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>

<ol>
	<li>Vauthier, C., Dubernet, C., Fattal, E., Pinto-Alphandary, H., Couvreur, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poly(alkylcyanoacrylates)+as+biodegradable+materials+for+biomedical+applications.">Poly(alkylcyanoacrylates) as biodegradable materials for biomedical applications.</a> Adv. Drug Deliver. Rev. 55, 519-548 (2003).</li><li>Wieser, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemistry+of+gluten+proteins.">Chemistry of gluten proteins.</a> Food Microbiol. 24, 115-119 (2007).</li><li>Bietz, J. A., Wall, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identity+of+high+molecular+weight+gliadin+and+ethanol+soluble+glutenin+subunits+of+wheat:+Relation+to+gluten+structure.">Identity of high molecular weight gliadin and ethanol soluble glutenin subunits of wheat: Relation to gluten structure.</a> Cereal Chem. 57, 415-421 (1980).</li><li>Kim, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+composites+by+using+gliadin+as+a+bonding+material.">Production of composites by using gliadin as a bonding material.</a> J. Cereal Sci. 54, 168-172 (2011).</li><li>Kim, S., Kim, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+gliadin-poly(ethyl+cyanoacrylate)+nanoparticles+for+hydrophilic+coating.">Production of gliadin-poly(ethyl cyanoacrylate) nanoparticles for hydrophilic coating.</a> J. Nanopart. Res. 16, 1-10 (2014).</li><li>Behan, N., Birkinshaw, C., Clarke, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poly+n-butyl+cyanoacrylate+nanoparticles:+a+mechanistic+study+of+polymerisation+and+particle+formation.">Poly n-butyl cyanoacrylate nanoparticles: a mechanistic study of polymerisation and particle formation.</a> Biomaterials. 22, 1335-1344 (2001).</li><li>Nicolas, J., Couvreur, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+poly(alkyl+cyanoacrylate)-based+colloidal+nanomedicines.">Synthesis of poly(alkyl cyanoacrylate)-based colloidal nanomedicines.</a> Wiley Interdiscip. Rev. Nanomed. Nanobiotechnol. 1, 111-127 (2009).</li><li>Kim, S., Evans, K., Biswas, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+BSA-poly(ethyl+cyanoacrylate)+nanoparticles+as+a+coating+material+that+improves+wetting+property.">Production of BSA-poly(ethyl cyanoacrylate) nanoparticles as a coating material that improves wetting property.</a> Colloid Surface. B. 107, 68-75 (2013).</li><li>Lander, L. M., Siewierski, L. M., Brittain, W. J., Vogler, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+systematic+comparison+of+contact+angle+methods.">A systematic comparison of contact angle methods.</a> Langmuir. 9, 2237-2239 (1993).</li><li>Davies, J., Nunnerley, C. S., Brisley, A. C., Edwards, J. C., Finlayson, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+Dynamic+Contact+Angle+Profile+Analysis+in+Studying+the+Kinetics+of+Protein+Removal+from+Steel+Glass,+Polytetrafluoroethylene,+Polypropylene,+Ethylenepropylene+Rubber,+and+Silicone+Surfaces.">Use of Dynamic Contact Angle Profile Analysis in Studying the Kinetics of Protein Removal from Steel Glass, Polytetrafluoroethylene, Polypropylene, Ethylenepropylene Rubber, and Silicone Surfaces.</a> J. Colloid Interf. Sci. 182, 437-443 (1996).</li><li>Giolando, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nano-crystals+of+titanium+dioxide+in+aluminum+oxide:+A+transparent+self-cleaning+coating+applicable+to+solar+energy.">Nano-crystals of titanium dioxide in aluminum oxide: A transparent self-cleaning coating applicable to solar energy.</a> Sol. Energy. 97, 195-199 (2013).</li></ol>

Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.

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 fre...

