Bu çalışma, Plazma Bilim ve Teknoloji NSF / DOE Ortaklığı tarafından desteklenen (NSF Hibe No CBET-0.853.777 ve DOE Grant No DE-SC0001169), STTR Faz I projesi (NSF STTR FAZ I No.1010133). Yazarlar, yay deneyleri destekleyen Fusion Enerji Bilimler Office tarafından desteklenen PPPL Offsite Araştırma Programı teşekkür etmek istiyorum.

1. Anot hazırlık <ol><li> Ölçek nikel tozu (% 99.8, 300 mesh) ve katalizör tozu olarak 4.2:1 molar radyo göre itriyum tozu (% 99.9, 40 mesh). </li><li> Çok iyi katalizör tozu (% 99,9995, 200 mesh), grafit tozu ile karıştırın. Karışık toz sıkıca içi boş grafit çubuk (5 mm dış çaplı, 2.5 mm iç çapı ve 75 mm uzunluğunda) içine doldurun. Ni: C toplam molar radyo emin olun Y anot çubuk 94.8:4.2:1. SWCNT 9 sentezlemek için optimum oranıdır. </li><li> Katot çubuk (saf grafit, 13 mm çap) ve silindirik odasının içine doldurulmuş anot çubuk (paslanmaz çelik, 152 mm çapında ve 254 mm uzunluğunda) yükleyin. Yaklaşık 3 mm katot ve anot arasındaki boşluk mesafeyi ayarlayın. </li></ol> 2. Yüzey kurulum <ol><li> Interelectrode ekseninden yaklaşık 25 mm mesafede odanın içinde prizmasinin bir daimi mıknatıs (25 mm × 25 mm × 100 mm) yerleştirin. Ultra-High-Temp Alnico mıknatısdeneyde, 650 gram ağırlığa sahiptir. Interelectrode boşluğu alt daimi mıknatıs hakkında h = 75 mm (Şekil 1a) arasındaki mesafe yer almaktadır yapılandırma kullanın. </li><li> 25 mm ile 0,3 mm kalınlığı molibden levha (% 99,95) × 100 mm dikdörtgen şeklinde kesin. Aseton ve etanol ile 30 dakika süreyle% 50 sonicating genlik, 150 w çıkış gücü ve 40 kHz frekans ultrasonik dismembrator yüzey kontaminasyonu çıkarın. </li><li> Molibden levha takılarak sabit mıknatıslı bir tarafında yükleyin ve bu yan elektrotlar doğru döndürün. </li><li> Manyetik alan, bir Gaussmetre interelectrode boşluğu ölçün. Elektrotlar arasındaki ortalama manyetik alan yaklaşık 0.06 T. tutun </li></ol> 3. Ark plazma Ateşleme <ol><li> Pompa basıncı az 10 -1 Torr vakum ve daha sonra helyum (% 99.995) ile doldurdum 500 Torr silindirik odasının aşağı. </li><li> Ark elektrotlar DC weldi bağlayınng güç kaynağı ve güç kaynağı kurmak yaklaşık 75 A. akımın </li><li> Ark akımı, ark gerilimi ve deneme sonrası analizi için oda basıncı gerçek zamanlı değerleri kaydedin. </li><li> Aynı anda iki dijital kamera ile sağ ve ön görüş alanınız arkın video başlayın. 1 saniye sonra yayın başlangıç ​​anlık Şekil 1b gösterilmiştir (ön viewport) (sağ viewport) ve Şekil 1d. </li><li> 15 saniye boyunca yay çalıştırın. En az 20 dakika süreyle, doğal konveksiyon ile oda serinleyin. </li></ol> 4. Post-sentez analizi ve karakterizasyonu <ol><li> Ark plazmasının jet yönettiği molibden levha yüzeyi birikimi pul yırtma cımbız kullanın. Başka bir örnek katot siyah yakalı toplanır. SEM altında depolanması pul her iki tarafın morfolojisi (KV kullanılan 30 hızlandırma voltaj) dikkat edin. </li><li> Için numune hazırlama ile ilgili olarak<html> 60 dakika boyunca% 50 genlik sonicating ultrasonik dismembrator kullanarak sonicating sonra metanol-dağınık SWCNT çözüm süspansiyon döküm damla TEM analizi, numune ince filmler elde edilmiştir. JEOL TEM metanol çözüm buharlaşma sonra 100 KV gerilim altında ince film morfolojisi dikkate alınmalıdır. Örnek faiz pozisyonu için, elektron kırınımı deseni TEM ile ilişkili 50 cm CCD kamera uzunluğu ile elde edilebilir. </li><li> Karşılık gelen dalga boyu 514 nm, Raman spektroskopisi holografik optik ile 200 mW LEXEL 3000 Ar iyon lazer (ayarlanabilir tek hat çıkışı), 0,5 m spektrometre ve sıvı azot CCD dedektör soğutmalı dayalı bir mikro-Raman Sistemi yapıldı 2.33 eV enerji. Raman ölçümleri aralığı 100 cm -1 ile 3100 cm -1 kaplıydı ve grafen gevreği yüzey üzerinde gerçekleştirildi. </li></ol> 5. Temsilcisi Sonuçlar &quot;&gt; Odasının sağ ve ön