Die Autoren danken dem Institut für Chemie und das Graduiertenkolleg in Missouri State University für ihre Unterstützung dieses Projektes. Wir erkennen auch die Elektronenmikroskopie-Labor an der Friedrich National Laboratory for Cancer Research für die Nutzung ihrer Transmissionselektronenmikroskop und kohlenstoffbeschichtetes Gitter.

1. Synthese von Indium-Phosphid / Zinksulfid (InP / ZnS) Quantum Dots <ol><li> Synthese von Indiumphosphid (InP) Quantum Dot Cores <ol><li> Setzen Sie einen 100 ml Rundkolben, 3-Hals-Kolben mit einem 12-Zoll-Kondensator. Mit einem Vakuum für 1 Stunde 30 ml Oleylamin (OLA), 0,398 g Indium (III) chlorid (InCl 3), 0,245 g Zink (II) chlorid (ZnCl 2) und rühren während bei RT zu evakuieren. Die Lösung sollte mit einem weißen Niederschlag farblos erscheinen. </li><li> Unter Verwendung eines Heizmantels mit einem Thermoelement und proportional-integral-derivative (PID) Temperaturregler, erhöhen die Temperatur der Lösung auf 120 ° C. Evakuieren die Lösung unter Vakuum für 20 min mit niedrigem Siedepunkt, um Verunreinigungen zu entfernen, die Kernwachstum auswirken können. Anmerkung: Es ist zwar möglich, ein Sandbad und Thermometer zu verwenden, unter Verwendung eines Heizmantels und PID erhöht die Homogenität und Reproduzierbarkeit der Reaktionsprodukte. </li><li> Unter Schutzgas (zB, N 2), die Lösung unter Rückfluss und die Temperatur auf 220 ° C für 15 min erhöhen. Die InCl 3 und ZnCl 2 vollständig aufzulösen, wodurch eine blassgelbe Lösung. Lassen Sie die Temperatur für 10 min zu stabilisieren. </li><li> Spülen Sie eine Einweg, 3 ml Kunststoffspritze und 4 Zoll, 22 G-Nadel mit Stickstoffgas. Unter Verwendung der Spritze, liefern schnell 0,5 ml Tris (dimethylamino) phosphin (TDMAP) an die InCl &amp; sub3; -Lösung. Die Temperatur der Lösung sinkt leicht und kehrt zu 220 ° C. Die Lösung ändert sich von transparent, hellgelb bis opak, schwarz. </li><li> Nach 9,5 min, der Reaktionskolben aus dem Heizmantel entfernen, bis die Temperatur unter 200 ° C sinkt. Um die Integrität der InP-Kerne schützen, gehen direkt an die ZnS-Beschichtung in Schritt 1.2.1. </li></ol></li><li> Synthese von Zinksulfid (ZnS) Quantum Dot Shells <ol><li> Setzen Sie den Reaktionskolben aus Schritt 1.1.5 auf einem Heizpilz und stabilisieren die temperatur bei 200 ° C. Langsam 3,58 g Dodecanthiol (DDT) im Verlauf von 15 sec auf die Lösung, die InP-Quantenpunkte hinzuzufügen. Lassen Sie die Lösung für 1 Stunde zu reagieren. Anmerkung: ZnS Schalendicke kann durch Erhöhen oder Verringern der Menge an Zinkstearat in Schritt 1.2.4 hinzugefügt variiert werden. Die Veränderung der Menge an ZnCl 2 oder Dodecanthiol in Schritten 1.1.1 und 1.2.1 kann erheblich die Qualität der Quantenpunkte beeinflussen, indem sie die Reaktionskinetik zu ändern. <ol><li> Danach entfernen die Reaktionskolben aus dem Heizmantel und die Lösung auf etwa 60 ° C zu kühlen. </li></ol></li><li> Sobald die InP / ZnS Lösung erreicht ~ 60 ° C, 10 ml Hexan und übertragen die gesamte Lösung von etwa 45 ml bis 50 ml-Polypropylen-Zentrifugenröhrchen. Zentrifugieren Sie die Probe (3.000 × g für 10 min) nicht umgesetzten festen Vorläufer zu entfernen. </li><li> übertragen Sie vorsichtig den Überstand in ein 250-ml-Polypropylen-Zentrifugenflasche, 200 ml Aceton und Zentrifuge die Lösung (3.000 xg für 10 min) InP / ZnS QDs auszufällen. Dieses Volumen kann auch gleichmäßig in vier 50-ml-Röhrchen für die Zentrifugation aufgespalten werden, wenn eine Zentrifuge mit den notwendigen Rotor / Zubehör, das nicht zur Verfügung steht. Dekantieren des Überstandes und trocknen Sie die QD Pellet gründlich mit Stickstoffgas Aceton zu entfernen. </li><li> Resuspendieren der Quantenpunkte in 20 ml OLA Beschallung verwenden, übertragen auf einen 50 ml Rundboden, 3-Hals-Kolben mit 0,474 g Zinkstearat und umrühren. Evakuieren die Lösung unter Vakuum für 20 min bei RT. </li><li> Unter Stickstoffgas, die Temperatur auf 180 ° C erhöht und damit die Reaktion 3 Stunden ablaufen. Zwar gibt es keine merklichen visuellen Änderungen zu der Reaktionslösung, die bei dieser Reaktion auftreten, erhöht Dicke ZnS Schale Zinkstearat Hinzufügen somit QY Erhöhung durch Oberflächenpassivierung QD 12 zu verbessern. Sobald die Reaktion abgeschlossen ist, die Kolben aus dem Heizmantel entfernen und die Lösung auf etwa 60 ° C zu kühlen. </li><li> Sobald die InP / ZnS solutiauf Lauf ~ 60 ° C, in den ein 50 ml Polypropylenzentrifugenröhrchen 20 ml Hexan und übertragen. Zentrifugieren Sie die Probe (3.000 × g für 10 min) auf nicht umgesetzte Zinkstearat entfernen. </li><li> übertragen Sie vorsichtig den