Funding was provided in part by BU and the NIH R01CA149561. The authors wish to thank the electrospinning/electrospraying team including Stefan Yohe, Eric Falde, Joseph Hersey, and Julia Wang for their helpful discussions and contributions to the preparation and characterization of superhydrophobic biomaterials.

The authors declare that they have no competing financial interests.

הגישה שלנו לבניית חומרי הידרופובי מפולימרים ביו-רפואיים משלבת כימיה פולימר סינתטית עם טכניקות עיבוד פולימרים של electrospinning וelectrospraying. טכניקות אלה מספקים גם סיבים או חלקיקים, בהתאמה. באופן ספציפי, חומרים-הידרופובי polycaprolactone ופולי (-glycolide שיתוף lactide-) מבוסס מוכנים באמ...

משטחי הידרופובי בדרך כלל מסווגים כמציגים קשר ברור מים זוויות גדולות מ -150 מעלות עם hysteresis זווית מגע נמוך. משטחים אלה מיוצרים על ידי החדרת חספוס פני השטח גבוה על חומרי אנרגיית משטח נמוכים להקמת ממשק אוויר נוזלי מוצקה וכתוצאה מכך שמתנגד הרטבת 1-6. בהתאם לשיטת הייצור, משטחים דקים או רב שכבתיים סופר-הידרופובי, ציפויי מצע הידרופובי רב שכבתיים, או מבנים-הידרופובי אפילו בתפזורת יכולה להיות מוכן. דחיית מים קבועים או חצי קבוע זה רכוש שימושי שמועסק להכין משטחי ניקוי עצמי 7, מכשירי microfluidic 8, אנטי עכירות משטחי תא / חלבון 9,10, משטחי הפחתת גרירת 11, ומכשירי משלוח הסמים 12 15. לאחרונה, חומרים-הידרופובי גירויים מגיבים מתוארים בי שאינם רטוב למדינה רטובה מופעל על ידי כימי, פיזי, או רמזים סביבתיים (למשל, אור, pH, טמפרטורה, אולטרסאונד, ולהחיל פוטנציאל חשמלי / הנוכחי) 14,16-20, וחומרים אלה מוצאים שימוש ליישומים נוספים 21-25. משטחי הידרופובי סינטטיים הראשונים שהוכנו על ידי טיפול במשטחי חומר עם methyldihalogenosilanes 26, והיו בעל ערך המוגבל ליישומים ביו-רפואיים, כחומרים המשמשים לא היו מתאימים לשימוש בvivo. במסמך זה אנו מתארים את ההכנה של פני השטח וחומרי הידרופובי בתפזורת מפולימרים ביולוגית. הגישה שלנו כרוכה electrospinning או electrospraying תערובת פולימר המכילה פוליאסטר מתכלה, ביולוגית אליפטי כמרכיב העיקרי, מסומם עם קופולימר הידרופובי מורכב מפוליאסטר ופולי (קרבונט גליצרול)-שונה stearate 27-30. טכניקות הייצור לספק את חספוס פני השטח המשופר ונקבובי ובבתוך FibeRS או החלקיקים, בהתאמה, בעוד שהשימוש בdopant קופולימר מספק פולימר אנרגיית משטח נמוך שמשתלב עם פוליאסטר ויכולים להיות electrospun או electrosprayed 27,31,32 ביציבות. פוליאסטר aliphatic מתכלה כגון פולי (חומצה לקטית) (PLA), פולי (חומצה גליקולית) (PGA), פולי (חומצה לקטית -glycolic שיתוף דיאלקטרי) (PLGA), וpolycaprolactone (PCL) הם פולימרים המשמשים במכשירים שאושרו-קליני ובולט במחקר ביו-רפואי בגלל חומרים שאינם רעיל, פריקות ביולוגית, והקלה של סינתזה 33. PGA וPLGA לראשונה במרפאת כתפרי bioresorbable בשנתי ה -1960 ו -1970 המוקדמות, בהתאמה 34-37. מאז, פולי אלה (חומצות הידרוקסיות) עובדו למגוון רחב של גורמי צורה ספציפי ליישום אחרים, כגון מיקרו 38,39 וחלקיקי 40,41, הוופלים / דיסקים 42, משתלב 27,43, קצף 44, ו סרטים 45 </sup&gt;. פוליאסטר אליפטי, כמו גם פולימרים אחרים בעלי עניין ביו-רפואי, ניתן electrospun לייצר מבני ננו או רשת מיקרופייבר בעל שטח פנים גבוה ונקבובי, כמו גם חוזק מתיחה. טבלה 1 רשימות electrospun הפולימרים סינטטיים עבור יישומים ביו-רפואיים שונים ו המקבילים אזכור. Electrospinning וelectrospraying טכניקות מהירות ומסחרית-ניתן להרחבה. שתי טכניקות דומות אלה מסתמכות על יישום מתח גבוה (דחייה אלקטרוסטטית) כדי להתגבר על המתח של פתרון פולימר משטח / להמס בהתקנת משאבת מזרק כפי שהוא מכוון ליעד מעוגן 46,47. כאשר טכניקה זו משמשת בשילוב עם פולימרים אנרגיית פני השטח נמוכים (פולימרים הידרופובי כגון פולי (monostearate -glycerol שיתוף caprolactone-)), בסופר-הידרופוביות תערוכת חומרים שהתקבלו. כדי להמחיש גישת עיבוד זה בכלל סינטטי וחומריםלבניית חומרי הידרופובי מפולימרים ביו-רפואיים, אנו מתארים את הסינתזה של polycaprolactone- הידרופובי ופולי (-glycolide שיתוף lactide-) חומרים מבוססי כדוגמאות מייצגות. פולי בהתאמה dopants קופולימר (monostearate -glycerol שיתוף caprolactone-) ופולי (monostearate -glycerol שיתוף lactide-) מסונתזים ראשון, ולאחר מכן מעורבב עם polycaprolactone ופולי (-glycolide שיתוף lactide-), בהתאמה, ובסופו electrospun או electrosprayed. חומרי כתוצאה מכך הם מתאפיינים בgoniometry הדמיה וזווית מגע SEM, ונבדקו במבחנה ובהתאמה הביולוגית vivo. לבסוף, הרטבה בתפזורת באמצעות משתלב הידרופובי תלת ממדים נבחנה באמצעות טומוגרפיה microcomputed חומר ניגוד.