görüş alanınız aynı anda elde edilen video görüntüleri Şekil 1b gösterilmiştir, d h = 75 mm. Bu görüntüler eksenel simetrik ark sütunu ile karşılaştırıldığında önemli bir dış manyetik alanın varlığında ark plazma sütun pertürbasyon göstermek bir manyetik alan 10 olmadan durumda gözlenen. Şekil 2a ve 2b, sırasıyla manyetik alan olmadan katot yaka ve B = 0.06 Tesla manyetik alan ile TEM altında toplanan SWCNT ve katalizör parçacıkların tipik morfoloji gösterir . Bu manyetik alan ile SWCNT bireysel SWCNT arasındaki van der Waals etkileşimi nedeniyle 2 ila 20 nm arasında değişen çaplarda demetleri içine yakın dolu olduğu görülebilir. Karşılaştırıldığında, manyetik alan olmadan SWCNT demetler halinde büyük çaplı ve Raman spektrum analizi ile tutarlı büyük bireysel çapı, var. Ayrıca, manyetik alan caŞekil 2a ve 2b gösterilen yüksek saflıkta SWCNT n sonucu. Manyetik alan en ilginç etkisi grafen gevreği aynı işlemi molibden sayfaya yakın birikimi gevreği yüzey elde edilebilir. Şekil 2c ve 2d SEM ve TEM grafen gevreği görüntülerin yanı sıra birkaç- . yerde alınan numunenin elde edilen tabaka grafen ark plazmasının jetleri karşılık gelmektedir. Şekil 2d içerlek grafen ile ilişkili elektron kırınım gösterir. Elektron kırınımı altıgen nokta desen sipariş kristal yapıları kanıt sunmaktadır. Raman spektrumu grafen gevreği ve SWCNT karakterizasyonu için güçlü bir araçtır. Grafen gözlenen tipik zirveleri, 514 nm dalgaboyu kullanarak, G ve 2D zirveleri ~ 1600 cm -1 ve -1 sırasıyla ~ 2700 cm . Gpik tüm sp2 karbon malzemeler görülebilir düzlemde titreşimler kaynaklanmaktadır. 2B tepe D tepe ikinci dereceden ancak dördüncü dereceden fonon momentumu döviz çift rezonans süreci nedeniyle düzensiz sistemleri bile görülür. Bu grafen karakterizasyonu önemli bir rol oynar. Yoğunluğu (2D) / I (G), yaklaşık 4 monolayer grafen ve sonraki tabakaların yanı sıra azalır, böylece grafen tabakalarının kalınlığı tahmin etmek mümkün. 11 Şekil 3 gösterir I değeri (2D ) / (G) birkaç katman grafen kanıt olabilir, 1 civarındadır. 120 ve 350 cm -1 Raman spektrumu arasında radyal solunum modu (RBM) C atomlarının radyal yönde tutarlı bir titreşim frekansı üzerinden nanotüp çapını tanımlamak için kullanılabilir . Frekans ve SWCNT çapı arasındaki deneysel ilişki ω RBM = A / d t + B, parametreler odemetleri oluşan tipik SWCNT için sırasıyla f ve 234 ve 10 cm -1 eşit B,. Şekil 3, ve manyetik alan olmadan SWCNT RBM frekansları, 1,52 ve 1,14 nm ortalama bireysel SWCNT çapları karşılık gelen 163,8 ve 215,2 cm -1, sırasıyla . <img alt="Şekil 1." src="/files/ftp_upload/3455/3455fig1.jpg" /> Şekil 1 FEMM 4.2 yazılımı ile simüle manyetik alan dağılımı (a), sağ viewport (b), interelectrode boşluğu konumlandırılmış durumda boşluk elektrot pozisyonu ve yönü manyetik alan şematik diyagramı ark plazmasının jet fotoğraf kalıcı mıknatıs (c) alt üzerinde 75 mm, ön viewport (d) ark plazmasının jet fotoğraf hakkında. <img alt="Şekil 2." src="/files/ftp_upload/3455/3455fig2.jpg" /> Şekil 2 sentezlenmiş Temsilcisi TEM görüntüManyetik alan olmadan SWCNT demetleri (a) ve (b) manyetik alan, manyetik alan (c) ve manyetik alan ile grafen TEM görüntü ile sentezlenen grafen gevreği tipik SEM görüntü SWCNT demetleri. Ankastre grafen kristal yapısını gösteren seçilen alanın elektron kırınım. <img alt="Şekil 3." src="/files/ftp_upload/3455/3455fig3.jpg" /> Şekil 3: 100-3100 cm -1 aralığında manyetik alan ile numunelerin Raman spektrumu . Ankastre: RBM frekansları çevresinde bir manyetik alan olmadan örnekleri Raman spektrumu. <img alt="Şekil 4." src="/files/ftp_upload/3455/3455fig4.jpg" /> Şekil 4, karbon ve nikel elektrotlar sağ ve sol tarafta gösterilen yoğunlukları, aynı bölgede bir arada bulunduğu 60 Not A. ark ve nikel karbon nano büyüme bölge ve sayı yoğunluğu .

