This material is based upon work supported by the U.S. Department of Homeland Security under Grant Award Number 2010-ST-061-FD0001 through a grant awarded by the National Center for Food Protection and Defense at the University of Minnesota. Disclaimer: The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Department of Homeland Security or the National Center for Food Protection and Defense.

1. Silbernanopartikelsynthese 15 <ol><li> Man löst 18 mg Silbernitrat in 100 ml Reinstwasser (18.2 ΩU) und Vortex für 5 Sek. </li><li> Man löst 27 mg Natriumzitratdihydrat in 1 ml Wasser und Vortex für 5 Sek. </li><li> Übertragen Sie alle der hergestellten Silbernitratlösung zu einem Erlenmeyerkolben mit Rührstab und stellte die Flasche auf einem Magnet heißen Platte enthält. Wird der Kolben unter kräftigem Rühren mit einer Rührgeschwindigkeit von 700 Umdrehungen pro Minute bei ~ 350 ° C (Einstellung Temperatur auf der Platte). </li><li> Beim Kochen, fügen sofort alle der vorbereiteten Natriumcitratlösung zu den Erlenmeyerkolben gegeben und die Lösung verlassen für weitere 25 min zum Sieden, bis die Lösung grünlich braun wird, die die Bildung von Ag-Nanopartikeln zeigt. </li><li> Entfernen Sie den Kolben von der heißen Platte und legen Sie sie auf einem anderen Magnetplatte (nicht erhitzen) und rühren O / N in der gleichen Rührgeschwindigkeit bei RT, bis die Mischung erreicht einen stabilen Zustand, mit einer konstanten Farbe und Transparency. Verwenden Sie ein UV-VIS-Spektrometer der Absorption der hergestellten Silber-Nanopartikel, um festzustellen, wenn nötig. </li><li> Verdünne die Endmischung mit ultrareinem Wasser auf 100 ml. </li><li> Verwenden Sie einen Zetasizer die Größe der Silber-Nanopartikel zu messen, wenn notwendig, nach dem Protokoll des Herstellers. </li><li> Übertragen Sie die Ag-Kolloid zu einem verschlossenen Behälter und schützen sie vor Licht mit Aluminiumfolie. Das Kolloid kann bei Bedarf für 2 Monate bei 4-7 ° C im Kühlschrank aufbewahrt werden. </li></ol> 2. Herstellung eines SERS Aktive Filter Membrane <ol><li> Man löst 2,92 g Natriumchlorid (NaCl) in 100 ml Wasser, um eine 50 mM NaCl-Lösung herzustellen. </li><li> 1 ml der 5 mM NaCl-Lösung in 1 ml der hergestellten Silber-Nanopartikel und mischen sie auf einem Taumelmischer für 10 Minuten bei 20 Umdrehungen pro Minute. Dieser Schritt ist die Silber-Nanopartikel in Ag-Nanocluster zu aggregieren. </li><li> Platzieren einer Filtermembran (PVDF, 0,1 um Porengrße) in einem Filterhalter, die an einer Spritze befestigt werden kann. Der kleinere Porengröße Membran war found wirksamer als die größere Porengröße Membran (dh 0,22 um) in Trapping Ag-Nanocluster und Erzeugen konsistenter Signale. </li><li> Last 2 ml der hergestellten Ag-Nanocluster in die Spritze für die Filtration. Bringen Sie den Filterhalter an der Spritze und manuell das gesamte Volumen von Ag-Nanocluster durch die Membran in einer Fließrate von 1 Tropfen / s übergeben. Die Membran Fallen Ag-Nanocluster, eine SERS-aktiven Filtermembran bilden. </li><li> Nehmen Sie die Filtermembran aus dem Filterhalter. Besondere Vorsicht ist geboten, wenn die Membran am äußeren Rand, die eine Pinzette keine Beschädigung der Membran zu gewährleisten. Luft trocknen für ca. 3 min und Platz Membran