This research was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Canada Research Chairs Program, and Simon Fraser University. This work made use of 4D LABS shared facilities supported by the Canada Foundation for Innovation (CFI), British Columbia Knowledge Development Fund (BCKDF) and Simon Fraser University.

1. Synthese des NaYF 4 / Yb 3+ / Er 3+ Hochskalierungs-Nanopartikel (UCNP) <ol><li> Richten Sie das Gerät wie folgt: <ol><li> Legen Sie eine 250 ml Heizmantel auf einer regelmäßigen Rührplatte und stecken Sie den Mantel auf das Thermoelement. </li><li> Legen Sie einen 250 ml-Rundkolben mit einem magnetischen Rührstab auf den Heizmantel mit der richtigen Spann ausgestattet. </li><li> Befestigen Sie einen Luftadapter an der linken Hals des Rundkolben und verbinden diese Luftadapter an den Schlenk-Linie mit Kunststoffschlauch. </li><li> Bringen Sie ein Glasteil an der rechten Hals des Rundkolben und fixieren ein Thermometer-Adapter auf das Glasteil. Legen Sie die Temperatursonde in den Kolben durch die Thermometer-Adapter und stecken Sie diese in das Thermoelement. </li><li> Bringen Sie einen Destillationskopf in die Mitte Hals des Rundkolben. Legen Sie einen Anschlag auf der Oberseite der Destillationsaufsatz. Verbinden Sie den Kopf mit einem Kondensator, gefolgt von einer Vakuum distillatIonen-Adapter und ein 50 ml-Rundkolben. Schließen Sie die Vakuumdestillation Adapter, um eine Waschflasche durch Kunststoffschlauch. </li></ol></li><li> Wiegt 1,17 g (3,9 mmol) Yttriumacetat, 0,439 g Ytterbium acetat und 0,0727 g (0,1 mmol) von Erbium Acetat und sie in der Reaktionsrundkolben. </li><li> 30 ml Oleinsäure und 75 ml Octadecen zu dem Kolben mit Hilfe eines Messzylinders. </li><li> Spülen der Seite des Reaktionsrundkolben mit 5 ml Methanol, um sicherzustellen, dass keine Ölsäure und Octadecen zu den Seiten des Reaktionskolbens fest. </li><li> Verbinden Sie den Reaktionskolben zu einer Doppelverteiler Schlenklinie und schalten Sie das entsprechende Ventil, das an das Stickstoffleitung angeschlossen Reaktionskolben zu halten. </li><li> Einschalten des Thermoelement, die Temperatur auf 80 ° C und heizen das System auf dieser Temperatur gehalten. Bei 80 ° C und nach alle Ausgangsmaterialien gelöst werden, entfernen Sie den Heizmantel und reagieren lassen,Abkühlen auf 30 ° C. </li><li> Wenn die Temperatur 30 ° C erreicht, nehmen Sie den Destillationskopf, schalten Sie die Luftadapter von der linken Hals bis in die Mitte Nacken und schließen Sie die linke Hals mit einem Stopfen. Langsam einführen Vakuum in den Reaktionskolben durch Drehen des Ventils auf der Schlenk-Linie von der Stickstoffleitung mit der Vakuumleitung. Alle Komponenten mit niedrigem Siedepunkt wird aus dem Reaktions an dieser Stelle gezogen werden. </li><li> Wenn die Lösung sprudeln stoppt, erwecken die Temperatur auf 115 ° C in einer Geschwindigkeit von 5 ° C / min. </li><li> Sobald die Temperatur erreicht 115 ° C, zu halten diese Temperatur für 15 Minuten, dann entfernen Sie den Heizmantel und Abkühlen der Reaktion auf 50 ° C. Danach schnell wechseln die durch Wiederanbringen des Destillationskopf in die Mitte Nacken und der Luft-Adapter auf der linken Seite den Kopf zurück in die ursprüngliche Form einzurichten. </li><li> Abwiegen 0,74 g (12,5 mmol) NaOH und 0,50 g (20,0 mmol) NH 4 F während des Kühlprozesses und auflösenin 50 ml Methanol durch Beschallung. </li><li> Nach der Ultraschallbehandlung, gießen Sie die Lösung in die Reaktionsrundkolben und spülen Sie die Seiten des Kolbens mit 5 ml MeOH. </li><li> Lassen die Lösung unter Rühren bei 50 ° C für 30 min. </li><li> Erhöhung der Temperatur auf 75 ° C, um das Methanol zu destillieren. </li><li> Während der Destillation, leeren Sie den Sammelkolben, wenn notwendig. Nachdem die Destillation beendet ist, zu erhitzen, um die Reaktion bis 300 ° C unter Stickstoffschutz so schnell wie möglich. </li><li> Sobald die Temperatur 300 ° C erreicht, halten diese Temperatur für 1 