080 مل). ملاحظة: اللزوجة العالية لهذا البوليمر يجعل pipetting لعملي. </li><li style=";text-align:right;direction:rtl"> ماصة 1.02 مل من ن الهيبتان إلى القارورة. إضافة 2 قطرات من السطحي غير الأيونية (صوربيتان monoleate) إلى القارورة. ماصة 0.3 مل من محلول الملح و 0.45 مل من DI-الماء إلى قارورة. </li><li style=";text-align:right;direction:rtl"> ختم قارورة زجاجية قبل الشد الغطاء بإحكام. هزة بقوة لمدة 60 ثانية لبدء مستحلب قبل البدء صوتنة. </li></ol></li><li style=";text-align:right;direction:rtl"> بناء المياه حمام جهاز Sonicator <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ملء sonicator مع الماء تصل إلى الحد الأدنى من خط التعبئة. إضافة 250 مل من ماء الصنبور إلى كوب 400 مل. ملء كوب 400 مل مع الثلج بحيث أن مستوى الماء فقط عند الحافة. </li><li style=";text-align:right;direction:rtl"> ضع هذه الكأس داخل المياه sonicator حمام. تحقق من خط التعبئة، على sonicator، وتعديل إذا لزم الأمر. وضع عصابة تقف مباشرة بجوار sonicator المياه حمام. </li><li style=";text-align:right;direction:rtl"> باستخدام اثنين من عصابة تقف والمشابك، والموقف منها بحيث يتم تمديد ذراع خارج، عمودي على الحلبة الوقوف وتمديد واحدة أخرى نحو حمام مائي بحيث يشير إلى أسفل في كوب مملوء بالماء الجليد. نعلق المشبك أخرى إلى الحلبة الوقوف مع ميزان حرارة أسفل في كوب 400 مل بحيث يمكن رصد درجة الحرارة في جميع أنحاء صوتنة. </li></ol></li><li style=";text-align:right;direction:rtl"> Emulsifالإجراءات ication <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ضع القارورة التي تحتوي على مستحلب بحيث يتم مغمورة بالكامل في كوب 400 مل من خلال تأمين عليه في المشبك جاحظ أسفل إلى الدورق. </li><li style=";text-align:right;direction:rtl"> تأكد من أن قارورة زجاجية تحتوي على خليط PDMS لا لمس جانبي الكأس للقضاء على الحرارة الناتجة عن الاحتكاك. </li><li style=";text-align:right;direction:rtl"> بدوره على sonicator وضبط الوقت صوتنة لمدة 7 دقائق. لأن مستحلب هو الحرارة جدا حساسة، تأكد من أن درجة الحرارة داخل الدورق ما بين 0 و 5 درجات مئوية طوال صوتنة. بدء صوتنة بمجرد أن درجة الحرارة داخل الدورق أمر مرغوب فيه. </li><li style=";text-align:right;direction:rtl"> بعد 7 دقائق من صوتنة، إزالة القارورة وبلطف يهز / دوامة لمدة 1 دقيقة، وعقد قمة القارورة للقضاء على أي كتل التي يمكن أن تشكل في مستحلب. </li><li style=";text-align:right;direction:rtl"> تخلص من محتويات الدورق. إعادة ملء مع 250 مل من الماء وإضافة الجليد إلى التعبئة لفي حدود 1 سم أعلى الدورق. </li><li style=";text-align:right;direction:rtl"> ضع القارورة مرة أخرى في المشبك. يغرق تحت الماء المثلج لresumالبريد صوتنة لمدة 7 دقائق. </li><li style=";text-align:right;direction:rtl"> كرر الخطوات من 1.3.3 إلى 1.3.6 ليصبح المجموع فترات صوتنة ثمانية، 7 دقيقة، أو حتى صوتنة يبدو أن متجانسة وعدم وجود كتل موجودة. تخزين في RT. ملاحظة: يجب أن يكون استحلاب مستقرة لعدة أيام، ولكن يمكن استردادها من قبل صوتنة على النحو الوارد أعلاه في 7 دقيقة فترات حتى يبدو متجانسا. تخزين في RT. </li></ol></li></ol> 2. عبر ربط <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> الإعداد لإضافة Triethoxysilane / السطحي الحل <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ماصة 5.4 مل triethoxysilane في أنبوب الاختبار. ضع في أنبوب اختبار رف تحت غطاء محرك السيارة لاستخدامها لاحقا. </li><li style=";text-align:right;direction:rtl"> ملء كوب 400 مل مع الماء المثلج ووضعه تحت غطاء محرك السيارة. التالي إلى المكان كوب 400 مل حلقة تقف مع المشبك المرفقة، بمد مباشرة عبر افتتاح الكأس. وسيكون هذا هو حمام كريم لإضافة triethoxysilane. </li><li style=";text-align:right;direction:rtl"> وضع صفيحة ساخنة على الجانب الآخر من موقف حلقة. ملء كوب 800 مل مع ما يقرب من 700 مل منماء الصنبور. وضعه على طبق ساخن. </li><li style=";text-align:right;direction:rtl"> بدوره على طبق ساخن والحفاظ على درجة حرارة 75 إلى 85 درجة مئوية داخل كوب 800 مل. إرفاق المشبك مع ميزان حرارة لموقف حلقة حتى درجة حرارة المياه داخل الدورق 800 مل يمكن رصدها. </li><li style=";text-align:right;direction:rtl"> إنتاج حل للتوتر السطحي عن طريق إذابة 0.5 غرام من دوديسيل كبريتات الصوديوم إلى 375 مل من الماء (4.62 ملم). إضافة حوالي 10 مل من محلول السطحي لنظيف، فارغة أنبوب الاختبار. </li><li style=";text-align:right;direction:rtl"> نعلق المشبك أخرى إلى الحلبة الوقوف تحت غطاء محرك السيارة مع أنبوب الاختبار السطحي المضمون بحيث مستوياته السائل تحت سطح الماء داخل الدورق 800 مل. سماح 10 دقيقة للموازنة الحرارية. </li><li style=";text-align:right;direction:rtl"> الرطب قطعة من ورق الترشيح ووضعه في الجزء العلوي من قمع صغير. ضع الجذعية من القمع داخل دورق مخروطي 250 مل ووضع قارورة تحت غطاء محرك السيارة. </li></ol></li><li style=";text-align:right;direction:rtl"> إضافة Triethoxysilane <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> ضع قارورة مستحلب في المشبك على منقار مياه الجليدإيه داخل غطاء محرك السيارة. ضع الخليط PDMS في المشبك بحيث محتويات قنينة هي تحت سطح الماء. إضافة triethoxysilane تسبب رد فعل الطاردة للحرارة، لذلك يجب أن تبقى مستحلب الباردة من أجل الحفاظ على هيكلها. </li><li style=";text-align:right;direction:rtl"> إزالة الغطاء من قارورة زجاجية لتجنب الغازي بناء. </li><li style=";text-align:right;direction:rtl"> صب ببطء أنبوب اختبار يحتوي على triethoxysilane في قارورة زجاجية في تيار مستمر على مدى ما يقرب من 10 ثانية (حوالي 0.5 مل / ثانية). تنبيه: إضافة triethoxysilane ء تفاعل طارد للحرارة والإفراج عن كلوريد الهيدروجين الكاوية (حمض الهيدروكلوريك) الغاز. سوف القارورة تصبح ساخنة للغاية وسوف الغازات السامة تتطور من الخليط. لا يحرك محتويات أثناء إضافة triethoxysilane. </li><li style=";text-align:right;direction:rtl"> بعد إضافة triethoxysilane تماما، وإثارة بلطف محتويات مع ضجة قضيب الزجاج بينما يرتدي القفازات الواقية الحرارة. الانتظار لمدة 2 دقيقة أو حتى توقف الغاز المتطورة من القارورة. </li><li style=";text-align:right;direction:rtl"> الفلبسبب عبر ربط، لا توجد مرحلة فصل واضح في العينة. إذا كتل موجودة، وختم قارورة ويهز صارم لمدة 20 ثانية في حين عقد القارورة التي كتبها الغطاء. </li></ol></li><li style=";text-align:right;direction:rtl"> إنتاج حبة <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> استخدام نظيفة، الزجاج ماصة باستير لرسم مستحلب عبر ربط من قارورة زجاجية. إضافة