Name: quantitative sers detection of uric acid via formation of precise plasmonic nanojunctions within aggregates of gold nanoparticles and cucurbit[n]uril
Uploaded: 2020-10-03T13:00:00.000+00:00
Duration: 10 min 2 s
Description: Watch this Scientific Journal Video about Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril at JoVE.

TCL感谢英国皇家学会研究补助金2016 R1（RG150551）和UCL BEAMS未来领袖奖的支持，该奖项由EPSRC的机构赞助奖（EP/P511262/1）资助。WIKC，TCL和IPP感谢A * STAR-UCL研究实习计划通过EPSRC M3S CDT（EP / L015862 / 1）资助的学生奖学金。GD和TJ要感谢EPSRC M3S CDT（EP / L015862 / 1）赞助他们的学生奖学金。TJ和TCL感谢Camtech Innovations对TJ学生的贡献。所有作者都感谢伦敦大学学院开放获取基金。

1. 金核素的合成
<ol><li>通过传统的图尔克维奇方法合成金种子26<ol>
<li>通过溶解98.5mg HAuCl4 ， 制备10 mL 25 mM HAuCl4溶液3H2O前驱体与10mL去离子水在玻璃小瓶中。 注意:将少量HAuCl4 前驱体转移到称量船中，并使用塑料刮刀代替金属刮刀称量晶体，因为HAuCl4 前驱体会腐蚀金属实验室器具。称量步骤应尽可能快地进行，因为HAuCl4 具有吸湿性，因此会通过从大气中吸收水分来增加其重量。HAuCl4 具有高度腐蚀性，可引起严重的皮肤灼伤和眼睛损伤。处理时要格外小心。</li>
		<li>通过将64.5mg柠檬酸钠粉末与0.5mL去离子水溶解在玻璃瓶中来制备0.5mL 500mM柠檬酸钠溶液。</li>
		<li>在250 mL蓝封瓶中用99 mL水稀释1 mL 25 mM HAuCl4 溶液，得到100 mL 0.25 mM HAuCl4 溶液。</li>
		<li>将 99.5 mL 0.25 mM HAuCl4 溶液加入配备冷凝器的 250 mL 三颈圆底烧瓶中。在剧烈搅拌下将溶液加热至90°C并保持温度15分钟。</li>
		<li>将0.5mL的500mM柠檬酸钠溶液注入反应混合物中，并保持温度并搅拌，直到溶液的颜色变成红宝石红色。 注意:反应大约需要30分钟。</li>
	</ol></li>
	<li>通过动力学控制方法对Au NPs进行种子生长13
	<ol>
<li>将合成的Au种子溶液冷却至70°C。</li>
		<li>通过将154.8mg柠檬酸钠粉末与10mL去离子水溶解在玻璃瓶中来制备10mL 60mM柠檬酸钠溶液。</li>
		<li>向Au种子注入0.67mL的25mM HAuCl4 溶液和0.67mL的60mM柠檬酸钠溶液，时间间隔为2分钟。</li>
		<li>重复步骤1.2.3，逐渐将Au NPs的尺寸增加到40nm。 注意:大约需要10个生长步骤才能达到40nm。所需的实际步骤数可能取决于精确的设置。</li>
	</ol></li>
	<li>使用自动合成器对金NPs进行种子生长（图2）
	<ol>
<li>将第1节中制备的25mL Au种子溶液转移到50mL锥形离心管中，并在热混合器中冷却至70°C。 注:使用放置在装有25 mL水的50 mL离心管中的热电偶温度计监测热混合器内部的温度。</li>
