Name: a protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating
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感谢Jason阿德金斯先生专家的技术援助。

1.脱脂商业醇溶蛋白<ol><li>测量150毫升丙酮与量筒并倒入250ml锥形烧瓶中。 <ol><li>而与在RT磁力搅拌器的自旋棒搅拌，加入30克工业醇溶蛋白粉末。密封烧瓶用铝箔开幕，并保持在引擎盖搅拌O / N。 </li></ol></li><li>滤液用滤纸将溶液。 <ol><li>洗用新鲜的丙酮（约50ml）滤液。静置10分钟，以使丙酮流失。 </li><li>用滤纸一起传送滤液下方，以一个大的盘，如细胞培养物正方形培养皿中。覆盖整个盘具有大滤纸残留丙酮的蒸发变慢。 </li><li>允许滤液在引擎盖O / N完全干燥。存储脱脂醇溶蛋白中在RT气密容器。 </li></ol></li></ol> 2.纯化醇溶蛋白的制备<ol><li>测量150毫升西澳之三用量筒和倾入到1000ml锥形瓶中。 <ol><li>测量350 ml的双无水乙醇与量筒倒入同一千毫升Erlenmeyer烧瓶。直到没有气泡从溶液混合物产生与旋杆 - （1000转800）剧烈搅拌。 </li></ol></li><li>边搅拌，添加20克脱脂商业醇溶蛋白粉。一次添加少量醇溶以避免结块包含空气在中间形成。继续搅拌O / N。 </li><li>转移整体解决方案的1000ml量筒。静置两天。在此期间，杂质将在缸的底部沉淀。 </li><li>将上清转移到旋转蒸发器与一个移液管，并且从上清液中尽可能除去乙醇。如乙醇的百分比减少，醇溶蛋白会出现在溶液中聚合。 </li><li>浸入/甲醇旋转冷冻含有麦胶蛋白的溶液聚集/干冰混合物并冷冻干燥在真空下-70℃。冷冻干燥之前，请确保整个解决方案中没有任何液体冻结。 注:冻干醇溶将形成多孔的固体。 </li><li>粉碎用研钵和杵将冷冻干燥的麦醇溶蛋白，并用咖啡研磨机研磨以得到细粉（&lt;0.5毫米）。产物转移到在RT气密容器和存储。 </li></ol> ECA 3.聚合反应与醇溶蛋白<ol><li>放置一个闪烁瓶（容积约为20毫升）在称量天平和皮。添加3.2克蒸馏水和6.8克无水乙醇在scitillation小瓶中。 </li><li>移动至闪烁瓶中上磁力搅拌器，放入一个磁自旋棒（20×3毫米），到小瓶，并且剧烈搅拌（800 - 1000转），直到从含水乙醇混合物没有产生气泡。 </li><li>添加40微升4当量盐酸的到小瓶中，同时搅拌。加入20毫克醇溶蛋白进入，而STI小瓶<html> RRING，并继续搅拌，直到醇溶蛋白粉末完全溶解在含水乙醇混合物。 </li><li>确保后醇溶蛋白的解决方案是清楚的肉眼，慢慢加入80 - 100微升ECA，而搅拌速度仍是800 - 1000 RPM。 <ol><li>降低搅拌速度至500rpm，并继续搅拌1小时。随着反应的进行，观察浊度这表明在聚合反应正在进行中。 </li></ol></li><li>当反应终止时，将溶液转移到离心管中，和平衡管的重量。以10,000×g离心20分钟离心的反应产物。在此期间，副产物的沉淀物和纳米颗粒保留在supernantant。副产物的主要成分是PACA均聚物。 </li><li>离心机之后，用移液管向一个闪烁瓶中（或任何气密容器）传送所生成的纳米粒子悬浮液（上清液），并将其存储在RT。 </li></ol>产品称号"&gt; 4。表征<ol><li>通过在20毫升闪烁瓶中3.2克水和6.8克无水乙醇混合制备出10克68重量％乙醇水溶液，搅拌至无气泡从溶液混合物产生的。 <ol><li>添加40微升4当量盐酸的到该溶液混合物中，同时进行搅拌。加入50μl纳米颗粒悬浮液的向制备的乙醇溶液中，同时进行搅拌。 </li></ol></li><li>通过使用上述制备的样品溶液测量用动态光散射（DLS）的纳米颗粒的大小，并按照制造商的说明。 注:最终产物的尺寸必须小于200纳米。如果它大于200纳米时，产品将不会对在延长的时间周期是稳定的。当就业ECA已经不新鲜了较大的纳米粒子产生的。 </li></ol> 5.检查产品的<ol><li>制备玻璃板诸如手镜。玻璃板表面用肥皂清水洗净。 - [R樱雪玻璃板的表面流动的水。干燥清洁的表面或不为下一个步骤干燥使用。 </li><li>喷洒）在玻璃板上的一部分在3.6中得到的纳米颗粒悬浮液，并冲洗掉立即用流动的水的表面上。 </li><li>喷玻璃板的表面上纯净水。观察涂层（含纳米粒子悬浮液喷）表面保持水层，同时未涂层的表面是清楚的。 </li></ol>

