עבודה זו נתמכה על ידי נבחרת מדעי הטבע קרן של סין (' קט ' 51420105006 ו- 51322501). אנו מודים דניאל לדיון מועיל שלו על הרעיונות צמיגות גבוהה.

<ol>
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C., Kumacheva, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+production+of+biopolymer+microcapsules+with+controlled+morphology.">Microfluidic production of biopolymer microcapsules with controlled morphology.</a> J. Am. Chem. Soc. 127, 8058-8063 (2005).</li><li>Abate, A. R., Kutsovsky, M., Seiffert, S., Windbergs, M., Pinto, L. F., Rotem, A., Utada, A. S., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+monodisperse+microparticles+from+non-Newtonian+polymer+solutions+with+microfluidic+devices.">Synthesis of monodisperse microparticles from non-Newtonian polymer solutions with microfluidic devices.</a> Adv. Mater. 23, 1757-1760 (2011).</li><li>Seo, M., Nie, Z., Xu, S., Mok, M., Lewis, P. C., Graham, R., Kumacheva, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+microfluidic+reactors+for+polymer+particles.">Continuous microfluidic reactors for polymer particles.</a> Langmuir. 21, 11614-11622 (2005).</li><li>Duncanson, W. J., Lin, T., Abate, A. R., Seiffert, S., Shah, R. K., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+advanced+microparticles+for+encapsulation+and+controlled+release.">Microfluidic synthesis of advanced microparticles for encapsulation and controlled release.</a> Lab Chip. 12, 2135-2145 (2012).</li><li>Song, H., Chen, D. L., Ismagilov, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactions+in+droplets+in+microfluidic+channels.">Reactions in droplets in microfluidic channels.</a> Angew. Chem. Int. Ed. 45, 7336-7356 (2006).</li><li>Chen, H., Zhao, Y., Li, J., Guo, M., Wan, J., Weitz, D. A., Stone, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactions+in+double+emulsions+by+flow-controlled+coalescence+of+encapsulated+drops.">Reactions in double emulsions by flow-controlled coalescence of encapsulated drops.</a> Lab Chip. 11, 2312-2315 (2011).</li><li>Wang, P., Li, J., Nunes, J., Hao, S., Liu, B., Chen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Droplet+micro-reactor+for+internal+gelation+to+fabricate+ZrO2+ceramic+microspheres.">Droplet micro-reactor for internal gelation to fabricate ZrO2 ceramic microspheres.</a> J. Am. Ceram. Soc. 100, 41-48 (2017).</li><li>Chen, H., Man, J., Li, Z., Li, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+generation+of+high-viscosity+droplets+by+surface-controlled+breakup+of+segment+flow.">Microfluidic generation of high-viscosity droplets by surface-controlled breakup of segment flow.</a> ACS Appl. Mater. Interfaces. 9, 21059-21064 (2017).</li><li>Man, J., Li, Z., Li, J., Chen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+inversion+of+slug+flow+on+step+surface+to+form+high+viscosity+droplets+in+microchannel.">Phase inversion of slug flow on step surface to form high viscosity droplets in microchannel.</a> Appl. Phys. Lett. 110, 181601 (2017).</li></ol>

המחברים אין לחשוף.

שלב-היפוך זרימה ושיתוף המכשיר מספק שיטה פשוטה וישר קדימה לייצר טיפות צמיגות גבוהה monodisperse. המכשיר הזה יש מבנה דומה להתקני זרימה ושיתוף נפוצים, כמו מבנה בסיסי תזרים משותף מורכב של אבוב מוכנס בצינור האמצעי, היציאה אשר מחובר לשקע אבובים. עם זאת, ישנם שני הבדלים עיקריים בין שלב-היפוך זרימה ושית?...