		<li>在 3 mL 鲁尔锁一次性注射器中加入 2.5 mL 25 mM HAuCl4 溶液。用2.5 mL 60 mM柠檬酸钠溶液填充另一个3 mL鲁尔锁一次性注射器。</li>
		<li>将注射器放入注射泵中，并使用鲁尔到微密适配器将PEEK管（内径150μm）连接到注射器。将管子插入热混合器中含有Au种子溶液的离心管中。</li>
		<li>设置两个注射泵，在20分钟（每分钟8.357μL）内分配0.1675 mL溶液。</li>
		<li>将热混合器转速设置为700 rpm，然后在含有25 mM HAuCl4溶液的注射泵上按"启动"。</li>
		<li>2分钟后，在含有60mM柠檬酸钠溶液的注射泵上按 开始 。</li>
		<li>开始HAuCl4 溶液注射后30分钟，除去等分试样的Au NP溶液进行分析。</li>
		<li>重复步骤1.3.5 – 1.3.7，逐渐将Au NPs的直径增加到40nm。 注意:该设置可用于通过增加步骤1.3.4中添加的反应物的体积，一步将Au NPs生长到40nm。这是通过增加分配时间同时保持相同的注射速率来实现的。</li>
	</ol></li>
</ol>2. 金核素的表征
<ol><li>紫外-可见光谱<ol>
<li>将1 mL Au NP溶液加入半微量石英比色皿中。</li>
		<li>打开光谱仪。</li>
		<li>将波长范围设置为 400 - 800 nm。</li>
		<li>获取每个样品的紫外-可见光谱。</li>
	</ol>
</li>
	<li>动态光散射<ol>
<li>用0.22μm过滤器将样品溶液过滤到塑料半微比色皿中。</li>
		<li>打开 DLS 仪器。</li>
		<li>将温度设置为25°C并平衡60秒。</li>
		<li>测量每个样品的流体动力学尺寸。</li>
	</ol>
</li>
	<li>透射电子显微镜<ol>
<li>将 5 μL 样品溶液液滴滴浇注到 C 涂层的 300 目 Cu 网格上，并在空气中干燥。 注意:对于更浓缩的Au NP溶液样品，需要稀释才能在TEM网格上获得均匀分散的Au NPs。</li>
		<li>在200 kV加速电压下使用TEM为每个样品采集多个TEM图像。</li>
		<li>使用ImageJ计算平均尺寸和标准偏差，测量每个样品的200 Au NP的直径。</li>
	</ol>
</li>
</ol>3. CB7-UA复合物的形成
<ol><li>0.4 mM CB7溶液的制备<ol>
<li>向15毫升玻璃瓶中加入4.65毫克CB7。 注:CB7的用量是根据CB7（= 1163 Da）的公式重量计算的，该公式重量已被文献中的大多数报告所采用。然而，CB7固体样品通常含有合成和纯化步骤中留下的水，HCl，甲醇和其他盐，有助于样品中的自重约为10-20%。滞留的溶剂和盐不能通过在真空炉或其他方式中加热来去除。它们的量因不同批次的样品而异，但可以使用元素分析进行量化。然而，所提出的方案对CB7样品中存在未定量的溶剂和盐不敏感。</li>
		<li>向小瓶中加入10 mL水并拧紧盖子。</li>
		<li>在室温下对样品进行超声处理，直到CB7固体完全溶解。 注:CB7是根据文献27 合成的，但它也是市售的。</li>
	</ol>
</li>
	<li>0.4 mM UA溶液的制备<ol>
<li>向50 mL离心管中加入2.69mg UA。</li>
		<li>向管中加入40 mL水并拧紧盖子。</li>
		<li>使用热混合器将温度设置为70°C，速度设置为800 rpm，时间设置为2小时，从而旋转样品溶液。让溶液冷却至室温。 注:UA在水中的溶解度较低（0.40 mM）5。如果UA粉末尚未完全溶解，则旋转更长时间。或者，超声处理可用于促进溶解。</li>
