Name: microhoneycomb monoliths prepared by the unidirectional freeze-drying of cellulose nanofiber based sols: method and extensions
Uploaded: 2018-05-24T13:30:00
Description: Watch this Scientific Journal Video about Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions at JoVE.com

עבודה זו נתמכה על ידי הלאומי בסיסי מחקר תוכנית של סין (2014CB932400), הלאומי מדעי הטבע קרן של סין (' קט ' 51525204 ו- U1607206) פרוייקט מחקר בסיסי שנג'ן (מס ' JCYJ20150529164918735). בנוסף, ברצוננו להודות בע מ Daicel-Allnex, JSR ושות' פוליאוריתנים המספקת בחביבות, קצף טבעי, בהתאמה.

1. הכנת 1 wt % 2,2,6,6-Tetramethylpiperidin-1-oxyl (טמפו)-מתווכת תאית מחמצנים סול Nanofiber (TOCN)
הערה: סול מוגדר השעיה colloidal חלקיקי מוצק קטן מאוד במדיום נוזלי רציפה.
<ol><li>להשעות 66.7 גר' זולה קראפט מולבן של Nadelholz (NBKP, המכיל 12 גרם תאית) ב- 700 מ ל מים (DI) יונים עם מסית מכני ב- 300 סל ד כעשרים דקות.</li>
	<li>להוסיף 20 מ"ל...

<ol>
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השלב הקריטי ביותר להשגת את MHMs הוא הצעד מקפיא חד כיווני, במהלך מים עפור יוצרים גבישי קרח טורי ולדחוף את dispersoid הצידה כדי ליצור את המסגרת. תהליך ההקפאה חד כיווני בעיקרון כרוך העברה תרמית בין סול מבשר את הקירור. ההתקנה שלנו, מכונת וטבלו שימשה להוספת צינור PP המכיל של סול קודמן לתוך הקירור (חנקן נ?...

כחומר חדש לגמרי, microhoneycomb מונולית (מסומן MHM) לאחרונה משכה תשומת לב אדירה בין שדות רב תחומי1,2,3,4,5, 6 , 7 , 8. MHM הוכן לראשונה על ידי Mukai ס' ואח . באמצעות ששונה חד כיווני ליופיליזציה (UDF) גישה כמו מונולית עם מערך של microchannels ישר עם דמוי חלת דבש חתכי רוחב9. MHM הנו ליתרונות הכלליים של מבנים חלת דבש, קרי, פסיפס יעיל, יחס חוזק למשקל גבוה, לחץ נמוך. יתרה מכך, לעומת המונולית חלת דבש עם מידה ערוץ גדול יותר, MHM יש הרבה שטח פנים גדול יותר ספציפי. השיטה UDF כרוך בצמיחה חד כיווני של גבישי קרח והפרדה שלב בו זמנית על הקפאה. לאחר הסרת גבישי הקרח, מתקבל רכיב מוצק יצוק על ידי הקריסטל קרח. המורפולוגיה שהוקמה על ההפרדה שלב תלוי באופי מהותי של מבשר (סול או ג'ל), ברוב המקרים, lamella10, סיבים11, עצם דג12 מבנים צפויים להקים במקום MHMs. כתוצאה מכך, היווצרות של MHMs דווחה רק ב מבשרי מוגבל, זה משמעותי יש הקשו המגוון של רכושם כימי. לאחרונה גילינו כי תאית nanofibers יש פונקציה הבימוי מבנה חזק לקראת הקמת המבנה MHM דרך תהליך UDF13. פשוט על ידי ערבוב של nanofibers תאית עם רכיבים אחרים של מים מסיסות, זה אפשרי להכין מגוון של MHMs עם מאפיינים כימיים שונים. יתר על כן, הערוץ הגדלים והצורות החיצוני שלהם הם בגמישות ובנוחות מבוקרת13. לפיכך, MHMs צפויים לשמש מסננים, תומך זרז, זרימה מסוג אלקטרודות, חיישנים, פיגומים biomaterials.
בנייר זה, קודם נסביר את הטכניקה הכנה בסיסית של MHMs הפיזור מימית של תאית nanofibers לאורך התהליך UDF בפירוט. יתר על כן, נדגים הכנת סוגים שונים של MHMs ללא הפרדות צבע.