auf einem Glasträger. </li><li> Raman Detektion des SERS-Substrat <ol><li> Stellen Sie die Raman Instrument zu einem 780 nm Wellenlängenlaser mit einer Laserleistung von 5 mW, Bestrahlungszeit von 1 sec und Belichtungszahl von 2. Stellen Sie die mikroskopische Objektiv zu 10X. Stellen Sie sicher, das Ziel auf der Software entsprechend zu gesetzt ist. &lt;/ Li&gt; <li> Setzen Sie den Glasobjektträger mit der Membran auf der Oberseite auf die Plattform des Raman-Instruments und verwenden das Mikroskop auf der Oberfläche der Membran zu konzentrieren. </li><li> Wähle zufällig 8-10 Flecken von der Membranoberfläche und das Instrument wird sie automatisch in Folge sammeln. Offene spektralen Daten im Hersteller-Software für die Analyse. </li></ol></li></ol> 3. Anwendung der Active Filter System SERS zum Nachweis chemischer Kontaminanten <ol><li> Bereiten Sie eine 10 ppb Ferbam Lösung. Achtung: Ferbam ist sehr volatil. Vorsichtsmaßnahmen (Atemschutzmaske und Schutzbrille), wenn die feste wiegen. <ol><li> Wiegen Sie 2 mg Ferbam Pulver und löst ihn in 20 ml 50% Acetonitril (10 ml Acetonitril und 10 ml Wasser), um eine Stammlösung (100 ppm) zu machen. Mischen Sie den Kolben für 30 Sekunden. </li><li> Nehmen Sie 1 ml der 100 ppm Ferbam Lösung in einem Reagenzglas und fügen 9 ml 50% Acetonitril 10 ppm-Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li><li> Nehmen Sie 1 ml der10 ppm Lösung in einem Reagenzglas und fügen 9 ml 50% Acetonitril eine 1 ppm-Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li><li> Nehmen Sie 1 ml der 1 ppm Lösung in einem Reagenzglas und fügen 9 ml 50% Acetonitril eine 100-ppb-Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li><li> Nehmen Sie 1 ml der 100-ppb-Lösung in einem Reagenzglas und fügen 9 ml 50% Acetonitril 10 ppb Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li></ol></li><li> Bereiten Sie eine 1 ppm Ampicillin Lösung. <ol><li> Wiegen 10 mg Ampicillin Pulver und löst ihn in 100 ml Wasser auf 100 ppm Ampicillin-Lösung zu machen. Mischen Sie den Kolben für 30 Sekunden. </li><li> Nehmen Sie 1 ml der 100 ppm-Lösung in einem Reagenzglas und fügen 9 ml Wasser zu einer 10 ppm Ampicillin-Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li><li> Nehmen Sie 1 ml der 10-ppm-Lösung in einem Reagenzglas und fügen 9 ml Wasser zu einer 1 ppm Ampicillin-Lösung zu machen. Mischen Sie den Schlauch für 5 Sek. </li></ol></li><li> Setzen Sie die Filtermembran zurück in den Filterhalter, mit dem NP beschichtete Seite nach oben zeigt. &lt;/ Li&gt; <li> Last 5 ml einer Probe in eine neue Spritze, und dann hängen Sie es an den Filterhalter mit einer Ag-beschichtete Membran im Inneren. </li><li> geben manuell das gesamte Volumen der Probe durch die Membran in einer Fließrate von 1 Tropfen / s. Zielmoleküle können auf den auf der Filtermembran beschichteten Nanopartikeln adsorbiert und konzentriert werden. </li><li> Trennen Filtermembran aus dem Filterhalter, der Luft trocknen lassen für etwa 3 min und Messen der Signale des Raman-Instrument unter Verwendung der gleichen Methode wie in Schritt 2.6 beschrieben. </li><li> Wiederholen Sie Schritt 2,2 bis 2,6, um eine weitere Ag-beschichteten Membran vor, und ergeben sich aus Schritt 3.3 für den Nachweis der anderen Probe. </li></ol>