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There are several critical steps in the production of the nanoparticle suspension. If the purified gliadin contains impurities, the reaction with ECA will produce side products. Although these unwanted products can be removed from the reaction medium during the centrifugation stage, it lowers the yield of the major product. If the gliadin solution prepared during experimental step 2.3) does not show clear separation between supernatant and precipitate after two days, the solution needs to stand for longer time. Using fresh ECA is of utmost important because the shelf life of ECA is limited. 
The partially polymerized ECA in old ECA produces larger size nanoparticles that are not stable in the suspension medium. The concentration of the each reactant can be modified. However, the size and stability of the final product will be affected by the modification. Therefore it is necessary to see if the produced nanoparticles form aggregates or not. An optical microscope can be used for this purpose as the size of aggregates is in the range of a few micrometers. The produced nanoparticles begin to decompose at higher than 120 &#176;C. If the temperature of the coated surface has been raised to higher than 120 &#176;C, it needs to be coated again. The coated surface is stable under normal conditions. Unless the coated material is exposed to harsh conditions such as heating to higher than 120 &#176;C or immersing in alkaline water, the coating did not show any sign of degradation for several months.
The advantage of the coating process presented here is that the coating takes place very quickly because the coating process involves the fast adsorption of nanoparticles onto the glass (or other materials). The reason for adopting protein as a part of nanoparticle is that protein molecules possess both positive and negative charges in its backbone. Therefore, the hydrophilicity is not affected by the change in the pH of contacting water droplets. Coating via chemical reaction with glass is a slow process and requires toxic chemicals11 which could be a limitation of this technique. The presented coating can be applied in many different areas, such as: on glass (or Plexiglas) windows (automobile, building) for better view on rainy days; on metals for pre-treatment for chrome coating; on laparoscopes to prevent lens-fogging during laparoscopic surgery; on solar cells to prevent watermarks left after rain; and for post-treatment of janitorial work for fast drying and preventing water stains.

The goal of this article is to show the protocol for the preparation of nanoparticle suspension that modifies the wetting property of materials by a simple spray. The presented nanoparticle suspension is made from alkyl cyanoacrylate1 and a cereal protein, gliadin2,3. During the manufacturing process, protein aggregates are formed in aqueous ethanol4. Subsequent reaction with monomer (alkyl cyanoacrylate) produces the nanoparticle that is comprised of a protein core surrounded by linear polymer chains [poly(alkyl cyanoacrylate)]5.
Poly(alkyl cyanoacrylate)s are biodegradable and have been used for the production of nanoparticles via emulsion polymerization6. This reaction is spontaneously initiated by the hydroxyl groups dissociated from water or by other nucleophilic groups in the reaction medium7. In the case of the reaction presented in this article, the amine groups on the surface of protein aggregates initiate the polymerization reaction of alkyl cyanoacrylate monomers5,8. As a result of this reaction, nanoparticles are formed in the reaction medium. The core of the nanoparticle is protein aggregates and the outer layer is poly(alkyl cyanoacrylate) (PACA) chains. The prepared nanoparticle has a strong affinity on most materials (more precisely, any material which PACA can adsorb to) and adheres onto their surface to form a thin coating on a nanometer scale. A simple spray coating instantly turns the surface of the materials hydrophilic.
Gliadin is one of the main fractions of gluten, which is in the endosperms of wheat. Gliadins are mainly monomeric proteins with molecular weights around 28,000 - 55,000. Non-covalent bonds such as hydrogen bonds, ionic bonds and hydrophobic bonds are responsible for the aggregation of gliadins2. Although gliadin is chosen as a reactant in this article, many other proteins can also be used for the same purpose. However, the reaction condition needs to be modified accordingly because the condition for inducing aggregation is dependent on the type of protein to be employed8. Compared with other proteins, gliadin is more readily available, purification is simple, and production cost is low. Although ethyl cyanoacrylate (ECA) is chosen as a monomer for the presented reaction, other alkyl cyanoacrylates can also be used for the same reaction. The reason for choosing ECA is that it is readily available at low cost.