<ol>
	<li>Dai, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrical+transport+properties+and+field+effect+transistors+of+carbon+nanotubes.">Electrical transport properties and field effect transistors of carbon nanotubes.</a> Nano. 1, 1-13 (2006).</li><li>Lai, K. W. C., Xi, N., Fung, C. K. M., Chen, H. Z., Tarn, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+the+band+gap+of+carbon+nanotube+for+infrared+sensors.">Engineering the band gap of carbon nanotube for infrared sensors.</a> Applied Physics Letters. 95, 221107-221107 (2009).</li><li>Gabor, N. M., Zhong, Z. H., Bosnick, K., Park, J., McEuen, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extremely+Efficient+Multiple+Electron-Hole+Pair+Generation+in+Carbon+Nanotube+Photodiodes.">Extremely Efficient Multiple Electron-Hole Pair Generation in Carbon Nanotube Photodiodes.</a> Science. 325, 1367-1371 (2009).</li><li>Liu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+storage+in+single-walled+carbon+nanotubes+at+room+temperature.">Hydrogen storage in single-walled carbon nanotubes at room temperature.</a> Science. 286, 1127-1129 (1999).</li><li>Keidar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic-field-enhanced+synthesis+of+single-wall+carbon+nanotubes+in+arc+discharge.">Magnetic-field-enhanced synthesis of single-wall carbon nanotubes in arc discharge.</a> Journal of Applied Physics. 103, 094318-094318 (2008).</li><li>Li, J., Volotskova, O., Shashurin, A., Keidar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlling+Diameter+Distribution+of+Catalyst+Nanoparticles+in+Arc+Discharge.">Controlling Diameter Distribution of Catalyst Nanoparticles in Arc Discharge.</a> Journal of Nanoscience and Nanotechnology. 11, 10047-10052 (2011).</li><li>Volotskova, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tailored+Distribution+of+Single-Wall+Carbon+Nanotubes+from+Arc+Plasma+Synthesis+Using+Magnetic+Fields.">Tailored Distribution of Single-Wall Carbon Nanotubes from Arc Plasma Synthesis Using Magnetic Fields.</a> Acs. Nano. 4, 5187-5192 (2010).</li><li>Volotskova, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-step+synthesis+and+magnetic+separation+of+graphene+and+carbon+nanotubes+in+arc+discharge+plasmas.">Single-step synthesis and magnetic separation of graphene and carbon nanotubes in arc discharge plasmas.</a> Nanoscale. 2, 2281-2285 (2010).</li><li>Farhat, S., Scott, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+the+arc+process+modeling+for+fullerene+and+nanotube+production.">Review of the arc process modeling for fullerene and nanotube production.</a> Journal of Nanoscience and Nanotechnology. 6, 1189-1210 (2006).</li><li>Keidar, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increasing+the+length+of+single-wall+carbon+nanotubes+in+a+magnetically+enhanced+arc+discharge.">Increasing the length of single-wall carbon nanotubes in a magnetically enhanced arc discharge.</a> Applied Physics Letters. 92, 043129-043129 (2008).</li><li>Ferrari, A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Raman+spectrum+of+graphene+and+graphene+layers.">Raman spectrum of graphene and graphene layers.</a> Physical Review Letters. 97, 187401-187401 (2006).</li></ol>