	</ol>
</li>
	<li>0.4 mM UA溶液的顺序稀释<ol>
<li>在15 mL玻璃瓶中用5 mL水稀释5 mL 0.4 mM UA溶液，得到10 mL 0.2 mM UA溶液。拧紧盖子并超声处理30秒。</li>
		<li>重复步骤3.3.1，使用适量的UA和水，如表1所述。</li>
	</ol>
</li>
	<li>CB7-UA复合物的制备<ol>
<li>将0.75 mL的0.4 mM CB7溶液和0.75 mL的0.4 mM UA溶液加入1.5 mL试管中。盖上盖子并超声处理30秒。</li>
		<li>等待30分钟，以确保形成东宾综合体。</li>
		<li>重复步骤3.4.1 – 3.4.2，使用不同浓度的UA溶液。</li>
	</ol>
</li>
</ol>4. 用户获取的 SERS 传感
<ol><li>拉曼系统的实验设置（图3）<ol>
<li>打开 633 nm 氦氖激光器 （22.5 mW）。</li>
		<li>打开模块化拉曼光谱仪。</li>
		<li>打开计算机并启动软件。</li>
		<li>单击" 光谱学应用程序向导" 图标，然后选择" 拉曼"。</li>
		<li>开始新的收购。将积分时间设置为 30 秒，将扫描设置为平均值 5，将 boxcar 设置为 0。</li>
		<li>存储背景光谱并输入激光波长（即633nm）。 注意:积分时间是每次扫描的时间，平均扫描是平均扫描次数，以创建每个光谱，boxcar是平均28的相邻像素数。</li>
	</ol>
</li>
	<li>SERS基板的形成<ol>
<li>将0.9 mL的40nm Au NP溶液和0.1mL的预成型CB7-UA复合溶液加入1.5mL管中。盖上盖子并超声处理，直到溶液从红宝石红色变为紫色。 注意:也可以使用商用柠檬酸盐稳定的40nm Au NP溶液样品。通常，通过从浓缩的储备溶液样品中稀释，将局部表面等离子体共振（LSPR）峰的光密度调节至1。样品中的柠檬酸盐浓度通常保持在2mM。</li>
		<li>将样品溶液转移到半微比色皿中。将比色皿放入拉曼样品架中，然后合上盖子。</li>
		<li>开始测量。</li>
		<li>设置自动保存以记录五个连续的SERS光谱。</li>
		<li>停止测量并更换样品。</li>
		<li>重复步骤4.2.1 – 4.2.5，使用不同浓度的CB7-UA溶液。 注意:发现聚集时间取决于纳米团聚体中UA的浓度，范围从0.1μM UA的30 s到20μM UA的30分钟，这是由于空CB7浓度的差异，这对介导Au NPs的聚集有重大贡献。对于CB7-UA复合物，一个门户被笨重的UA分子阻断，使其无法与Au NP表面结合，因此无法介导NP聚集体21。当溶液的颜色从红宝石红色变为紫色时，样品就可以进行测量了。</li>
	</ol>
</li>
</ol>5. 数据分析
<ol><li>数据处理<ol>
<li>将带有非对称最小二乘 （ALS） 插件的基线下载并安装到 Origin 中。 注意:ALS 插件需要 OriginPro。</li>
		<li>将原始数据插入到源中。</li>
		<li>根据每个样品的五个SERS光谱计算平均值。将该值除以激光器的功率（即22.5 mW）和积分时间（即30 s）。</li>
		<li>单击 ALS 图标以打开对话框。将非对称因子设置为 0.001，阈值设置为 0.03%，将平滑因子设置为 2，将迭代次数设置为 20，以校正每个平均频谱的基线。</li>
		<li>使用按 y 偏移的堆叠线绘制不同 UA 浓度的 SERS 光谱。输出应为强度（计数 s-1 mW-1）与拉曼位移 （cm-1）。</li>
	</ol>
</li>
</ol>