Überstand in ein 250-ml-Polypropylen-Zentrifugenflasche, 200 ml Aceton und Zentrifuge die Lösung (3000 g für 10 min) InP / ZnS-QDs zu fällen. Dekantieren Sie vorsichtig den Überstand und gründlich mit Stickstoffgas trocken Aceton zu entfernen. </li><li> Man löst den InP / ZnS QD Pellet in 30 ml Hexan. Vortex und beschallen die Lösung kurz vollständige Dispersion zu gewährleisten. </li><li> Wiederholen Reinigungsschritte 1.2.6-1.2.8 zwei weitere Male gründliche Entfernung von überschüssigem organischen Liganden zu gewährleisten. Wechselwirkungen zwischen dem amphiphilen Polymer und dem QD in Schritt 1.2 kann in Gegenwart von überschüssigem Liganden beeinträchtigt werden. </li><li> Mit Berechnungen von Xie detailliert, et al. 16, bestimmen die Größe und Konzentration der synthetisierten InP / ZnS-QDs mit UV-Vis-Spektroskopie. <br/&gt; Anmerkung: Die wichtige spektrale Charakteristik für diese Analyse ist die Schulter des Absorptionspeaks. Die Wellenlänge und Absorptionswert des Maximums dieser Schulter dient dazu, die Größe und die Konzentration der Quantenpunkte zu berechnen, respectively. Diese Reaktion ergibt typischerweise etwa 5 &amp; mgr; mol QD mit einem Emissionspeak bei 600 nm. Bis QD der verschiedenen Farben synthetisieren, die Dauer und / oder Temperatur der Reaktion kann geändert werden. Eine längere Reaktionszeit und / oder höhere Temperatur der Lösung führt zu einer Rotverschiebung Emissionspeak. Zum Beispiel, Erhöhung der Reaktionstemperatur auf 240 ° C und Aufrechterhalten Reaktionszeit von 10 min wird in QD mit einem 680 nm höchstens Emissionen Spitze führen. Ebenso reduziert die Reaktionszeit auf 2 Minuten und verwendet Zinkchlorid Verdoppelung in QD mit einem 470 nm maximale Emissionsspitze führen. Diese InP / ZnS-QDs sind stabil für mindestens einen Monat bei 4 ° C im Dunkeln unter Schutzgas. </li></ol></li></ol> 2. WasserSolubilisierung von InP / ZnS-Quantenpunkte unter Verwendung eines amphiphilen Polymers <ol><li> Wasser Solubilisierungsmethode <ol><li> Unter Verwendung der InP / ZnS QD aus Schritt 1.2.10, verdünnte einen Teil der Quantenpunkte mit Hexan von 1 uM QD zu erhalten 1 ml. <ol><li> In einem Zentrifugenröhrchen, übertragen 0,25 ml InP / ZnS-QDs in jedes Röhrchen. 1 ml Aceton oder Methanol zu dem Zentrifugenröhrchen und Zentrifuge (3.000 × g für 10 min). Den Überstand sorgfältig entfernen und jeder Niederschlag in 1 ml Tetrahydrofuran (THF) lösen. </li><li> Übertragen Sie die InP / ZnS-QDs in THF in einen 100-ml-Rundkolben und verdünnt mit 16 ml THF. Um die Anzahl der Aggregate in der Lösung reduzieren, beschallen die Quantenpunkte für 5-10 min. </li></ol></li><li> Man löst 30 mg Poly (Maleinsäureanhydrid andhydride- alt -1-Octadecen), 3- (Dimethylamino) -1-propylamin (pMAL-d) in 10 ml Molekularreinem Wasser. Wasserbad Beschallung oder leichtem Rühren, bis die Lösung durchscheinend ist ausreichend, um das Polymer vollständig aufzulösen. DasVerwendung von Wirbel oder kräftigem Rühren kann viele Blasen erzeugen, die Wechselwirkung des Polymers mit dem QD behindert. In den 10 ml Polymerlösung auf den 100-ml-Rundkolben, der InP / ZnS-QDs in THF. </li><li> Verdampfen THF aus dem QD / Polymerlösung mit einem Rotationsverdampfer. Der Kolben wird in einem Eisbad während Eindampfen der Wechselwirkung zwischen dem Polymer und QD zu erleichtern. Je nach Stärke des Vakuums wird das meiste THF nach 10 min verdampft und die Lösung wird trüb. <ol><li> Sobald die Lösung auf 10 ml eingedampft wird, der Kolben vom Rotationsverdampfer entfernen und 30 ml molekularen Grad Wasser. Bringen Sie den Kolben am Rotationsverdampfer und weiter bis 2 ml zu verdampfen. Dieser letzte Verdampfungsschritt kann viele Stunden dauern; sicherzustellen, das Eisbad aufrechterhalten wird. </li></ol></li><li> Entfernen Sie die wasserlöslichen InP / ZnS-QDs aus dem Rundkolben mit einer Pipette. Filtern Sie die QD-Lösung mit einer 3 ml-Kunststoffspritze an einem 0,1 um Nylon syringe filtriert in ein 5 ml Zentrifugenröhrchen. </li><li> Legen Sie die Quantenpunkte in einer 20.000 MWCO-Membran Dialysestation und Dialyse gegen 0,05 M Boratpuffer pH 8,5, um überschüssige Polymer entfernen. (Langsam 0,05 M Natriumtetraborat-Decahydrat und 0,05 M Borsäure, unter starkem Rühren, bis der pH 8.5 ist diese Boratpufferlösung zu machen.) Einen Vakuumkonzentrator Verwendung konzentrieren sich die Quantenpunkte in Boratpuffer auf 1 ml. </li><li> Für die Lagerung, Säuberung der Lösung mit Stickstoffgas vor mit Parafilm versiegelt. Die wasserlöslichen InP / ZnS QD sind stabil für mindestens 4 Monate bei 4 ° C im Dunkeln. </li></ol></li></ol>