<table><tbody><tr><td>Ethyl cyanoacrylate (ECA) monomer</td><td>K&amp;amp;R International (Laguna Niguel, CA)</td><td>I-1605</td><td>Any pure ECA can be used.</td></tr><tr><td>Gliadin</td><td>MGP Ingredients, Inc (Atchison, KS)</td><td>Gift from the company</td><td>Gliadin can be purchased from Sigma-Aldrich (cat #: G3375-25G). Instead of gliadin, any commercial&amp;nbsp; gluten can be used.</td></tr><tr><td>HCl</td><td>Any</td><td></td><td>Any reagent grade chemical can be used.</td></tr><tr><td>Acetone</td><td>Any</td><td></td><td>Any reagent grade chemical can be used.</td></tr><tr><td>Methanol</td><td>Any</td><td></td><td>Any reagent grade chemical can be used.</td></tr><tr><td>Ethanol (100%)</td><td>Any</td><td></td><td>Any reagent grade chemical can be used.</td></tr><tr><td>Filter paper</td><td>Any</td><td></td><td>Any grade filter paper larger than 10 cm can be used.</td></tr><tr><td>Cell culture square dish</td><td>Any</td><td></td><td>Any dish larger than 20 x 20 cm can be used.</td></tr><tr><td>Coffee grinder</td><td>Any</td><td></td><td>Any coffee grinder can be used.</td></tr><tr><td>Rotary evaporator</td><td>Any</td><td></td><td>Any rotary evaporator can be used.</td></tr><tr><td>Freeze Dryer</td><td>Any</td><td></td><td>Any freeze dryer that can reach -70 &amp;deg;C can be used.</td></tr><tr><td>Centrifuge</td><td>Any</td><td></td><td>Any centrifuge that can apply 1,000 x g can be used.</td></tr><tr><td>Magnetic stirrer</td><td>Any</td><td></td><td>Any magnetic stirrer that can turn spin bar to 1,000 rpm can be used.</td></tr><tr><td>Dynamic Light Scattering (DLS)</td><td>Brookhaven Instruments Corporation</td><td>NanoBrook Omni Zeta Potential Analyzer</td><td>DLS from any company can be used.</td></tr><tr><td>Scanning Electron Microscope (SEM)</td><td>Carl Zeiss Inc.</td><td></td><td>Any SEM can be used.</td></tr><tr><td>Dynamic Contact Angle (DCA)</td><td>Thermo Cahn Instruments</td><td></td><td>Any DCA can be used.</td></tr></tbody></table>

a protocol for the production of gliadin-cyanoacrylate nanoparticles for hydrophilic coating