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K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Detection+of+Nitroexplosives+Using+Molecular+Recognition+within+Self-Assembled+Plasmonic+Nanojunctions.">Selective Detection of Nitroexplosives Using Molecular Recognition within Self-Assembled Plasmonic Nanojunctions.</a> The Journal of Physical Chemistry C. 123 (25), 15769-15776 (2019).</li><li>Kasera, S., Biedermann, F., Baumberg, J. J., Scherman, O. A., Mahajan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+SERS+Using+the+Sequestration+of+Small+Molecules+Inside+Precise+Plasmonic+Nanoconstructs.">Quantitative SERS Using the Sequestration of Small Molecules Inside Precise Plasmonic Nanoconstructs.</a> Nano Letters. 12 (11), 5924-5928 (2012).</li><li>Taylor, R. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Situ+SERS+Monitoring+of+Photochemistry+within+a+Nanojunction+Reactor.">In Situ SERS Monitoring of Photochemistry within a Nanojunction Reactor.</a> Nano Letters. 13 (12), 5985-5990 (2013).</li><li>Kasera, S., Herrmann, L. O., Barrio, J. d., Baumberg, J. J., Scherman, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+Multiplexing+with+Nano-Self-Assemblies+in+SERS.">Quantitative Multiplexing with Nano-Self-Assemblies in SERS.</a> Scientific Reports. 4, 6785 (2014).</li><li>Chio, W. I. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual-triggered+nanoaggregates+of+cucurbit[7]uril+and+gold+nanoparticles+for+multi-spectroscopic+quantification+of+creatinine+in+urinalysis.">Dual-triggered nanoaggregates of cucurbit[7]uril and gold nanoparticles for multi-spectroscopic quantification of creatinine in urinalysis.</a> Journal of Materials Chemistry C. 8, 7051-7058 (2020).</li><li>Turkevich, J., Stevenson, P. C., Hillier, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+study+of+the+nucleation+and+growth+processes+in+the+synthesis+of+colloidal+gold.">A study of the nucleation and growth processes in the synthesis of colloidal gold.</a> Discussions of the Faraday Society. 11, 55-75 (1951).</li><li>Lagona, J., Mukhopadhyay, P., Chakrabarti, S., Issacs, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+cucurbit[n]uril+family.">The cucurbit[n]uril family.</a> Angewandte Chemie International Edition. 44 (31), 4844-4870 (2005).</li><li>. OceanView Installation and Operation Manual Available from: <a target="_blank" href="https://www.oceaninsight.com/globalassets/catalog-blocks-and-images/manuals--instruction-old-logo/software/oceanviewio.pdf">https://www.oceaninsight.com/globalassets/catalog-blocks-and-images/manuals--instruction-old-logo/software/oceanviewio.pdf</a> (2013)</li><li>Mahajan, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Raman+and+SERS+spectroscopy+of+cucurbit[n]urils.">Raman and SERS spectroscopy of cucurbit[n]urils.</a> Physical Chemistry Chemical Physics. 12 (35), 10429-10433 (2010).</li><li>Langer, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Present+and+Future+of+Surface-Enhanced+Raman+Scattering.">Present and Future of Surface-Enhanced Raman Scattering.</a> ACS Nano. 14 (1), 28-117 (2020).</li><li>Pilot, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Review+on+Surface-Enhanced+Raman+Scattering.">A Review on Surface-Enhanced Raman Scattering.</a> Biosensors. 9 (2), 57 (2019).</li><li>Bantz, K. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progress+in+SERS+biosensing.">Recent progress in SERS biosensing.</a> Physical Chemistry Chemical Physics. 13 (24), 11551-11567 (2011).</li><li>Moore, T. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+Vitro+and+In+Vivo+SERS+Biosensing+for+Disease+Diagnosis.">In Vitro and In Vivo SERS Biosensing for Disease Diagnosis.</a> Biosensors. 8 (2), 46 (2018).</li><li>Bonifacio, A., Cervo, S., Sergo, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Label-free+surface-enhanced+Raman+spectroscopy+of+biofluids:+fundamental+aspects+and+diagnostic+applications.">Label-free surface-enhanced Raman spectroscopy of biofluids: fundamental aspects and diagnostic applications.</a> Analytical and Bioanalytical Chemistry. 407 (27), 8265-8277 (2015).</li><li>Jeong, H. H., Choi, E., Ellis, E., Lee, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+gold+nanoparticles+for+biomedical+applications:+from+hybrid+structures+to+multi-functionality.">Recent advances in gold nanoparticles for biomedical applications: from hybrid structures to multi-functionality.</a> Journal of Materials Chemistry B. 7 (22), 3480-3496 (2019).</li><li>Premasiri, W. R., Clarke, R. H., Womble, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Urine+Analysis+by+Laser+Raman+Spectroscopy.">Urine Analysis by Laser Raman Spectroscopy.</a> Lasers in Surgery and Medicine. 28 (4), 330-334 (2001).</li><li>Lu, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Superhydrophobic+silver+film+as+a+SERS+substrate+for+the+detection+of+uric+acid+and+creatinine.">Superhydrophobic silver film as a SERS substrate for the detection of uric acid and creatinine.</a> Biomedical Optics Express. 9 (10), 4988-4997 (2018).</li><li>Feig, D. I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serum+Uric+Acid:+A+Risk+Factor+and+a+Target+for+Treatment.">Serum Uric Acid: A Risk Factor and a Target for Treatment.</a> Journal of the American Society of Nephrology. 17 (4), 69-73 (2006).</li><li>Maiuolo, J., Oppedisano, F., Gratteri, S., Muscoli, C., Mollace, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+uric+acid+metabolism+and+excretion.">Regulation of uric acid metabolism and excretion.</a> International Journal of Cardiology. 213, 8-14 (2016).</li></ol>