הדור של טיפות הופכת טכנולוגיית במגוון רחב של יישומים, כגון תרופות, חומרים סינתזה, bioprinting תלת-ממד, מבחני תא מזון הנדסה1,2,3,4 , 5 , 6. Microfluidic מכשירים עם צומת t7,8, שיתוף זרימה1,9, או התמקדות זרימה10,11 מבנים נמצאים בשימוש נרחב ליצירת monodisperse טיפות אמולסיה יחיד. מבחר של תקופה רציפה צמיגיים יותר יקל על היווצרות של טיפות12, צמיגויות של שני נוזלים רציפה והתפזרו נמצאות בדרך כלל מתחת 0.1 Pas droplet מיקרופלואידיקה13. עם זאת, ביישומים רבים, השלב התפזרו ייתכן צמיגות כמה מאות פעמים גבוה מזה של מים, כגון גליצרול14, פתרונות המכיל חלקיקים15, חלבונים16או פולימרים17 , 18 , 19, בעוד שקשה להשיג monodisperse טיפות ישירות מתוך צמיגות גבוהה נוזלים באורווה מטפטף המשטר11 בהתקנים microfluidic, במיוחד עבור נוזלים עם צמיגות η > 1 Pa·s14 ,17,18,19. יתר על כן, זה היה דיווח13,18 כי שיטות microfluidic טיפוסי droplet היווצרות דורשים נוזלים עם צמיגות נמוכה יחסית, מתח פנים מתונה כדי בצורה אחידה טיפות טפטוף יציב המשטר.
עבור שלב התפזרו עם צמיגות קצת יותר 0.1 Pas גדולה, ישנם מספר גישות אפשריות כדי להקל על היווצרות droplet עם צומת t אופייני, זרימה משותפת או התמקדות זרימה התקנים microfluidic: (1) ירידה צמיגות התפזרו שלב על ידי דילול זה ממס נדיף11,20; (2) להקטין את היחס צמיגות התפזרו אל-רציף לחלוטין על ידי הגדלת צמיגות של1,שלב רציף11; (3) להקטין את קצב הזרימה של שלב התפזרו לערך נמוך ביותר, תוך שמירה על 14,19יחס קצב זרימה רציפה התפזרו גבוהה. עם זאת, גישות אלה אינן מעשיות עבור נוזלים עם צמיגות גבוהה בהרבה, כפי שהם תפחית באופן משמעותי את קצב הייצור תוך העלאת באופן דרמטי את הצריכה של הממס תנודתי או השלב רציפה. ב- addtion, דווח כי מספר פתרונות פולימרים צמיגות גבוהה עם η > 1 Pa·s עדיין לא שברה תוך טיפות עם הגישות הנ ל17,19.
ישנם גם מספר עיצובים משופרת של מכשירים microfluidic אשר מציגים את שלב שלישי של נוזל לתוך המערכת, אשר מקלה על הדור של טיפות צמיגות גבוהה. החידושים כוללים: בועות הציג בפני לחתוך חוט jetting טיפות21, נוזל לליווי immiscible עם צמיגות בינונית, הציג את שלב הביניים בין השלב dipsersed מתמשך שלב18, ו microreactors הציג לייצר טיפות צמיגות גבוהה שני מבשרי צמיגות נמוכה21,22,23. עם זאת, כמו אחד יותר נוזלים מעורב בתהליך, המערכת הופך מורכב יותר, המכשירים עובדים בדרך כלל הרבה צר יותר זרימה המשטר מאשר המכשירים אופייני לדור של טיפות אמולסיה יחיד.
כדי ליצור monodisperse טיפות ישירות מנוזל צמיגות גבוהה עם η > 1 Pa·s, השטח שבשליטת שלב-היפוך שיטות כבר חקרו24. כמו הדור של טיפות צמיגות נמוכה יותר מזו של טיפות צמיגות גבוהה12, טיפות מוארך צמיגות נמוכה בשלב רציף צמיגות גבוהה קודם מופקות בעזרת מבנה טיפוסי זרימה משותפת, ואז נפרדנו עקב לשינוי של משטח wettability במורד הזרם של המבנה זרימה ושיתוף. הנוזל צמיגות נמוכה שפורסמו הפוך מכמס את הנוזל צמיגות גבוהה במורד הזרם לתוך טיפות, כך היפוך פאזה הושלמה. על פי מנגנון היפוך פאזה, monodisperse צמיגות גבוהה טיפות ניתן להפיק המבוסס על התקן הזרימה משותף טיפוסי, בזמן היציאה של המכשיר זרימה ושיתוף מטופלים כדי להיות שנרטבו מאת הנוזל צמיגות נמוכה, והוא מחובר אז אל צינור רחב יותר24 ,25.