<ol>
	<li>Alivisatos, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Semicondictor+clusters,+nanocrystals,+and+quantum+dots.">Semicondictor clusters, nanocrystals, and quantum dots.</a> Science. 271 (5251), 933-937 (1996).</li><li>Michalet, X., 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=Quantum+dots+for+live+cells,+in+vivo+imaging,+and+diagnostics.">Quantum dots for live cells, in vivo imaging, and diagnostics.</a> Science. 307 (5709), 538-544 (2005).</li><li>Jaiswal, J. K., Mattoussi, H., Mauro, J. M., Simon, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+multiple+color+imaging+of+live+cells+using+quantum+dot+bioconjugates.">Long-term multiple color imaging of live cells using quantum dot bioconjugates.</a> Nat. Biotechnol. 21 (1), 47-51 (2009).</li><li>Deerinck, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+application+of+fluorescent+quantum+dots+to+confocal,+multiphoton,+and+electron+microscopic+imaging.">The application of fluorescent quantum dots to confocal, multiphoton, and electron microscopic imaging.</a> Toxicol. Pathol. 36 (1), 112-116 (2008).</li><li>Smith, A. M., Duan, H., Mohs, A. M., Nie, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioconjugated+quantum+dots+for+in+vivo+molecular+and+cellular+imaging.">Bioconjugated quantum dots for in vivo molecular and cellular imaging.</a> Adv. Drug Deliv. Rev. 60 (11), 1226-1240 (2008).</li><li>Jamieson, 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=Biological+applications+of+quantum+dots.">Biological applications of quantum dots.</a> Biomaterials. 28 (31), 4717-4732 (2007).</li><li>Lidke, D. S., Arndt-Jovin, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+takes+a+quantum+leap.">Imaging takes a quantum leap.</a> Physiology. 19, 322-325 (2004).</li><li>Fichter, K. M., Flajolet, M., Greengard, P., Vu, T. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetics+of+G-protein-couple+receptor+endosomal+trafficking+pathways+revealed+by+single+quantum+dots.">Kinetics of G-protein-couple receptor endosomal trafficking pathways revealed by single quantum dots.</a> Proc. Natl. Acad. Sci. U.S.A. 107 (43), 18658-18663 (2010).</li><li>Smith, A. M., Ruan, G., Rhyner, M. N., Nie, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+luminescent+quantum+dots+for+in+vitro+molecular+and+cellular+imaging.">Engineering luminescent quantum dots for in vitro molecular and cellular imaging.</a> Ann. Biomed. Eng. 34 (1), 3-14 (2006).</li><li>Derfus, A. M., Chan, W. C. W., Bhatia, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+cytotoxicity+of+semiconductor+quantum+dots.">Probing the cytotoxicity of semiconductor quantum dots.</a> Nano Lett. 4 (1), 11-18 (2004).</li><li>Brunetti, V., 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=InP/ZnS+as+a+safer+alternative+to+CdSe/ZnS+core/shell+quantum+dots:+in+vitro+and+in+vivo+toxicity+assessment.">InP/ZnS as a safer alternative to CdSe/ZnS core/shell quantum dots: in vitro and in vivo toxicity assessment.</a> Nanoscale. 5 (1), 307-317 (2013).</li><li>Song, 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=Amine-derived+synthetic+approach+to+color-tunable+InP/ZnS+quantum+dots+with+high+fluorescent+qualities.">Amine-derived synthetic approach to color-tunable InP/ZnS quantum dots with high fluorescent qualities.</a> J. Nanopart. Res. 15 (1750), (1750).</li><li>Dabbousi, B. O., 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=(CdSe)ZnS+core-shell+quantum+dots:+Synthesis+and+characterization+of+a+size+series+of+highly+luminescent+nanocrystallites.">(CdSe)ZnS core-shell quantum dots: Synthesis and characterization of a size series of highly luminescent nanocrystallites.</a> J. Phys. Chem. B. 101 (46), 9463-9475 (1997).</li><li>Micic, O. I., Curtis, C. J., Jones, K. M., Sprague, J. R., Nozik, A. J. <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+characterization+of+InP+quantum+dots.">Synthesis and characterization of InP quantum dots.</a> J. Phys. Chem. 98 (19), 4966-4969 (1994).</li><li>Qi, L., Gao, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantum+dot-amphipol+nanocomplex+for+intracellular+delivery+and+realtime+imaging+of+siRNA.">Quantum dot-amphipol nanocomplex for intracellular delivery and realtime imaging of siRNA.</a> ACS Nano. 2 (7), 1403-1410 (2008).</li><li>Xie, R., Zheng, L., Peng, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nucleation+kinetics+vs+chemical+kinetics+in+the+initial+formation+of+semiconductor+nanocrystals.">Nucleation kinetics vs chemical kinetics in the initial formation of semiconductor nanocrystals.</a> J. Am. Chem. Soc. 131 (42), 15457-15466 (2009).</li><li>Williams, A. T. R., Winfield, S. A., Miller, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relative+fluorescence+quantum+yields+using+a+computer-controlled+luminescence+spectrometer.">Relative fluorescence quantum yields using a computer-controlled luminescence spectrometer.</a> Analyst. 108, 1067-1071 (1983).</li><li>Schindelin, 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=Fiji:+An+open-source+platform+for+biological-image+analysis.">Fiji: An open-source platform for biological-image analysis.</a> Nat. Methods. 9 (7), 676-682 (2012).</li><li>Schnieder, C. A., Rasband, W. S., Eliceiri, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIH+image+to+ImageJ:+25+years+of+image+analysis.">NIH image to ImageJ: 25 years of image analysis.</a> Nat. Methods. 9, 671-675 (2012).</li><li>Jin, Y., Kannan, S., Wu, M., Zhao, J. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toxicity+of+luminescent+silica+nanoparticles+to+living+cells.">Toxicity of luminescent silica nanoparticles to living cells.</a> Chem. Res. Toxicol. 20 (8), 1126-1133 (2007).</li><li>Corazzari, I., Gilardino, A., Dalmazzo, S., Fubini, B., Lovisolo, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+of+CdSe/ZnS+quantum+dots+in+the+lysosomal+acidic+compartment+of+cultured+neurons+and+its+impact+on+viability:+potential+role+of+ion+release.">Localization of CdSe/ZnS quantum dots in the lysosomal acidic compartment of cultured neurons and its impact on viability: potential role of ion release.</a> Toxicol. In Vitro. 27 (2), 752-759 (2013).</li><li>Pons, T., Uyeda, H. T., Medintz, I., Mattoussi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrodynamic+dimensions,+electrophoretic+mobility,+and+stability+of+hydrophilic+quantum+dots.">Hydrodynamic dimensions, electrophoretic mobility, and stability of hydrophilic quantum dots.</a> J. Phys. Chem. B. 110 (41), 20308-20316 (2006).</li><li>Durisic, N., Wiseman, P., Grutter, P., Heyes, 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=A+common+mechanism+underlies+the+dark+fraction+formation+and+fluorescence+blinking+of+quantum+dots.">A common mechanism underlies the dark fraction formation and fluorescence blinking of quantum dots.</a> ACS Nano. 3 (5), 1167-1175 (2009).</li><li>Vermehren-Schmaedick, A., 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=Heterogeneous+intracellular+trafficking+dynamics+of+brain-derived+neurotropic+factor+complexes+in+the+neuronal+soma+revealed+by+single+quantum+dot+tracking.">Heterogeneous intracellular trafficking dynamics of brain-derived neurotropic factor complexes in the neuronal soma revealed by single quantum dot tracking.</a> PLoS ONE. 9 (4), e95113 (2014).</li></ol>