<table border="0" cellpadding="0" cellspacing="0" width="572">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Nadelholz Bleached Kraft Pulp</td>
			<td style="width:100px;">Seioko PMC company</td>
			<td style="width:89px;">CSF=600</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">TEMPO</td>
			<td style="width:100px;">Macklin Inc.</td>
			<td style="width:89px;">T819129</td>
			<td style="width:167px;">98%</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NaBr</td>
			<td style="width:100px;">Macklin Inc.</td>
			<td style="width:89px;">S818075</td>
			<td style="width:167px;">AR, 99%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">NaClO</td>
			<td style="width:100px;">Aladin Inc.</td>
			<td style="width:89px;">S101636</td>
			<td style="width:167px;">6-14 wt% active chlorine basis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">SBR colloid</td>
			<td style="width:100px;">JSR corp.</td>
			<td style="width:89px;">TRD102A</td>
			<td style="width:167px;">48.5 wt%</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">TiO2</td>
			<td style="width:100px;">Sinopharm Chemical Reagent Co., Ltd.</td>
			<td style="width:89px;">A63725402</td>
			<td style="width:167px;">crystalline anatase phase</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">carbon fiber</td>
			<td style="width:100px;">Shenzhen Xian&#8217;gu Ltd.</td>
			<td style="width:89px;">XGCP-300</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Nitric acid</td>
			<td style="width:100px;">Huada Reagent Ltd.</td>
			<td style="width:89px;">7697-37-2</td>
			<td style="width:167px;">65-68 wt%</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Mixer</td>
			<td style="width:100px;">Scientific Industries, Inc</td>
			<td style="width:89px;">G-560</td>
			<td style="width:167px;">the mixer&#160;</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Mechanical blender</td>
			<td style="width:100px;">Waring Lab Ltd.</td>
			<td style="width:89px;">MX1000XTX</td>
			<td style="width:167px;">For disintegrating cellulose bundles into nanofibers.</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:216px;">Homogenizer</td>
			<td style="width:100px;">Scientz Ltd.</td>
			<td style="width:89px;">HXF-DY</td>
			<td style="width:167px;">For dispersing TiO2 nanoparticles</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">pH meter&#160;</td>
			<td style="width:100px;">Horiba Ltd.</td>
			<td style="width:89px;">F-74BW</td>
			<td></td>
		</tr>
	</tbody>
</table>

microhoneycomb monoliths prepared by the unidirectional freeze-drying of cellulose nanofiber based sols: method and extensions

מבנים חלת דבש מונוליטי היה אטרקטיבי לשדות רב תחומיים בשל יחס חוזק למשקל גבוה שלהם. במיוחד, הפסלים microhoneycomb (MHMs) עם סרגל מיקרומטר ערוצים צפויים כמו פלטפורמות יעילות תגובות והפרדות בגלל שלהם פני שטחים גדולים. עד עכשיו, MHMs הוכנו על ידי שיטה חד-כיוונית ליופיליזציה (UDF) רק מ מבשרי מוגבלת מאוד. במסמך זה, אנו מדווחים על פרוטוקול שממנו ניתן להשיג סדרה של MHMs המורכב מרכיבים שונים. לאחרונה, מצאנו את הפונקציה nanofibers תאית כסוכן ברורים הבימוי מבנה לקראת היווצרות של MHMs לאורך התהליך UDF. על ידי ערבוב של nanofibers תאית עם חומרים מסיסים במים שלא עונות MHMs, ניתן להכין מגוון רחב של MHMs ללא הפרדות צבע. זה מעשיר באופן משמעותי חוקת כימי MHMs לכיוון מיכלים.

מורפולוגיות לתפקידים שונים של MHM-TOCN לאורך הכיוון של הקפאה חד כיווני חקירה, באיור 2. עם המיקום להיות רחוק יותר בחלק התחתון של MHM-TOCN, התגלה שינוי הדרגתי מורפולוגיה (איור 2, דיון). על ידי הצגת רכיב שני לתוך סול TOCN לטופס של סול תערובת הומו?...

Watch this Scientific Journal Video about Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions at JoVE.com

Microhoneycomb Monoliths Prepared by the Unidirectional Freeze-drying of Cellulose Nanofiber Based Sols: Method and Extensions

כאן, אנו מציגים פרוטוקול כללי כדי להכין מגוון הפסלים microhoneycomb (MHMs) ב איזה נוזל יכול לעבור דרך עם טיפה בלחץ נמוך מאוד. MHMs שהושג צפויים לשמש מסננים, זרז תומך, זרימה מסוג אלקטרודות, חיישנים, פיגומים עבור biomaterials.