作者没有什么可透露的。

协议中描述的自动合成方法允许可重复地合成尺寸增加的Au NPs。虽然有一些元素仍然需要手动进行，例如在种子合成过程中快速添加柠檬酸钠并定期检查以确保PEEK管是安全的，但这种方法允许大尺寸（高达40nm）的Au NPs，这通常需要多次手动注射HAuCl4 和柠檬酸钠， 通过长时间的连续加法合成。
可以进行进一步的表征以阐明CB配合物的基本性质。例如，宿主 - 客体复合...

尿酸是嘌呤核苷酸代谢的最终产物，是血清和尿液中诊断痛风，先兆子痫，肾脏疾病，高血压，心血管疾病和糖尿病等疾病的重要生物标志物1，2，3，4，5。目前用于尿酸检测的方法包括比色酶法、高效液相色谱法和毛细管电泳，这些方法既耗时又昂贵，并且需要复杂的样品制备6，7，8，9。
表面增强拉曼光谱是一种用于常规床旁诊断的有前途的技术，因为它允许通过其振动指纹选择性检测生物分子，并提供许多优点，如高灵敏度，快速响应，易用性以及无或最少的样品制备。基于贵金属纳米颗粒（例如，Au NPs）的SERS衬底可以通过表面等离子体共振引起的强电磁增强10将分析物分子的拉曼信号增强4至10个数量级10。与耗时的复杂金属纳米复合材料12相比，定制尺寸的Au NPs可以很容易地合成，因此由于其优越的性能13，14，15，16，因此被广泛用于生物医学应用。将大环分子，葫芦[n]尿素（CBn，其中n = 5-8，10）附着在Au NPs的表面上可以进一步增强分析物分子的SERS信号，因为高度对称和刚性的CB分子可以控制Au NPs之间的精确间距，并通过形成宿主 - 客体复合物将分析物分子定位在中心或靠近等离子体热点（图1）17，18，19，20.以前使用Au NP的SERS研究示例:CBn纳米聚集物包括硝基爆破剂，多环芳烃，二氨基二苯乙烯，神经递质和肌酐21，22，23，24，25，SERS测量在比色皿中进行或通过将小液滴加载到定制的样品架上。该检测方案对于快速定量具有高再现性的复杂基质中的生物标志物特别有用。
本文使用模块化光谱仪展示了一种简单的方法来形成CB7的宿主 - 客体复合物和重要的生物标志物UA，并通过CB7介导的Au NPs在水介质中的聚集物以0.2μM的检测限量化UA，这在诊断和临床应用中是有希望的。

<table><tbody><tr><td>40 nm gold nanoparticles</td><td>NanoComposix</td><td>AUCN40-100M</td><td>NanoXact, 0.05 mg/ mL, bare (citrate)</td></tr><tr><td>Centrifuge tube</td><td>Corning Falcon</td><td>14-432-22</td><td>50 mL volume</td></tr><tr><td>Cucurbit[7]uril</td><td>Lab-made</td><td></td><td>see ref. 19</td></tr><tr><td>Gold(III) chloride trihydrate</td><td>Sigma aldrich</td><td>520918</td><td>&amp;ge;99.9% trace metals basis</td></tr><tr><td>Luer lock disposable syringe</td><td>Cole-Parmer</td><td>WZ-07945-15</td><td>3 mL volume</td></tr><tr><td>Luer-to-MicroTight adapter</td><td>LuerTight</td><td>P-662</td><td>360 &amp;mu;m outer diameter Tubing to Luer Syringe</td></tr><tr><td>PEEK tubing</td><td>IDEX</td><td>1572</td><td>360 &amp;mu;m outer diameter, 150 &amp;mu;m inner diameter</td></tr><tr><td>PEEK tubing cutter</td><td>IDEX</td><td>WZ-02013-30</td><td>Capillary Polymer Chromatography Tubing Cutter For 360 &amp;micro;m to 1/32&quot; OD tubing</td></tr><tr><td>Raman spectrometer</td><td>Ocean Optics</td><td>QE pro</td><td></td></tr><tr><td>Sodium citrate tribasic dihydrate</td><td>Sigma aldrich</td><td>S4641</td><td>ACS reagent, &amp;ge;99.0%</td></tr><tr><td>Sonicator</td><td></td><td></td><td></td></tr><tr><td>Standard Probe</td><td>Digi-Sense</td><td>WZ-08516-55</td><td>Type-K</td></tr><tr><td>Syringe pump</td><td>Aladdin</td><td>ALADDIN2-220</td><td>2 syringes, maximum syringe volume 60 mL</td></tr><tr><td>Thermocouple thermometer</td><td>Digi-Sense</td><td>WZ-20250-91</td><td>Single-Input Thermocouple Thermometer with NIST-Traceable Calibration</td></tr><tr><td>ThermoMixer</td><td>Eppendorf</td><td>5382000031</td><td>With an Eppendorf SmartBlock for 50 mL tubes</td></tr><tr><td>Uric acid</td><td>Sigma aldrich</td><td>U2625</td><td>&amp;ge;99%, crystalline</td></tr></tbody></table>

quantitative sers detection of uric acid via formation of precise plasmonic nanojunctions within aggregates of gold nanoparticles and cucurbit[n]uril

