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Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules

Fluorescence titration of methylene blue, rhodamine B and rhodamine 6G (R6G) by silver nanoparticle (AgNP) all resulted in an initial steep quenching curve followed with a sharp turn and a much flatter quenching curve. At the turn, there are about 200,000 dye molecules per a single AgNP, signifying...

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Autores principales: Deng, Hua, Yu, Hongtao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6720720/
https://www.ncbi.nlm.nih.gov/pubmed/31416283
http://dx.doi.org/10.3390/ma12162592
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author Deng, Hua
Yu, Hongtao
author_facet Deng, Hua
Yu, Hongtao
author_sort Deng, Hua
collection PubMed
description Fluorescence titration of methylene blue, rhodamine B and rhodamine 6G (R6G) by silver nanoparticle (AgNP) all resulted in an initial steep quenching curve followed with a sharp turn and a much flatter quenching curve. At the turn, there are about 200,000 dye molecules per a single AgNP, signifying self-assembly of approximately 36-layers of dye molecules on the surface of the AgNP to form a micelle-like structure. These fluorescence-quenching curves fit to a mathematical model with an exponential term due to molecular self-assembly on AgNP surface, or we termed it “self-assembly shielding effect”, and a Stern-Volmer term (nanoparticle surface enhanced quenching). Such a “super-quenching” by AgNP can only be attributed to “pre-concentration” of the dye molecules on the nanoparticle surface that yields the formation of micelle-like self-assembly, resulting in great fluorescence quenching. Overall, the fluorescence quenching titration reveals three different types of interactions of dye molecules on AgNP surface: 1) self-assembly (methylene blue, rhodamine B and R6G), 2) absorption/tight interaction (tryptamine and fluorescein), and 3) loose interaction (eosin Y). We attribute the formation of micelle-like self-assembly of these three dye molecules on AgNP to their positive charge, possession of nitrogen atoms, and with relatively large and flat aromatic moieties.
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spelling pubmed-67207202019-09-10 Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules Deng, Hua Yu, Hongtao Materials (Basel) Article Fluorescence titration of methylene blue, rhodamine B and rhodamine 6G (R6G) by silver nanoparticle (AgNP) all resulted in an initial steep quenching curve followed with a sharp turn and a much flatter quenching curve. At the turn, there are about 200,000 dye molecules per a single AgNP, signifying self-assembly of approximately 36-layers of dye molecules on the surface of the AgNP to form a micelle-like structure. These fluorescence-quenching curves fit to a mathematical model with an exponential term due to molecular self-assembly on AgNP surface, or we termed it “self-assembly shielding effect”, and a Stern-Volmer term (nanoparticle surface enhanced quenching). Such a “super-quenching” by AgNP can only be attributed to “pre-concentration” of the dye molecules on the nanoparticle surface that yields the formation of micelle-like self-assembly, resulting in great fluorescence quenching. Overall, the fluorescence quenching titration reveals three different types of interactions of dye molecules on AgNP surface: 1) self-assembly (methylene blue, rhodamine B and R6G), 2) absorption/tight interaction (tryptamine and fluorescein), and 3) loose interaction (eosin Y). We attribute the formation of micelle-like self-assembly of these three dye molecules on AgNP to their positive charge, possession of nitrogen atoms, and with relatively large and flat aromatic moieties. MDPI 2019-08-14 /pmc/articles/PMC6720720/ /pubmed/31416283 http://dx.doi.org/10.3390/ma12162592 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Deng, Hua
Yu, Hongtao
Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title_full Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title_fullStr Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title_full_unstemmed Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title_short Silver Nanoparticle Surface Enabled Self-Assembly of Organic Dye Molecules
title_sort silver nanoparticle surface enabled self-assembly of organic dye molecules
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6720720/
https://www.ncbi.nlm.nih.gov/pubmed/31416283
http://dx.doi.org/10.3390/ma12162592
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