Stunde. Bei Bedarf decken das Setup mit Aluminiumfolie, um die Temperatur zu halten. Dann entfernen Wärmequelle, die die Reaktion auf Raumtemperatur abkühlen lassen. </li><li> Sobald es auf Raumtemperatur abgekühlt, teilen Sie die Lösung gleichmäßig in drei Zentrifugenröhrchen (50 ml Tuben, etwa 35 ml Lösung pro jedem Röhrchen), und füllen Sie den Schlauch an die 50 ml-Maßstab unter Verwendung wasserfreies Ethanol. Centrifuge alle ter Röhrchen bei 3.400 xg für 15 min. Nach Zentrifugation sollten die UCNPs auf der Seite der Rohre in Form eines weißen Niederschlags beobachtet werden. </li><li> Überstand verwerfen und redispergieren die UCNPs Pellets in Hexan (7,5 ml Hexan pro jeder Röhre), dann von oben bis das Rohr mit Ethanol bis zur 50 ml-Maßstab. Zentrifugenröhrchen erneut bei 3.400 × g für 15 min. </li><li> Sobald die Zentrifugation abgeschlossen ist, den Überstand verwerfen und redispergieren die festen UCNPs in 30 ml CHCl 3 zur weiteren Verwendung. </li></ol> 2. Montage des Wasser dispergierbare Nanoanordnungen, die organische Farbstoffmoleküle und Hochskalierungs-Nanopartikel <ol><li> Auflösen 25 mg (0,0147 mmol) Poly (styrol-alt-Maleinsäureanhydrid) (PSMA) in 3 ml CHCl 3 in ein Szintillationsfläschchen mit einem magnetischen Rührstab versehen ist. Diese Menge ist eine optimierte Menge nach mehreren Studien. </li><li> Fügen Sie 250 ul (47 mg / ml) des upconverting Nanopartikel Chloroform-Stammlösung zu dem scintillation Fläschchen. </li><li> Verschließe das Röhrchen und legen Sie es auf dem magnetischen Rührplatte und rühren Sie die Lösung bei Raumtemperatur für 2 Std. </li><li> Wiegen 160 mg (0,0773 mmol) Polyetheramin 2070 und löst ihn in 1 ml CHCl 3. Dann fügen Sie diese Lösung für das Szintillationsfläschchen in einer Portion mit einer Pipette. Die Lösung wird sich bis blassgelb, die die Reaktion von Polyetheramin 2070 mit den Anhydridgruppen am PSMA. </li><li> Auch weiterhin die Lösung über Nacht bei Raumtemperatur rühren. </li><li> Die entsprechende Menge organischer Farbstoffmoleküle dann verzichten sie in die Szintillationsfläschchen in einer Portion, rühren Sie die resultierende Lösung für 1 Stunde. <ol><li> Für die Probe TPP-NP (Polymerhülle, Tetraphenylporphyrin und upconverting Nanopartikel Nanoanordnung enthält), direkt hinzufügen 1 mg Tetraphenylporphyrins auf die Szintillationsfläschchen. Für die Probe DAE-UCNP (Nanoanordnung Polymerhülle, Diarylethen-Moleküle und Nanopartikel enthalten upconvertings), ist die Menge jeder Diarylethen-Moleküle 2 × 10 -7 mol. Fügen Sie die beiden Diarylethen-Moleküle in die Reaktionslösung. Die Volumina der beiden Diarylethen-Moleküle sind: DAE-1o (1,8 mM), 111 ul und DAE-2o (1,6 mM), 125 &amp; mgr; l. </li></ol></li><li> Entfernen der CHCl 3 Lösungsmittel unter reduziertem Druck mit einem Rotationsverdampfer, dann werden 3 ml 0,001 M wässrigen NaOH (pH ≈ 11) zu der Szintillationsampulle dann beschallen das Fläschchen bis eine milchige Suspension wird gebildet. </li><li> Legen Sie das Fläschchen wieder auf dem Rotationsverdampfer, und entfernen Sie vorsichtig die verbleibende CHCl 3, bis die Suspension wurde auf eine klare Lösung verwandelt. </li><li> Übertragen der Lösung aus dem Szintillationsfläschchen zwei 1,5 ml konischen Zentrifugenröhrchen, dann zentrifugieren die Lösung bei 20.600 × g für 25 min. </li><li> Überstand verwerfen, dann fügen insgesamt 3 ml entionisiertem H 2 O in den beiden Rohren (1,5 ml pro Röhrchen), beschallen die Rohre, um die Pellets zu redispergierenin entionisiertem H 2 O. </li><li> Wieder Zentrifugieren Sie die beiden Rohre an 20.600 × g für 25 min. </li><li> Überstand verwerfen, dann fügen Sie insgesamt 3 ml entionisiertem H 2 O in den beiden Rohren (1,5 ml pro Röhrchen). Beschallen der Rohre, um die Pellets in dem deionisierten H 2 O. redispergieren </li><li> Filtern der wässrigen Nanoteilchen-Dispersion Probe durch einen 0,2 um-Spritzenfilter, um die endgültige Probe für weitere Tests zu erhalten. </li></ol>