<ol>
	<li>Albrecht, M. G., Creighton, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomalously+intense+Raman+spectra+of+pyridine+at+a+silver+electrode.">Anomalously intense Raman spectra of pyridine at a silver electrode.</a> J. Am. Chem. Soc. 99 (15), 5215-5217 (1977).</li><li>Schatz, G. C., Young, M. A., Van Duyne, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Electromagnetic mechanism of SERS. Surface-enhanced Raman scattering. , 19-45 (2006).</li><li>Matijevic, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+properties+of+uniform+size+colloids.">Preparation and properties of uniform size colloids.</a> Chem. Mater. 5 (4), 412-426 (1993).</li><li>Nickel, U., zu Castell, A., P&#246;ppl, K., Schneider, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+silver+colloid+produced+by+reduction+with+hydrazine+as+support+for+highly+sensitive+surface-enhanced+Raman+spectroscopy.">A silver colloid produced by reduction with hydrazine as support for highly sensitive surface-enhanced Raman spectroscopy.</a> Langmuir. 16 (23), 9087-9091 (2000).</li><li>Khanna, P. K., Subbarao, V. V. V. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanosized+silver+powder+via+reduction+of+silver+nitrate+by+sodium+formaldehydesulfoxylate+in+acidic+pH+medium.">Nanosized silver powder via reduction of silver nitrate by sodium formaldehydesulfoxylate in acidic pH medium.</a> Mater. Lett. 57 (15), 2242-2245 (2003).</li><li>Henglein, A., Giersig, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+colloidal+silver+nanoparticles:+capping+action+of+citrate.">Formation of colloidal silver nanoparticles: capping action of citrate.</a> J. Phys. Chem. B. 103 (44), 9533-9539 (1999).</li><li>Sun, X., Li, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colloidal+carbon+spheres+and+their+core/shell+structures+with+noble-metal+nanoparticles.">Colloidal carbon spheres and their core/shell structures with noble-metal nanoparticles.</a> Angew. Chem. Int. Edit. 43 (5), 597-601 (2004).</li><li>Lu, L., 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=Seed-mediated+growth+of+large,+monodisperse+core-shell+gold-silver+nanoparticles+with+Ag-like+optical+properties.">Seed-mediated growth of large, monodisperse core-shell gold-silver nanoparticles with Ag-like optical properties.</a> Chem. Commun. (2), 144-145 (2002).</li><li>Aslan, K., Wu, M., Lakowicz, J. R., Geddes, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+core-shell+Ag@SiO2+nanocomposites+for+metal-enhanced+fluorescence+and+single+nanoparticle+sensing+platforms.">Fluorescent core-shell Ag@SiO2 nanocomposites for metal-enhanced fluorescence and single nanoparticle sensing platforms.</a> J. Am. Chem. Soc. 129 (6), 1524-1525 (2007).</li><li>Lu, Y., Yin, Y., Li, Z. Y., Xia, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+self-assembly+of+Au@+SiO2+core-shell+colloids.">Synthesis and self-assembly of Au@ SiO2 core-shell colloids.</a> Nano. Lett. 2 (7), 785-788 (2002).</li><li>Link, S., Wang, Z. L., El-Sayed, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alloy+formation+of+gold-silver+nanoparticles+and+the+dependence+of+the+plasmon+absorption+on+their+composition.">Alloy formation of gold-silver nanoparticles and the dependence of the plasmon absorption on their composition.</a> J. Phys. Chem. B. 103 (18), 3529-3533 (1999).</li><li>He, L., 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=Rapid+Detection+of+Ricin+in+Milk+Using+Immunomagnetic+Separation+Combined+with+Surface+Enhanced+Raman+Spectroscopy.">Rapid Detection of Ricin in Milk Using Immunomagnetic Separation Combined with Surface Enhanced Raman Spectroscopy.</a> J. Food. Sci. 76 (5), N49-N53 (2011).</li><li>Zheng, J., He, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surface-Enhanced+Raman+Spectroscopy+for+the+Chemical+Analysis+of+Food.">Surface-Enhanced Raman Spectroscopy for the Chemical Analysis of Food.</a> Compr. Rev. Food. Sci. F. 13 (3), 317-328 (2014).</li><li>He, L., Haynes, C. L., Diez-Gonzalez, F., Labuza, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+detection+of+a+foreign+protein+in+milk+using+IMS-SERS.">Rapid detection of a foreign protein in milk using IMS-SERS.</a> J. Raman. Spectrosc. 42 (6), 1428-1434 (2011).</li><li>Wei, W. Y., White, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+filter-based+approach+to+surface+enhanced+Raman+spectroscopy+for+trace+chemical+detection.">A simple filter-based approach to surface enhanced Raman spectroscopy for trace chemical detection.</a> Analyst. 137 (5), 1168-1173 (2012).</li><li>Cheng, M. L., Tsai, B. C., Yang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+nanoparticle-treated+filter+paper+as+a+highly+sensitive+surface-enhanced+Raman+scattering+(SERS)+substrate+for+detection+of+tyrosine+in+aqueous+solution.">Silver nanoparticle-treated filter paper as a highly sensitive surface-enhanced Raman scattering (SERS) substrate for detection of tyrosine in aqueous solution.</a> Anal. Chim. Acta. 708 (1), 89-96 (2011).</li><li>Fierro-Mercado, P. M., Hern&#225;ndez-Rivera, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+sensitive+filter+paper+substrate+for+SERS+trace+explosives+detection.">Highly sensitive filter paper substrate for SERS trace explosives detection.