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 border="0" cellpadding="0" cellspacing="0" width="580">
	<tbody>
		<tr height="85">
			<td height="85" style="height:85px;width:143px;">Ethyl cyanoacrylate (ECA) monomer</td>
			<td style="width:113px;">K&#38;R International (Laguna Niguel, CA)</td>
			<td style="width:107px;">I-1605</td>
			<td style="width:219px;">Any pure ECA can be used.</td>
		</tr>
		<tr height="106">
			<td height="106" style="height:106px;width:143px;">Gliadin</td>
			<td style="width:113px;">MGP Ingredients, Inc (Atchison, KS)</td>
			<td style="width:107px;">Gift from the company</td>
			<td style="width:219px;">Gliadin can be purchased from Sigma-Aldrich (cat #: G3375-25G). Instead of gliadin, any commercial&#160; gluten can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">HCl</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any reagent grade chemical can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Acetone</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any reagent grade chemical can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Methanol</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any reagent grade chemical can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Ethanol (100%)</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any reagent grade chemical can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Filter paper</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any grade filter paper larger than 10 cm can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Cell culture square dish</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any dish larger than 20 cm x 20 cm can be used.</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:143px;">Coffee grinder</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any coffee grinder can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Rotary evaporator</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any rotary evaporator can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Freeze Dryer</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any freeze dryer that can reach - 70&#176;C can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Centrifuge</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any centrifuge that can apply 1000 x g can be used.</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:143px;">Magnetic stirrer</td>
			<td style="width:113px;">Any</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any magnetic stirrer that can turn spin bar to 1000 RPM can be used.</td>
		</tr>
		<tr height="85">
			<td height="85" style="height:85px;width:143px;">Dynamic Light Scattering (DLS)</td>
			<td style="width:113px;">Brookhaven Instruments Corporation</td>
			<td style="width:107px;">NanoBrook Omni Zeta Potential Analyzer</td>
			<td style="width:219px;">DLS from any company can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Scanning Electron Microscope (SEM)</td>
			<td style="width:113px;">Carl Zeiss Inc.</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">Any SEM can be used.</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:143px;">Dynamic Contact Angle (DCA)</td>
			<td style="width:113px;">Thermo Cahn Instruments</td>
			<td style="width:107px;"></td>
			<td style="width:219px;">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...

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 ...

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Chemistry

6.8K 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

Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies

Physical interactions among the lipid-embedded alpha-helical domains of membrane proteins play a crucial role in folding and assembly of membrane protein complexes and in dynamic processes such as transmembrane (TM) signaling and regulation of cell-surface protein levels. Understanding the structural features driving the association of particular sequences requires sophisticated biophysical and biochemical analyses of TM peptide complexes. However, the extreme hydrophobicity of TM domains makes them very difficult to manipulate using standard peptide chemistry techniques, and production of suitable study material often proves prohibitively challenging. Identifying conditions under which peptides can adopt stable helical conformations and form complexes spontaneously adds a further level of difficulty. Here we present a procedure for the production of homo- or hetero-dimeric TM peptide complexes from materials that are expressed in E. coli, thus allowing incorporation of stable isotope labels for nuclear magnetic resonance (NMR) or non-natural amino acids for other applications relatively inexpensively. The key innovation in this method is that TM complexes are produced and purified as covalently associated (disulfide-crosslinked) assemblies that can form stable, stoichiometric and homogeneous structures when reconstituted into detergent, lipid or other membrane-mimetic materials. We also present carefully optimized procedures for expression and purification that are equally applicable whether producing single TM domains or crosslinked complexes and provide advice for adapting these methods to new TM sequences.

Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.

生产二硫键稳定的跨膜肽复合物的结构研究

Physical  interactions among the lipid-embedded alpha-helical domains of membrane  proteins play a crucial role in folding and assembly of membrane ...

科研

化学

Thin-layer Chromatographic (TLC) Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth.&#160;The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions.&#160;This paper describes standard protocols for TLC and contact bioautography&#160;with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light.&#160;Zones are cut out and incubated face down onto agar inoculated with the test microorganism.&#160;Inhibitory bands are visualized by staining the agar plates with tetrazolium red.&#160;The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen.&#160;The TLC methods apply to many types of plant extracts&#160;and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species.

Thin-layer Chromatographic TLC Separations and Bioassays of Plant Extracts to Identify Antimicrobial Compounds

Methods are described for thin-layer chromatographic (TLC) separation of plant extracts and contact bioautography to identify antibacterial metabolites. The methods are applied to the screening of red clover phenolic compounds inhibiting hyper&#160;ammonia-producing bacteria (HAB) native to the bovine rumen.

薄层色谱（TLC）分离和植物提取物的生物测定识别抗菌化合物

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl4 to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na+[Au(OH4-x)Clx]-) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated &#62;300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.

根据环境条件的金纳米粒子的稳定低聚簇的大小控制合成的一种简便方法

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

协议的合成<em&gt;邻</em&gt; -trifluoromethoxylated苯胺类化合物

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

功能性降冰片烯的催化聚合插入一种简单高效的协议

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

A Protocol for Safe Lithiation Reactions Using Organolithium Reagents

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented.

The safe and proper use of organolithium reagents is described.

使用有机锂试剂的一个协议安全的锂化反应

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents ...

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 &plusmn; 10%, n = 8) and excellent radiochemical purity (&gt;99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

A detailed procedure for the synthesis of a 125I-labeled azide and the radiolabeling of dibenzocyclooctyne (DBCO)-group-conjugated, 13-nm-sized gold nanoparticles using a copper-free click reaction is described.

一个优化的协议通过使用金纳米粒子的放射性标记效率<sup&gt; 125</sup&gt;我标记的叠氮辅基

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient ...

The MPLEx Protocol for Multi-omic Analyses of Soil Samples

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic, and lipidomic (multi-omic) studies are transforming our ability to understand and characterize microbial communities in environmental and biological systems. These measurements are even enabling enhanced analyses of complex soil microbial communities, which are the most complex microbial systems known to date. Multi-omic analyses, however, do have sample preparation challenges, since separate extractions are typically needed for each omic study, thereby greatly amplifying the preparation time and amount of sample required. To address this limitation, a 3-in-1 method for the simultaneous extraction of metabolites, proteins, and lipids (MPLEx) from the same soil sample was created by adapting a solvent-based approach. This MPLEx protocol has proven to be both simple and robust for many sample types, even when utilized for limited quantities of complex soil samples. The MPLEx method also greatly enabled the rapid multi-omic measurements needed to gain a better understanding of the members of each microbial community, while evaluating the changes taking place upon biological and environmental perturbations.

A protocol is presented for simultaneously extracting metabolites, proteins, and lipids from a single soil sample, allowing reduced sample preparation times and enabling multi-omic mass spectrometry analyses of samples with limited quantities.

土壤样品多涨价可能分析的 MPLEx 协议

Mass spectrometry (MS)-based integrated metaproteomic, metabolomic, and lipidomic (multi-omic) studies are transforming our ability to understand and ...

Automation of a Positron-emission Tomography (PET) Radiotracer Synthesis Protocol for Clinical Production

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological targets and processes. However, the increasing number of different tracers creates challenges for their production at radiopharmacies. While historically it has been practical to dedicate a custom-configured radiosynthesizer and hot cell for the repeated production of each individual tracer, it is becoming necessary to change this workflow. Recent commercial radiosynthesizers based on disposable cassettes/kits for each tracer simplify the production of multiple tracers with one set of equipment by eliminating the need for custom tracer-specific modifications. Furthermore, some of these radiosynthesizers enable the operator to develop and optimize their own synthesis protocols in addition to purchasing commercially-available kits. In this protocol, we describe the general procedure for how the manual synthesis of a new PET tracer can be automated on one of these radiosynthesizers and validated for the production of clinical-grade tracers. As an example, we use the ELIXYS radiosynthesizer, a flexible cassette-based radiochemistry tool that can support both PET tracer development efforts, as well as routine clinical probe manufacturing on the same system, to produce [18F]Clofarabine ([18F]CFA), a PET tracer to measure in vivo deoxycytidine kinase (dCK) enzyme activity. Translating a manual synthesis involves breaking down the synthetic protocol into basic radiochemistry processes that are then translated into intuitive chemistry &#34;unit operations&#34; supported by the synthesizer software. These operations can then rapidly be converted into an automated synthesis program by assembling them using the drag-and-drop interface. After basic testing, the synthesis and purification procedure may require optimization to achieve the desired yield and purity. Once the desired performance is achieved, a validation of the synthesis is carried out to determine its suitability for the production of the radiotracer for clinical use.

Automation of a Positron-emission Tomography PET Radiotracer Synthesis Protocol for Clinical Production

Positron-emission tomography (PET) imaging sites that are involved in multiple early clinical research trials need robust and versatile radiotracer manufacturing capabilities. Using the radiotracer [18F]Clofarabine as an example, we illustrate how to automate the synthesis of a radiotracer using a flexible, cassette-based radiosynthesizer and validate the synthesis for clinical use.

用于临床生产的正电子发射层析成像 (PET) 放射性同位素示踪合成协议的自动化

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological ...

Gene-therapy Inspired Polycation Coating for Protection of DNA Origami Nanostructures

DNA origami nanostructures hold an immense potential to be used for biological and medical applications. However, low-salt conditions and nucleases in physiological fluids induce denaturation and degradation of self-assembled DNA nanostructures. In non-viral gene delivery, enzymatic degradation of DNA is overcome by the encapsulation of the negatively charged DNA in a cationic shell. Herein, inspired by gene delivery advancements, a simple, one-step and robust methodology is presented for the stabilization of DNA origami nanostructures by coating them with chitosan and linear polyethyleneimine. The polycation coating efficiently protects DNA origami nanostructures in Mg-depleted and nuclease-rich media. This method also preserves the full addressability of enzyme- and aptamer-based functionalization of DNA nanostructures.

Here, a protocol for the protection of DNA origami nanostructures in Mg-depleted and nuclease-rich media using natural cationic polysaccharide chitosan and synthetic linear polyethyleneimine (LPEI) coatings is presented.

基因治疗诱导聚化涂层保护 dna 折纸纳米结构

DNA origami nanostructures hold an immense potential to be used for biological and medical applications. However, low-salt conditions and nucleases in ...

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

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