本文介绍用于生产基于蛋白的纳米颗粒，通过一个简单的喷涂改变疏水性表面的亲水性的协议。这些纳米颗粒通过烷基氰基丙烯酸酯的谷蛋白（麦醇溶蛋白）的分子的表面上的聚合反应来制备。烷基氰基丙烯酸酯为单体时，它被施加到材料的表面，可以立即在RT聚合。其聚合反应是通过在表面上的弱碱性或亲核物种，包括湿气的痕量启动。一旦聚合，聚合氰基丙烯酸烷基酯显示出很强的亲和力与对象材料，因为腈基是在聚（烷基氰基丙烯酸酯）的支柱。蛋白也作为引发剂用于这种聚合反应，因为它们含有能引发氰基丙烯酸酯的聚合胺基。如果聚集的蛋白用作一种引发剂，蛋白聚集是由疏水包围聚（烷基氰基丙烯酸酯）的烷基腈基丙烯酸酯的聚合反应后链。通过控制实验条件下，在纳米范围内的颗粒产生。所产生的纳米颗粒容易吸附到大多数材料，包括玻璃，金属，塑料，木材，皮革和织物的表面上。当材料的表面喷涂所生成的纳米颗粒悬浮液，并用水漂洗，纳米颗粒的胶束结构改变其构象，和亲水性蛋白质暴露在空气中。其结果是，纳米颗粒涂覆的表面改变为亲水性的。

纳米颗粒可在不同的反应条件来制备。醇溶蛋白形式聚集在广泛的乙醇含量5。然而，聚集体的大小需要是因为附加层（ 即 ，聚合的ECA）将被添加到该聚集到尽可能小，这个过程将作出最后的大小。如果颗粒的最终尺寸过大时，粒子将是不稳定的，并会容易地沉淀。因此，68％乙醇水溶液被选为反应介质4。所产生的纳米颗粒的大小是几百纳米的数量级上。用于与所产生的纳米粒子的亲水性涂层的工作机制如下所述。 为材料的涂层，这种纳米颗粒悬浮液（悬浮于68％乙醇中）喷洒接着用水漂洗掉靶材料的表面上。当南<html>悬浮在含水乙醇oparticles是靶材料的表面上喷涂，含水乙醇容易传播到更广泛的领域，因为乙醇的表面张力很低。含水乙醇的这个扩频操作快速，均匀提供靶材料的表面上的悬浮纳米颗粒。输送的纳米颗粒吸附到材料，因为佩克链的纳米颗粒的表面上的亲和力强。随后加入水改变纳米颗粒的构象。换句话说，所述纳米颗粒将打开其结构，以暴露内部的亲水性蛋白质在空气中。作为这种构象变化的结果，涂覆材料的表面变为亲水性的8。理解纳米颗粒的这种构象变化，这种情况是通过将纳米颗粒成各种乙醇溶液和监测zeta电位模仿。 1"SRC ="/文件/ ftp_upload / 54147 / 54147fig1.jpg"/&gt; 图1 Zeta电位和在各种一 queous乙醇溶液 制成的纳米粒子的直径 。该图显示了每个纳米粒子改变其构象和作为悬浮介质的乙醇含量降低其表面变得亲水。这是与纳米粒子的亲水性涂层的工作机制。误差棒代表平均值的标准误差。 <a href="https://www.jove.com/files/ftp_upload/54147/54147fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 图1显示了作为周围悬浮介质含有较少乙醇，从68％至50％在68％含水乙醇中制备的纳米颗粒粉碎成较小的颗粒。在此乙醇含量范围，ζ电位的误差棒是大的，这意味着<html>表面电荷的分布相当广泛，而且颗粒没有得到很好的稳定。随着水含量的增加，Zeta电位的绝对值急剧增大，直到乙醇含量降低到30％。这意味着，每个纳米颗粒的表面被高电荷和粒子表面的亲水性显著增加。在这之后，由于纳米粒子形成聚集体的Zeta电位的变化不大。当纳米颗粒悬浮液被用于亲水性涂层，因为颗粒吸附材料的表面上的这个聚集体形成不会发生。总之，对于亲水性涂层的方法包括喷射纳米颗粒悬浮液中，纳米粒子的吸附靶材料，和内蛋白分子与空气的暴露的表面上。在现实中，整个涂层过程发生在不到一分钟。 上传/ 54147 / 54147fig2.jpg"/&gt; 图2. 吸附纳米粒子。