Die Autoren haben nichts zu offenbaren.

Dieses Protokoll beschreibt die Synthese hochFluoreszenz InP / ZnS QD, die in vielen biologischen Systemen verwendet werden können. Die QD-Produkte hier synthetisiert zeigte einen einzelnen Peak Fluoreszenzemission bei 600 nm mit einer FWHM von 73 nm (Abbildung 1) zentriert ist, die zu anderen zuvor beschriebenen Synthesen 12 vergleichbar ist. Die Reaktionszeit und Reaktionstemperatur sind sehr wichtige Schritte wegen ihrer tiefgreifende Wirkung auf QD Synthesequalität und Reproduzierbarkei...

A correction was made to: <a href="http://www.jove.com/video/53684/synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical" target="_blank">Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications</a>. There was an error with an author's given name. The author's name was corrected to:
Katye M. Fichter
from:
Kathryn M. Fichter

A correction was made to: <a href="http://www.jove.com/video/53684/synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical" target="_blank">Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications</a>.

Erratum: Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

Quantum Dots (QD) sind halbleitende Nanokristalle, die fluoreszierende Eigenschaften aufweisen, wenn sie mit Licht bestrahlt ein. Aufgrund ihrer geringen Größe (2-5 nm), die viele größere Biomoleküle ähnlich ist, und eine einfache Biofunktionalisierung, QD sind ein äußerst attraktives Werkzeug für biomedizinische Anwendungen. Sie haben Verwendung in der biologischen Kennzeichnung, Einzelmolekül-Lebendzell-Imaging, Arzneimittelabgabe, in-vivo-Bildgebung, Erregernachweis und Zellverfolgung, unter vielen anderen Anwendungen gefunden 08.02. CD-basierten Quantenpunkte wurden am häufigsten in biomedizinischen Anwendungen verwendet, wegen ihrer intensiven Fluoreszenz und schmale Emissionspeakbreiten 9. Allerdings haben Bedenken wegen der möglichen Toxizität von Cadmium angehoben worden 2+ -Ionen 10, die durch den Abbau des Nanopartikel freigesetzt werden können. Vor kurzem InP-basierten Quantenpunkte wurden als Alternative zu CD-basierten Quantenpunkte untersucht, weil sie viele Fluoreszenzeigenschaften beibehaltenvon CD-basierten Quantenpunkte und kann biokompatibler 11 sein. CD-basierten Quantenpunkte wurden signifikant toxisch zu sein als InP-basierten Quantenpunkte in in vitro-Tests in Konzentrationen so niedrig wie 10 Uhr, nach nur 48 Stunden 11 gefunden. Die Fluoreszenzemissionsfarbe von QD ist größen abstimmbaren 1. Das heißt, wenn die Größe der QD zunimmt, nimmt die Fluoreszenzemission der roten verschoben. Die Größe und Größen Dispersität der QD-Produkte können durch Ändern der Temperatur, Reaktionsdauer, oder Vorläuferkonzentrationsbedingungen während der Reaktion 12 modifiziert werden. Während die Emissionsspitze von InP QD ist typischerweise breiter und weniger intensiv als CD-basierte QD, InP Quantenpunkte können in einer Vielzahl von Farben hergestellt werden entworfen spektrale Überlappung zu vermeiden, und 12 für die meisten Anwendungen ausreichend intensiven biomedizinischen sind. Die Synthese in diesem Protokoll detailliert ergibt QD mit einer roten Emissionsspitze bei 600 nm zentriert ist. Sind mehrere Schritte af genommenter Synthese der QD-Kerne, die optische Integrität der Quantenpunkte zu erhalten und sie für biologische Anwendungen kompatibel zu machen. Die Oberfläche des Kern QD müssen vor Oxidation oder Oberflächenfehler geschützt werden, die dazu führen können Abschrecken; Daher wird ein ZnS Schale über den Kern beschichtet InP / ZnS (core / shell) QDS 13 zu erzeugen. Diese Beschichtung wurde die Photolumineszenz des QD Produkt zu schützen gezeigt. Die Gegenwart von Zinkionen während InP QD-Synthese wurde 12 gezeigt, um Oberflächenfehler zu begrenzen, sowie Abnahme Größenverteilung. Selbst bei der Anwesenheit von Zn 2+ in dem