等离子体科学和技术（NSF / DOE伙伴关系，这项工作是支持NSF批准号：CBET - 0853777和能源部批准号：DE - SC0001169），STTR第一期工程（NSF STTR期我No.1010133）。作者要感谢PPPL异地聚变能源科学办公室支持支持弧实验的研究计划。

1。阳极制备<ol><li>规模的镍粉（99.8％，300目）和钇粉（99.9％，40目）按4.2:1作为催化剂粉末的摩尔电台。 </li><li>混合石墨粉末的催化剂粉末（99.9995％，200目），非常好。填充到中空石墨棒（外直径5毫米，2.5毫米内径和75毫米的长度）牢牢的混合粉。确保总摩尔电台的C：倪：在阳极棒Ÿ是94.8:4.2:1，这是最佳比例合成单壁碳纳米管9。 </li><li>安装阴极杆（纯石墨，直径13毫米）和内圆柱腔的填充阳极棒（不锈钢，直径为152毫米和254毫米的长度）。调整阴极和阳极之间的差距约3毫米的距离。 </li></ol> 2。基板安装<ol><li>将长方体内室在距离约25毫米的极间轴永磁（25毫米× 25毫米× 100毫米）。超高温的铝镍钴磁铁在实验中，有650克的重量。使用时，极间的差距是关于H = 75毫米（ 图1a）由永久磁铁的底部的距离放置的配置。 </li><li>剪下的0.3毫米厚度25毫米的钼板（99.95％）× 100毫米的长方形。取出丙酮和乙醇超声50％的幅度，150 W的输出功率和40 kHz的频率为30分钟的超声波dismembrator的表面污染。 </li><li>安装附加永磁一侧的钼板材，电极转向这一面。 </li><li>极间的差距由高斯计测量磁场。保持电极之间的磁场平均约为0.06 T. </li></ol> 3。电弧等离子体点火<ol><li>泵圆柱腔压力小于10 -1托真空，然后填充氦气（99.995％）至500托。 </li><li>电弧电极连接直流weldi吴电源和成立约75答：电弧电流电源</li><li>记录的电弧电流，电弧电压和压力后的实验分析室的实时值。 </li><li>启动电弧同时由两个数码相机的权利和前视口中的视频。 1弧秒后开始的快照如图1b所示（右视口）和图1d（前视口）。 </li><li>运行15秒的弧线。通过自然对流降温室至少20分钟。 </li></ol> 4。合成后的分析和表征<ol><li>使用镊子撕下从表面钼表是针对电弧等离子体喷射沉积片状。另一个样品是采自阴极黑领。扫描电子显微镜下观察沉积片状双方的形态（加速电压为30千伏是）。 </li><li>关于样品制备<html> TEM分析，薄膜样品，获得铸造暂停甲醇 - 分散SWCNT溶液后60分钟使用50％的超声振幅超声波dismembrator的超声​​下降。 JEOL透射电镜下观察薄膜的甲醇溶液挥发后的100千伏的电压形态。对于样品中的兴趣地位，可与CCD相机长50厘米，与透射电镜电子衍射。 </li><li>拉曼光谱是基于一个200兆瓦的LEXEL 3000氩离子激光器（可调的单行输出），全息光学，0.5米光谱仪和液氮冷却的CCD探测器的微拉曼系统;波长为514纳米，它对应于2.33 eV的能量。拉曼光谱测量覆盖100厘米-1至3100 cm - 1的范围，并进行石墨薄片表面上。 </li></ol> 5。代表性的成果“&gt;视频快照，同时从分庭的权利和前视口中获得如图1b所示，为H D = 75毫米。