<table><tbody><tr><td>Silicone oil</td><td>Sigma-Aldrich</td><td>85409</td><td></td></tr><tr><td>Cis-2-Phenyl-1,3-dioxan-5-ol</td><td>Sigma-Aldrich</td><td>13468</td><td></td></tr><tr><td>Benzyl bromide</td><td>Sigma-Aldrich</td><td>B17905</td><td>Toxic, lacrymator/eye irritant, use in chemical fume hood</td></tr><tr><td>Potassium hydroxide</td><td>Sigma-Aldrich</td><td>221473</td><td>Corrosive</td></tr><tr><td>Rotary evaporator</td><td>Buchi</td><td>R-124</td><td></td></tr><tr><td>High-vacuum pump</td><td>Welch</td><td>8907</td><td></td></tr><tr><td>Nitrogen, ultra high purity</td><td>Airgas</td><td>NI UHP300</td><td>Compressed gas</td></tr><tr><td>Tetrahydrofuran, stabilized with BHT</td><td>Pharmaco-Aaper</td><td>346000</td><td>Flammable. Dried through column of XXX</td></tr><tr><td>Dichloromethane</td><td>Pharmaco-Aaper</td><td>313000</td><td>Flammable, toxic.</td></tr><tr><td>Separatory funnel (1 L)</td><td>Fisher Scientific</td><td>13-678-606</td><td></td></tr><tr><td>Sodium sulfate</td><td>Sigma-Aldrich</td><td>239313</td><td></td></tr><tr><td>Ethanol, absolute</td><td>Pharmaco-Aaper</td><td>111USP200</td><td>Flammable, toxic.</td></tr><tr><td>Buchner funnel</td><td>Fisher Scientific</td><td>FB-966-F</td><td></td></tr><tr><td>Methanol</td><td>Pharmaco-Aaper</td><td>339000ACS</td><td>Flammable, toxic.</td></tr><tr><td>Hydrochloric acid</td><td>Sigma-Aldrich</td><td>320331</td><td>Corrosive. Diluted to 2N in distilled water.</td></tr><tr><td>Ethyl chloroformate, 97%</td><td>Sigma-Aldrich</td><td>185892</td><td>Toxic, flammable, harmful to environment</td></tr><tr><td>Triethylamine (anhydrous)</td><td>Sigma-Aldrich</td><td>471283</td><td>Toxic, flammable, harmful to environment</td></tr><tr><td>Diethyl ether</td><td>Pharmaco-Aaper</td><td>373ANHACS</td><td>Highly flammable. Purified through XXX column.</td></tr><tr><td>3,6-Dimethyl-1,4-dioxane-2,5-dione (D,L-lactide)</td><td>Sigma-Aldrich</td><td>303143</td><td></td></tr><tr><td>Tin (II) ethylhexanoate</td><td>Sigma-Aldrich</td><td>S3252</td><td>Toxic.</td></tr><tr><td>&amp;epsilon;-caprolactone (97%)</td><td>Sigma-Aldrich</td><td>704067</td><td></td></tr><tr><td>Toluene, anhydrous</td><td>Sigma-Aldrich</td><td>244511</td><td>Flammable, toxic.</td></tr><tr><td>Glass syringe</td><td>Hamilton Company</td><td>1700-series</td><td></td></tr><tr><td>Deuterated chloroform</td><td>Cambridge Isotopes Laboratories, Inc.</td><td>DLM-29-10</td><td>Toxic</td></tr><tr><td>Nuclear magnetic resonance instrument</td><td>Varian</td><td>V400</td><td></td></tr><tr><td>Palladium on carbon catalyst</td><td>Strem Chemicals, Inc.</td><td>46-1707</td><td></td></tr><tr><td>Hydrogenator unit</td><td>Parr</td><td>3911</td><td></td></tr><tr><td>Hydrogenator shaker vessel</td><td>Parr</td><td>66CA</td><td></td></tr><tr><td>Hydrogen</td><td>Airgas</td><td>HY HP300</td><td>Highly flammable.</td></tr><tr><td>Diatomaceous earth</td><td>Sigma-Aldrich</td><td>22140</td><td></td></tr><tr><td>2H,2H,3H,3H-perflurononanoic acid</td><td>Oakwood Products, Inc.</td><td>10519</td><td>Toxic.</td></tr><tr><td>Stearic acid</td><td>Sigma-Aldrich</td><td>S4751</td><td></td></tr><tr><td>N,N&amp;rsquo;-dicyclohexylcarbodiimide</td><td>Sigma-Aldrich</td><td>D80002</td><td>Toxic, irritant.</td></tr><tr><td>4-(dimethylamino) pyridine</td><td>Sigma-Aldrich</td><td>107700</td><td>Toxic.</td></tr><tr><td>Hexanes</td><td>Pharmaco-Aaper</td><td>359000ACS</td><td>Toxic, flammable.</td></tr><tr><td>Gel permeation chromatography (GPC) system</td><td>Rainin</td><td></td><td></td></tr><tr><td>GPC column</td><td>Waters</td><td>WAT044228</td><td></td></tr><tr><td>Differential scanning calorimeter</td><td>TA Instruments</td><td>Q100</td><td></td></tr><tr><td>Chloroform</td><td>Pharmaco-Aaper</td><td>309000ACS</td><td>Toxic.</td></tr><tr><td>N,N-dimethylformamide</td><td>Sigma-Aldrich</td><td>227056</td><td>Toxic, flammable.</td></tr><tr><td>Polycaprolactone, MW 70-90 kg/mol</td><td>Sigma-Aldrich</td><td>440744</td><td></td></tr><tr><td>Poly(lactide-co-glycolide), MW 136 kg/mol</td><td>Evonik Industries</td><td>LP-712</td><td></td></tr><tr><td>10 ml glass syringe</td><td>Hamilton Company</td><td>81620</td><td></td></tr><tr><td>18 AWG blunt needle</td><td>BRICO Medical Supplies</td><td>BN1815</td><td></td></tr><tr><td>Electrospinner enclosure box</td><td>Custom-built</td><td>N/A</td><td>Made of acrylic panels</td></tr><tr><td>High voltage DC supply</td><td>Glassman High Voltage, Inc.</td><td>PS/EL30R01.5</td><td>High voltages, electrocution hazard</td></tr><tr><td>Linear (translating) stage</td><td>Servo Systems Co.</td><td>LPS-12-20-0.2</td><td>Optional</td></tr><tr><td>Programmable motor &amp;amp; power supply</td><td>Intelligent Motion Systems, Inc.</td><td>MDrive23 Plus</td><td>Optional</td></tr><tr><td>24V DC motor &amp;amp; power supply</td><td>McMaster-Carr</td><td>6331K32</td><td>Optional</td></tr><tr><td>Aluminum collector drum</td><td>Custom-built</td><td></td><td>Optional</td></tr><tr><td>Syringe pump</td><td>Fisher Scientific</td><td>78-0100I</td><td></td></tr><tr><td>Inverted optical microscope</td><td>Olympus</td><td>IX70</td><td></td></tr><tr><td>Scanning electron microscope</td><td>Carl Zeiss</td><td>Supra V55</td><td></td></tr><tr><td>Conductive copper tape</td><td>3M</td><td>16072</td><td></td></tr><tr><td>Aluminum SEM stubs</td><td>Electron Microscopy Sciences</td><td>75200</td><td></td></tr><tr><td>Contact angle goniometer</td><td>Kruss</td><td>DSA100</td><td></td></tr><tr><td>Propylene glycol</td><td>Sigma-Aldrich</td><td>W294004</td><td>Toxic.</td></tr><tr><td>Ethylene glycol</td><td>Sigma-Aldrich</td><td>324558</td><td>Toxic.</td></tr><tr><td>Ioxaglate</td><td>Guerbet</td><td></td><td></td></tr><tr><td>Fetal bovine serum</td><td>American Type Culture Collection</td><td>30-2020</td><td></td></tr><tr><td>Micro-computed tomography instrument</td><td>Scanco</td><td></td><td></td></tr><tr><td>Image analysis software (Analyze)</td><td>Mayo Clinic</td><td></td><td></td></tr><tr><td>Tensile tester</td><td>Instron</td><td>5848</td><td></td></tr><tr><td>Micrometer</td><td>Multitoyo</td><td>293-340</td><td></td></tr><tr><td>Calipers</td><td>Fisher Scientific</td><td>14-648-17</td><td></td></tr></tbody></table>

fabricating superhydrophobic polymeric materials for biomedical applications

חומרים-הידרופובי, עם משטחים בעלי מדינות רטובות שאינן קבועות או metastable, הם עניין למספר היישומים ביו-רפואיים ותעשייתיים. כאן אנו מתארים כיצד electrospinning או electrospraying תערובת פולימר המכילה פוליאסטר מתכלה, ביולוגית אליפטי (למשל, polycaprolactone ופולי (שיתוף -glycolide lactide-)), כמרכיב המרכזי, מסומם עם קופולימר הידרופובי מורכב מפוליאסטר וstearate- פולי שונה (קרבונט גליצרול) מקנה ביולוגי-הידרופובי. טכניקות הייצור של electrospinning או electrospraying לספק חספוס פני השטח המשופר ונקבובי ובבתוך הסיבים או החלקיקים, בהתאמה. השימוש בdopant קופולימר אנרגיית משטח נמוך שמשתלב עם פוליאסטר ויכולים להיות electrospun או electrosprayed יציבות מקנה חומרי הידרופובי אלה. פרמטרים חשובים כגון גודל סיבים, הרכב dopant קופולימר ו / או שיתוףncentration, וההשפעות שלהם על יכולת רטיבות הם דנו. זה שילוב של כימיה של פולימרים והנדסת תהליך מאפשר גישה תכליתית לפתח חומרים ספציפיים ליישום תוך שימוש בטכניקות להרחבה, אשר עשויה להכליל לכיתה רחבה יותר של פולימרים עבור מגוון רחב של יישומים.

באמצעות סדרה של שינויים כימיים, 2-אחד 5-benzyloxy-1,3-dioxan-מונומר פחמה הפונקציונלי הוא מסונתז כלבנים גבישים (איור 1 א) טוב. 1 H NMR מאשר את המבנה (איור 1) וספקטרומטר מסה ו ניתוח יסודות לאשר את הרכב. זה מוצק אז copolymerized עם או D, -lactide L או ε-caprolactone באמצעות...

Watch this Scientific Journal Video about Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications at JoVE.com

Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition.

בודה חומרים פולימריים עבור יישומים ביו-הידרופובי

Superhydrophobic materials, with surfaces possessing permanent or metastable non-wetted states, are of interest for a number of biomedical and industrial ...

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19.1K Views.  Boston University. Two- and three-dimensional superhydrophobic polymeric materials are prepared by electrospinning or electrospraying biodegradable polymers blended with a lower surface energy polymer of similar composition. 

Video: Fabricating Superhydrophobic Polymeric Materials for Biomedical Applications

Microfabricated Platforms for Mechanically Dynamic Cell Culture

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or fundamental cell biology studies is limited by current bioreactor technologies, which cannot simultaneously apply a variety of mechanical stimuli to cultured cells. In order to address this issue, we have developed a series of microfabricated platforms designed to screen for the effects of mechanical stimuli in a high-throughput format. In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and further demonstrate how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

In this protocol, we demonstrate the fabrication of a microactuator array of vertically displaced posts on which the technology is based, and how this base technology can be modified to conduct high-throughput mechanically dynamic cell culture in both two-dimensional and three-dimensional culture paradigms.

פלטפורמות microfabricated לתרבות Cell דינמי מכאני

The ability to systematically probe in vitro cellular response to combinations of mechanobiological stimuli for tissue engineering, drug discovery or ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

ניתוח ההלחנה מתקדם של מרוכבים Nanoparticle-פולימר באמצעות דימות פלואורסצנטי ישיר

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Engineering

Microfluidic Fabrication of Polymeric and Biohybrid Fibers with Predesigned Size and Shape

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and used to dictate the shape as well as the diameter of a core stream.&#160;Grooves in the top and bottom of a microfluidic channel were designed to direct the sheath fluid and shape the core fluid.&#160;By matching the viscosity and hydrophilicity of the sheath and core fluids, the interfacial effects are minimized and complex fluid shapes can be formed.&#160;Controlling the relative flow rates of the sheath and core fluids determines the cross-sectional area of the core fluid.&#160;Fibers have been produced with sizes ranging from 300 nm to ~1 mm, and fiber cross-sections can be round, flat, square, or complex as in the case with double anchor fibers. Polymerization of the core fluid downstream from the shaping region solidifies the fibers.&#160;Photoinitiated click chemistries are well suited for rapid polymerization of the core fluid by irradiation with ultraviolet light.&#160;Fibers with a wide variety of shapes have been produced from a list of polymers including liquid crystals, poly(methylmethacrylate), thiol-ene and thiol-yne resins, polyethylene glycol, and hydrogel derivatives. Minimal shear during the shaping process and mild polymerization conditions also makes the fabrication process well suited for encapsulation of cells and other biological components.

Two adjacent fluids passing through a grooved microfluidic channel can be directed to form a sheath around a prepolymer core; thereby&#160;determining both shape and cross-section. Photoinitiated polymerization, such as thiol click chemistry, is well suited for rapidly solidifying the core fluid into a microfiber with predetermined size and shape.

ייצור מיקרופלואידי של סיבים פולימריים וביוהיברידים עם גודל וצורה מעוצבים מראש

A &#8220;sheath&#8221; fluid passing through a microfluidic channel at low Reynolds number can be directed around another &#8220;core&#8221; stream and ...

Preparation and High-temperature Anti-adhesion Behavior of a Slippery Surface on Stainless Steel

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 &#176;C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.

Slippery surfaces provide a new way to solve the adhesion problem. This protocol describes how to fabricate slippery surfaces at high temperatures. The results demonstrate that the slippery surfaces showed anti-wetting for liquids and a remarkable anti-adhesion effect on soft tissues at high temperatures.

הכנה והתנהגות אנטי אדהזיה בטמפרטורות גבוהות של משטח חלקלק-נירוסטה

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A ...

Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in industry. The wettability of the produced surface was analyzed by bouncing drop experiments and the topography was analyzed by confocal microscopy. In addition, we show various methodologies to measure its durability and anti-icing properties. Superhydrophobic surfaces hold a special texture that must be preserved to keep their water-repellency. To fabricate durable surfaces, we followed two strategies to incorporate a resistant texture. The first strategy is a direct incorporation of roughness to the metal substrate by acid etching. After this surface texturization, the surface energy was decreased by silanization or fluoropolymer deposition. The second strategy is the growth of a ceria layer (after surface texturization) that should enhance the surface hardness and corrosion resistance. The surface energy was decreased with a stearic acid film.
The durability of the superhydrophobic surfaces was examined by a particle impact test, mechanical wear by lateral abrasion, and UV-ozone resistance. The anti-icing properties were explored by studying the ability to repeal subcooled water, freezing delay, and ice adhesion.

We illustrate several methodologies to produce superhydrophobic metal surfaces and to explore their durability and anti-icing properties.

ייצור של משטחי מתכת Superhydrophobic עבור יישומים ציפוי אנטי

Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in ...

Thin Film Composite Silicon Elastomers for Cell Culture and Skin Applications: Manufacturing and Characterization

In this protocol, we present methods to fabricate thin elastomer composite films for advanced cell culture applications and for the development of skin adhesives. Two different poly-(dimethyl siloxanes) (PDMS and soft skin adhesive (SSA)), have been used for in depth investigation of biological effects and adhesive characteristics. The composite films consist of a flexible backing layer and an adhesive top coating. Both layers have been manufactured by doctor blade application technique. In the present investigation, the adhesive behavior of the composite films has been investigated as a function of the layer thickness or a variation of the Young&#39;s modulus of the top layer. The Young&#39;s modulus of PDMS has been changed by varying the base to crosslinker mixing ratio. In addition, the thickness of SSA films has been varied from approx. 16 &#181;m to approx. 320 &#181;m. Scanning electron microscopy (SEM) and optical microscopy have been used for thickness measurements. The adhesive properties of elastomer films depend strongly on the film thickness, the Young&#39;s modulus of the polymers and surface characteristics. Therefore, normal adhesion of these films on glass substrates exhibiting smooth and rough surfaces has been investigated. Pull-off stress and work of separation are dependent on the mixing ratio of silicone elastomers.
Additionally, the thickness of the soft skin adhesive placed on top of a supportive backing layer has been varied in order to produce patches for skin applications. Cytotoxicity, proliferation and cellular adhesion of L929 murine fibroblasts on PDMS films (mixing ratio 10:1) and SSA films (mixing ratio 50:50) have been conducted. We have shown here, for the first time, the side by side comparison of thin composite films manufactured of both polymers and present the investigation of their biological- and adhesive properties.

A protocol for the manufacturing process of polymeric thin film composite structures possessing either different Young&#39;s moduli or thicknesses is presented. Films are produced for advanced cell culture studies or as skin adhesives.

דק אלסטומרים סיליקון מורכב הסרט תרבית תאים ואפליקציות עור: ייצור ואפיון

In this protocol, we present methods to fabricate thin elastomer composite films for advanced cell culture applications and for the development of skin ...

Developmental Biology

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.