Reaktionsmedium, Synthese von InZnP sind höchst unwahrscheinlich 12. Nach der Beschichtung, was InP / ZnS-QDs in hydrophoben Liganden, wie Trioctylphosphinoxid (TOPO) oder Oleylamin 12,14 beschichtet. Ein amphiphiles Polymer mit hydrophoben Liganden auf der Oberfläche QD sowie Schüttwassermolekülen interagieren, um Wasserlöslichkeit 15 verleihen. Amphiphile Polymere mit carboxylate chemischen Gruppen können als &quot;chemische Griffe&quot; verwendet werden, um die QD funktionalisieren. Dieses Protokoll beschreibt die Synthese und Funktionalisierung von wasserlöslichen InP / ZnS QD mit sehr intensiven Fluoreszenzemission und relativ geringe Größe-Dispersität. Diese Quantenpunkte sind möglicherweise weniger toxisch als häufig verwendete CdSe / ZnS-Quantenpunkte. Hierin stellt die Synthese von InP / ZnS-QDs eine praktische Alternative zum CD-basierten Quantenpunkte für biomedizinische Anwendungen.

<table><tbody><tr><td>Oleylamine</td><td>Acros</td><td>129540010</td><td></td></tr><tr><td>Zinc(II) chloride</td><td>Sigma</td><td>030-003-00-2</td><td></td></tr><tr><td>Indium(III) chloride</td><td>Chem-Impex</td><td>24560</td><td></td></tr><tr><td>Tris(dimethylamino)phosphine</td><td>Encompass</td><td>50-901-10500</td><td></td></tr><tr><td>1-dodecanethiol</td><td>Acros</td><td>117625000</td><td></td></tr><tr><td>Hexanes</td><td>Fisher Sci</td><td>H292-4</td><td></td></tr><tr><td>Acetone</td><td>TransChemical</td><td>UN 1090</td><td></td></tr><tr><td>Zinc Stearate</td><td>Aldrich Chem</td><td>307564-1KG</td><td></td></tr><tr><td>Tetrahydrofuran</td><td>Acros</td><td>34845-0010</td><td></td></tr><tr><td>Molecular Water</td><td>Fisher Sci</td><td>BP2470-1</td><td></td></tr><tr><td>Poly(maleic anhyrdride-&lt;em&gt;alt&lt;/em&gt;-1-tetradecene), 3-(dimethylamino)-1-propylamine derivative</td><td>Sigma</td><td>90771-1G</td><td></td></tr><tr><td>Boric acid</td><td>Fisher Sci</td><td>BP168-500</td><td></td></tr><tr><td>Sodium Tetraborate Decahydrate</td><td>Fisher Sci</td><td>BP175-500</td><td></td></tr><tr><td>Rhodamine B</td><td>Aldrich Chem</td><td>R95-3</td><td></td></tr><tr><td>Nitrogen gas</td><td>Airgas</td><td>UN1066</td><td></td></tr><tr><td>Trypan blue</td><td>Thermo Sci</td><td>SV30084.01</td><td></td></tr><tr><td>3 ml plastic Luer-lock syringe</td><td>BD</td><td>309657</td><td></td></tr><tr><td>Luer-lock Needle</td><td>Air-Tite</td><td>8300014471</td><td>4 inch, 22 gauge</td></tr><tr><td>50 ml polypropyene centrifuge tube</td><td>Falcon</td><td>352098</td><td></td></tr><tr><td>250 ml centrifuge bottle</td><td>Thermo Sci</td><td>05-562-23</td><td>Nalgene PPCO</td></tr><tr><td>5 ml centrifuge tubes</td><td>Argos-Tech</td><td>T2076</td><td></td></tr><tr><td>1.5 ml microcentrifuge tubes</td><td>Bio Plas</td><td>4150</td><td></td></tr><tr><td>0.1 &amp;mu;m Syringe filter</td><td>Whatman</td><td>6786-1301</td><td>Puradisc 13 mm nylon filter</td></tr><tr><td>Slide-A-Lyzer MINI Dialysis Unit</td><td>Thermo Sci</td><td>69590</td><td>20,000 MWCO</td></tr><tr><td>Rotary Evaporator</td><td>Heidolph</td><td></td><td></td></tr><tr><td>Centrifuge 5072</td><td>Eppendorf</td><td></td><td>Swinging Bucket with 50&amp;nbsp;ml tube adapters</td></tr><tr><td>Lambda 650 UV/VIS Spectrometer</td><td>Perkin Elmer</td><td></td><td>UV-Vis Spectrophotometer</td></tr><tr><td>LS 55 Fluorescence Spectrometer</td><td>Perkin Elmer</td><td></td><td>Fluorometer</td></tr><tr><td>Axio Observer.A1</td><td>Zeiss</td><td></td><td>epifluorescence microscope</td></tr><tr><td>AxioCam MRm</td><td>Zeiss</td><td></td><td>CCD Camera</td></tr><tr><td>Tecnai TF20 Microscope</td><td>FEI</td><td></td><td>Transmisison Electron Miscroscope</td></tr><tr><td>TEM Eagle CCD</td><td>FEI</td><td></td><td>TEM CCD Camera</td></tr><tr><td>NanoBrook Omni DLS</td><td>Brookhaven</td><td></td><td>Dynamic Light Scattering Instrument</td></tr></tbody></table>