SEM的扫描电镜图像显示纳米颗粒的玻璃板的表面上的分布。由于均匀分布的纳米粒子，可见光的透射率不会显著的影响。 <a href="https://www.jove.com/files/ftp_upload/54147/54147fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 与纳米颗粒的涂层的结果，颗粒被吸附在靶材料的表面上。 图2示出了吸附在玻璃板的表面上的纳米颗粒。该图像是用场致发射扫描电子显微镜（SEM）。该SEM图像表明，所有的颗粒尺寸看起来小于100nm。由于样品溅射SEM成像之前涂敷，然而，应该有粒径的一些收缩时这一过程。该SEM图像表明，纳米颗粒被很好地分散在玻璃板的表面上，并有颗粒之间有足够的空间用于将光穿过。这种空间粒子的分布和颗粒的小尺寸（ 即 ，尺寸比可见光的波长小）解释为什么在玻璃板的透明性没有太大影响的涂层。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td></td><td>涂装前</td><td>涂层后</td></tr><tr><td>玻璃</td><td> 25.5±1.5° </td><td> 8.9±0.8° </td></tr><tr><td>聚苯乙烯</td><td> 52.7±1.2° </td><td> 6.8±0.8° </td></tr></tbody></table> 表1:底物的接触角之前和与纳米粒子涂覆之后。 表1示出由动态接触角（DCA）仪器测得的实验数据。在该试验中，使用了威廉米悬片法来确定纳米颗粒涂层的上表面可湿性9的效果。接触角的测定，是通过浸渍制成的材料的板，以被测试到的纳米颗粒悬浮液并用蒸馏水几秒钟的流漂洗制备的样品。所制备的板连续地浸渍在和从蒸馏水去除。涉及界面张力的浸入深度曲线作图和用于计算后退接触角10。在表中，示出了两个例子，玻璃和塑料（聚苯乙烯）的表面张力，滴后的涂布显著。 <img alt="图3" src="/files/ftp_upload/54147/54147fig3.jpg" /> 图3. 亲水涂料（1）的聚碳酸酯塑料表面的右半边示范涂有纳米粒子，而左半边是无涂层。当整个表面用喷雾器水洒，涂层表面没有形成水滴。 <a href="https://www.jove.com/files/ftp_upload/54147/54147fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 该涂层作用可容易地通过前和涂布后比较润湿效果可视化。 图3展示了一个塑料，聚碳酸酯的表面上的亲水性涂层的作用。而顶面的右半涂布，左半是完整的。洒在S这些表面的urface清楚地表明了涂层的效果。右半形成非常薄的水膜，而左半边形成水滴表示水不润湿的表面上。 <img alt="图4" src="/files/ftp_upload/54147/54147fig4.jpg" /> 图4.亲水涂料（2）。驾驶的汽车的座椅窗口的示范涂布的纳米粒子，而后排乘客窗口是涂覆。当两个窗户被用的洒水洒，涂层表面没有形成水滴。 <a href="https://www.jove.com/files/ftp_upload/54147/54147fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 额外的示范，所产生的纳米颗粒喷雾汽车玻璃（ 图4）的表面上。驾驶座窗口涂覆有纳米粒子，而不是涂在后排乘客的窗口。当水被同时在玻璃窗的喷涂，而在未涂覆玻璃形成水滴喷雾的水形成在涂覆的玻璃的薄水层。此照片清楚地表明，涂覆的玻璃提供了比未涂覆的一大部分更好的可视性。