<table>
	<tbody>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>8240</td>
			<td>Square - Miniature Hollow Glass Tubing, I.D.=0.4mm, OD=0.8mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>CV2033</td>
			<td>Round - Miniature Hollow Glass Tubing, I.D.=0.2mm, O.D.=0.33mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>CV1017</td>
			<td>Round - Miniature Hollow Glass Tubing, I.D.=0.1mm, O.D.=0.17mm</td>
		</tr>
		<tr>
			<td>VitroTubes Glass Tubing</td>
			<td>VitroCom</td>
			<td>Q14606</td>
			<td>Square - Miniature Hollow Glass Tubing, I.D.=1.05mm+0.1/-0, OD=1.5mm</td>
		</tr>
		<tr>
			<td>Standard Glass Capillaries</td>
			<td>WPI</td>
			<td>1B100-6</td>
			<td>Round - Glass Tubing, I.D.=0.58mm, O.D.=1.00mm</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>10010618</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin Liquid</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>30139828</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly(vinyl alcohol), PVA-124</td>
			<td>Sinopharm Chemical Reagent Beijing</td>
			<td>30153084</td>
			<td></td>
		</tr>
		<tr>
			<td>Span 80</td>
			<td>Sigma-Aldrich</td>
			<td>85548</td>
			<td></td>
		</tr>
		<tr>
			<td>Starch</td>
			<td>Sigma-Aldrich</td>
			<td>S9765</td>
			<td></td>
		</tr>
		<tr>
			<td>Trichloro(octadecyl)silane</td>
			<td>Sigma-Aldrich</td>
			<td>104817</td>
			<td></td>
		</tr>
		<tr>
			<td>Toluidine Blue O</td>
			<td>Sigma-Aldrich</td>
			<td>T3260</td>
			<td></td>
		</tr>
		<tr>
			<td>Honey</td>
			<td></td>
			<td></td>
			<td>Chaste tree honey, common food product purchased from supermarket</td>
		</tr>
		<tr>
			<td>DEVCON 5 Minute Epoxy</td>
			<td>ITW&#160;</td>
			<td></td>
			<td>Epoxy glue</td>
		</tr>
		<tr>
			<td>Blunt Tip Stainless Steel Dispensing Needles (Luer Lock)</td>
			<td>Suzhou Lanbo Needle, China</td>
			<td>LTA820050</td>
			<td>20G x 1/2&#34;&#160;</td>
		</tr>
		<tr>
			<td>Tungsten/Carbide Scriber</td>
			<td>Ullman</td>
			<td>1830</td>
			<td>For cutting glass tubing</td>
		</tr>
		<tr>
			<td>Microscope Slides</td>
			<td>Sail Brand</td>
			<td>7101</td>
			<td>76.2 mm x 25.4 mm, Thickness 1 - 1.2 mm</td>
		</tr>
		<tr>
			<td>Polyethylene Tubing</td>
			<td>Scientific Commodities</td>
			<td>BB31695-PE/5</td>
			<td>I.D. = 0.86 mm, O.D. = 1.32 mm</td>
		</tr>
		<tr>
			<td>Syringe Pumps</td>
			<td>Longer Pump, China</td>
			<td>LSP01-1A</td>
			<td>3 pumps needed for the experiments</td>
		</tr>
	</tbody>
</table>

fabricating high-viscosity droplets using microfluidic capillary device with phase-inversion co-flow structure