synthesis of cd-free inp/zns quantum dots suitable for biomedical applications

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, quantum dots should be highly fluorescent and small/monodisperse in size. While commonly used cadmium-based quantum dots possess these qualities, they are potentially toxic due to the possible release of Cd2+ ions through nanoparticle degradation. Indium-based quantum dots, specifically InP/ZnS, have recently been explored as a viable alternative to cadmium-based quantum dots due to their relatively similar fluorescence characteristics and size. The synthesis presented here uses standard hot-injection techniques for effective nanoparticle growth; however, nanoparticle properties such as size, emission wavelength, and emission intensity can drastically change due to small changes in the reaction conditions. Therefore, reaction conditions such temperature, reaction duration, and precursor concentration should be maintained precisely to yield reproducible products. Because quantum dots are not inherently soluble in aqueous solutions, they must also undergo surface modification to impart solubility in water. In this protocol, an amphiphilic polymer is used to interact with both hydrophobic ligands on the quantum dot surface and bulk solvent water molecules. Here, a detailed protocol is provided for the synthesis of highly fluorescent InP/ZnS quantum dots that are suitable for use in biomedical applications.

Die unbeschichteten InP Kerne zeigen keinen wesentlichen sichtbare Fluoreszenz mit dem Auge. Allerdings InP / ZnS (core / shell) Quantenpunkte erscheinen hell unter UV-Bestrahlung von Auge zu fluoreszieren. Die Fluoreszenz von InP / ZnS-QDs wurde mit Fluoreszenz-Spektroskopie charakterisiert. Das Fluoreszenzspektrum von QD in Hexanen (Abbildung 1) bei 533 nm angeregt wird mit einer Halbwertsbreite (FWHM) von 73 nm bei 600 nm zentriert einen Hauptpeak zeigt. Während Exti...

Watch this Scientific Journal Video about Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications at JoVE.com

Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

In this protocol, the synthesis of Cd-free InP/ZnS quantum dots (QDs) is detailed. InP-based QDs are gaining popularity due to the toxicity of Cd2+ ions that may be released through nanoparticle degradation. After synthesis, QDs are solubilized in water using an amphiphilic polymer for use in biomedical applications.

Synthese von Cd-frei InP / ZnS-Quantenpunkte Geeignet für biomedizinische Anwendungen

Fluorescent nanocrystals, specifically quantum dots, have been a useful tool for many biomedical applications. For successful use in biological systems, ...

synthesis-cd-free-inpzns-quantum-dots-suitable-for-biomedical

Research

JoVE Journal

Chemistry

13.5K Aufrufe.  Missouri State University. In this protocol, the synthesis of Cd-free InP/ZnS quantum dots (QDs) is detailed. InP-based QDs are gaining popularity due to the toxicity of Cd2+ ions that may be released through nanoparticle degradation. After synthesis, QDs are solubilized in water using an amphiphilic polymer for use in biomedical applications.

Serie: Synthesis of Cd-free InP/ZnS Quantum Dots Suitable for Biomedical Applications

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

Compact Quantum Dots für Einzelmolekül-Imaging

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

Forschung

Ingenieurwesen

Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.

A protocol for the seeded synthesis of rod-shaped and tetrapod-shaped multicomponent nanostructures consisting of CdS and CdSe is presented.

Gesetzt Synthese von CdSe / CdS-Nanokristalle Rod und Tetrapod

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

Chemie

Solubilization and Bio-conjugation of Quantum Dots and Bacterial Toxicity Assays by Growth Curve and Plate Count