</a> Int. J. Spectrosc. 2012, 716527 (2012).</li><li>Tran, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Subnanogram+detection+of+dyes+on+filter+paper+by+surface-enhanced+Raman+scattering+spectrometry.">Subnanogram detection of dyes on filter paper by surface-enhanced Raman scattering spectrometry.</a> Anal. Chem. 56 (4), 824-826 (1984).</li><li>Wu, D., Fang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+adsorption+behavior+of+p-hydroxybenzoic+acid+on+a+silver-coated+filter+paper+by+surface+enhanced+Raman+scattering.">The adsorption behavior of p-hydroxybenzoic acid on a silver-coated filter paper by surface enhanced Raman scattering.</a> J. Colloid Interface Sci. 265 (2), 234-238 (2003).</li><li>Wigginton, K. R., Vikesland, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gold-coated+polycarbonate+membrane+filter+for+pathogen+concentration+and+SERS-based+detection.">Gold-coated polycarbonate membrane filter for pathogen concentration and SERS-based detection.</a> Analyst. 135 (6), 1320-1326 (2010).</li><li>Berthod, A., Laserna, J. J., Winefordner, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+by+surface+enhanced+Raman+spectroscopy+on+silver+hydrosols+and+silver+coated+filter+papers.">Analysis by surface enhanced Raman spectroscopy on silver hydrosols and silver coated filter papers.</a> J Pharm Biomed Anal. 6 (6), 599-608 (1988).</li><li>Ackermann, K. R., Henkel, T., Popp, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+Online+Detection+of+Low-Concentrated+Drugs+via+a+SERS+Microfluidic+System.">Quantitative Online Detection of Low-Concentrated Drugs via a SERS Microfluidic System.</a> ChemPhysChem. 8 (18), 2665-2670 (2007).</li><li>Walter, A., M&#228;rz, A., Schumacher, W., R&#246;sch, P., Popp, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+a+fast,+high+specific+and+reliable+discrimination+of+bacteria+on+strain+level+by+means+of+SERS+in+a+microfluidic+device.">Towards a fast, high specific and reliable discrimination of bacteria on strain level by means of SERS in a microfluidic device.</a> Lab. Chip. 11 (6), 1013-1021 (2011).</li><li>Lee, 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=Fast+and+sensitive+trace+analysis+of+malachite+green+using+a+surface-enhanced+Raman+microfluidic+sensor.">Fast and sensitive trace analysis of malachite green using a surface-enhanced Raman microfluidic sensor.</a> Anal. Chim. Acta. 590 (2), 139-144 (2007).</li><li>Guo, H., 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=Analysis+of+Silver+Nanoparticles+in+Antimicrobial+Products+Using+Surface-Enhanced+Raman+Spectroscopy+(SERS).">Analysis of Silver Nanoparticles in Antimicrobial Products Using Surface-Enhanced Raman Spectroscopy (SERS).</a> Environ. Sci. Technol. 49 (7), 4317-4324 (2015).</li><li>Narayanan, V. A., Begun, G. M., Stokes, D. L., Sutherland, W. S., Vo-Dinh, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+Raman+and+surface+enhanced+Raman+scattering+(SERS)+spectra+of+some+fungicides+and+related+chemical+compounds.">Normal Raman and surface enhanced Raman scattering (SERS) spectra of some fungicides and related chemical compounds.</a> J. Raman. Spectrosc. 23 (5), 281-286 (1992).</li><li>Kang, J. S., Hwang, S. Y., Lee, C. J., Lee, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SERS+of+dithiocarbamate+pesticides+adsorbed+on+silver+surface;+thiram.">SERS of dithiocarbamate pesticides adsorbed on silver surface; thiram.</a> Bull. Korean. Chem. Soc. 23 (11), 1604-1610 (2002).</li><li>Li, Y. T., 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=Rapid+and+sensitive+in-situ+detection+of+polar+antibiotics+in+water+using+a+disposable+Ag-graphene+sensor+based+on+electrophoretic+preconcentration+and+surface-enhanced+Raman+spectroscopy.">Rapid and sensitive in-situ detection of polar antibiotics in water using a disposable Ag-graphene sensor based on electrophoretic preconcentration and surface-enhanced Raman spectroscopy.</a> Biosens. Bioelectron. 43, 94-100 (2013).</li><li>Clarke, S. J., Littleford, R. E., Smith, W. E., Goodacre, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+monitoring+of+antibiotics+using+Raman+and+surface+enhanced+Raman+spectroscopy.">Rapid monitoring of antibiotics using Raman and surface enhanced Raman spectroscopy.</a> Analyst. 130 (7), 1019-1026 (2005).</li><li>Zheng, J., Pang, S., Labuza, T. P., He, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semi-quantification+of+surface-enhanced+Raman+scattering+using+a+handheld+Raman+spectrometer:+a+feasibility+study.">Semi-quantification of surface-enhanced Raman scattering using a handheld Raman spectrometer: a feasibility study.</a> Analyst. 138 (23), 7075-7078 (2013).</li><li>Zheng, J., Pang, S., Labuza, T. P., He, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+surface-enhanced+Raman+scattering+detection+using+a+handheld+and+a+bench-top+Raman+spectrometer:+A+comparative+study.">Evaluation of surface-enhanced Raman scattering detection using a handheld and a bench-top Raman spectrometer: A comparative study.</a> Talanta. 129, 79-85 (2014).</li></ol>