הדור של טיפות monodisperse עם צמיגות גבוהה מאז ומתמיד אתגר ב מיקרופלואידיקה droplet. . הנה, נדגים שלב-היפוך זרימה ושיתוף התקן לייצר מדים צמיגות גבוהה טיפות נוזל צמיגות נמוכה. המכשיר נימי microfluidic יש מבנה הזרימה שיתוף משותף עם יציאתו מתחבר צינור רחב יותר. טיפות מאורך של הנוזל צמיגות נמוכה תחילה כמוסות על ידי הנוזל צמיגות גבוהה במבנה זרימה ושיתוף. כמו טיפות צמיגות נמוכה מוארך זורמת דרך היציאה, אשר מטופלת כדי להיות שנרטבו מאת הנוזל צמיגות נמוכה, היפוך פאזה ואז הנגרמת על ידי הדבקה של טיפות צמיגות נמוכה עד לקצה היציאה, כשהתוצאה היא ההופכי עוקבות ומגעים הנוזל צמיגות גבוהה. ניתן לכוונן את הגודל של טיפות צמיגות גבוהה הנובעת על-ידי שינוי יחס קצב זרימת הנוזל נמוך ברמת צמיגות הנוזל צמיגות גבוהה. נדגים מספר דוגמאות טיפוסיות של הדור של טיפות צמיגות גבוהה עם צמיגות עד 11.9 Pas, כגון פתרון גליצרול, מותק, עמילן, פולימר. השיטה מספקת גישה פשוטה ליצירת טיפות צמיגות גבוהה monodisperse, שבו ניתן להשתמש במגוון רחב של יישומים מבוססי-droplet, כגון סינתזה של חומרים, תרופות, תא assay, בביו-הנדסה, מזון הנדסה.

מכשיר נימי microfluidic עם שלב-היפוך, מבנה הזרימה שיתוף תוכנן לייצר טיפות צמיגות גבוהה מימית monodisperse, כפי שמוצג באיור 1A. איור 1, השלב מימית צמיגות גבוהה היה גליצרול, שבו יש צמיגות ηw = 1.4 Pas; השלב נמוך-צמיגות שמן היה שמן פראפין, שבו יש צמיגו?...

Watch this Scientific Journal Video about Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure at JoVE.com

Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure

בדיית טיפות צמיגות גבוהה באמצעות המכשיר נימי Microfluidic עם שלב-היפוך זרימה ושיתוף מבנה

שלב-היפוך זרימה ושיתוף התקן הוא הפגין ליצירת monodisperse טיפות צמיגות גבוהה מעל Pas 1, מה שקשה להבין ב מיקרופלואידיקה droplet.

The generation of monodisperse droplets with high viscosity has always been a challenge in droplet microfluidics. Here, we demonstrate a phase-inversion ...

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10.2K Views.  University of Science and Technology Beijing. שלב-היפוך זרימה ושיתוף התקן הוא הפגין ליצירת monodisperse טיפות צמיגות גבוהה מעל Pas 1, מה שקשה להבין ב מיקרופלואידיקה droplet.

Video: Fabricating High-viscosity Droplets using Microfluidic Capillary Device with Phase-inversion Co-flow Structure

Fabricating Nanogaps by Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two electrodes-and generating them in practical quantities-is still challenging. The preparation of nanogap electrodes using nanoskiving, which is a form of edge lithography, is a fast, simple and powerful technique. This method is an entirely mechanical process which does not include any photo- or electron-beam lithographic steps and does not require any special equipment or infrastructure such as clean rooms. Nanoskiving is used to fabricate electrically addressable nanogaps with control over all three dimensions; the smallest dimension of these structures is defined by the thickness of the sacrificial layer (Al or Ag) or self-assembled monolayers. These wires can be manually positioned by transporting them on drops of water and are directly electrically-addressable; no further lithography is required to connect them to an electrometer.

The fabrication of electrically addressable, high-aspect-ratio (> 1000:1) metal nanowires separated by gaps of single nanometers using either sacrificial layers of aluminum and silver or self-assembled monolayers as templates is described. These nanogap structures are fabricated without a clean room or any photo- or electron-beam lithographic processes by a form of edge lithography known as nanoskiving.

בודה Nanogaps ידי Nanoskiving

There are several methods of fabricating nanogaps with controlled spacings, but the precise control over the sub-nanometer spacing between two ...

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Copper (I) binding by metallochaperone transport proteins prevents copper oxidation and release of the toxic ions that may participate in harmful redox reactions. The Cu (I) complex of the peptide model of a Cu (I) binding metallochaperone protein, which includes the sequence MTCSGCSRPG (underlined is conserved), was determined in solution under inert conditions by NMR spectroscopy.
NMR is a widely accepted technique for the determination of solution structures of proteins and peptides. Due to difficulty in crystallization to provide single crystals suitable for X-ray crystallography, the NMR technique is extremely valuable, especially as it provides information on the solution state rather than the solid state. Herein we describe all steps that are required for full three-dimensional structure determinations by NMR. The protocol includes sample preparation in an NMR tube, 1D and 2D data collection and processing, peak assignment and integration, molecular mechanics calculations, and structure analysis. Importantly, the analysis was first conducted without any preset metal-ligand bonds, to assure a reliable structure determination in an unbiased manner.

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

The NMR-solution structure of a metallochaperone model peptide with Cu (I) was determined, and a detailed protocol from sample preparation and 1D and 2D data collection to a three-dimensional structure is described.

Copper (I) binding by metallochaperone transport proteins prevents copper oxidation and release of the toxic ions that may participate in harmful redox ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

אלקטרופורזה הנימים לפקח פפטיד האריך על Chitosan סרטים בזמן אמת

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

Using Capillary Electrophoresis to Quantify Organic Acids from Plant Tissue: A Test Case Examining Coffea arabica Seeds

Carboxylic acids are organic acids containing one or more terminal carboxyl (COOH) functional groups. Short chain carboxylic acids (SCCAs; carboxylic acids containing three to six carbons), such as malate and citrate, are critical to the proper functioning of many biological systems, where they function in cellular respiration and can serve as indicators of cell health. In foods, organic acid content can have significant impact on taste, with increased SCCA levels resulting in a sour or &#34;acid&#34; taste. Because of this, methods for the rapid analysis of organic acid levels are of particular interest to the food and beverage industries. Unfortunately, however, most methods used for SCCA quantification are dependent on time-consuming protocols requiring the derivatization of samples with hazardous reagents, followed by costly chromatographic and/or mass spectrometric analyses. This method details an alternate method for the detection and quantification of organic acids from plant material and food samples using free zonal capillary electrophoresis (CZE), sometimes simply referred to as capillary electrophoresis (CE). CZE provides a cost-effective method for measuring SCCAs with a low limit of detection (0.005 mg/ml). This article details the extraction and quantification of SCCAs from plant samples. While the method provided focuses on measurement of SCCAs from coffee beans, the method provided can be applied to multiple plant-based food materials.

Using Capillary Electrophoresis to Quantify Organic Acids from Plant Tissue: A Test Case Examining Coffea arabica Seeds

This article presents a method for the detection and quantification of organic acids from plant material using free zonal capillary electrophoresis. An example of the potential application of this method, determining the effects of a secondary fermentation on organic acid levels in coffee seeds, is provided.

באמצעות אלקטרופורזה נימים לכמת חומצות אורגניות מרקמות צמח: מקרה מבחן בחינה<em&gt; קפה ערביקה</em&gt; זרעים

Carboxylic acids are organic acids containing one or more terminal carboxyl (COOH) functional groups. Short chain carboxylic acids (SCCAs; carboxylic ...

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

A protocol for the analysis of gels formed from the optoelectronic conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) using small and ultra-small angle neutron scattering in both the presence and absence of illumination is presented.

