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A Novel Physical Approach for Cationic-Thiolate Protected Fluorescent Gold Nanoparticles.

Ishida Y, Lee C, Yonezawa T - Sci Rep (2015)

Bottom Line: Knowledge on the synthesis of cationically charged fluorescent gold nanoparticles (Au NPs) is limited because the electrostatic repulsion between cationic ligands on the surface of NP hinders the formation of small Au NPs (usually less than ca. 2 nm) during nucleation in solvents.By controlling mercaptan concentration the size and photophysical characteristics of Au NPs were directly controlled, resulting in near IR fluorescence with a 0.9% of absolute quantum yield.Cationically charged fluorescent metal NPs are promising, especially in biological fields, and this work provides a novel methodology towards the synthesis of a new series of functional metal NPs.

View Article: PubMed Central - PubMed

Affiliation: Division of Material Science and Engineering, Faculty of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.

ABSTRACT
Knowledge on the synthesis of cationically charged fluorescent gold nanoparticles (Au NPs) is limited because the electrostatic repulsion between cationic ligands on the surface of NP hinders the formation of small Au NPs (usually less than ca. 2 nm) during nucleation in solvents. We herein propose a novel methodology for a synthesis of water-dispersible, cationic-thiolate protected fluorescent Au NPs by the sputtering of Au into liquid matrix containing thiolate ligands. By controlling mercaptan concentration the size and photophysical characteristics of Au NPs were directly controlled, resulting in near IR fluorescence with a 0.9% of absolute quantum yield. Cationically charged fluorescent metal NPs are promising, especially in biological fields, and this work provides a novel methodology towards the synthesis of a new series of functional metal NPs.

No MeSH data available.


Size of Au NPs prepared at various concentrations of TC from 0 to 0.5 M in DG.
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f4: Size of Au NPs prepared at various concentrations of TC from 0 to 0.5 M in DG.

Mentions: Figure 3 shows the representative transmission electron microscopy (TEM) images and size-distribution histograms of Au NPs prepared at 0 and 0.5 M TC. The average sizes of Au NPs prepared at 0 and 0.5 M of TC were 6.7 ± 3.2 and 2.0 ± 0.7 nm, respectively. This difference in their particle sizes reflects the change in plasmon absorption, as shown in Fig. 2. The change in particle size as a function of TC concentration is shown in Fig. 4. From Fig. 4, it is obvious that a higher TC concentration produces smaller Au NPs. This tendency can be simply explained by the collision probability between TC and Au NPs inside and at the interface of DG. Thus, this result clearly indicates that the size of Au NPs is controllable by the concentration of the thiol-stabilizer in the liquid matrix.


A Novel Physical Approach for Cationic-Thiolate Protected Fluorescent Gold Nanoparticles.

Ishida Y, Lee C, Yonezawa T - Sci Rep (2015)

Size of Au NPs prepared at various concentrations of TC from 0 to 0.5 M in DG.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4612736&req=5

f4: Size of Au NPs prepared at various concentrations of TC from 0 to 0.5 M in DG.
Mentions: Figure 3 shows the representative transmission electron microscopy (TEM) images and size-distribution histograms of Au NPs prepared at 0 and 0.5 M TC. The average sizes of Au NPs prepared at 0 and 0.5 M of TC were 6.7 ± 3.2 and 2.0 ± 0.7 nm, respectively. This difference in their particle sizes reflects the change in plasmon absorption, as shown in Fig. 2. The change in particle size as a function of TC concentration is shown in Fig. 4. From Fig. 4, it is obvious that a higher TC concentration produces smaller Au NPs. This tendency can be simply explained by the collision probability between TC and Au NPs inside and at the interface of DG. Thus, this result clearly indicates that the size of Au NPs is controllable by the concentration of the thiol-stabilizer in the liquid matrix.

Bottom Line: Knowledge on the synthesis of cationically charged fluorescent gold nanoparticles (Au NPs) is limited because the electrostatic repulsion between cationic ligands on the surface of NP hinders the formation of small Au NPs (usually less than ca. 2 nm) during nucleation in solvents.By controlling mercaptan concentration the size and photophysical characteristics of Au NPs were directly controlled, resulting in near IR fluorescence with a 0.9% of absolute quantum yield.Cationically charged fluorescent metal NPs are promising, especially in biological fields, and this work provides a novel methodology towards the synthesis of a new series of functional metal NPs.

View Article: PubMed Central - PubMed

Affiliation: Division of Material Science and Engineering, Faculty of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628, Japan.

ABSTRACT
Knowledge on the synthesis of cationically charged fluorescent gold nanoparticles (Au NPs) is limited because the electrostatic repulsion between cationic ligands on the surface of NP hinders the formation of small Au NPs (usually less than ca. 2 nm) during nucleation in solvents. We herein propose a novel methodology for a synthesis of water-dispersible, cationic-thiolate protected fluorescent Au NPs by the sputtering of Au into liquid matrix containing thiolate ligands. By controlling mercaptan concentration the size and photophysical characteristics of Au NPs were directly controlled, resulting in near IR fluorescence with a 0.9% of absolute quantum yield. Cationically charged fluorescent metal NPs are promising, especially in biological fields, and this work provides a novel methodology towards the synthesis of a new series of functional metal NPs.

No MeSH data available.