The authors have nothing to disclose.

Einer der kritischen Schritte in diesem Protokoll ist das Silber-Nanopartikel-Synthese, wo gleichmäßige Silber-Nanopartikel der Schlüssel für konsistente Ergebnisse sind. Die Erwärmungszeit und die Konzentrationen von Vorstufen werden müssen präzise gesteuert. Die durchschnittliche Größe von 80 nm AGNPS Zubereitung ist, die durch die Zetasizer gemessen wurde (Daten nicht gezeigt). Ein weiterer kritischer Schritt ist das Salz Aggregation, wo die Salzkonzentration und Aggregationszeit müssen genau gesteuert werd...

Oberflächenverstärkten Raman-Spektroskopie (SERS) ist eine Technik, die Kombination von Raman-Spektroskopie mit Nanotechnologie. Die Intensität der Raman-Streuung von Analyten an Edelmetallnano Oberflächen wird durch die lokalisierte Oberflächenplasmonenresonanz stark verbessert. 1 Silber-Nanopartikel (Ag NPs) sind bei weitem die am häufigsten verwendeten SERS Substrate aufgrund seiner hohen Verstärkung Fähigkeit. 2 Bisher wurden verschiedene Syntheseverfahren von Ag-NPs entwickelt. 3-6 Ag-Nanopartikeln allein so wirksam SERS Substrate verwendet werden können, oder mit anderen Materialien und Strukturen kombiniert, um die Empfindlichkeit und / oder Funktionalität zu verbessern. 7-11 SERS-Techniken haben große Kapazität für die Detektion verschiedener Spurenmengen von Kontaminanten in Lebensmitteln und Umweltproben zeigten 12 Traditionell gibt es zwei allgemeine Möglichkeiten zur Herstellung eines SERS Beispiel:.. Lösungs-und-Substrat-basierte Verfahren 13 Die Lösungs-method verwendet NP Kolloide mit Proben zu mischen. Dann wird das NP-Analyt-Komplexes unter Verwendung von Zentrifugation gesammelt und auf einem festen Träger für die Raman-Messung nach dem Trocknen aufgebracht. Das Substrat-basierten Verfahren wird in der Regel durch Aufbringen von mehreren Mikroliter einer flüssigen Probe auf die vorgefertigte feste Substrat aufgebracht. 14 sind jedoch keine dieser beiden Methoden effektiv und geeignet für eine große Menge an Probenvolumen. Mehrere Änderungen der SERS-Assays überwand die Volumengrenzen, wie die Integration eines Filtersystems 15-21 oder den Einbau einer Mikrofluidik-Vorrichtung. 21-24 Die modifizierten SERS-Assays große Verbesserung in der Empfindlichkeit und Machbarkeit gezeigt haben, für die chemische Verunreinigungen Überwachung in großen Wasserproben. Hier zeigen wir die detaillierte Protokoll der Herstellung und Anwendung einer Spritzenfilter basierend SERS Verfahren Spurenmenge an Pestizid Ferbam und Antibiotikum Ampicillin zu detektieren.