הפסלים Microhoneycomb שהוכנו על ידי ליופיליזציה חד כיווני של Nanofiber תאית מבוססת Sols: שיטת והרחבות

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb ...

This method can help answer key questions about achieving functional MHM materials for applications such as filtration, catalyst supporting, flow type batteries, sensors and bio-scaffolds. The main advantage of this technique is that it utilizes the structure directing function of cellulose nanofibers and can realize constitutional control of the targeted MHMs. This method can help answer key questions about achieving functional MHM materials for applications such as filtration, catalyst supporting, flow type batteries, sensors and bio-scaffolds.Demonstrating the procedure with myself and Cong Wang, a grad student from our laboratory. To begin preparing the tempo-mediated oxidized cellulose nanofiber sol, first combine 66.7 grams of softwood bleached kraft pulp with 700 microliters of deionized water. Mechanically agitate the mixture for 20 minutes at 300 rpm.Over the course of one minute, slowly add to the stirring kraft pulp suspension 20 milliliters each of a 7.5 gram per liter aqueous tempo solution and 75 gram per liter aqueous sodium bromide solution. Begin continuously monitoring the pH of the mixture with a pH meter. Adjust the mixture pH to about 10.5 with a three molar sodium hydroxide solution.Then, over the course of several minutes, slowly pipette into the suspension 63.8 grams of aqueous sodium hypochlorite with 6 to 14%active chlorine. After addition is complete, continue adjusting the pH back to 10.5 whenever it drops to about 10. Once the pH decrease slows, time how long it takes for the pH to drop from 10.5 to 10 to determine how often to check on the mixture during the reaction.Allow the tempo mediated oxidation to proceed normally for a bout 2.5 hours from the start of the sodium hypochlorite addition. Afterwards, filtrate the reaction mixture through a filter. And collect the oxidized cellulose nanofiber.Then, agitate the oxidized cellulose fibers in 1.2 liters of deionized water. Rinse the fibers three times in this way. Dry a small portion of the washed fiber paste overnight in an oven at 60 degrees Celsius to determine the solid content of the paste.Calculate the quantity of water needed to make a 1%by weight sol from the paste. Then transfer the washed fiber paste to laboratory grade blender. Add an appropriate amount of DI water to adjust the concentration of the mixture to 2%by weight.Vigorously blend the paste to disintegrate the oxidized cellulose fibers into nanofibers. Begin with low power blending before vigorously blending the paste at high power. Add one fifth of the needed volume of deionized water to the paste, and blend thoroughly.Repeat this process four more times to obtain the 1%by weight tempo mediated oxidized cellulose nanofiber sol. Store the sol at four degrees Celsius. We hear extracting is constant of the resulting TOCN sol.If it is hot enough, the MHM is likely to be obtained through the newly added process. Normally, the viscosity must be greater than 20, 000 millipascal second. Prior to preparing the tempo mediated oxidized cellulose nanofiber surface oxidized carbon fiber mixed sol, reflux 1.7 grams of 300 mesh carbon fiber in 150 milliliters of concentrated nitric acid to obtain the surface oxidized carbon fibers.Then, place in a 20 milliliter glass vial, 01 grams of the prepared surface oxidized carbon fibers, and 10 grams of the 1%by weight tempo mediated oxidized cellulose nanofiber sol. Manually shake the mixture until the surface oxidized carbon fibers are evenly distributed throughout the sol. Sonicate the mixture for five minutes to obtain an evenly dispersed TOCN SOCF mixed sol.Store the sol at four degrees Celsius. To begin preparing a microhoneycomb monolith, fill the bottom five centimeters of the 13 by 150 millimeter or similarly sized polypropylene tube with glass beads as filler material. Slowly load at least 2.7 milliliters of the chosen sol into the tube, ensuring that the sol level is about 22 millimeters or more above the glass beads.Avoid disturbing the sol unnecessarily to minimize the formation of bubbles in the tube. Use a narrow tipped pipette to carefully remove from the sol any bubbles that were introduced during the loading process. Store the sol sample at four degrees Celsius overnight.Then connect the sample tube to a dipping instrument for a unidirectional freezing. Place a Dewar of liquid nitrogen under the tube. Freeze the sol at an emerging speed of either 50 centimeters per hour for the TOCN sol or 20 centimeters per hour for the mixed sols.Keep the sol frozen once unidirectional freezing is complete. We use our cool time to constantly cool the frozen TOCN sol side hook to prevent it from sleep which will lead to the deterioration of the micromorphology of the resulting monolith. Use a saw to cut open the polypropylene tube.Crack the frozen sol into several pieces using pliers. Freeze dry the frozen sol pieces at minus ten degrees Celsius, minus five degrees Celsius, and zero degrees Celsius for one day each sequentially to obtain the microhoneycomb monolith. Unidirectionally freezing 1%by weight TOCN sol at 50 centimeters per hour without glass beads resulted in a gradual change in orientation and channel size along the freezing direction.The microhoneycomb morphology was retained longitudinally throughout the monolith. The bottom centimeter of the monolith was oriented toward the center of the bulk. A well-aligned honeycomb morphology was obtained two centimeters from the bottom.The microhoneycomb channel size increased from 10 micrometers between the second and third centimeters of the monolith and then remained stable. Overall, the unidirectional freezing effect showed no influence on the morphology past three centimeters. The channel size could be tuned by altering the dipping speed and the temperature of the coolant.Tempo oxidized cellulose nanofibers strongly tended to form the microhoneycomb structure via the unidirectional freezing process even in the presence of a second component. A mixed sol with styrene butadiene rubber yielded a composited microhoneycomb monolith with smooth walls. Tempo oxidized cellulose nanofiber microhoneycomb monoliths also supported titanium oxide nanoparticles in a well-ordered microhoneycomb monolith with nanoparticles adhering to the microhoneycomb walls.A mixed sol with SOCF yielded a novel substructure in which the carbon fibers bridged the neighboring microhoneycomb walls. The unidirectional freeze-drying technique is a novel approach through which many regular microstructures can be obtained. We first had the idea for this method will be so well in random microhoneycomb morphology in a wood pattern.It seems the major component of the wood is cellulose. We began to try imbuing up a similar construction with cellulose. Once mastered, this technique can be used to construct many other functional composite MHMs for targeted applications.

Research

JoVE Journal

Bioengineering

Improved Method for the Preparation of a Human Cell-based, Contact Model of the Blood-Brain Barrier

שיפר שיטה להכנה מבוססת תאים, דגם מגע אנושי של מחסום דם המוח

The blood-brain barrier (BBB) comprises impermeable but adaptable brain capillaries which tightly control the brain environment. Failure of the BBB has ...

Manufacturing Of Robust Natural Fiber Preforms Utilizing Bacterial Cellulose as Binder

ייצור של תבניות ייצרו מראש חזקות סיבים טבעיים ניצול קטריאלי תאית כמו בינדר

A novel method of manufacturing rigid and robust natural fiber preforms is presented here. This method is based on a papermaking process, whereby loose ...

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method

היווצרות של microarrays Biomembrane עם שיטת הרכבה מבוססת מגב

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are ...

Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

Electrospun nanofiber פיגומים עם דרגות בארגון סיבים

The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible ...

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer (SALB) Method

Biomembrane Fabrication by the Solvent-assisted Lipid Bilayer SALB Method

ייצור Biomembrane ידי השומנים bilayer (SALB) השיטה בסיוע מרכך

In order to mimic cell membranes, the supported lipid bilayer (SLB) is an attractive platform which enables in vitro investigation of membrane-related ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

סינתזה של nanofiber קראטין מבוסס על הנדסה ביו רפואית

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of ...

A Net Mold-based Method of Scaffold-free Three-Dimensional Cardiac Tissue Creation

שיטה המבוססת על עובש נטו הבריאה ברקמת הלב לגרדום ללא תלת מימדי

This protocol describes a novel and easy net mold-based method to create three-dimensional (3-D) cardiac tissues without additional scaffold material. ...

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

זיהוי של אנדוטוקסין ניסוחים-Nano באמצעות מבחני Lysate (LAL) Amoebocyte Limulus

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Seeding and Implantation of a Biosynthetic Tissue-engineered Tracheal Graft in a Mouse Model

Seeding, השרשת biosynthetic הוחלף נגזר רקמות מהונדסים בקנה הנשימה השתלה במודל של עכברים

Treatment options for congenital or secondary long segment tracheal defects have historically been limited due to an inability to replace functional ...

3D Printed Porous Cellulose Nanocomposite Hydrogel Scaffolds

3D מודפס נקבובי תאית Nanocomposite הידרוג פיגומים

This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with ...