这些照片反映了外部磁场的存在电弧等离子体柱的轴对称弧柱比较显著扰动观察到的情况下没有一个磁场10。 图2A和2B显示阴极无磁场的领子和透射电子显微镜下的B = 0.06特斯拉的磁场，分别收集的单壁碳纳米管和催化剂颗粒的典型形态。由此可以看出磁场单壁碳纳米管是紧密堆积成捆，直径范围从2至20纳米，由于个人单壁碳纳米管之间的相互作用的范德华的。相比较而言，没有磁场的单壁碳纳米管束的直径较大和较大的个体的直径，这与拉曼光谱的分析是一致的。此外，磁场CA在与图2a和图2b所示的纯度较高的单壁碳纳米管的n个结果。 最有趣的磁场影响石墨薄片可以从表面沉积片，这是钼板在同一进程中密切获得。图2C和 2D显示的石墨薄片的SEM和TEM图像以及数层石墨的位置采取样本获得相当于电弧等离子体喉。 图2d中的插图显示的电子衍射图案与石墨相关联。六角形点电子衍射呈现有序的晶体结构的证据。 拉曼光谱是一个强大的工具石墨片和单壁碳纳米管的特性。在石墨观察到典型的峰〜1600厘米-1和2700厘米-1分别为G和2D峰，激发波长为514纳米。在G峰源于在平面上可观察到的所有SP2碳材料的振动。 2D峰是一个二阶的D峰，但即使在非无序系统，由于第四阶声子动量交换双共振过程。它起着至关重要的作用在石墨表征。强度我（2D）/我（G）是单层石墨约4和后续图层此外下降，从而有可能估计石墨层的厚度。11图 3表示，我的价值（ 2D） /我（G）是1左右，可少层石墨的证据。可用于识别通过在径向方向的C原子的相干振动频率的碳纳米管直径的径向呼吸模（RBM）的120和350厘米-1拉曼光谱之间。之间的频率和单壁碳纳米管直径的实验关系RBM的ω= A / D T + B，其中参数Øf一个和b等于234和10厘米-1，分别形成了典型的单壁碳纳米管束。从图3中，没有磁场的单壁碳纳米管RBM的频率是163.8和215.2 厘米 -1，相应的平均个人的单壁碳纳米管直径为1.52和1.14 nm，分别。 <img alt="图1。" src="/files/ftp_upload/3455/3455fig1.jpg" /> 图1。论坛经济部长会议4.2软件模拟的磁场分布（a），电弧等离子体喷射的照片从右边的视口（B），电极的位置和方向的磁场时，极间的差距是定位的差距示意图约75毫米以上的永久磁铁（C）的底部，以及电弧等离子体喷射从前面的视口（D）的照片。 <img alt="图2。" src="/files/ftp_upload/3455/3455fig2.jpg" /> 图2代表TEM图像合成。（一）无磁场的单壁碳纳米管束和单壁碳纳米管束与磁场（B），典型的磁场（C），和TEM图像与磁场的石墨合成的石墨薄片的SEM图像。插图是选定区域的石墨晶体结构的电子衍射花样。 <img alt="图3。" src="/files/ftp_upload/3455/3455fig3.jpg" /> 图3在100至3100厘米-1范围内的磁场与样品的拉曼光谱。插图：没有RBM的频率周围磁场的样品的拉曼光谱。 <img alt="图4。" src="/files/ftp_upload/3455/3455fig4.jpg" /> 图4纳米结构的生长地区和碳和镍60答：请注意，碳和镍电极上的左，右右手边所示的密度，在同一地区并存的弧数密度。