Watch this Scientific Journal Video about A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating at JoVE.com

A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic. The produced nanoparticle is an assembly of gliadin-cyanoacrylate diblock copolymers. Spray coating with the produced nanoparticle changes the surface of target material to a hydrophilic surface.

一种醇溶蛋白氰基丙烯酸酯纳米粒子为亲水涂料生产协议

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic by a simple spray ...

a-protocol-for-production-gliadin-cyanoacrylate-nanoparticles-for

Nanyang Technological University

Research

JoVE Journal

Chemistry

6.9K 次观看.  USDA/ARS/NCAUR. This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic. The produced nanoparticle is an assembly of gliadin-cyanoacrylate diblock copolymers. Spray coating with the produced nanoparticle changes the surface of target material to a hydrophilic surface.

视频: A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating

Formulation of Diblock Polymeric Nanoparticles through Nanoprecipitation Technique

Nanotechnology is a relatively new branch of science that involves harnessing the unique properties of particles that are nanometers in scale (nanoparticles). Nanoparticles can be engineered in a precise fashion where their size, composition and surface chemistry can be carefully controlled. This enables unprecedented freedom to modify some of the fundamental properties of their cargo, such as solubility, diffusivity, biodistribution, release characteristics and immunogenicity. Since their inception, nanoparticles have been utilized in many areas of science and medicine, including drug delivery, imaging, and cell biology1-4. However, it has not been fully utilized outside of "nanotechnology laboratories" due to perceived technical barrier. In this article, we describe a simple method to synthesize a polymer based nanoparticle platform that has a wide range of potential applications. 
The first step is to synthesize a diblock co-polymer that has both a hydrophobic domain and hydrophilic domain. Using PLGA and PEG as model polymers, we described a conjugation reaction using EDC/NHS chemistry5 (Fig 1). We also discuss the polymer purification process. The synthesized diblock co-polymer can self-assemble into nanoparticles in the nanoprecipitation process through hydrophobic-hydrophilic interactions.
The described polymer nanoparticle is very versatile. The hydrophobic core of the nanoparticle can be utilized to carry poorly soluble drugs for drug delivery experiments6. Furthermore, the nanoparticles can overcome the problem of toxic solvents for poorly soluble molecular biology reagents, such as wortmannin, which requires a solvent like DMSO. However, DMSO can be toxic to cells and interfere with the experiment. These poorly soluble drugs and reagents can be effectively delivered using polymer nanoparticles with minimal toxicity. Polymer nanoparticles can also be loaded with fluorescent dye and utilized for intracellular trafficking studies. Lastly, these polymer nanoparticles can be conjugated to targeting ligands through surface PEG. Such targeted nanoparticles can be utilized to label specific epitopes on or in cells7-10.

This article describes a nanoprecipitation method to synthesize polymer-based nanoparticles using diblock co-polymers. We will discuss the synthesis of diblock co-polymers, the nanoprecipitation technique, and potential applications.

制定通过Nanoprecipitation技术嵌段聚合物纳米粒子

Nanotechnology is a relatively new branch of science that involves harnessing the unique properties of particles that are nanometers in scale ...

科研

生物工程

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

SDF-1α - 壳聚糖硫酸葡聚糖纳米粒子的制备与表征

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

化学

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

使用聚苯乙烯<em&gt;块</em&gt; - 聚（丙烯酸）涂层的金属纳米颗粒作为单体他们均聚物和共聚物聚合

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

碳水化合物和聚酸酐纳米粒子功能化的高通量合成

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Preparation of Hydroxy-PAAm Hydrogels for Decoupling the Effects of Mechanotransduction Cues

It is now well established that many cellular functions are regulated by interactions of cells with physicochemical and mechanical cues of their extracellular matrix (ECM) environment. Eukaryotic cells constantly sense their local microenvironment through surface mechanosensors to transduce physical changes of ECM into biochemical signals, and integrate these signals to achieve specific changes in gene expression. Interestingly, physicochemical and mechanical parameters of the ECM can couple with each other to regulate cell fate. Therefore, a key to understanding mechanotransduction is to decouple the relative contribution of ECM cues on cellular functions.
Here we present a detailed experimental protocol to rapidly and easily generate biologically relevant hydrogels for the independent tuning of mechanotransduction cues in vitro. We chemically modified polyacrylamide hydrogels (PAAm) to surmount their intrinsically non-adhesive properties by incorporating hydroxyl-functionalized acrylamide monomers during the polymerization. We obtained a novel PAAm hydrogel, called hydroxy-PAAm, which permits immobilization of any desired nature of ECM proteins. The combination of hydroxy-PAAm hydrogels with microcontact printing allows to independently control the morphology of single-cells, the matrix stiffness, the nature and the density of ECM proteins. We provide a simple and rapid method that can be set up in every biology lab to study in vitro cell mechanotransduction processes. We validate this novel two-dimensional platform by conducting experiments on endothelial cells that demonstrate a mechanical coupling between ECM stiffness and the nucleus.

We present a new polyacrylamide hydrogel, called hydroxy-PAAm, that allows a direct binding of ECM proteins with minimal cost or expertise. The combination of hydroxy-PAAm hydrogels with microcontact printing facilitates independent control of many cues of the natural cell microenvironment for studying cellular mechanostransduction.

去耦力学传递线索的影响制备羟基聚丙烯酰胺水凝胶的

It is now well established that many cellular functions are regulated by interactions of cells with physicochemical and mechanical cues of their ...

Synthesis of Thermogelling Poly(N-isopropylacrylamide)-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering

Injectable biomaterials are defined as implantable materials that can be introduced into the body as a liquid and solidify in situ. Such materials offer the clinical advantages of being implanted minimally invasively and easily forming space-filling solids in irregularly shaped defects. Injectable biomaterials have been widely investigated as scaffolds for tissue engineering. However, for the repair of certain load-bearing areas in the body, such as the intervertebral disc, scaffolds should possess adhesive properties. This will minimize the risk of dislocation during motion and ensure intimate contact with the surrounding tissue, providing adequate transmission of forces. Here, we describe the preparation and characterization of a scaffold composed of thermally sensitive poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAM-g-CS) and alginate microparticles. The PNIPAAm-g-CS copolymer forms a viscous solution in water at RT, into which alginate particles are suspended to enhance adhesion. Above the lower critical solution temperature (LCST), around 30 &#176;C, the copolymer forms a solid gel around the microparticles. We have adapted standard biomaterials characterization procedures to take into account the reversible phase transition of PNIPAAm-g-CS. Results indicate that the incorporation of 50 or 75 mg/ml&#160;alginate particles into 5% (w/v) PNIPAAm-g-CS solutions quadruple the adhesive tensile strength of PNIPAAm-gCS alone (p&#60;0.05). The incorporation of alginate microparticles also significantly increases swelling capacity of PNIPAAm-g-CS (p&#60;0.05), helping to maintain a space-filling gel within tissue defects. Finally, results of the in vitro toxicology assay kit, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and Live/Dead viability assay indicate that the adhesive is capable of supporting the survival and proliferation of encapsulated Human Embryonic Kidney (HEK) 293 cells over 5 days.

Synthesis of Thermogelling PolyN-isopropylacrylamide-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering

An injectable tissue engineering scaffold composed of poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAm-g-CS)-containing alginate microparticles was prepared. The adhesive strength, swelling properties and in vitro biocompatibility are analyzed in this study. The characterization techniques developed here may be applicable to other thermogelling systems.

组织工程热胶凝聚（N-异丙基丙烯酰胺） - 接枝 - 硫酸软骨素复合材料的海藻酸钠微粒的合成

Injectable biomaterials are defined as implantable materials that can be introduced into the body as a liquid and solidify in situ. Such materials offer ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

通过反应挤出、微流体、自组装和电纺丝制备多长尺度可降解 Thermoresponsive 水凝胶

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

Synthesis of Stimuli-responsive Nanogels using Aqueous One-step Crosslinking and Co-nanopolymerization

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to their versatile bottom-up synthesis and biocompatibility. While various methods have been employed for nanogel synthesis to date, very few have achieved it without the use of harsh organic solvents or high temperatures that can damage the integrity of the biological payload. In contrast, the methodology presented here accomplishes the synthesis of sub-100 nm sized, protein-loaded nanogels using mild reaction conditions. Here, we present a method for the non-covalent encapsulation of protein-based payloads within nano-gels that were synthesized using an aqueous-based, single-step, crosslinking copolymerization technique. In this technique, we initially electrostatically bind a protein-based payload to a cationic quaternary ammonium monomer and simultaneously cross-link and co-polymerize it using ammonium persulfate and N,N,N&#39;,N&#39;-tetramethylethylenediamine to form nanogels that entrap the protein payload. The size and polydispersity index of the nanogels is determined using dynamic light scattering (DLS), while the surface morphology is assessed by transmission electron microscopy (TEM). The mass of protein entrapped within nanogels is determined by calculating the encapsulation efficiency. Furthermore, the controlled-release ability of the nanogels via the gradual degradation of redox-responsive structural elements is also assessed in bioreduction assays. We provide examples of nanoparticle optimization data to demonstrate all caveats of nanogel synthesis and characterization using this technique. In general, uniformly sized nanogels were obtained with an average size of 57 nm and a polydispersity index value of 0.093. A high encapsulation efficiency of 76% was achieved. Furthermore, the nanogels exhibited controlled release of up to 86% of the encapsulated protein by gradual degradation of novel redox-responsive components in the presence of glutathione over 48 h.

Nanogels are an excellent and versatile nanoparticle platform for the delivery of biologics. Stimuli-responsive poly(ethylene) glycol-based polymeric nano-gels, capable of encapsulating protein-based payloads, were synthesized using a one-step cross-linking co-nanopolymerization strategy in aqueous conditions. The optimal fabrication and characterization of these novel nanoparticles are presented here.

使用水性一步交联和共纳米聚合合成刺激响应纳米凝胶

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to ...

Flash NanoPrecipitation for the Encapsulation of Hydrophobic and Hydrophilic Compounds in Polymeric Nanoparticles

The formulation of a therapeutic compound into nanoparticles (NPs) can impart unique properties. For poorly water-soluble drugs, NP formulations can improve bioavailability and modify drug distribution within the body. For hydrophilic drugs like peptides or proteins, encapsulation within NPs can also provide protection from natural clearance mechanisms. There are few techniques for the production of polymeric NPs that are scalable. Flash NanoPrecipitation (FNP) is a process that uses engineered mixing geometries to produce NPs with narrow size distributions and tunable sizes between 30 and 400 nm. This protocol provides instructions on the laboratory-scale production of core-shell polymeric nanoparticles of a target size using FNP. The protocol can be implemented to encapsulate either hydrophilic or hydrophobic compounds with only minor modifications. The technique can be readily employed in the laboratory at milligram scale to screen formulations. Lead hits can directly be scaled up to gram- and kilogram-scale. As a continuous process, scale-up involves longer mixing process run time rather than translation to new process vessels. NPs produced by FNP are highly loaded with therapeutic, feature a dense stabilizing polymer brush, and have a size reproducibility of &#177; 6%.

Flash NanoPrecipitation (FNP) is a scalable approach to produce polymeric core-shell nanoparticles. Lab-scale formulations for the encapsulation of hydrophobic or hydrophilic therapeutics are described.

闪速纳米沉淀法包聚物纳米粒子中疏水亲水化合物的作用

The formulation of a therapeutic compound into nanoparticles (NPs) can impart unique properties. For poorly water-soluble drugs, NP formulations can ...

Injectable Supramolecular Polymer-Nanoparticle Hydrogels for Cell and Drug Delivery Applications

These methods describe how to formulate injectable, supramolecular polymer-nanoparticle (PNP) hydrogels for&#160;use as biomaterials. PNP hydrogels are composed of two components: hydrophobically modified cellulose as the network polymer and self-assembled core-shell nanoparticles that act as non-covalent cross linkers through dynamic, multivalent interactions. These methods describe both the formation of these self-assembled nanoparticles through nanoprecipitation as well as the formulation and mixing of the two components to form hydrogels with tunable mechanical properties. The use of dynamic light scattering (DLS) and rheology to characterize the quality of the synthesized materials is also detailed. Finally, the utility of these hydrogels for drug delivery, biopharmaceutical stabilization, and cell encapsulation and delivery is demonstrated through in vitro experiments to characterize&#160;drug release, thermal stability, and cell settling and viability. Due to its biocompatibility, injectability, and mild gel formation conditions, this hydrogel system is a readily tunable platform suitable for a range of biomedical applications.

This protocol describes the synthesis and formulation of injectable, supramolecular polymer-nanoparticle (PNP) hydrogel biomaterials. Applications of these materials for drug delivery, biopharmaceutical stabilization, and cell encapsulation and delivery are demonstrated.

用于细胞和药物输送应用的可注射超分子-纳米粒子水凝胶

These methods describe how to formulate injectable, supramolecular polymer-nanoparticle (PNP) hydrogels for&#160;use as biomaterials. PNP hydrogels are ...