Biz ifşa etmek başka bir şey var.

Interelectrode boşluğu daimi mıknatıs alttan h = 75 mm uzaklıkta yerleştirilir olduğu durumda, Şekil 1b ve 1d gösterilen görüntü kareleri, mıknatıs pozisyon değişimi (mıknatıs kayma test dikkat edilmelidir Şekil 1c gösterildiği J × B kuvvet yönünde karşılık gelen x-yönünde ark jet akış sapma z-ekseni üzerinde mıknatıs dönüm) sonuçları boyunca. Aynı zamanda yay plazma sütun geometri anot nikel katalizör kaldırarak değişmedi old...

Özel reaktifler ve ekipman Tablo: <table border="1"><tbody><tr><th> Reaktifi Adı </th><th> Şirket </th><th> Katalog numarası </th><th> Yorumlar (isteğe bağlı) </th></tr><tr><td> Metanol </td><td> Acros Organics </td><td> 423950010 </td><td></td></tr><tr><td> Nikel tozu </td><td> Alfa Aesar </td><td> 10581 </td><td></td></tr><tr><td> Yttrium toz </td><td> Acros Organics </td><td> 318060050 </td><td></td></tr><tr><td> Grafit toz </td><td> Alfa Aesar </td><td> 40799 </td><td></td></tr><tr><td> Hollow grafit çubuk </td><td> Satürn Sektörler </td><td> POCO EDM 3 </td><td></td></tr><tr><td> Sürekli mıknatıs </td><td> McMaster-Carr </td><td> 57315K51 </td><td></td></tr><tr><td> Molibden levha </td><td> Dingqi Sci. ve Tech. </td><td> 080504-11 </td><td></td&gt; </tr><tr><td> Ultrasonik dismembrator </td><td> Fisher Scientific </td><td> Model 150T </td><td></td></tr><tr><td> Hall-etkisi Gaussmetre </td><td> AI </td><td> Model 100 </td><td></td></tr><tr><td> Kaynak güç kaynağı </td><td> Miller Electric </td><td> Altın Yıldız 600SS </td><td></td></tr><tr><td> Vakum pompası </td><td> J / B </td><td> DV-85N </td><td></td></tr><tr><td> SEM </td><td> Zeiss </td><td> LEO 1430VP </td><td></td></tr><tr><td> TEM </td><td> JEOL </td><td> 1200 EX </td><td></td></tr><tr><td> Raman </td><td> Horiba </td><td> HR800 </td><td></td></tr></tbody></table>

simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma

Tek duvarlı karbon nanotüpler (SWCNT) ve grafen Karbon nanoyapıların günümüzde moleküler sensörler, alan etkili transistör ve süper ince ve esnek 1-4 elektronik cihazlar için çok umut verici bir uygulama nedeniyle bilim adamları bir tufan ilgi çekmektedir . Anodik ark deşarjı anot malzemesi erozyon tarafından desteklenen gelişmekte olan yapıları göreceli olarak daha yüksek sıcaklıkta, belirli bir denge dışı süreçler ve yüksek karbon malzemenin bir akını sağlayabilir en pratik ve en etkili yöntemlerden biri, ve dolayısıyla- sentezlenmiş ürünler birkaç yapısal kusurlar ve daha iyi kristallik var. Ark deşarjı karbon nanoyapıların sentezini kontrol edilebilirlik ve esnekliği artırmak, manyetik alanlar ark plazmasının güçlü manyetik yanıtlarına göre sentez işlemi sırasında uygulanan olabilir. Gösterildi manyetik gelişmiş ark discharge gibi grafen sentezi 8 yol, SWCNT 5 ortalama uzunluğu artırmak, metalik katalizör parçacıklarını ve karbon nanotüpler 6 çapı dağılımı dar, metal ve yarı iletken karbon nanotüpler 7 oranı değiştirebilir . Ayrıca, homojen olmayan bir manyetik alan yay mevcut normal bileşeni ile tanıştığında, plazmalar jet J × B yönde boyunca Lorentz kuvveti oluşturmak ve karbon iyon parçacıkların etkin bir şekilde sağlanabilmesi yapmak ve vurgulamak faydalı olacaktır örnekler ısı akısı. Sonuç olarak, aynı anda, büyük ölçekli grafen gevreği ve yüksek saflıkta tek duvarlı karbon nanotüpler bu yeni manyetik gelişmiş anodik ark yöntemi ile üretildi. Arc görüntüleme, taramalı elektron mikroskobu (SEM), transmisyon elektron mikroskobu (TEM) ve Raman spektroskopisi karbon nanoyapıların karakterizasyonu analiz istihdam edilmiştir. Bu bulgular;fırsatlarının geniş spektrumlu yay koşullarını kontrol yoluyla plazmalardaki üretilen nanoyapıların özellikleri ile işlemek için.

Watch this Scientific Journal Video about Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma at JoVE.com

Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

Anodik ark deşarjı çeşitli karbon nanoyapıların sentezlemek için en pratik ve verimli yöntemlerden biridir. Ark kontrol edilebilirlik ve esnekliğini artırmak için, homojen olmayan bir manyetik alan, büyük ölçekli grafen gevreği ve yüksek saflıkta tek duvarlı karbon nanotüpler, tek adımlı bir sentez süreci ile tanıştı.

Tek duvarlı Karbon Nanotüpler Eşzamanlı Sentezi ve Manyetik geliştirilmiş Arc Plazma Grafen

Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very ...

simultaneous-synthesis-single-walled-carbon-nanotubes-graphene

Research

JoVE Journal

Bioengineering

15.2K Görüntüleme.  The George Washington University. Anodik ark deşarjı çeşitli karbon nanoyapıların sentezlemek için en pratik ve verimli yöntemlerden biridir. Ark kontrol edilebilirlik ve esnekliğini artırmak için, homojen olmayan bir manyetik alan, büyük ölçekli grafen gevreği ve yüksek saflıkta tek duvarlı karbon nanotüpler, tek adımlı bir sentez süreci ile tanıştı.

Video: Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

Graphene Coatings for Biomedical Implants

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with nanometer thick layers of graphene for applications as a stent material. Graphene was grown on copper substrates via chemical vapor deposition and then transferred onto nitinol substrates. In order to understand how the graphene coating could change biological response, cell viability of rat aortic endothelial cells and rat aortic smooth muscle cells was investigated. Moreover, the effect of graphene-coatings on cell adhesion and morphology was examined with fluorescent confocal microscopy. Cells were stained for actin and nuclei, and there were noticeable differences between pristine nitinol samples compared to graphene-coated samples. Total actin expression from rat aortic smooth muscle cells was found using western blot. Protein adsorption characteristics, an indicator for potential thrombogenicity, were determined for serum albumin and fibrinogen with gel electrophoresis. Moreover, the transfer of charge from fibrinogen to substrate was deduced using Raman spectroscopy. It was found that graphene coating on nitinol substrates met the functional requirements for a stent material and improved the biological response compared to uncoated nitinol. Thus, graphene-coated nitinol is a viable candidate for a stent material.

Graphene offers potential as a coating material for biomedical implants. In this study we demonstrate a method for coating nitinol alloys with nanometer thick layers of graphene and determine how graphene may influence implant response.

Biyomedikal implantlar için Grafen Kaplamalar

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with ...