<ol>
	<li>Fery-Forgues, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+organic+nanocrystals+and+non-doped+nanoparticles+for+biological+applications.">Fluorescent organic nanocrystals and non-doped nanoparticles for biological applications.</a> Nanoscale. 5 (18), 8428-8442 (2013).</li><li>Vollrath, A., Schubert, S., Schubert, U. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescence+imaging+of+cancer+tissue+based+on+metal-free+polymeric+nanoparticles.">Fluorescence imaging of cancer tissue based on metal-free polymeric nanoparticles.</a> J. Mater. Chem. B. 1, 1994-2007 (2013).</li><li>Cheng, X., Lowe, S. B., Reecec, P. J., Gooding, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colloidal+silicon+quantum+dots:+from+preparation+to+the+modification+of+self-assembled+monolayers+(SAMs)+for+bio-applications.">Colloidal silicon quantum dots: from preparation to the modification of self-assembled monolayers (SAMs) for bio-applications.</a> Chem. Soc. Rev. 43, 2680-2700 (2014).</li><li>Luo, P. G., 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=Carbon-based+quantum+dots+for+fluorescence+imaging+of+cells+and+tissues.">Carbon-based quantum dots for fluorescence imaging of cells and tissues.</a> RSC Adv. 4, 10791-10807 (2014).</li><li>Wang, Y., Hu, R., Lin, G., Roy, I., Yong, K. -. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functionalized+Quantum+Dots+for+Biosensing+and+Bioimaging+and+Concerns+on+Toxicity.">Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on Toxicity.</a> ACS Appl. Mater. Interfaces. 5 (8), 2786-2799 (2013).</li><li>Kairdolf, B. 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=Semiconductor+Quantum+Dots+for+Bioimaging+and+Biodiagnostic+Applications.">Semiconductor Quantum Dots for Bioimaging and Biodiagnostic Applications.</a> Annu. Rev. Anal. Chem. 6 (1), 143-162 (2013).</li><li>Huang, B., Bates, M., Zhuang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Super-Resolution+Fluorescence+Microscopy.">Super-Resolution Fluorescence Microscopy.</a> Annu. Rev. Biochem. 78, 993-1016 (2009).</li><li>F&#246;lling, 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=Photochromic+Rhodamines+Provide+Nanoscopy+with+Optical+Sectioning.">Photochromic Rhodamines Provide Nanoscopy with Optical Sectioning.</a> Angew. Chem. Int. Ed. 46 (33), 6266-6270 (2007).</li><li>F&#246;lling, 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=Fluorescence+Nanoscopy+with+Optical+Sectioning+by+Two-Photon+Induced+Molecular+Switching+using+Continuous-Wave+Lasers.">Fluorescence Nanoscopy with Optical Sectioning by Two-Photon Induced Molecular Switching using Continuous-Wave Lasers.</a> Chem. Phys. Chem. 9 (2), 321-326 (2008).</li><li>Bossi, M., 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=Multicolor+Far-Field+Fluorescence+Nanoscopy+through+Isolated+Detection+of+Distinct+Molecular+Species.">Multicolor Far-Field Fluorescence Nanoscopy through Isolated Detection of Distinct Molecular Species.</a> Nano Lett. 8 (8), 2463-2468 (2008).</li><li>Berns, M. W., Krasieva, T., Sun, C. &. #. 8. 2. 1. 1. ;. H., Dvornikov, A., Rentzepis, P. 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+polarity+dependent+fluorescence+"switch"+in+live+cells.">A polarity dependent fluorescence "switch" in live cells.</a> Photochem. Photobiol. B: Biol. 75, 51-56 (2004).</li><li>Zou, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amphiphilic+Diarylethene+as+a+Photoswitchable+Probe+for+Imaging+Living+Cells.">Amphiphilic Diarylethene as a Photoswitchable Probe for Imaging Living Cells.</a> J. Am. Chem. Soc. 130 (47), 15750-1 (2008).</li><li>Westphal, 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=Video-Rate+Far-Field+Optical+Nanoscopy+Dissects+Synaptic+Vesicle+Movement.">Video-Rate Far-Field Optical Nanoscopy Dissects Synaptic Vesicle Movement.</a> Science. 320, 246-249 (2008).</li><li>Zhuang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+Switches+Based+on+Photochromic+Compounds.">Fluorescent Switches Based on Photochromic Compounds.</a> Nat Photonics. 3, 365-367 (2009).