<table><tbody><tr><td>Ampicillin</td><td>Fisher Scientific</td><td>BP1760-5</td><td>N/A</td></tr><tr><td>Ferbam</td><td>Chem Service</td><td>N-11970-250MG</td><td>98+%</td></tr><tr><td>Silver nitrate</td><td>Sigma Aldrich</td><td>209139</td><td>99.0+%</td></tr><tr><td>Sodium citrate dehydrate</td><td>Sigma Aldrich</td><td>W302600</td><td>99+%</td></tr><tr><td>Sodium chloride</td><td>Sigma Aldrich</td><td>S7653</td><td>99.5+%</td></tr><tr><td>EMD Millipore Durapore PVDF Membrane Filters</td><td>Fisher Scientific</td><td>VVLP01300</td><td>0.10 &amp;micro;m Pore Size, hydrophilic</td></tr><tr><td>Polycarbonate Filter Holders</td><td>Cole-Parmer</td><td>EW-29550-40</td><td>13 mm diameter</td></tr><tr><td>Analog Vortex Mixer</td><td>Fisher Scientific</td><td>02-215-365</td><td>N/A</td></tr><tr><td>Nutating Mixers</td><td>Fisher Scientific</td><td>05-450-213</td><td>N/A</td></tr><tr><td>DXR Raman spectroscope</td><td>Thermo Scientific</td><td>IQLAADGABFFAHCMAPB</td><td>Laser power: 1 mW&lt;br /&gt; Exposure time: 5 sec</td></tr></tbody></table>

a filter-based surface enhanced raman spectroscopic assay for rapid detection of chemical contaminants

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be applied to the detection of various chemical contaminants. Silver nanoparticles (Ag NPs) are synthesized via reduction of silver nitrate by sodium citrate. Then the NPs are aggregated by sodium chloride to form nanoclusters that could be trapped in the pores of the filter membrane. A syringe is connected to the filter holder, with a filter membrane inside. By loading the nanoclusters into the syringe and passing through the membrane, the liquid goes through the membrane but not the nanoclusters, forming a SERS-active membrane. When testing the analyte, the liquid sample is loaded into the syringe and flowed through the Ag NPs coated membrane. The analyte binds and concentrates on the Ag NPs coated membrane. Then the membrane is detached from the filter holder, air dried and measured by a Raman instrument. Here we present the study of the volume effect of Ag NPs and sample on the detection sensitivity as well as the detection of 10 ppb ferbam and 1 ppm ampicillin using the developed assay.

Die wichtigsten Schritte dieses Versuches wurden in der schematischen Darstellung (Abbildung 1). Abbildung 2 demonstriert die Bedeutung der optimierten Volumen AGNPS in der Membranbeschichtung zu verwenden, um die Empfindlichkeit maximiert zu erreichen. 1 ml der Silber-Nanopartikel bietet das stärkste Signal, wenn Ferbam verwenden, im Vergleich zu 0,5 ml (unzureichende Beschichtung) oder 2 ml (zuviel Beschichtung). <p class="jove_content" fo:keep-to...

Watch this Scientific Journal Video about A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants at JoVE.com

A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants

Ein Verfahren zur Herstellung und Durchführung der filterbasierten oberflächenverstärkten Raman-Spektroskopie (SERS) Assay zum Nachweis von chemischen Verunreinigungen (dh Pestizid Ferbam und Antibiotikum Ampicillin) dargestellt.

Ein Filter-basierten oberflächenverstärkter Raman-spektroskopische Assay zum schnellen Nachweis von chemischen Verunreinigungen

We demonstrate a method to fabricate highly sensitive surface-enhanced Raman spectroscopic (SERS) substrates using a filter syringe system that can be ...

a-filter-based-surface-enhanced-raman-spectroscopic-assay-for-rapid

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

9.3K Aufrufe.  University of Massachusetts Amherst.  Ein Verfahren zur Herstellung und Durchführung der filterbasierten oberflächenverstärkten Raman-Spektroskopie (SERS) Assay zum Nachweis von chemischen Verunreinigungen (dh Pestizid Ferbam und Antibiotikum Ampicillin) dargestellt. 

Serie: A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants

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.

Herstellung eines UV-Vis und Raman-Spektroskopie Immunoassay-Plattform

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

Forschung

Biochemie

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.

Oberflächenverstärkte Raman-Spektroskopie Detektion von Biomolekülen Mit EBL Fabricated nanostrukturierte Substrate

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

Ingenieurwesen

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

A method for species identification of botanical material by direct analysis in real time-high resolution mass spectrometry and multivariate statistical analysis is presented.

Schnelle Hochdurchsatz-Spezies Identifizierung von Pflanzen von Material mit Direktanalyse in Echtzeit hochauflösender Massenspektrometrie

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

Chemie

Preparation and Application of a New Bacterial Biosensor for the Presumptive Detection of Gunshot Residue

MicRoboCop is a biosensor that has been designed for a unique application in forensic chemistry. MicRoboCop is a system made up of three devices that, when used together, can indicate the presence of gunshot residue (GSR) by producing a fluorescence signal in the presence of three key analytes (antimony, lead, and organic components of GSR). The protocol describes the synthesis of the biosensors using Escherichia coli (E. coli), and the analytical chemistry methods used to evaluate the selectivity and sensitivity of the sensors. The functioning of the system is demonstrated by using GSR collected from the inside of a spent cartridge casing. Once prepared, the biosensors can be stored until needed and can be used as a test for these key analytes. A positive response from all three analytes provides a presumptive positive test for GSR, while each individual device has applications for detecting the analytes in other samples (e.g., a detector for lead contamination in drinking water). The main limitation of the system is the time required for a positive signal; future work may involve studying different organisms to optimize the response time.

A protocol is presented using synthetic biology techniques to synthesize a set of bacterial biosensors for the analysis of gunshot residue, and to test the functioning of the devices for their intended use using fluorescence spectroscopy.

Vorbereitung und Anwendung eines neuen bakteriellen Biosensors für die präventive Erkennung von Gunshot Residue

MicRoboCop is a biosensor that has been designed for a unique application in forensic chemistry. MicRoboCop is a system made up of three devices that, ...

Multiplex Chemical Imaging Based on Broadband Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps at high speed, and high spatial resolution of thin samples by directly interrogating their molecular vibrations. In its standard implementation, SRS microscopy is narrowband and forms images with only a single vibrational frequency at a time. However, this approach not only hinders the chemical specificity of SRS but also neglects the wealth of information encoded within vibrational spectra. 
These limitations can be overcome by broadband SRS, an implementation capable of extracting a vibrational spectrum per pixel of the image in parallel. This delivers hyperspectral data that, when coupled with chemometric analysis, maximizes the amount of information retrieved from the specimen. Thus, broadband SRS improves the chemical specificity of the system, allowing the quantitative determination of the concentration of the different constituents of a sample. Here, we report a protocol for chemical imaging with broadband SRS microscopy, based on a home-built SRS microscope operating with a custom differential multichannel-lock-in amplifier detection. It discusses the sample preparation, alignment of the SRS apparatus, and chemometric analysis. By acquiring vibrational Raman spectra, the protocol illustrates how to identify different chemical species within a mixture, determining their relative concentrations.

We present a protocol to acquire chemical images with broadband stimulated Raman scattering (SRS) microscopy. Based on an SRS microscope that operates with differential multichannel-lock-in detection, the protocol describes the sample preparation, adjustment of the SRS apparatus, and chemometrics to disentangle different constituents of chemically heterogeneous samples.

Chemische Multiplex-Bildgebung auf Basis einer breitbandstimulierten Raman-Streumikroskopie

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps ...

Direct Comparison of Hyperspectral Stimulated Raman Scattering and Coherent Anti-Stokes Raman Scattering Microscopy for Chemical Imaging

Stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) microscopy are the most widely used coherent Raman scattering imaging technologies. Hyperspectral SRS and CARS imaging offer Raman spectral information at every pixel, which enables better separation of different chemical compositions. Although both techniques require two excitation lasers, their signal detection schemes and spectral properties are quite different. The goal of this protocol is to perform both hyperspectral SRS and CARS imaging on a single platform and compare the two microscopy techniques for imaging different biological samples. The spectral focusing method is employed to acquire spectral information using femtosecond lasers. By using standard chemical samples, the sensitivity, spatial resolution, and spectral resolution of SRS and CARS in the same excitation conditions (i.e., power at the sample, pixel dwell time, objective lens, pulse energy) are compared. The imaging contrasts of CARS and SRS for biological samples are juxtaposed and compared. The direct comparison of CARS and SRS performances would allow for optimal selection of the modality for chemical imaging.