Biyomühendislik

Localization and Relative Quantification of Carbon Nanotubes in Cells with Multispectral Imaging Flow Cytometry

Carbon-based nanomaterials, like carbon nanotubes (CNTs), belong to this type of nanoparticles which are very difficult to discriminate from carbon-rich cell structures and de facto there is still no quantitative method to assess their distribution at cell and tissue levels. What we propose here is an innovative method allowing the detection and quantification of CNTs in cells using a multispectral imaging flow cytometer (ImageStream, Amnis). This newly developed device integrates both a high-throughput of cells and high resolution imaging, providing thus images for each cell directly in flow and therefore statistically relevant image analysis. Each cell image is acquired on bright-field (BF), dark-field (DF), and fluorescent channels, giving access respectively to the level and the distribution of light absorption, light scattered and fluorescence for each cell. The analysis consists then in a pixel-by-pixel comparison of each image, of the 7,000-10,000 cells acquired for each condition of the experiment. Localization and quantification of CNTs is made possible thanks to some particular intrinsic properties of CNTs: strong light absorbance and scattering; indeed CNTs appear as strongly absorbed dark spots on BF and bright spots on DF with a precise colocalization.
This methodology could have a considerable impact on studies about interactions between nanomaterials and cells given that this protocol is applicable for a large range of nanomaterials, insofar as they are capable of absorbing (and/or scattering) strongly enough the light.

In this study, the main purpose was to monitor the cellular uptake and eventual exocytosis of carbon nanotubes (CNTs). From this perspective, we proposed here a unique method using multispectral imaging flow cytometry allowing a quantification and localization of CNTs in a statistically relevant number of cells.

Çokspektrumlu Görüntüleme Sitometrisi ile Hücreleri yerelleştirme ve Karbon nanotüpler Bağıl Kantitasyonu

Carbon-based nanomaterials, like carbon nanotubes (CNTs), belong to this type of nanoparticles which are very difficult to discriminate from carbon-rich ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of this hydrogel are two protein block-copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. A highly hydrophilic random coil is inserted into one of the block-copolymers for water retention. Mixing of the two protein block copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit with crosslinkers at either end that rapidly self-assembles into a hydrogel. This hydrogel is very stable under both acidic and basic conditions, at temperatures up to 50 &#176;C, and in organic solvents. The hydrogel rapidly reforms after shear-induced rupture. Incorporation of a &#34;docking station peptide&#34; into the hydrogel building block enables convenient incorporation of &#34;docking protein&#34;-tagged target proteins. The hydrogel is compatible with tissue culture growth media, supports the diffusion of 20 kDa molecules, and enables the immobilization of bioactive globular proteins. The application of the intein-mediated protein hydrogel as an organic-solvent-compatible biocatalyst was demonstrated by encapsulating the horseradish peroxidase enzyme and corroborating its activity.

We present the synthesis of a split-intein-mediated protein hydrogel. The building blocks of this hydrogel are two protein copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. Mixing of the two protein copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit that self-assembles into a hydrogel. This hydrogel is highly pH- and temperature-stable, compatible with organic solvents, and easily incorporates functional globular proteins.

Bir Intein aracılı yapay protein Hidrojel sentezi

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (&#949;-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young&#39;s modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Electrospun nanofibers have a high surface area to weight ratio, excellent mechanical integrity, and support cell growth and proliferation. These nanofibers have a wide range of biomedical applications. Here we fabricate keratin/ PCL nanofibers, using the electrospinning technique, and characterize the fibers for possible applications in tissue engineering.

Biyomedikal Mühendisliği için keratin bazlı nanofiber sentezi

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

Engineering Molecular Recognition with Bio-mimetic Polymers on Single Walled Carbon Nanotubes

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the optical window where biological samples are most transparent. Here, we outline techniques to adsorb amphiphilic polymers and polynucleic acids onto the surface of SWNTs to engineer their corona phases and create novel molecular sensors for small molecules and proteins. These functionalized SWNT sensors are both biocompatible and stable. Polymers are adsorbed onto the nanotube surface either by direct sonication of SWNTs and polymer or by suspending SWNTs using a surfactant followed by dialysis with polymer. The fluorescence emission, stability, and response of these sensors to target analytes are confirmed using absorbance and near-infrared fluorescence spectroscopy. Furthermore, we demonstrate surface immobilization of the sensors onto glass slides to enable single-molecule fluorescence microscopy to characterize polymer adsorption and analyte binding kinetics.