ייצור של התקנים השבירה-אינדקס-מתאימים עבור מיקרופלואידיקה ביו

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

Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars

We present microfabrication protocols for rendering intrinsically wetting materials repellent to liquids (omniphobic) by creating gas-entrapping microtextures (GEMs) on them comprising cavities and pillars with reentrant and doubly reentrant features. Specifically, we use SiO2/Si as the model system and share protocols for two-dimensional (2D) designing, photolithography, isotropic/anisotropic etching techniques, thermal oxide growth, piranha cleaning, and storage towards achieving those microtextures. Even though the conventional wisdom indicates that roughening intrinsically wetting surfaces (&#952;o &#60; 90&#176;) renders them even more wetting (&#952;r &#60; &#952;o &#60; 90&#176;), GEMs demonstrate liquid repellence despite the intrinsic wettability of the substrate. For instance, despite the intrinsic wettability of silica &#952;o &#8776; 40&#176; for the water/air system, and &#952;o &#8776; 20&#176; for the hexadecane/air system, GEMs comprising cavities entrap air robustly on immersion in those liquids, and the apparent contact angles for the droplets are &#952;r &#62; 90&#176;. The reentrant and doubly reentrant features in the GEMs stabilize the intruding liquid meniscus thereby trapping the liquid-solid-vapor system in metastable air-filled states (Cassie states) and delaying wetting transitions to the thermodynamically-stable fully-filled state (Wenzel state) by, for instance, hours to months. Similarly, SiO2/Si surfaces with arrays of reentrant and doubly reentrant micropillars demonstrate extremely high contact angles (&#952;r &#8776; 150&#176;&#8211;160&#176;) and low contact angle hysteresis for the probe liquids, thus characterized as superomniphobic. However, on immersion in the same liquids, those surfaces dramatically lose their superomniphobicity and get fully-filled within &#60;1 s. To address this challenge, we present protocols for hybrid designs that comprise arrays of doubly reentrant pillars surrounded by walls with doubly reentrant profiles. Indeed, hybrid microtextures entrap air on immersion in the probe liquids. To summarize, the protocols described here should enable the investigation of GEMs in the context of achieving omniphobicity without chemical coatings, such as perfluorocarbons, which might unlock the scope of inexpensive common materials for applications as omniphobic materials. Silica microtextures could also serve as templates for soft materials.

Rendering SiO2/Si Surfaces Omniphobic by Carving Gas-Entrapping Microtextures Comprising Reentrant and Doubly Reentrant Cavities or Pillars

This work presents microfabrication protocols for achieving cavities and pillars with reentrant and doubly reentrant profiles on SiO2/Si wafers using photolithography and dry etching. Resulting microtextured surfaces demonstrate remarkable liquid repellence, characterized by robust long-term entrapment of air under wetting liquids, despite the intrinsic wettability of silica.

עיבוד SiO2/סי משטחים אומניפובי על ידי גילוף מיקרוטקסטורות גז-מיקרו הכוללת חללים מחדש ושני עמודים

We present microfabrication protocols for rendering intrinsically wetting materials repellent to liquids (omniphobic) by creating gas-entrapping ...

High-throughput Identification of Bacteria Repellent Polymers for Medical Devices

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as contributing to antimicrobial resistance. One possible avenue for the reduction of device-associated infections is the identification of bacteria-repellent polymer coatings for these devices, which would prevent bacterial binding at the initial attachment step. A method for the identification of such repellent polymers, based on the parallel screening of hundreds of polymers using a microarray, is described here. This high-throughput method resulted in the identification of a range of promising polymers that resisted binding of various clinically relevant bacterial species individually and also as multi-species communities. One polymer, PA13 (poly(methylmethacrylate-co-dimethylacrylamide)), demonstrated significant reduction in attachment of a number of hospital isolates when coated onto two commercially available central venous catheters. The method described could be applied to identify polymers for a wide range of applications in which modification of bacterial attachment is important.

A high-throughput microarray method for the identification of polymers which reduce bacterial surface binding on medical devices is described.

זיהוי תפוקה גבוהה של חיידקים פולימרים דוחה עבור אביזרים ומכשור רפואי

Medical devices are often associated with hospital-acquired infections, which place enormous strain on patients and the healthcare system as well as ...

Synthesis of Hydrogels with Antifouling Properties As Membranes for Water Purification

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and thus achieving stable water permeability through membranes over time. Here, we report a facile method to prepare hydrogels based on zwitterions for membrane applications. Freestanding films can be prepared from sulfobetaine methacrylate (SBMA) with a crosslinker of poly(ethylene glycol) diacrylate (PEGDA) via photopolymerization. The hydrogels can also be prepared by impregnation into hydrophobic porous supports to enhance the mechanical strength. These films can be characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine the degree of conversion of the (meth)acrylate groups, using goniometers for hydrophilicity and differential scanning calorimetry (DSC) for polymer chain dynamics. We also report protocols to determine the water permeability in dead-end filtration systems and the effect of foulants (bovine serum albumin, BSA) on membrane performance.

This paper reports practical methods to prepare hydrogels in freestanding films and impregnated membranes and to characterize their physical properties, including water transport properties.

סינתזה של הידרוג עם מאפייני Antifouling ופלטות לטיהור מים

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and ...