قطرة من الحكمة في حل السطحي (الذي يجب أن يكون قائما بين 75 و 85 درجة مئوية) في أنبوب الاختبار يأخذ أقل وقت ممكن في ما بين قطرات مستحلب عبر ربط. </li><li style=";text-align:right;direction:rtl"> 30 ثانية إلى 1 دقيقة بعد إضافة مستحلب، فإن الحل السطحي تبدأ ببطء لتطوير الغاز حيث تبدأ المواد الصلبة لتشكيل داخل أنبوب الاختبار. </li><li style=";text-align:right;direction:rtl"> في حين يرتدي قفازات واقية للحرارة، واتخاذ أنبوب الاختبار من المشبك وتصب محتوياته بالكامل في جهاز الترشيح تحت غطاء محرك السيارة. مرشح لمدة 5 دقائق. إزالة ورقة الترشيح من مرشح. </li><li style=";text-align:right;direction:rtl"> نقل المواد الصلبة التي تمت تصفيتها على كوب ساعة وحبات منفصلة للO / N التجفيف تحت حالعود. يمكن تأجيل تنظيف حبات أجل غير مسمى. متجر الخرز في RT تجفف في قارورة زجاجية محكمة الغلق لحين الحاجة إليها، ونظيفة مباشرة قبل استخدامها. </li></ol></li><li style=";text-align:right;direction:rtl"> حبة التنظيف <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> إنشاء جهاز الترشيح آخر تحت غطاء محرك السيارة ووضع حبات المجففة داخل القمع على رأس ورقة الترشيح. </li><li style=";text-align:right;direction:rtl"> استخدام زجاجة غسل بلاستيكية مملوءة DI-الماء لشطف حبات بلطف، وتتحرك حول لهم قليلا لضمان تشطف كل الخرز. </li><li style=";text-align:right;direction:rtl"> السماح حبات جافة لمدة 1 ساعة عن طريق وضعها على الزجاج ووتش تحت غطاء محرك السيارة. استخدام زجاجة غسل مليئة hexanes لشطف الخرز باستخدام نفس الأسلوب لالشطف بالماء. </li><li style=";text-align:right;direction:rtl"> وضع الخرز على الزجاج ووتش. وضع الزجاج ووتش والخرز تحت غطاء محرك السيارة لتجف. </li><li style=";text-align:right;direction:rtl"> بعد حبات جافة تماما، ووضعها في قارورة زجاجية صغيرة قابل للغلق وتخزينها في RT لاستخدامها في المستقبل. </li></ol></li><li style=";text-align:right;direction:rtl"> تركيب الخرز للإعدادات تحليل SEM وSEM <ol style=";text-align:right;direction:rtl"><li style=";text-align:right;direction:rtl"> وضع شريط من تأليفالكربون شريط موصل uble من جانب وعلى رأس كعب على الذي يقام الخرز. باستخدام مقص، وتقليم حول كعب لضمان عدم توقف الشريط على الحواف. </li><li style=";text-align:right;direction:rtl"> ضع قطعة من ورق الترشيح تحت كعب على سطح مستو. إزالة الطبقة العليا من الشريط بحيث يتعرض الجانب السفلي لاصقة. </li><li style=";text-align:right;direction:rtl"> صب بلطف الخرز على كعب. وبعض حبات العصا إلى الشريط، ولكن معظم سوف ترتد والأرض على ورقة الترشيح. صب هذه العودة إلى القارورة حتى لو بقيت على ورقة الترشيح. كرر إذا لزم الأمر، وغسل أي الخرز (وفقا ل2.4.2 إلى 2.4.5) التي تصبح ملوثة. </li><li style=";text-align:right;direction:rtl"> لضمان حبات آمنة على كعب، استخدم حقنة لمبة وضربة طفيفة عن كثب على سطح كعب. صب مزيد من الخرز على كعب إلا إذا كان عدد قليل انضمت إلى الشريط. التأكد من أن جميع حبات آمنة قبل وضع كعب في غرفة SEM واخلاء عليه. </li><li style=";text-align:right;direction:rtl"> مرة واحدة وقد شنت العينات بشكل صحيح أنهم الآن على استعداد للخضوع SEM الشرجيسيس 15. جمع الصور في وضع LOW VAC في 15 كيلو لتحسين القرار من الميزات سطح حبة ل. </li></ol></li></ol>