פיקוח על ההשפעות של תאורה על המבנה של פולימר מצומדת ג'לים באמצעות פיזור נייטרון

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and ...

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) and fluorocarbon oil (perfluoro-n-octane, PFO) in aqueous surfactant (sodium dodecylsulfate, SDS) solutions. Since fluorocarbon oils are immiscible with hydrocarbon oils, the two oils are separated. Emulsions are prepared by stirring styrene/PFO/aqueous SDS solution mixtures at 80 &#176;C. The type of emulsions and the morphology of droplets in the emulsions are observed by light microscope and scanning confocal fluorescence microscope. It is found that oil droplets with Janus-type morphologies consisting of mutually immiscible styrene and PFO are formed in aqueous SDS solutions. Polystyrene particles are fabricated by radical polymerization of the ternary mixtures of styrene/PFO/aqueous SDS solution at 80 &#176;C. The morphologies of the polystyrene are confirmed by scanning electron microscopy and scanning transmission electron microscopy observations. These observations show the preparation of hollow polystyrene particles with a single hole on the surface. To our knowledge, this method is a novel strategy using the immiscibility of hydrocarbon and fluorocarbon oils. The hollow particles can also be applied to the preparation of microcapsules.

A protocol for the fabrication of hollow polymer particles and microcapsules by radical polymerization using emulsions consisting of styrene, perfluoro-n-octane, and aqueous SDS (sodium dodecylsulfate) solution is presented.

הכנה של חלקיקים פוליסטירן חלול מהמיקרו קפסולות מאת פלמור הרדיקלית של ג'אנוס טיפות של פחמימנים, שמנים Fluorocarbon

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal structure and probing the hydrogen-bond (H-bond) dynamics of the water molecules adsorbed on solid surfaces are fundamental issues of water science, which remains a great challenge owing to the light mass and small size of hydrogen. Scanning tunneling microscopy (STM) is a promising tool for attacking these problems, thanks to its capabilities of sub-&#197;ngstr&#246;m spatial resolution, single-bond vibrational sensitivity, and atomic/molecular manipulation. The designed experimental system consists of a Cl-terminated tip and a sample fabricated by dosing water molecules in situ onto the Au(111)-supported NaCl(001) surfaces. The insulating NaCl films electronically decouple the water from the metal substrates, so the intrinsic frontier orbitals of water molecules are preserved. The Cl-tip facilitates the manipulation of the single water molecules, as well as gating the orbitals of water to the proximity of Fermi level (EF) via tip-water coupling. This paper outlines the detailed methods of submolecular resolution imaging, molecular/atomic manipulation, and single-bond vibrational spectroscopy of interfacial water. These studies open up a new route for investigating the H-bonded systems at the atomic scale.

Here, we present a protocol to investigate the structure and dynamics of interfacial water at the atomic scale, in terms of submolecular resolution imaging, molecular manipulation, and single-bond vibrational spectroscopy.

חיטוט את המבנה ואת הדינמיקה של מים פנים עם סריקה מיקרוסקופ מינהור וספקטרוסקופיה

Water/solid interfaces are ubiquitous and play a key role in many environmental, biophysical, and technological processes. Resolving the internal ...

Synthesis and Structure Determination of &#181;-Conotoxin PIIIA Isomers with Different Disulfide Connectivities