</li><li>Cusido, J., Deniz, E., Raymo, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+Switches+Based+on+Photochromic+Compounds.">Fluorescent Switches Based on Photochromic Compounds.</a> Eur. J. Org. Chem. 13, 2031-2045 (2009).</li><li>Raymo, F. M., Tomasulo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electron+and+energy+transfer+modulation+with+photochromic+switches.">Electron and energy transfer modulation with photochromic switches.</a> Chem. Soc. Rev. 34, 327-336 (2005).</li><li>Feringa, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Molecular Switches. , (2010).</li><li>Tian, H., Yang, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progresses+on+diarylethene+based+photochromic+switches.">Recent progresses on diarylethene based photochromic switches.</a> Chem. Soc. Rev. 33, 85-97 (2004).</li><li>Ubaghs, L., Sud, D., Branda, N. R., Perepichka, I. D., Perepichka, D., Branda, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook in Thiophene-Based Materials: Applications in Organic Electronics and Photonics. 2, (2009).</li><li>Norsten, T. B., Branda, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoregulation+of+Fluorescence+in+a+Porphyrinic+Dithienylethene+Photochrome.">Photoregulation of Fluorescence in a Porphyrinic Dithienylethene Photochrome.</a> J. Am. Chem. Soc. 123 (8), 1784-1785 (2001).</li><li>Giordano, L., Jovin, T. M., Irie, M., Jares-Erijman, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diheteroarylethenes+as+Thermally+Stable+Photoswitchable+Acceptors+in+Photochromic+Fluorescence+Resonance+Energy+Transfer+(pcFRET).">Diheteroarylethenes as Thermally Stable Photoswitchable Acceptors in Photochromic Fluorescence Resonance Energy Transfer (pcFRET).</a> J. Am. Chem. Soc. 124 (25), 7481-7489 (2002).</li><li>F&#246;lling, 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=Synthesis+and+Characterization+of+Photoswitchable+Fluorescent+Silica+Nanoparticles.">Synthesis and Characterization of Photoswitchable Fluorescent Silica Nanoparticles.</a> Small. 4 (1), 134-142 (2008).</li><li>Jeong, 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=Photoreversible+cellular+imaging+using+photochrome-conjugated+fullerene+silica+nanoparticles.">Photoreversible cellular imaging using photochrome-conjugated fullerene silica nanoparticles.</a> Chem. Commun. 47, 10668-10670 (2011).</li><li>Gai, S., Li, C., Yang, P., Lin, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+progress+in+rare+earth+micro/nanocrystals:+soft+chemical+synthesis,+luminescent+properties,+and+biomedical+applications.">Recent progress in rare earth micro/nanocrystals: soft chemical synthesis, luminescent properties, and biomedical applications.</a> Chem. Rev. 114 (4), 2343-2389 (2014).</li><li>Carling, C. -. J., Boyer, J. -. C., Branda, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multimodal+fluorescence+modulation+using+molecular+photoswitches+and+upconverting+nanoparticles.">Multimodal fluorescence modulation using molecular photoswitches and upconverting nanoparticles.</a> Org. Biomol. Chem. 10, 6159-6168 (2012).</li><li>Wu, T., Boyer, J. -. C., Barker, M., Wilson, D., Branda, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+"Plug-and-Play"+Method+to+Prepare+Water-Soluble+Photoresponsive+Encapsulated+Upconverting+Nanoparticles+Containing+Hydrophobic+Molecular+Switches.">A "Plug-and-Play" Method to Prepare Water-Soluble Photoresponsive Encapsulated Upconverting Nanoparticles Containing Hydrophobic Molecular Switches.</a> Chem. Mater. 25 (12), (2013).</li><li>Wu, T., Kaur, S., Branda, N. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Energy+transfer+between+amphiphilic+porphyrin+polymer+shells+and+upconverting+nanoparticle+cores+in+water-dispersible+nano-assemblies.">Energy transfer between amphiphilic porphyrin polymer shells and upconverting nanoparticle cores in water-dispersible nano-assemblies.</a> Org. Biol. Chem. 13, 2317-2322 (2015).</li><li>Irie, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photochromism:+Memories+and+Switches+Introduction.">Photochromism: Memories and Switches Introduction.</a> Chem. Rev. 100 (5), 1683-1684 (2000).</li></ol>