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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concave+porosity+non-polar+beads+by+a+modified+microbubble+fabrication.">Concave porosity non-polar beads by a modified microbubble fabrication.</a> Mater. Lett. 98, 105-107 (2013).</li><li>Flegler, S. L., Heckman, J. W., Klomparens, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Scanning and Transmission Electron Microscopy: An Introduction. , 151-155 (1995).</li><li>Brunauer, S., Emmett, P. H., Teller, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+Gases+in+Multimolecular+Layers.">Adsorption of Gases in Multimolecular Layers.</a> J. Am. Chem. Soc. 60 (2), 309-319 (1938).</li><li>Sing, K. S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+porous+materials:+past,+present+and+future.">Characterization of porous materials: past, present and future.</a> Colloids Surf. A. 241 (1), 3-7 (2004).</li></ol>

The authors have nothing to disclose.

حبات المنتجة باستخدام هذا البروتوكول (وعن طريق ضبط تركيز بالكهرباء والهوية) تختلف جوهريا عن تلك المنتجة مع قوة مستحلب المنخفض الأيونية، كما رأينا من خلال المقارنة بين الشكل 1A إلى الصور SEM أخرى في الشكل 1. لدينا التقرير الأولي تستخدم شركة ال...

Polydimethylsiloxane (PDMS) is one of the most widely used silicone compounds. Its biocompatibility has led to widespread use in implant and other biomedical engineering structures1,2. It is trivially cross-linked into elastic structures using an organosilyl compound (such as triethoxysilane), a simple and reliable procedure which has made it useful for cast polymer applications where some flexibility is required3. Once cross-linked, PDMS is largely inert, particularly in biological conditions, and is therefore useful for a variety of food and medical applications4,5. Ease of casting, chemical inertness, and hydrophobicity have made it a natural choice for microfluidic devices6,7. Its affinity for non-halogenated, non-polar organic compounds has made it a popular stationary phase in separations chemistry8-10. 
Recently, microbubble fabrications have been used to generate porous beads for use as catalyst structural substrates or in chemical separations11,12. In both applications, ideal materials will have a maximized surface-area-to-volume (SAV) ratio for best efficiency. In a microbubble fabrication process, microstructuring of materials is typically accomplished by isolating the polymer in aliphatic &#8220;microbubbles&#8221; by emulsification in an aqueous continuous phase. The initial report of microporous PDMS beads produced them by mechanical emulsification of two phases (aliphatic and aqueous)13. The stock PDMS liquid (and its cross-linking agent) is dissolved into the aliphatic phase, which is structured into microscopic beads by being forced to cavitate within the (continuous) aqueous phase. The emulsification is stabilized by the addition of a non-ionic surfactant. When the emulsion is added dropwise to a heated bath, solid beads form by agglomeration of the microbubbles into clusters of tiny spheres of cross-linked PDMS. Our goal in this protocol is to modify this procedure to develop beads with an inverted porosity to improve the SAV ratio of the material.
As reported previously, control of the beads can be directed to some extent by the aliphatic:aqueous ratios in the emulsion. However, we have reported recently that addition of platinum(IV) chloride (PtCl4) inverts the porosity: materials are formed in which the PDMS is riddled with concave pores14. This indicates that the aqueous layer cavitates inside the aliphatic one, despite having similar aliphatic:aqueous ratios to those published in the original work13. The primary advantage of our method is that this concave porosity should naturally result in an increased SAV ratio, and thus, improved efficiency for analytical chemistry applications. While we are continuing to explore the specific effects of the addition of the platinum compound, we show here that the same effect can be accomplished using any aqueously soluble ionic compound, though perhaps to a reduced extent. Because our techniques also differ in some key aspects from what has been previously reported, we present our protocols here as a video to encourage others to extend our methods. Most notably, we use a common bath sonicator of the type used to clean glassware or other equipment, rather than the (considerably more expensive) probe sonicator often used in microbubble fabrication. This adjusted approach to the microbubble fabrication procedure could potentially be extended for the production of large quantities of bulk materials as well, creating porous sheets or slabs which could have applications for biomedical devices, aerospace and automotive industry, or substrates for chemical catalysis. Users seeking to generate high-SAV-ratio, microstructured materials using other similar polymers for such analyses may find that our protocols can be extended to any polymer for which the microbubble emulsion technique can be applied.

<table border="0">
	<tbody>
		<tr>
			<td>Poly(dimethylsiloxane), vinyl terminated</td>
			<td>Sigma-Aldrich</td>
			<td>68083-19-2</td>
			<td></td>
		</tr>
		<tr>
			<td>n-Heptane</td>
			<td>Sigma-Aldrich</td>
			<td>142-82-5</td>
			<td>Flammable</td>
		</tr>
		<tr>
			<td>Triethoxysilane</td>
			<td>Sigma-Aldrich</td>
			<td>998-30-1</td>
			<td>Flammable, Accutely Toxic</td>
		</tr>
		<tr>
			<td>Sorbitan Monoleate (Span-80)</td>
			<td>Fluker</td>
			<td>1338-43-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Platinum (IV) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>13454-96-1</td>
			<td>Accutely Toxic</td>
		</tr>
		<tr>
			<td>Zinc (II) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7646-85-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr>
			<td>2.8L Water Bath Sonicator</td>
			<td>VWR</td>
			<td>97043-964</td>
			<td></td>
		</tr>
	</tbody>
</table>

microbubble fabrication of concave-porosity pdms beads

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is particularly useful for separations applications. Porous polydimethylsiloxane (PDMS) beads can be produced by heat-curing such an emulsion, allowing the interface between the aqueous and aliphatic phases to mold the morphology of the polymer. In the procedures described here, both polymer and crosslinker (triethoxysilane) are sonicated together in a cold-bath sonicator. Following a period of cross-linking, emulsions are added dropwise to a hot surfactant solution, allowing the aqueous phase of the emulsion to separate, and forming porous polymer beads. We demonstrate that this method can be tuned, and the SAV ratio optimized, by adjusting the electrolyte content of the aqueous phase in the emulsion. Beads produced in this way are imaged with scanning electron microscopy, and representative SAV ratios are determined using Brunauer&#8211;Emmett&#8211;Teller (BET) analysis. Considerable variability with the electrolyte identity is observed, but the general trend is consistent: there is a maximum in SAV obtained at a specific concentration, after which porosity decreases markedly.

وتظهر الصور SEM تمثيلية من الخرز الناشئة من المستحلبات مع الظروف بالكهرباء مختلفة في الشكل 1. ويبين الشكل 1A حبة مشابهة لتلك التي حصلت عليها DuFaud، وآخرون. 13، المنتجة باستخدام إجراءاتنا، دون إضافة أي بالكهرباء. الخرز هو مبي?...

Watch this Scientific Journal Video about Microbubble Fabrication of Concave-porosity PDMS Beads at JoVE.com

Microbubble Fabrication of Concave-porosity PDMS Beads

Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized.

تصنيع Microbubble من الخرز PDMS مقعرة المسامية

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is ...

microbubble-fabrication-of-concave-porosity-pdms-beads

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JoVE Journal

Chemistry

8.2K Views.  Western Kentucky University. Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized. 

Video: Microbubble Fabrication of Concave-porosity PDMS Beads

Fabrication of Large-area Free-standing Ultrathin Polymer Films

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films. Typically, ultrathin films are prepared using either sacrificial layers, which may damage the film or affect its mechanical properties, or they are made on freshly cleaved mica, a substrate that is difficult to scale. Further, the size of ultrathin film is typically limited to a few square millimeters. In this method, we modify a surface with a polyelectrolyte that alters the strength of adhesion between polymer and deposition substrate. The polyelectrolyte can be shown to remain on the wafer using spectroscopy, and a treated wafer can be used to produce multiple films, indicating that at best minimal amounts of the polyelectrolyte are added to the film. The process has thus far been shown to be limited in scalability only by the size of the coating equipment, and is expected to be readily scalable to industrial processes. In this study, the protocol for making the solutions, preparing the deposition surface, and producing the films is described.

We describe a method for the fabrication of large-area (up to 13 cm diameter) and ultrathin (as thin as 8 nm) polymer films. Instead of using a sacrificial interlayer to delaminate the film from its substrate, we use a self-limiting surface treatment suitable for arbitrarily large areas.

تلفيق منطقة كبيرة قائمة بذاتها سامسونج بوليمر أفلام

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films.  Typically, ultrathin films are prepared ...

Flow-pattern Guided Fabrication of High-density Barcode Antibody Microarray

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this report, we renovate the antibody microarray technology by using a novel approach for manufacturing and by introducing new features. The fabrication of our high-density antibody microarray is accomplished through perpendicularly oriented flow-patterning of single stranded DNAs and subsequent conversion mediated by DNA-antibody conjugates. This protocol outlines the critical steps in flow-patterning DNA, producing and purifying DNA-antibody conjugates, and assessing the quality of the fabricated microarray. The uniformity and sensitivity are comparable with conventional microarrays, while our microarray fabrication does not require the assistance of an array printer and can be performed in most research laboratories. The other major advantage is that the size of our microarray units is 10 times smaller than that of printed arrays, offering the unique capability of analyzing functional proteins from single cells when interfacing with generic microchip designs. This barcode technology can be widely employed in biomarker detection, cell signaling studies, tissue engineering, and a variety of clinical applications.

This protocol outlines the fabrication of a large-scale, multiplexed two-dimensional DNA or antibody array, with potential applications in cell signaling studies and biomarker detection.

تدفق نمط تلفيق إرشادية للعالي الكثافة الباركود الأجسام المضادة ميكروأري

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this ...

Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst immobilization for improved production yield and sustained synthesis. Described herewith is the experimental procedure for the development of such a system consisting of two E. coli strains that express functionally complementary enzymes. Together, these two enzymes can function co-operatively to mediate the regeneration of expensive cofactors for improving the product yield of the bioreaction. In addition, the method of synthesizing an immobilized form of the coupled biocatalytic system by encapsulation of whole cells in calcium alginate beads is reported. As an example, we present the improved biosynthesis of L-xylulose from L-arabinitol by coupling E. coli cells expressing the enzymes L-arabinitol dehydrogenase or NADH oxidase. Under optimal conditions and using an initial concentration of 150 mM L-arabinitol, the maximal L-xylulose yield reached 96%, which is higher than those reported in the literature. The immobilized form of the coupled whole-cell biocatalysts demonstrated good operational stability, maintaining 65% of the yield obtained in the first cycle after 7 cycles of successive re-use, while the free cell system almost completely lost the catalytic activity. Therefore, the methods reported here provides two strategies that could help improve the industrial production of L-xylulose, as well as other value-added compounds requiring the use of cofactors in general.

Presented is the protocol for co-immobilizing whole-cell biocatalysts for cofactor regeneration and improved reusability, using the production of L-xylulose as an example. The cofactor regeneration is achieved by coupling two Escherichia coli strains expressing functionally complementary enzymes; the whole-cell biocatalyst immobilization is achieved by cell encapsulation in calcium alginate beads.

تجميد البيولوجية الحفازة متعدد في الخرز الجيني للالعامل المساعد تجديد وتحسين إعادة استخدام

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

تأثير الهجين طرق Perovskite التصنيع على تشكيل السينمائي، التركيب الإلكتروني، وأداء الخلايا الشمسية

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...

Fabrication and Testing of Photonic Thermometers

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

We describe the process of fabrication and testing of photonic thermometers.