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus highly important to avoid undesired disulfide bond formation during peptide synthesis, because it may result in a completely different peptide structure, and consequently altered bioactivity. However, the correct formation of multiple disulfide bonds in a peptide is difficult to obtain by using standard self-folding methods such as conventional buffer oxidation protocols, because several disulfide connectivities can be formed. This protocol represents an advanced strategy required for the targeted synthesis of multiple disulfide-bridged peptides which cannot be synthesized via buffer oxidation in high quality and quantity. The study demonstrates the application of a distinct protecting group strategy for the synthesis of all possible 3-disulfide-bonded peptide isomers of &#181;-conotoxin PIIIA in a targeted way. The peptides are prepared by Fmoc-based solid phase peptide synthesis using a protecting group strategy for defined disulfide bond formation. The respective pairs of cysteines are protected with trityl (Trt), acetamidomethyl (Acm), and tert-butyl (tBu) protecting groups to make sure that during every oxidation step only the required cysteines are deprotected and linked. In addition to the targeted synthesis, a combination of several analytical methods is used to clarify the correct folding and generation of the desired peptide structures. The comparison of the different 3-disulfide-bonded isomers indicates the importance of accurate determination and knowledge of the disulfide connectivity for the calculation of the three-dimensional structure and for interpretation of the biological activity of the peptide isomers. The analytical characterization includes the exact disulfide bond elucidation via tandem mass spectrometry (MS/MS) analysis which is performed with partially reduced and alkylated derivatives of the intact peptide isomer produced by an adapted protocol. Furthermore, the peptide structures are determined using 2D nuclear magnetic resonance (NMR) experiments and the knowledge obtained from MS/MS analysis.

Cysteine-rich peptides fold into distinct three-dimensional structures depending on their disulfide connectivity. Targeted synthesis of individual disulfide isomers is required when buffer oxidation does not lead to the desired disulfide connectivity. The protocol deals with the selective synthesis of 3-disulfide-bonded peptides and their structural analysis using NMR and MS/MS studies.

סינתזה וקביעת מבנה ממוצע-Conotoxin Isomers PIIIA עם Connectivities דיסולפידי שונים

Peptides with a high number of cysteines are usually influenced regarding the three-dimensional structure by their disulfide connectivity. It is thus ...

Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.

A detailed protocol is described for the separation, identification, and characterization of proteoforms in protein samples using capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS). The protocol can be used for the high-resolution characterization of proteoforms in simple protein samples and the large-scale identification of proteoforms in complex proteome samples.

בקנה מידה גדול פרוטאומיקס מלמעלה למטה באמצעות ספקטרומטר מסה של טנדם אלקטרופורזה של אזור נים

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down ...

High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug crisis in public health. Conventional urine drug testing based on a two-tier immunoassay screen followed by a gas chromatography-tandem mass spectrometry (GC-MS/MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) method are expensive and prone to bias while being limited to targeted panels of known drugs of abuse (DoA). Herein, we outline an improved method for drug surveillance that allows for the resolution and detection of an expanded panel of DoA and their metabolites when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). Multiplexed separations of ten urine samples with a quality control by CE (&lt; 3 min/sample) in conjunction with full-scan data acquisition using a time-of-flight mass spectrometer (TOF-MS) under positive ion mode detection allows for the identification and quantification of DoA above recommended cut-off levels. An excellent resolution of drug isomers and isobars, including background interferences, are achieved when using MSI-CE-MS with an electrokinetic spacer between sample segments, where accurate mass/molecular formula together with the comigration of a matching deuterated internal standard and the detection of one or more bio-transformed metabolites facilitate DoA identification over a wider detection window. Additionally, urine samples can be analyzed directly without enzyme deconjugation for the rapid screening without complicated sample workup. MSI-CE-MS enables the surveillance of a broad spectrum of DoA that is required for the treatment monitoring of high-risk patients, including confirming prescribed drug adherence, revealing illicit drug use/substitution, and evaluating optimal dosage regimes as required for new advances in precision medicine.

Here we describe a high-throughput method for comprehensive drug surveillance that allows for the improved resolution and detection of large panels of drugs of abuse and their metabolites, with quality control based on multisegment injection-capillary electrophoresis-mass spectrometry.

מעקב סמים תפוקה גבוהה ומקיף באמצעות ספקטרומטר מסה אלקטרופורזה הזרקה-נימי Multisegment

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug ...

בדיית טיפות צמיגות גבוהה באמצעות המכשיר נימי Microfluidic עם שלב-היפוך זרימה ושיתוף מבנה

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