Quantum dots (QDs) are fluorescent semiconductor nanoparticles with size-dependent emission spectra that can be excited by a broad choice of wavelengths. QDs have attracted a lot of interest for imaging, diagnostics, and therapy due to their bright, stable fluorescence1,2 3,4,5. QDs can be conjugated to a variety of bio-active molecules for binding to bacteria and mammalian cells6.
QDs are also being widely investigated as cytotoxic agents for targeted killing of bacteria. The emergence of multiply-resistant bacterial strains is rapidly becoming a public health crisis, particularly in the case of Gram negative pathogens 7. Because of the well-known antimicrobial effect of certain nanomaterials, especially Ag, there are hundreds of studies examining the toxicity of nanoparticles to bacteria 8. Bacterial studies have been performed with other types of semiconductor nanoparticles as well, especially TiO2 9,10-11, but also ZnO12 and others including CuO 13. Some comparisons of bacterial strains have been performed in these studies, usually comparing a Gram negative strain with a Gram positive. With all of these particles, mechanisms of toxicity are attributed to oxidation: either the photogeneration of reactive oxygen species (ROS) by the particles or the direct release of metal ions that can cause oxidative toxicity. Even with these materials, results of different studies vary greatly. In some studies the Gram positive test strain is reportedly more sensitive than the Gram negative 10; in others it is the opposite 14. These studies have been well reviewed 15.
In all nanoparticle studies, particle composition, size, surface chemistry, sample aging/breakdown, and wavelength, power, and duration of light exposure can all dramatically affect the results. In addition, synthesis byproducts and solvents must be considered16 17. High-throughput screening techniques are needed to be able to develop effective new nanomedicine agents.
CdTe QDs have anti-microbial effects alone18 or in combination with antibiotics. In a previous study, we showed that coupling of antibiotics to CdTe can increase toxicity to bacteria but decrease toxicity to mammalian cells, due to decreased production of reactive oxygen species from the conjugates19. Although it is unlikely that cadmium-containing compounds will be approved for use in humans, such preparations could be used for disinfection of surfaces or sterilization of water.
In this protocol, we give a straightforward approach to solubilizing CdTe QDs with mercaptopropionic acid (MPA). The QDs are ready to use within an hour. We then demonstrate coupling to an antimicrobial agent.
The second part of the protocol demonstrates a 96-well bacterial inhibition assay using the conjugated and unconjugated QDs. The optical density is read over many hours, permitting the effects of QD addition and light exposure to be evaluated immediately as well as after a recovery period. We also illustrate a colony count for quantifying bacterial survival.

Nanoparticles such as semiconductor quantum dots (QDs) can be used to create photoactivatable agents for anti-microbial or anti-cancer applications. This technique shows how to water-solubilize cadmium telluride (CdTe) QDs, conjugate them to an antibiotic, and perform a bacterial inhibition assay based upon growth curves and plate count.

Solubilisierung und Bio-Konjugation von Quantenpunkten und bakterielle Toxizitätstests von Wachstumskurve und Keimzahl

Quantum dots (QDs) are fluorescent semiconductor nanoparticles with size-dependent emission spectra that can be excited by a broad choice of wavelengths. ...

Biotechnik

Synthesis of Ligand-free CdS Nanoparticles within a Sulfur Copolymer Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature solvents. These coordinating ligands help solubilize and stabilize the nanoparticles while in solution, and can influence the resulting size and reactivity of the nanoparticles during their formation. Despite the ubiquity of using ligands during synthesis, the presence of aliphatic ligands on the nanoparticle surface can result in a number of problems during the end use of the nanoparticles, necessitating further ligand stripping or ligand exchange procedures. We have developed a way to synthesize cadmium sulfide (CdS) nanoparticles using a unique sulfur copolymer. This sulfur copolymer is primarily composed of elemental sulfur, which is a cheap and abundant material. The sulfur copolymer has the advantages of operating both as a high temperature solvent and as a sulfur source, which can react with a cadmium precursor during nanoparticle synthesis, resulting in the generation of ligand free CdS. During the reaction, only some of the copolymer is consumed to produce CdS, while the rest remains in the polymeric state, thereby producing a nanocomposite material. Once the reaction is finished, the copolymer stabilizes the nanoparticles within a solid polymeric matrix. The copolymer can then be removed before the nanoparticles are used, which produces nanoparticles that do not have organic coordinating ligands. This nascent synthesis technique presents a method to produce metal-sulfide nanoparticles for a wide variety of applications where the presence of organic ligands is not desired.

Herein we present a method to synthesize ligand-free cadmium sulfide (CdS) nanoparticles based on a unique sulfur copolymer. The sulfur copolymer operates as a high temperature solvent and a sulfur source during the nanoparticle synthesis and stabilizes the nanoparticles after the reaction.

Synthese von Ligand freien CdS-Nanopartikel innerhalb eines Schwefel-Copolymer-Matrix

Aliphatic ligands are typically used during the synthesis of nanoparticles to help mediate their growth in addition to operating as high-temperature ...

Advanced Compositional Analysis of Nanoparticle-polymer Composites Using Direct Fluorescence Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise composition of these materials is essential, especially in the design of surface catalysts, where the surface concentration of the active component determines the activity of the material. Antimicrobial materials which utilize nanoparticles are a particular focus of this technology. Recently swell encapsulation has emerged as a technique for inserting antimicrobial nanoparticles into a host polymer matrix. Swell encapsulation provides the advantage of localizing the incorporation to the external surfaces of materials, which act as the active sites of these materials. However, quantification of this nanoparticle uptake is challenging. Previous studies explore the link between antimicrobial activity and surface concentration of the active component, but this is not directly visualized. Here we show a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of CdSe/ZnS nanoparticles can be accurately visualized through cross-sectional fluorescence imaging. Using this method, we can quantify the uptake of nanoparticles via swell encapsulation and measure the surface concentration of encapsulated particles, which is key in optimizing the activity of functional materials.

Here we present a reliable method to monitor the incorporation of nanoparticles into a polymer host matrix via swell encapsulation. We show that the surface concentration of cadmium selenide quantum dots can be accurately visualized through cross-sectional fluorescence imaging.