这项工作描述了一种快速且高度灵敏的方法，用于通过表面增强拉曼光谱（SERS）定量检测重要的生物标志物尿酸（UA），使用模块化光谱仪对指纹区域中的多个特征峰具有约0.2μM的低检测限。这种生物传感方案由大环，葫芦[7]uril（CB7）和UA之间的宿主 - 客体络合以及随后在自组装的Au NP:CB7纳米聚集体内形成精确的等离子体纳米结介导。基于经典的柠檬酸盐还原方法，还进行了SERS底物所需尺寸的简单Au NP合成，并可以选择使用实验室制造的自动合成器来促进。该方案可以很容易地扩展到体液中生物标志物的多重检测，用于临床应用。

在所提出的Au NP合成中，紫外 - 可见光谱显示LSPR峰在10个生长步骤后从521 nm移动到529 nm（图4A，B），而DLS数据显示随着Au NPs的尺寸从25.9 nm增加到42.8 nm而窄尺寸分布（图4C，D）。从TEM图像（图4E）测量的G0，G5和G10的平均尺寸分别为20.1±2.1nm，32.5±2.3nm和40.0±2.2nm，每种情况下计数200个颗粒。这些结果表明，?...

Watch this Scientific Journal Video about Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril at JoVE.

Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril

在水溶液中形成葫芦[7]尿酸和尿酸的宿主 - 客体复合物，然后向Au NP溶液中加入少量，以使用模块化光谱仪进行定量表面增强拉曼光谱（SERS）传感。

通过在金纳米颗粒和葫芦的聚集体中形成精确的等离子体纳米结来定量检测尿酸

This work describes a rapid and highly sensitive method for the quantitative detection of an important biomarker, uric acid (UA), via surface-enhanced ...

quantitative-sers-detection-uric-acid-via-formation-precise-plasmonic

Research

JoVE Journal

Chemistry

Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril

3.8K 次观看.  University College London (UCL). 在水溶液中形成葫芦[7]尿酸和尿酸的宿主 - 客体复合物，然后向Au NP溶液中加入少量，以使用模块化光谱仪进行定量表面增强拉曼光谱（SERS）传感。

视频: Quantitative SERS Detection of Uric Acid via Formation of Precise Plasmonic Nanojunctions within Aggregates of Gold Nanoparticles and Cucurbit[n]uril

Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform

Immunoassays are used to detect proteins based on the presence of associated antibodies. Because of their extensive use in research and clinical settings, a large infrastructure of immunoassay instruments and materials can be found. For example, 96- and 384-well polystyrene plates are available commercially and have a standard design to accommodate ultraviolet-visible (UV-Vis) spectroscopy machines from various manufacturers. In addition, a wide variety of immunoglobulins, detection tags, and blocking agents for customized immunoassay designs such as enzyme-linked immunosorbent assays (ELISA) are available.
Despite the existing infrastructure, standard ELISA kits do not meet all research needs, requiring individualized immunoassay development, which can be expensive and time-consuming. For example, ELISA kits have low multiplexing (detection of more than one analyte at a time) capabilities as they usually depend on fluorescence or colorimetric methods for detection. Colorimetric and fluorescent-based analyses have limited multiplexing capabilities due to broad spectral peaks. In contrast, Raman spectroscopy-based methods have a much greater capability for multiplexing due to narrow emission peaks. Another advantage of Raman spectroscopy is that Raman reporters experience significantly less photobleaching than fluorescent tags1. Despite the advantages that Raman reporters have over fluorescent and colorimetric tags, protocols to fabricate Raman-based immunoassays are limited. The purpose of this paper is to provide a protocol to prepare functionalized probes to use in conjunction with polystyrene plates for direct detection of analytes by UV-Vis analysis and Raman spectroscopy. This protocol will allow researchers to take a do-it-yourself approach for future multi-analyte detection while capitalizing on pre-established infrastructure.

Nanoparticle-based optical probes have been designed as a vehicle for detecting antigens using Raman and UV-Vis spectroscopy. Here we describe a protocol for preparing such probes for a UV-Vis/Raman spectroscopy immunoassay in such a way to incorporate future multiplexing capabilities.

制造的UV-Vis和拉曼光谱免疫平台

Immunoassays are used to detect proteins based on the presence of associated antibodies. Because of their extensive use in research and clinical settings, ...

科研

生物化学

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

表面增强拉曼光谱检测生物分子利用EBL装配纳米衬底

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

工程学

Surface-enhanced Resonance Raman Scattering Nanoprobe Ratiometry for Detecting Microscopic Ovarian Cancer via Folate Receptor Targeting

Ovarian cancer represents the deadliest gynecologic malignancy. Most patients present at an advanced stage (FIGO stage III or IV), when local metastatic spread has already occurred. However, ovarian cancer has a unique pattern of metastatic spread, in that tumor implants are initially contained within the peritoneal cavity. This feature could enable, in principle, the complete resection of tumor implants with curative intent. Many of these metastatic lesions are microscopic, making them hard to identify and treat. Neutralizing such micrometastases is believed to be a major goal towards eliminating tumor recurrence and achieving long-term survival. Raman imaging with surface enhanced resonance Raman scattering nanoprobes can be used to delineate microscopic tumors with high sensitivity, due to their bright and bioorthogonal spectral signatures. Here, we describe the synthesis of two &#39;flavors&#39; of such nanoprobes: an antibody-functionalized one that targets the folate receptor &#8212; overexpressed in many ovarian cancers &#8212; and a non-targeted control nanoprobe, with&#160;distinct spectra. The nanoprobes are co-administered intraperitoneally to mouse models of metastatic human ovarian adenocarcinoma. All animal studies were approved by the Institutional Animal Care and Use Committee of Memorial Sloan Kettering Cancer Center. The peritoneal cavity of the animals is surgically exposed, washed, and scanned with a Raman microphotospectrometer. Subsequently, the Raman signatures of the two nanoprobes are decoupled using a Classical Least Squares fitting algorithm, and their respective scores divided to provide a ratiometric signal of folate-targeted over untargeted probes. In this way, microscopic metastases are visualized with high specificity. The main benefit of this approach is that the local application into the peritoneal cavity &#8212; which can be done conveniently during the surgical procedure &#8212; can tag tumors without subjecting the patient to systemic nanoparticle exposure. False positive signals stemming from non-specific binding of the nanoprobes onto visceral surfaces can be eliminated by following a ratiometric approach where targeted and non-targeted nanoprobes with distinct Raman signatures are applied as a mixture. The procedure is currently still limited by the lack of a commercial wide-field Raman imaging camera system, which once available will allow for the application of this technique in the operating theater.

Ovarian cancer forms metastases throughout the peritoneal cavity. Here, we present a protocol to make and use folate-receptor targeted surface-enhanced resonance Raman scattering nanoprobes that reveal these lesions with high specificity via ratiometric imaging. The nanoprobes are administered intraperitoneally to living mice, and the derived images correlate well with histology.

表面增强共振拉曼散射纳米探针比比法检测微卵巢癌的意义上

Ovarian cancer represents the deadliest gynecologic malignancy. Most patients present at an advanced stage (FIGO stage III or IV), when local metastatic ...

癌症研究

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity and convenient colorimetric readout. However, high densities of nanoparticles are typically needed for detection. The available synthesis-based enhancement protocols are either limited to gold and silver nanoparticles or rely on precise enzymatic control and optimization. Here, we present a protocol to enhance the colorimetric readout of gold, silver, silica, and iron oxide nanoprobes. It was observed that the colorimetric signal can be improved by up to a 10000-fold factor. The basis for such signal enhancement strategies is the chemical reduction of Au3+ to Au0. There are several chemical reactions that enable the reduction of Au3+ to Au0. In the protocol, Good&#39;s buffers and H2O2 are used and it is possible to favor the deposition of Au0 onto the surface of existing nanoprobes, in detriment of the formation of new gold nanoparticles. The protocol consists of the incubation of the microarray with a solution consisting of chloroauric acid and H2O2 in 2-(N-morpholino)ethanesulfonic acid pH 6 buffer following the nanoprobe-based detection assay. The enhancement solution can be applied to paper and glass-based sensors. Moreover, it can be used in commercially available immunoassays as demonstrated by the application of the method to a commercial allergen microarray. The signal development requires less than 5 min of incubation with the enhancement solution and the readout can be assessed by naked eye or low-end image acquisition devices such as a table-top scanner or a digital camera.

Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis

In this work, a protocol for signal enhancement of nanoprobe-based biosensing is presented. The protocol is based on the reduction of chloroauric acid onto the surface of existing nanoprobes that consist of gold, silver, silica or iron-oxide nanoparticles.

原位金纳米粒子合成快速 Nanoprobe 信号增强

The use of nanoprobes such as gold, silver, silica or iron-oxide nanoparticles as detection reagents in bioanalytical assays can enable high sensitivity ...

化学

通过激光烧蚀合成纳米颗粒和纳米结构

Ultrafast Laser-Ablated Nanoparticles and Nanostructures for Surface-Enhanced Raman Scattering-Based Sensing Applications

The technique of ultrafast laser ablation in liquids has evolved and matured over the past decade, with several impending applications in various fields such as sensing, catalysis, and medicine. The exceptional feature of this technique is the formation of nanoparticles (colloids) and nanostructures (solids) in a single experiment with ultrashort laser pulses. We have been working on this technique for the past few years, investigating its potential using the surface-enhanced Raman scattering (SERS) technique in hazardous materials sensing applications. Ultrafast laser-ablated substrates (solids and colloids) could detect several analyte molecules at the trace levels/mixture form, including dyes, explosives, pesticides, and biomolecules. Here, we present some of the results achieved using the targets of Ag, Au, Ag-Au, and Si. We have optimized the nanostructures (NSs) and nanoparticles (NPs) obtained (in liquids and air) using different pulse durations, wavelengths, energies, pulse shapes, and writing geometries. Thus, various NSs and NPs were tested for their efficiency in sensing numerous analyte molecules using a simple, portable Raman spectrometer. This methodology, once optimized, paves the way for on-field sensing applications. We discuss the protocols in (a) synthesizing the NPs/NSs via laser ablation, (b) characterization of NPs/NSs, and (c) their utilization in the SERS-based sensing studies.

作者聚焦:通过液体中的激光烧蚀进行纳米颗粒合成的进展和应用 

Ultrafast laser ablation in liquid is a precise and versatile technique for synthesizing nanomaterials (nanoparticles [NPs] and nanostructures [NSs]) in liquid/air environments. The laser-ablated nanomaterials can be functionalized with Raman-active molecules to enhance the Raman signal of analytes placed on or near the NSs/NPs.

超快激光烧蚀纳米颗粒和纳米结构在基于表面增强拉曼散射的传感应用中的应用

The technique of ultrafast laser ablation in liquids has evolved and matured over the past decade, with several impending applications in various fields ...

用电化学方法分析单个纳米颗粒的异质性能

Tracking Electrochemistry on Single Nanoparticles with Surface-Enhanced Raman Scattering Spectroscopy and Microscopy

Studying electrochemical reactions on single nanoparticles is important to understand the heterogeneous performance of individual nanoparticles. This nanoscale heterogeneity remains hidden during the ensemble-averaged characterization of nanoparticles. Electrochemical techniques have been developed to measure currents from single nanoparticles but do not provide information about the structure and identity of the molecules that undergo reactions at the electrode surface. Optical techniques such as surface-enhanced Raman scattering (SERS) microscopy and spectroscopy can detect electrochemical events on individual nanoparticles while simultaneously providing information on the vibrational modes of electrode surface species. In this paper, a protocol to track the electrochemical oxidation-reduction of Nile Blue (NB) on single Ag nanoparticles using SERS microscopy and spectroscopy is demonstrated. First, a detailed protocol for fabricating Ag nanoparticles on a smooth and semi-transparent Ag film is described. A dipolar plasmon mode aligned along the optical axis is formed between a single Ag nanoparticle and Ag film. The SERS emission from NB fixed between the nanoparticle and the film is coupled into the plasmon mode, and the high-angle emission is collected by a microscope objective to form a donut-shaped emission pattern. These donut-shaped SERS emission patterns allow for the unambiguous identification of single nanoparticles on the substrate, from which the SERS spectra can be collected. In this work, a method for employing the SERS substrate as a working electrode in an electrochemical cell compatible with an inverted optical microscope is provided. Finally, tracking the electrochemical oxidation-reduction of NB molecules on an individual Ag nanoparticle is shown. The setup and the protocol described here can be modified to study various electrochemical reactions on individual nanoparticles.

作者聚焦:使用表面增强拉曼散射光谱和显微镜跟踪单个纳米颗粒的电化学  

The protocol describes how to monitor electrochemical events on single nanoparticles using surface-enhanced Raman scattering spectroscopy and imaging.

用表面增强拉曼散射光谱和显微镜跟踪单个纳米颗粒的电化学

Studying electrochemical reactions on single nanoparticles is important to understand the heterogeneous performance of individual nanoparticles. This ...

通过在金纳米颗粒和葫芦的聚集体中形成精确的等离子体纳米结来定量检测尿酸

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原位金纳米粒子合成快速 Nanoprobe 信号增强

超快激光烧蚀纳米颗粒和纳米结构在基于表面增强拉曼散射的传感应用中的应用

超快激光烧蚀纳米颗粒和纳米结构在基于表面增强拉曼散射的传感应用中的应用

超快激光烧蚀纳米颗粒和纳米结构在基于表面增强拉曼散射的传感应用中的应用

用表面增强拉曼散射光谱和显微镜跟踪单个纳米颗粒的电化学

用表面增强拉曼散射光谱和显微镜跟踪单个纳米颗粒的电化学

用表面增强拉曼散射光谱和显微镜跟踪单个纳米颗粒的电化学