This paper directly compares the resolution, sensitivity, and imaging contrasts of stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) integrated into the same microscope platform. The results show that CARS has a better spatial resolution, SRS gives better contrasts and spectral resolution, and both methods have similar sensitivity.

Direkter Vergleich der hyperspektralen stimulierten Raman-Streuung und der kohärenten Anti-Stokes-Raman-Streumikroskopie für die chemische Bildgebung

Stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS) microscopy are the most widely used coherent Raman scattering imaging ...

Synthese von Nanopartikeln und Nanostrukturen mittels Laserablation

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.

Autor im Rampenlicht: Fortschritte und Anwendungen in der Nanopartikelsynthese durch Laserablation in Flüssigkeiten 

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.

Ultraschnelle laserabgetragene Nanopartikel und Nanostrukturen für oberflächenverstärkte Raman-Streu-basierte Sensoranwendungen

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

Herstellung eines flexiblen Substrats für die SERS-Detektion von R6G und Thiram

Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) were synthesized through a complexation reaction involving silver nitrate (AgNO3) and ammonia, followed by reduction using glucose. The resulting AgNPs exhibited a uniform size distribution ranging from 20 nm to 50 nm. Subsequently, 3-aminopropyl triethoxysilane (APTES) was employed to modify a PDMS substrate that had been surface-treated with oxygen plasma. This process facilitated the self-assembly of AgNPs onto the substrate. A systematic evaluation of the impact of various experimental conditions on substrate performance led to the development of a SERS substrate with excellent performance and an Enhanced Factor (EF). Utilizing this substrate, impressive detection limits of 10-10 M for R6G (Rhodamine 6G) and 10-8 M for Thiram were achieved. The substrate was successfully employed for detecting pesticide residues on apples, yielding highly satisfactory results. The flexible SERS substrate demonstrates great potential for real-world applications, including detection in complex scenarios.

Autor im Rampenlicht: Entwicklung und Anwendung von flexiblen SERS-Substraten unter Verwendung synthetisierter AgNPs 

This protocol describes a fabrication method for a flexible substrate for surface-enhanced Raman scattering. This method has been used in the successful detection of low concentrations of R6G and Thiram.

Herstellung eines Polydimethylsiloxan (PDMS)-basierten flexiblen oberflächenverstärkten Raman-Streusubstrats (SERS) für die hochempfindliche Detektion

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) ...

Ein Filter-basierten oberflächenverstärkter Raman-spektroskopische Assay zum schnellen Nachweis von chemischen Verunreinigungen

Zusammenfassung

Weitere Videos entdecken

Kapitel in diesem Video

Herstellung eines UV-Vis und Raman-Spektroskopie Immunoassay-Plattform

Oberflächenverstärkte Raman-Spektroskopie Detektion von Biomolekülen Mit EBL Fabricated nanostrukturierte Substrate

Schnelle Hochdurchsatz-Spezies Identifizierung von Pflanzen von Material mit Direktanalyse in Echtzeit hochauflösender Massenspektrometrie

Vorbereitung und Anwendung eines neuen bakteriellen Biosensors für die präventive Erkennung von Gunshot Residue

Chemische Multiplex-Bildgebung auf Basis einer breitbandstimulierten Raman-Streumikroskopie

Direkter Vergleich der hyperspektralen stimulierten Raman-Streuung und der kohärenten Anti-Stokes-Raman-Streumikroskopie für die chemische Bildgebung

Ultraschnelle laserabgetragene Nanopartikel und Nanostrukturen für oberflächenverstärkte Raman-Streu-basierte Sensoranwendungen

Ultraschnelle laserabgetragene Nanopartikel und Nanostrukturen für oberflächenverstärkte Raman-Streu-basierte Sensoranwendungen

Ultraschnelle laserabgetragene Nanopartikel und Nanostrukturen für oberflächenverstärkte Raman-Streu-basierte Sensoranwendungen

Herstellung eines Polydimethylsiloxan (PDMS)-basierten flexiblen oberflächenverstärkten Raman-Streusubstrats (SERS) für die hochempfindliche Detektion