<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>

我们什么都没有透露。

在图1b和 1d所示的关于H = 75毫米永磁底部的距离放置的情况下，极间的差距，视频快照，应该指出，改变磁铁的位置（我们测试的磁铁移位沿Z轴和转动的磁铁）的结果偏离弧对应的J × B 力方向如图1c所示，在x方向的喷流。有人还指出，电弧等离子体柱的几何形状没有改变，从阳极去除镍催化剂。这意味着，磁场对镍催化剂颗粒运动的影响，不影响整体几何等离子体柱。?...

特定的试剂和设备表： <table border="1"><tbody><tr><th>试剂名称</th><th>公司</th><th>目录编号</th><th>评论（可选） </th></tr><tr><td>甲醇</td><td> Acros Organics公司</td><td> 423950010 </td><td></td></tr><tr><td>镍粉</td><td>阿法埃莎</td><td> 10581 </td><td></td></tr><tr><td>钇粉末</td><td> Acros Organics公司</td><td> 318060050 </td><td></td></tr><tr><td>石墨粉末</td><td>阿法埃莎</td><td> 40799 </td><td></td></tr><tr><td>中空石墨棒</td><td>土星工业</td><td> POCO的EDM 3 </td><td></td></tr><tr><td>永磁</td><td>麦克马斯特 - 卡尔</td><td> 57315K51 </td><td></td></tr><tr><td>钼表</td><td> Dingqi科学。高科技。 </td><td> 080504-11 </td><td></td&gt; </tr><tr><td>超声波 dismembrator </td><td> Fisher Scientific则</td><td>型号150T </td><td></td></tr><tr><td>霍尔效应磁强计</td><td>大赦国际</td><td>型号100 </td><td></td></tr><tr><td>焊接电源</td><td>米勒电器</td><td>黄金之星600SS </td><td></td></tr><tr><td>真空泵</td><td> J / B </td><td> DV - 85N </td><td></td></tr><tr><td>教育统筹局局长</td><td>蔡司</td><td> LEO 1430VP </td><td></td></tr><tr><td>透射电镜</td><td> JEOL </td><td> 1200 EX </td><td></td></tr><tr><td>拉曼</td><td>堀场</td><td> HR800 </td><td></td></tr></tbody></table>

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

如单壁碳纳米管（SWCNT）和石墨的碳纳米结构吸引蜂拥而至时下由于他们非常有前途的应用分子传感器，场效应晶体管，超薄，灵活的电子设备1-4学者的兴趣。阳极弧放电的阳极材料的侵蚀支持是最实际和最有效的方法之一，它可以提供特定的非平衡过程和碳材料的大量涌入，在相对较高的温度发展中国家的结构，因此，作为合成产品有一些结构上的缺陷和更好的结晶。 为了进一步提高电弧放电合成碳纳米结构的可控性和灵活性，磁场可以被应用在合成过程中根据电弧等离子体的强磁场的反应。事实证明，磁增强弧dischARGE可以增加5的单壁碳纳米管的平均长度，狭窄的金属催化剂颗粒和碳纳米管 6的直径分布，并改变金属的比例和半导体碳纳米管，以及导致石墨合成8。 此外，它是值得的备注，当我们引进与正常的电弧电流的组件非均匀磁场，洛伦兹力J × B的方向沿可以产生等离子体喷射，使碳离子颗粒有效地提供和热通量的样本。因此，大型石墨片和高纯度的单壁碳纳米管，同时产生这种新的磁增强阳极弧方法。电弧成像，扫描电子显微镜（SEM），透射电子显微镜（TEM）和拉曼光谱来分析碳纳米结构的表征。这些结果表明广泛的机会来操作，通过控制电弧条件产生的等离子体中的纳米结构的特性。

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

阳极电弧放电合成各种碳纳米结构的最实际和最有效的方法之一。为了提高电弧的可控性和灵活性，非均匀磁场被引入大型石墨片和高纯度的单壁碳纳米管的过程中一步合成。

同时合成单壁碳纳米管和石墨在电弧等离子体磁增强

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 次观看.  The George Washington University. 阳极电弧放电合成各种碳纳米结构的最实际和最有效的方法之一。为了提高电弧的可控性和灵活性，非均匀磁场被引入大型石墨片和高纯度的单壁碳纳米管的过程中一步合成。

视频: 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.

生物医学植入物的石墨涂料

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

科研

生物工程

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.

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.

内含肽介导的人工蛋白水凝胶的合成

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.

基于角蛋白纳米纤维生物医学工程合成

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.

工程分子识别与单壁碳纳米管仿生聚合物

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.

疏水货物封装有针对性的质膜交付在液晶纳米颗粒载体

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 纳米管作为研究半聚合物的万能工具

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.

用于组织工程应用的三维聚 (ε-内) 支架的熔体静电纺丝

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.

纤维素碳纤维溶胶单向冷冻干燥制备 Microhoneycomb 石柱: 方法和外延

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.

银纳米粒子改性多壁碳纳米管的合成及其抗菌活性和细胞毒性的评价

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