The authors have nothing to disclose.

Die nach diesem Protokoll synthetisierten Nanopartikel eine Größenverteilung von 20 bis 25 nm bei ungefähr 22,5 nm. 26,27 Sie können als kugelförmige Teilchen mit einem α-NaYF 4 Wirtsgitterstruktur klassifiziert werden zentriert. Es gibt zwei kritische Schritte in diesem Protokoll. Im UCNP Synthese ist es wichtig, die Erwärmungstemperatur und -zeit so präzise wie möglich zu halten, um eine enge Verteilung der Partikelgröße zu gewährleisten. Gleichzeitige Zugabe von NaOH und N...

Heute gibt es immer noch ein dringender Bedarf an neuen Arten von Bio-Imaging-Agenten zu entwickeln. Viele neue Fluoreszenzsonden sind gut dokumentiert. 1-6, wesentliche Verbesserungen in der Bildauflösung bleibt jedoch eine Herausforderung. 7 Eine praktische Methode ist es, direkt modulieren die Fluoreszenzsonden zwischen einer &#39;light&#39; emittierenden Zustand und einem &quot;dunklen&quot; Zustand abgeschreckt. 8-12 Diese besondere Methode wurde angewandt, um Technologien wie stimulierte Emission zu entwickeln (STED) Mikroskopie 13 und stochastischen optischen Rekonstruktionsmikroskopie (STORM). 14 Ein weiterer Ansatz, um die Fluoreszenz zu modulieren zu koppeln Licht ansprechende Chromophore gemeinsam mit fluoreszierenden Sonden. 15,16 Umschalten des photo Chromophor zwischen zwei Isomeren, wo nur eines der Isomere als effizienter Energietransfer-Akzeptor dienen können, ermöglicht die Kontrolle über Quenchen der Fluoreszenz von the Sonde durch Förster Resonance Energy Transfer (FRET) und andere Mechanismen. Das Ergebnis ist die Erzeugung eines emittierenden Zustand und einem abgeschreckten Zustand, der durch Belichtung der photoreaktiven Chromophor auf unterschiedliche Wellenlängen des Lichtes abwechseln können. Licht ansprechende Diarylethens Chromophore reversibel zwischen einem farblosen Ring-open-Isomer und einem farbigen Ring geschlossene Isomer bei Bestrahlung mit UV- und sichtbarem Licht umgeschaltet werden. 17-19 Die thermische Stabilität der beiden Isomere und abstimmbaren Absorptionsspektren der Ring geschlossen Isomer make Diarylethene sehr gute Kandidaten als steuerbare FRET-Akzeptoren. 20-23 Lanthaniden dotierten NaYF 4 upconverting Nanopartikel eignen sich für Bio-Imaging. 24 Diese Nanopartikel absorbieren Licht im nahen Infrarot und Licht in mehreren Regionen des sichtbaren Spektrums. Beispiele für Fluoreszenzmodulation durch die Kombination von Licht ansprechende Diarylethens Chromophore und Nanopartikel wurden vor,zuvor von unserer Arbeitsgruppe berichtet. 25-27, benötigt die in jedem Beispiel beschriebenen Systeme jedoch einen zusätzlichen Modifizierungs die Diarylethene an die Oberfläche der Nanopartikel, die die Entwicklung von verschiedenen Systemen erschwert befestigen. Hier zeigen wir ein einfaches &quot;Plug-and-Play&quot; Verfahren zu wasserdispergierbaren organischen Farbstoffmolekülen und auf Licht upconverting Nanopartikel mit einem Selbstorganisationsstrategie vorzubereiten. Die Wahl der Polymere; Poly (styrol-alt-Maleinsäureanhydrid) und Polyetheramin 2070 sowohl eine hydrophobe und hydrophile Umgebung. Die hydrophoben Abschnitte des Polymers beitragen, die normalerweise in Wasser unlöslichen organischen Molekülen und upconverting Nanopartikel zusammenzuhalten, während der hydrophile Bereich des Polymers ist kritisch für die Aufrechterhaltung der Wasserlöslichkeit. Wir werden zunächst die Synthese der Nanopartikel upconverting demonstrieren durch die thermische Keimbildungsmethode. Dann werden wir beweisen, how die organischen Moleküle und upconverting Nanopartikel in hydrophobe Bereiche der Polymerhülle eingekapselt und verbleiben durch einfaches Zusammen Rühren eine Lösung des upconverting Nanopartikeln Polymer und verschiedenen organischen Farbstoffmolekülen, gefolgt von einem geeigneten Aufarbeitungsverfahren in wässrigen Medien stabil. Wir zeigen auch, wie die Fluoreszenzemission der Anordnungen unter Verwendung externer Lichtbestrahlung zu modulieren. Wir erwarten, den Umfang der Verwendung dieser &quot;Plug-and-play&quot; Methode, um in Wasser dispergierbare Nanoanordnungen wird weiter expandieren.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>yttrium acetate</td>
			<td>sigma</td>
			<td>326046</td>
			<td>Yttrium(III) acetate hydrate</td>
		</tr>
		<tr>
			<td>ytterbium acetate</td>
			<td>sigma</td>
			<td>544973</td>
			<td>&#160;Ytterbium(III) acetate hydrate&#160;</td>
		</tr>
		<tr>
			<td>erbium acetate</td>
			<td>sigma</td>
			<td>325570</td>
			<td>Erbium(III) acetate hydrate</td>
		</tr>
		<tr>
			<td>oleic acid</td>
			<td>sigma</td>
			<td>75096</td>
			<td>analytical standard</td>
		</tr>
		<tr>
			<td>octadecene</td>
			<td>sigma</td>
			<td>O806&#160;</td>
			<td>Technical grade&#160;</td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td></td>
			<td>S5881&#160;</td>
			<td>reagent grade</td>
		</tr>
		<tr>
			<td>NH4F</td>
			<td></td>
			<td>216011</td>
			<td>ACS reagent</td>
		</tr>
		<tr>
			<td>poly(styrene-alt-maleic anhydride)</td>
			<td>sigma</td>
			<td>4422699</td>
			<td>Average Mn= 1700</td>
		</tr>
		<tr>
			<td>JeffAmine 2070</td>
			<td>Huntsman</td>
			<td>M-2070</td>
			<td></td>
		</tr>
		<tr>
			<td>Varian Carry 300</td>
			<td>Agilent</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>JDSU NIR laser</td>
			<td>JSDU</td>
			<td>L4-9897510-100M</td>
			<td>980 nm diode laser</td>
		</tr>
	</tbody>
</table>

a 'plug and play' method to create water-dispersible nanoassemblies containing an amphiphilic polymer, organic dyes and upconverting nanoparticles

In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate amphiphilic polymers in situ, and describe a protocol to encapsulate the prepared UCNPs and different organic dye molecules (porphyrins and diarylethenes) using polymer shells to form stable water-dispersible nanoassemblies. The nanoassembly samples containing both the UCNPs and the diarylethene organic dyes have interesting photochemical and photophysical properties. Upon 365 nm UV irradiation, the diarylethene group undergoes a visual color change. When the samples are irradiated with visible light of another specific wavelength, the color fades and the samples return to the initial colorless state. The samples also emit visible light from the UCNPs upon irradiation with 980 nm near-infrared light. The emission intensity of the samples can be tuned through alternate irradiation with UV and visible light. Modulation of fluorescence can be performed for many cycles without observable degradation of the samples. This versatile encapsulation procedure allows for the transfer of hydrophobic molecules and nanoparticles from an organic solvent to an aqueous medium. The polymer helps to maintain a lipid-like microenvironment for the organic molecules to aid in preservation of their photochemical behavior in water. Thus this method is ideal to prepare water-dispersible photoresponsive systems. The use of near-infrared light to activate upconverting nanoparticles allows for lower energy light to be used to activate photoreactions instead of more harmful ultraviolet light.

Absorptionsspektren und Photolumineszenz-Spektren wurden für die Proben DAE-UCNP gesammelt. Die Absorptionsspektren werden zum Vergleichen der spektralen Überlappung zwischen der geschlossenen Diarylethens Chromophoren und den Aufwärtswandler Nanopartikel eingesetzt. Fotografien der Proben (sowohl TPP-UCNP und DAE-UCNP) wurden ebenfalls eingeschlossen, um erfolgreiche Verkapselung von organischen Farbstoffmolekülen und upconverting Nanopartikel, die in der amphiphilen Polymerhüllen in der wässrigen Phase befinden,...

Watch this Scientific Journal Video about A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles at JoVE.com

A &#039;Plug and Play&#039; Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Organic dye molecules and oleic acid coated upconverting nanoparticles are not water-soluble. This protocol describes a &#8216;plug and play&#8217; method that enables the transfer of organic dye molecules and upconverting particles from their initial hydrophobic solvent to water.

A &#39;Plug and Play&#39; Methode, um Wasser dispergierbare Nanoanordnungen mit einem Gehalt eines amphiphilen Polymers, organische Farbstoffe und Hochskalierungs-Nanopartikel erstellen

In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate ...

a-plug-play-method-to-create-water-dispersible-nanoassemblies

Research

JoVE Journal

Chemistry

A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

9.8K Aufrufe.  Simon Fraser University. Organic dye molecules and oleic acid coated upconverting nanoparticles are not water-soluble. This protocol describes a ‘plug and play’ method that enables the transfer of organic dye molecules and upconverting particles from their initial hydrophobic solvent to water. 

Serie: A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The analysis of volatile and oxidation sensitive compounds by mass spectrometry is not easily achieved, as all state-of-the-art mass spectrometric methods require at least one sample preparation step, e.g., dissolution and dilution of the analyte (electrospray ionization), co-crystallization of the analyte with a matrix compound (matrix-assisted laser desorption/ionization), or transfer of the prepared samples into the ionization source of the mass spectrometer, to be conducted under atmospheric conditions. Here, the use of a sample inlet system is described which enables the analysis of volatile metal organyls, silanes, and phosphanes using a sector field mass spectrometer equipped with an electron impact ionization source. All sample preparation steps and the sample introduction into the ion source of the mass spectrometer take place either under air-free conditions or under vacuum, enabling the analysis of compounds highly susceptible to oxidation. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes, which have to be handled using inert conditions, such as the Schlenk technique. The principle of operation is presented in this video.

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes which have to be handled using inert conditions, such as the Schlenk technique.

Analyse flüchtiger und oxidationsempfindlichen Verbindungen mit einem kalten Einlasssystem und Elektronenstoß-Massenspektrometrie

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The ...

Forschung

Chemie

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Synthese und Charakterisierung von funktionalisierten Metall-organische Gerüste

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

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

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

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

Eine einfache Methode für die Größe kontrollierte Synthese von stabilen Oligomere Cluster von Goldclustern unter Umgebungsbedingungen

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

An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions

A comprehensive understanding of signaling pathways requires detailed knowledge regarding ligand-receptor interaction. This article describes two fast and reliable point-by-point protocols of enzyme-linked immunosorbent assays (ELISAs) for the investigation of ligand-receptor interactions: the direct ligand-receptor interaction assay (LRA) and the competition LRA. As a case study, the ELISA based analysis of the interaction between different lambda interferons (IFNLs) and the alpha subunit of their receptor (IL28RA) is presented: the direct LRA is used for the determination of dissociation constants (KD values) between receptor and IFN ligands, and the competition LRA for the determination of the inhibitory capacity of an oligopeptide, which was designed to compete with the IFNLs at their receptor binding site. Analytical steps to estimate KD and half maximal inhibitory concentration (IC50) values are described. Finally, the discussion highlights advantages and disadvantages of the presented method and how the results enable a better molecular understanding of ligand-receptor interactions.

The presented protocols describe two enzyme-linked immunosorbent assay (ELISA) based techniques for the rapid investigation of ligand-receptor interactions: The first assay allows the determination of dissociation constant between ligand and receptor. The second assay enables a rapid screening of blocking peptides for ligand-receptor interactions.

Ein ELISA-basierte Bindung und Wettbewerbsverfahren zu schnell zu bestimmen, Ligand-Rezeptor-Wechselwirkungen

A comprehensive understanding of signaling pathways requires detailed knowledge regarding ligand-receptor interaction. This article describes two fast and ...

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ethylene-propylene rubber, grafted with maleic anhydride, is thermo-reversibly cross-linked in two steps. The pending anhydride moieties are first modified with furfurylamine to graft furan groups to the rubber backbone. These pendant furan groups are then cross-linked with a bis-maleimide via a Diels-Alder coupling reaction. Both reactions can be performed under a broad range of experimental conditions and can easily be applied on a large scale. The material properties of the resulting Diels-Alder cross-linked rubbers are similar to a peroxide-cured ethylene/propylene/diene rubber (EPDM) reference. The cross-links break at elevated temperatures (&#62; 150 &#176;C) via the retro-Diels-Alder reaction and can be reformed by thermal annealing at lower temperatures (50-70 &#176;C). Reversibility of the system was proven with infrared spectroscopy, solubility tests and mechanical properties. Recyclability of the material was also shown in a practical way, i.e., by cutting a cross-linked sample into small parts and compression molding them into new samples displaying comparable mechanical properties, which is not possible for conventionally cross-linked rubbers.

A simple two-step approach involving rubber modification and cross-linking yields fully reworkable, elastic rubber products.

Die Herstellung und Eigenschaften von Thermo reversibel vernetzten Kautschuk Via Diels-Alder-Chemie

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ...