تصنيع واختبار الحرارة الضوئية

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

تصنيع واختبار أيروجيلس الحفاز أعدت عن طريق استخراج فوق الحرجة السريع

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Preparation of Poly(pentafluorophenyl acrylate) Functionalized SiO2 Beads for Protein Purification

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltrimethoxysilane (APTMS) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTMS. The deposition of APTMS and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.

Preparation of Polypentafluorophenyl acrylate Functionalized SiO2 Beads for Protein Purification

A protocol for the preparation of poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads is presented. The poly(PFPA) functionalized surface is then immobilized with antibodies and used successfully for the protein separation through immunoprecipitation.

إعداد Poly(pentafluorophenyl acrylate) فونكتيوناليزيد SiO2 حبات "تنقية البروتين"

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent ...

Fabrication of Thin Film Silver/Silver Chloride Electrodes with Finely Controlled Single Layer Silver Chloride

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin film silver electrodes. Thin film silver electrodes sized 80 &#181;m x 80 &#181;m and 160 &#181;m x 160 &#181;m were sputtered on quartz wafers with a chromium/gold (Cr/Au) layer for adhesion. After passivation, polishing and cathodic cleaning processes, the electrodes underwent galvanostatic oxidation with consideration of Faraday&#39;s Law of Electrolysis to form smooth layers of AgCl with a designated degree of coverage on top of the silver electrode. This protocol is validated by inspection of scanning electron microscope (SEM) images of the surface of the fabricated Ag/AgCl thin film electrodes, which highlights the functionality and performance of the protocol. Sub-optimally fabricated electrodes are fabricated as well for comparison. This protocol can be widely used to fabricate Ag/AgCl electrodes with specific impedance requirements (e.g., probing electrodes for impedance sensing applications like impedance flow cytometry and interdigitated electrode arrays).

This paper aims to present a method to form smooth and well-controlled films of silver chloride (AgCl) with designated coverage on top of thin film silver electrodes.

تصنيع رقيقة فيلم الفضة / الفضة كلوريد أقطاب مع التحكم بدقة طبقة واحدة كلوريد الفضة

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin ...

حبات معدلة بالبورفيرين في قياس التدفق الخلوي

Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or more fluorescent reagents, each functionalized with a different fluorescent molecule (fluorophore) that binds to cells selectively based on their phenotypic characteristics, such as cell surface antigen expression. The intensity of fluorescence from each reagent bound to cells can be measured on the flow cytometer using channels that detect a specified range of wavelengths. When multiple fluorophores are used, the light from individual fluorophores often spills over into undesired detection channels, which requires a correction to the fluorescence intensity data in a process called compensation. 
Compensation control particles, typically polymer beads bound to a single fluorophore, are needed for each fluorophore used in a cell labeling experiment. Data from compensation particles from the flow cytometer are used to apply a correction to the fluorescence intensity measurements. This protocol describes the preparation and purification of polystyrene compensation beads covalently functionalized with the fluorescent reagent meso-tetra(4-carboxyphenyl) porphine (TCPP) and their application in flow cytometry compensation. In this work, amine-functionalized polystyrene beads were treated with TCPP and the amide coupling reagent EDC (N-(3-dimethylaminopropyl)-N&#8242;-ethylcarbodiimide hydrochloride) at pH 6 and at room temperature for 16 h with agitation. The TCPP beads were isolated by centrifugation and resuspended in a pH 7 buffer for storage. TCPP-related particulates were observed as a byproduct. The number of these particulates could be reduced using an optional filtration protocol. The resultant TCPP beads were successfully used on a flow cytometer for compensation in experiments with human sputum cells labeled with multiple fluorophores. The TCPP beads proved stable following storage in a refrigerator for 300 days.

تسليط الضوء على المؤلف: حبات معدلة بالبورفيرين لاستخدامها كضوابط تعويض في قياس التدفق الخلوي  

The protocol describes how porphyrin-based compensation beads for flow cytometry are prepared by the reaction of amine-functionalized polystyrene beads with the porphyrin TCPP and the amide coupling reagent EDC. A filtration procedure is used to reduce the particulate byproducts.

حبات معدلة بالبورفيرين لاستخدامها كضوابط تعويض في قياس التدفق الخلوي

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or ...