Erweiterte Analyse der Zusammensetzung von Nanopartikel-Polymer Composites mittels direkter Fluoreszenz-Imaging

The fabrication of polymer-nanoparticle composites is extremely important in the development of many functional materials. Identifying the precise ...

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

Facette für Facette Verknüpfung von Form-anisotropen kolloidales Cadmium Chalkogenid Nanostrukturen

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

Enhanced Electron Injection and Exciton Confinement for Pure Blue Quantum-Dot Light-Emitting Diodes by Introducing Partially Oxidized Aluminum Cathode

Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation displays and solid-state lighting technologies. The brightness and efficiency of blue QDs-based light-emitting diodes (LEDs) remain inferior to their red and green counterparts, due to the inherently unfavorable energy levels of different colors of light. To solve these problems, a device structure should be designed to balance the injection holes and electrons into the emissive QD layer. Herein, through a simple autoxidation strategy, pure blue QD-LEDs which are highly bright and efficient are demonstrated, with a structure of ITO/PEDOT:PSS/Poly-TPD/QDs/Al:Al2O3. The autoxidized Al:Al2O3 cathode can effectively balance the injected charges and enhance radiative recombination without introducing an additional electron transport layer (ETL). As a result, high color-saturated blue QD-LEDs are achieved with a maximum luminance over 13,000 cd m-2, and a maximum current efficiency of 1.15 cd A-1. The easily controlled autoxidation procedure paves the way for achieving high-performance blue QD-LEDs.

A protocol is presented for fabricating high-performance, pure blue ZnCdS/ZnS-based quantum dots light-emitting diodes by employing an autoxidized aluminum cathode.

Verbesserte Elektroneninjektion und Exciton Entbindung für reine blaue Quantenpunkt-Leuchtdioden durch die Einführung von teilweise oxidierte Aluminium Kathode

Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation ...

Production and Targeting of Monovalent Quantum Dots

The multivalent nature of commercial quantum dots (QDs) and the difficulties associated with producing monovalent dots have limited their applications in biology, where clustering and the spatial organization of biomolecules is often the object of study. We describe here a protocol to produce monovalent quantum dots (mQDs) that can be accomplished in most biological research laboratories via a simple mixing of CdSe/ZnS core/shell QDs with phosphorothioate DNA (ptDNA) of defined length. After a single ptDNA strand has wrapped the QD, additional strands are excluded from the surface. Production of mQDs in this manner can be accomplished at small and large scale, with commercial reagents, and in minimal steps. These mQDs can be specifically directed to biological targets by hybridization to a complementary single stranded targeting DNA. We demonstrate the use of these mQDs as imaging probes by labeling SNAP-tagged Notch receptors on live mammalian cells, targeted by mQDs bearing a benzylguanine moiety.

We provide detailed instructions for the preparation of monovalent targeted quantum dots (mQDs) from phosphorothioate DNA of defined length. DNA wrapping occurs in high yield, and therefore, products do not require purification. We demonstrate the use of the SNAP tag to target mQDs to cell-surface receptors for live-cell imaging applications.

Produktion und Targeting von Monovalenter Quantenpunkte

The multivalent nature of commercial quantum dots (QDs) and the difficulties associated with producing monovalent dots have limited their applications in ...

Inkjet Printing All Inorganic Halide Perovskite Inks for Photovoltaic Applications

A method for synthesizing photoactive inorganic&#160;perovskite quantum dot inks and an inkjet printer deposition method, using the synthesized inks, are demonstrated. The ink synthesis is based on a simple wet chemical reaction and the inkjet printing protocol is a facile step by step method. The inkjet printed thin films have been characterized by X-ray diffraction, optical absorption spectroscopy, photoluminescent spectroscopy, and electronic transport measurements. X-ray diffraction of the printed quantum dot films indicates a crystal structure consistent with an orthorhombic room temperature phase with (001) orientation. In conjunction with other characterization methods, the X-ray diffraction&#160;measurements show high quality films can be obtained through the inkjet printing method.

A protocol for synthesizing inorganic-lead-halide hybrid perovskite quantum dot inks for inkjet printing and the protocol for preparing and printing the quantum dot inks in an inkjet printer with post characterization techniques are presented.

Inkjet-drucken alle anorganischen Halogenid-Perowskit-Tinten für photovoltaische Anwendungen

A method for synthesizing photoactive inorganic&#160;perovskite quantum dot inks and an inkjet printer deposition method, using the synthesized inks, are ...

Synthesis of In37P20(O2CR)51 Clusters and Their Conversion to InP Quantum Dots

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 clusters have been observed as intermediates in the synthesis of InP quantum dots from molecular precursors (In(O2CR)3, HO2CR, and P(SiMe3)3) and may be isolated as a pure reagent for subsequent study and use as a single-source precursor. These clusters readily convert to crystalline and relatively monodisperse samples of quasi-spherical InP quantum dots when subjected to thermolysis conditions in the absence of additional precursors above 200 &#176;C. The optical properties, morphology, and structure of both the clusters and quantum dots are confirmed using UV-Vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, and powder X-ray diffraction. The molecular symmetry of the clusters is additionally confirmed by solution-phase 31P NMR spectroscopy. This protocol demonstrates the preparation and isolation of atomically-precise InP clusters, and their reliable and scalable conversion to InP QDs.

Synthesis of In37P20O2CR51 Clusters and Their Conversion to InP Quantum Dots

A protocol for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots is presented.

Synthese vonIn 37P20(O2CR)51 Clustern und deren Umwandlung in InP Quantum Dots

This text presents a method for the synthesis of In37P20(O2C14H27)51 clusters and their conversion to indium phosphide quantum dots. The In37P20(O2CR)51 ...