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

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

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

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

Ein optimiertes Protokoll für die effiziente radioaktive Markierung von Gold-Nanopartikeln durch eine Verwendung von<sup&gt; 125</sup&gt; I-markiertem Azide prosthetische Gruppe

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

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a free-radical polymerization strategy to enable the modulation of the nanotube surface properties and produce supramolecular self-assembly of the nanostructures. First, a selective hydroxylation of the pristine nanotubes through a biphasic catalytically mediated oxidation reaction creates superficially distributed reactive sites at the sidewalls. The latter reactive sites are subsequently modified with methacrylic moieties using a silylated methacrylic precursor to create polymerizable sites. Those polymerizable groups can address further polymerization of styrene to produce a hybrid nanomaterial containing PS chains grafted to the nanotube sidewalls. The polymer-graft content, amount of silylated methacrylic moieties introduced and hydroxylation modification of the nanotubes are identified and quantified by Thermogravimetric Analysis (TGA). The presence of reactive functional groups hydroxyl and silylated methacrylate are confirmed by Fourier Transform Infrared Spectroscopy (FT-IR). Polystyrene-grafted carbon nanotube solutions in tetrahydrofuran (THF) provide wall-to-wall collinearly self-assembled nanotubes when cast samples are analyzed by transmission electron microscopy (TEM). Those self-assemblies are not obtained when suitable blanks are similarly cast from analogous solutions containing non-grafted counterparts. Therefore, this method enables the modification of the nanotube anisotropic patchiness at the sidewalls which results into spontaneous auto-organization at the nanoscale.

A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

Pfropfen Multiwalled Carbon Nanotubes mit Polystyrol Selbstmontage ermöglichen und anisotropen führt

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1 s. This enables us to follow the changes in the intensity (decay) and emission of the spectra over time. Using this method, it is possible to study diverse photophysical phenomena, such as the emission of phosphorescence, and the contributions of prompt and delayed fluorescence in molecules showing thermally activated delayed fluorescence (TADF). Remarkably, all spectra and decays are obtained in a single experiment. This can be done for solids (thin film, powder, crystal) and liquid samples, where the only limitations are the spectral sensitivity of the camera and the excitation wavelength (532 nm, 355 nm, 337 nm, and 266 nm). This technique is, thus, very important when investigating the excited state dynamics in organic emitters for their application in organic light-emitting diodes and other areas where triplet harvesting is of paramount importance. Since triplet states are strongly quenched by oxygen, emitters with efficient TADF luminescence, or those showing room temperature phosphorescence (RTP), must be correctly prepared in order to remove any dissolved oxygen from solutions and films. Otherwise, no long-lived emission will be observed. The method of degassing solid samples as presented in this work is basic and simple, but the degassing of liquid samples creates additional difficulties and is particularly interesting. A method of minimizing solvent loss and changing the sample concentration, while still enabling to remove oxygen in a very efficient and a repeatable manner, is presented in this work.

Here, we present a method of the spectroscopic characterization of organic molecules by means of time-resolved photoluminescence spectroscopy on the nanosecond-to-millisecond timescale in oxygen-free conditions. Methods to efficiently remove oxygen from the samples and, thus, limit luminescence quenching are also described.

Zeitaufgelöste photophysikalischen Charakterisierung der Triplett-Ernte organische Verbindungen in einer sauerstofffreien Umgebung verwenden eine iCCD Kamera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...

Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule on the vibrational level of energy. Raman and IR spectroelectrochemistry can be used for advanced characterization of the structural changes in the organic electroactive compounds. Here, the step-by-step analysis by means of Raman and IR spectroelectrochemistry is shown. Raman and IR spectroelectrochemical techniques provide complementary information about structural changes occurring during an electrochemical process, i.e. allows for the investigation of redox processes and their products. The examples of IR and Raman spectroelectrochemical analysis are presented, in which the products of the redox reactions, both in solution and solid state, are identified.

A protocol of step-by-step Raman and IR spectroelectrochemical analysis is presented.

Raman und IR Spectroelectrochemical Methoden als Werkzeuge konjugierte organische Verbindungen zu analysieren

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule ...

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, allowing for the synthesis of isotactic poly(&#945;-hydroxy acids) with expected molecular weights (&#62;140 kDa) and narrow molecular weight distributions (Mw/Mn &#60; 1.1). This ring-opening polymerization is mediated by Ni and Zn complexes in the presence of an alcohol initiator and a photoredox Ir catalyst, irradiated by a blue LED (400 - 500 nm). The polymerization is performed at a low temperature (-15 &#176;C) to avoid undesired side reactions. The complete monomer consumption can be achieved within 4 - 8 hours, providing a polymer close to the expected molecular weight with narrow molecular weight distribution. The resulted number-average molecular weight shows a linear correlation with the degree of polymerization up to 1000. The homodecoupling 1H NMR study confirms that the obtained polymer is isotactic without epimerization. This polymerization reported herein offers a strategy for achieving rapid, controlled O-carboxyanhydrides polymerization to prepare stereoregular poly(&#945;-hydroxy acids) and its copolymers bearing various functional side-chain groups.

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

A protocol for the controlled photoredox ring-opening polymerization of O-carboxyanhydrides mediated by Ni/Zn complexes is presented.

Kontrollierte Photoredox ringöffnende Polymerisation von O- Carboxyanhydrides vermittelt durch Ni/Zn-komplexe

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, ...