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Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer

A simple photochemical method for making conjoined bi-metallic gold-silver (Au/Ag) nanotwins, a new breed of nanoparticles (NPs), is developed. To the best of our knowledge, the photochemical method resulted in distinct, conjoined, bimetallic nanotwins that are different from any well-established al...

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Autores principales: Korir, Daniel K., Gwalani, Bharat, Joseph, Abel, Kamras, Brian, Arvapally, Ravi K., Omary, Mohammad A., Marpu, Sreekar B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523650/
https://www.ncbi.nlm.nih.gov/pubmed/30978992
http://dx.doi.org/10.3390/nano9040596
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author Korir, Daniel K.
Gwalani, Bharat
Joseph, Abel
Kamras, Brian
Arvapally, Ravi K.
Omary, Mohammad A.
Marpu, Sreekar B.
author_facet Korir, Daniel K.
Gwalani, Bharat
Joseph, Abel
Kamras, Brian
Arvapally, Ravi K.
Omary, Mohammad A.
Marpu, Sreekar B.
author_sort Korir, Daniel K.
collection PubMed
description A simple photochemical method for making conjoined bi-metallic gold-silver (Au/Ag) nanotwins, a new breed of nanoparticles (NPs), is developed. To the best of our knowledge, the photochemical method resulted in distinct, conjoined, bimetallic nanotwins that are different from any well-established alloyed or core-shell nanostructures in the literature. The conjoined Au-Ag NPs possessed surface plasmon resonance (SPR) properties of both metals. The bimetallic nanostructures possessing distinctive optical properties of both metals were obtained using Au NPs as seeds in the first step, followed by the addition of a silver precursor as feed in the second step during a photochemical irradiation process. In the first step, small, isotropic or large, anisotropic Au NPs are generated by photoinduced reduction within a biocompatible chitosan (CS) polymer. In the second step, a silver precursor (AgNO(3)) is added as the feed to the AuNPs seed, followed by irradiation of the solution in the ice-bath. The entire photochemical irradiation process resulting in the formation of bimetallic Au-AgNPs did not involve any other reducing agents or stabilizing agents other than the CS polymer stabilizer. The small, conjoined Au-Ag bi-metallic NPs exhibited SPR with peak maxima centering at ~400 nm and ~550 nm, whereas the large conjoined nanoparticles exhibited SPR with peak maxima centering at ~400 nm, 550 nm, and 680 nm, characteristic of both gold and silver surface plasmons in solution. The tunability in the SPR and size of the bimetallic NPs were obtained by varying the reaction time and other reaction parameters, resulting in average sizes between 30 and 100 nm. The SPR, size, distribution, and elemental composition of the bi-metallic NPs were characterized using UV-Vis absorption, electron microscopy, and energy dispersive X-ray spectroscopy (EDS) studies.
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spelling pubmed-65236502019-06-03 Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer Korir, Daniel K. Gwalani, Bharat Joseph, Abel Kamras, Brian Arvapally, Ravi K. Omary, Mohammad A. Marpu, Sreekar B. Nanomaterials (Basel) Communication A simple photochemical method for making conjoined bi-metallic gold-silver (Au/Ag) nanotwins, a new breed of nanoparticles (NPs), is developed. To the best of our knowledge, the photochemical method resulted in distinct, conjoined, bimetallic nanotwins that are different from any well-established alloyed or core-shell nanostructures in the literature. The conjoined Au-Ag NPs possessed surface plasmon resonance (SPR) properties of both metals. The bimetallic nanostructures possessing distinctive optical properties of both metals were obtained using Au NPs as seeds in the first step, followed by the addition of a silver precursor as feed in the second step during a photochemical irradiation process. In the first step, small, isotropic or large, anisotropic Au NPs are generated by photoinduced reduction within a biocompatible chitosan (CS) polymer. In the second step, a silver precursor (AgNO(3)) is added as the feed to the AuNPs seed, followed by irradiation of the solution in the ice-bath. The entire photochemical irradiation process resulting in the formation of bimetallic Au-AgNPs did not involve any other reducing agents or stabilizing agents other than the CS polymer stabilizer. The small, conjoined Au-Ag bi-metallic NPs exhibited SPR with peak maxima centering at ~400 nm and ~550 nm, whereas the large conjoined nanoparticles exhibited SPR with peak maxima centering at ~400 nm, 550 nm, and 680 nm, characteristic of both gold and silver surface plasmons in solution. The tunability in the SPR and size of the bimetallic NPs were obtained by varying the reaction time and other reaction parameters, resulting in average sizes between 30 and 100 nm. The SPR, size, distribution, and elemental composition of the bi-metallic NPs were characterized using UV-Vis absorption, electron microscopy, and energy dispersive X-ray spectroscopy (EDS) studies. MDPI 2019-04-11 /pmc/articles/PMC6523650/ /pubmed/30978992 http://dx.doi.org/10.3390/nano9040596 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 Communication
Korir, Daniel K.
Gwalani, Bharat
Joseph, Abel
Kamras, Brian
Arvapally, Ravi K.
Omary, Mohammad A.
Marpu, Sreekar B.
Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title_full Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title_fullStr Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title_full_unstemmed Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title_short Facile Photochemical Syntheses of Conjoined Nanotwin Gold-Silver Particles within a Biologically-Benign Chitosan Polymer
title_sort facile photochemical syntheses of conjoined nanotwin gold-silver particles within a biologically-benign chitosan polymer
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523650/
https://www.ncbi.nlm.nih.gov/pubmed/30978992
http://dx.doi.org/10.3390/nano9040596
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