We present a protocol for engineering the corona phase of near infrared fluorescent single walled carbon nanotubes (SWNTs) using amphiphilic polymers and DNA to develop sensors for molecular targets without known recognition elements.

Tek Karbon Nanotüp Bio-mimetik Polimerler ile Mühendislik Moleküler Tanıma

Semiconducting single-wall carbon nanotubes (SWNTs) are a class of optically active nanomaterial that fluoresce in the near infrared, coinciding with the ...

Targeted Plasma Membrane Delivery of a Hydrophobic Cargo Encapsulated in a Liquid Crystal Nanoparticle Carrier

The controlled delivery of drug/imaging agents to cells is critical for the development of therapeutics and for the study of cellular signaling processes. Recently, nanoparticles (NPs) have shown significant promise in the development of such delivery systems. Here, a liquid crystal NP (LCNP)-based delivery system has been employed for the controlled delivery of a water-insoluble dye, 3,3&#8242;-dioctadecyloxacarbocyanine perchlorate (DiO), from within the NP core to the hydrophobic region of a plasma membrane bilayer. During the synthesis of the NPs, the dye was efficiently incorporated into the hydrophobic LCNP core, as confirmed by multiple spectroscopic analyses. Conjugation of a PEGylated cholesterol derivative to the NP surface (DiO-LCNP-PEG-Chol) enabled the binding of the dye-loaded NPs to the plasma membrane in HEK 293T/17 cells. Time-resolved laser scanning confocal microscopy and F&#246;rster resonance energy transfer (FRET) imaging confirmed the passive efflux of DiO from the LCNP core and its insertion into the plasma membrane bilayer. Finally, the delivery of DiO as a LCNP-PEG-Chol attenuated the cytotoxicity of DiO; the NP form of DiO exhibited ~30-40% less toxicity compared to DiOfree delivered from bulk solution. This approach demonstrates the utility of the LCNP platform as an efficient modality for the membrane-specific delivery and modulation of hydrophobic molecular cargos.

A liquid crystal nanoparticle (LCNP) nanocarrier is exploited as a vehicle for the controlled delivery of a hydrophobic cargo to the plasma membrane of living cells.

Sıvı Kristal Nanopartikül Carrier bir Hidrofobik Kargo Encapsulated, hedeflenen Plazma Zarı Teslimat

The controlled delivery of drug/imaging agents to cells is critical for the development of therapeutics and for the study of cellular signaling processes. ...

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of flexible polymers nor of rigid rods. Underlying filaments remain outstretched due to their non-vanishing backbone stiffness, which is quantified via the persistence length (lp), but they are also subject to strong thermal fluctuations. Their finite bending stiffness leads to unique, non-trivial collective mechanics of bulk networks, enabling the formation of stable scaffolds at low volume fractions while providing large mesh sizes. This underlying principle is prevalent in nature (e.g., in cells or tissues), minimizing the high molecular content and thereby facilitating diffusive or active transport. Due to their biological implications and potential technological applications in biocompatible hydrogels, semiflexible polymers have been subject to considerable study. However, comprehensible investigations remained challenging since they relied on natural polymers, such as actin filaments, which are not freely tunable. Despite these limitations and due to the lack of synthetic, mechanically tunable, and semiflexible polymers, actin filaments were established as the common model system. A major limitation is that the central quantity lp cannot be freely tuned to study its impact on macroscopic bulk structures. This limitation was resolved by employing structurally programmable DNA nanotubes, enabling controlled alteration of the filament stiffness. They are formed through tile-based designs, where a discrete set of partially complementary strands hybridize in a ring structure with a discrete circumference. These rings feature sticky ends, enabling the effective polymerization into filaments several microns in length, and display similar polymerization kinetics as natural biopolymers. Due to their programmable mechanics, these tubes are versatile, novel tools to study the impact of lp on the single-molecule as well as the bulk scale. In contrast to actin filaments, they remain stable over weeks, without notable degeneration, and their handling is comparably straightforward.

Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity.

DNA nanotüpler Semiflexible polimerler eğitim için çok yönlü bir araç olarak

Mechanical properties of complex, polymer-based soft matter, such as cells or biopolymer networks, can be understood in neither the classical frame of ...

Melt Electrospinning Writing of Three-dimensional Poly(&#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology with great potential for biomedical applications. The technique facilitates the direct deposition of biocompatible polymer fibers to fabricate well-ordered scaffolds in the sub-micron to micro scale range. The establishment of a stable, viscoelastic, polymer jet between a spinneret and a collector is achieved using an applied voltage and can be direct-written. A significant benefit of a typical porous scaffold is a high surface-to-volume ratio which provides increased effective adhesion sites for cell attachment and growth. Controlling the printing process by fine-tuning the system parameters enables high reproducibility in the quality of the printed scaffolds. It also provides a flexible manufacturing platform for users to tailor the morphological structures of the scaffolds to their specific requirements. For this purpose, we present a protocol to obtain different fiber diameters using melt electrospinning writing (MEW) with a guided amendment of the parameters, including flow rate, voltage and collection speed. Furthermore, we demonstrate how to optimize the jet, discuss often experienced technical challenges, explain troubleshooting techniques and showcase a wide range of printable scaffold architectures.

Melt Electrospinning Writing of Three-dimensional Poly(&amp;#949;-caprolactone) Scaffolds with Controllable Morphologies for Tissue Engineering Applications

This protocol serves as a comprehensive guideline to fabricate scaffolds via electrospinning with polymer melts in a direct writing mode. We systematically outline the process and define the appropriate parameter settings for achieving targeted scaffold architectures.

Üç boyutlu Poly(ε-caprolactone) İskele kontrol edilebilir türleri morfoloji ile Electrospinning yazma doku mühendisliği uygulamaları için erime

This tutorial reflects on the fundamental principles and guidelines for electrospinning writing with polymer melts, an additive manufacturing technology ...

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

Monolithic honeycomb structures have been attractive to multidisciplinary fields due to their high strength-to-weight ratio. Particularly, microhoneycomb monoliths (MHMs) with micrometer-scale channels are expected as efficient platforms for reactions and separations because of their large surface areas. Up to now, MHMs have been prepared by a unidirectional freeze-drying (UDF) method only from very limited precursors. Herein, we report a protocol from which a series of MHMs consisting of different components can be obtained. Recently, we found that cellulose nanofibers function as a distinct structure-directing agent towards the formation of MHMs through the UDF process. By mixing the cellulose nanofibers with water soluble substances which do not yield MHMs, a variety of composite MHMs can be prepared. This significantly enriches the chemical constitution of MHMs towards versatile applications.

Here, we present a general protocol to prepare a variety of microhoneycomb monoliths (MHMs) in which fluid can pass through with an extremely low pressure drop. MHMs obtained are expected to be used as filters, catalyst supports, flow-type electrodes, sensors and scaffolds for biomaterials.

Tek yönlü selüloz Nanofiber dağılması tarafından hazırlanan Microhoneycomb yekpare dayalı sıra: Yöntem ve uzantıları

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

Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver MWCNTs were prepared by the reductive deposition of silver from an aqueous solution of AgNO3 on the oxidized MWCNTs. Given the unique color of the CNTs, it was not possible to apply them to the minimum inhibitory concentration or mitochondrial toxicity assays to evaluate the toxicity and antibacterial properties, since they would interfere with the assays. The inhibition zone and minimum bactericidal concentration for the Ag-MWCNTs were measured and Live/Dead and Trypan Blue assays were used to measure the toxicity and antibacterial properties without interfering with the color of the CNTs.

In this study, antimicrobial nanomaterials were synthesized by acidic oxidation of multiwalled carbon nanotubes and subsequent reductive deposition of silver nanoparticles. Antimicrobial activity and cytotoxicity tests were performed with the as-prepared nanomaterials.

Gümüş nano tanecikleri ve onların antibakteriyel faaliyetleri ve sitotoksik özellikleri değerlendirilmesi ile modifiye çok duvarlı karbon nanotüpler sentezi

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver ...