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Facile purification of colloidal NIR-responsive gold nanorods using ions assisted self-assembly.

Liu L, Guo Z, Xu L, Xu R, Lu X - Nanoscale Res Lett (2011)

Bottom Line: Therefore, it is essential for the purification of anisotropic gold nanoparticles.The key point of our strategy lies in different shape-dependent solution stability between anisotropic nanoparticles and symmetric ones and selective self-assembly and subsequent precipitation can be induced by introducing ions to the as-made nanorod solution.As a result, gold nanorods of excellent purity (97% in number density) have been obtained within a short time, which has been confirmed by SEM observation and UV-vis-NIR spectroscopy respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210011, China. luxiang1966@gmail.com.

ABSTRACT
Anisotropic metal nanoparticles have been paid much attention because the broken symmetry of these nanoparticles often leads to novel properties. Anisotropic gold nanoparticles obtained by wet chemical methods inevitably accompany spherical ones due to the intrinsically high symmetry of face-centred cubic metal. Therefore, it is essential for the purification of anisotropic gold nanoparticles. This work presents a facile, low cost while effective solution to the challenging issue of high-purity separation of seed-mediated grown NIR-responsive gold nanorods from co-produced spherical and cubic nanoparticles in solution. The key point of our strategy lies in different shape-dependent solution stability between anisotropic nanoparticles and symmetric ones and selective self-assembly and subsequent precipitation can be induced by introducing ions to the as-made nanorod solution. As a result, gold nanorods of excellent purity (97% in number density) have been obtained within a short time, which has been confirmed by SEM observation and UV-vis-NIR spectroscopy respectively. Based on the experimental facts, a possible shape separation mechanism was also proposed.

No MeSH data available.


Related in: MedlinePlus

SEM images of gold nanoparticles obtained by seed-mediated method. (a) as-made gold NR mixture; (b) purified gold NRs from the mixture shown in (a); (c) nanoparticles kept in supernatant after purification. All scale bars are 200 nm
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Figure 1: SEM images of gold nanoparticles obtained by seed-mediated method. (a) as-made gold NR mixture; (b) purified gold NRs from the mixture shown in (a); (c) nanoparticles kept in supernatant after purification. All scale bars are 200 nm

Mentions: Typical SEM images of as-made gold NRs before and after purification are given in Figure 1. The NRs have an average diameter of 10 nm and the average aspect ratio of 6.5, while the impurities are mainly quasi-spherical nanparticles with diameters ranging from 15 to 30 nm and cubic nanoparticles with an edge length of approximately 20 nm (Figure 1a). After purification, the content of impurities in NRs was found to be less than 3% in number density (Figure 1b). Furthermore, the number fraction of NRs decreased from approximately 78% for the as-made nanoparticles to approximately 15% for the nanoparticles kept in supernatant after purification (Figure 1c), suggesting that more than 80% of as-made gold NRs have been recovered through a single circle of the purification procedure.


Facile purification of colloidal NIR-responsive gold nanorods using ions assisted self-assembly.

Liu L, Guo Z, Xu L, Xu R, Lu X - Nanoscale Res Lett (2011)

SEM images of gold nanoparticles obtained by seed-mediated method. (a) as-made gold NR mixture; (b) purified gold NRs from the mixture shown in (a); (c) nanoparticles kept in supernatant after purification. All scale bars are 200 nm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211191&req=5

Figure 1: SEM images of gold nanoparticles obtained by seed-mediated method. (a) as-made gold NR mixture; (b) purified gold NRs from the mixture shown in (a); (c) nanoparticles kept in supernatant after purification. All scale bars are 200 nm
Mentions: Typical SEM images of as-made gold NRs before and after purification are given in Figure 1. The NRs have an average diameter of 10 nm and the average aspect ratio of 6.5, while the impurities are mainly quasi-spherical nanparticles with diameters ranging from 15 to 30 nm and cubic nanoparticles with an edge length of approximately 20 nm (Figure 1a). After purification, the content of impurities in NRs was found to be less than 3% in number density (Figure 1b). Furthermore, the number fraction of NRs decreased from approximately 78% for the as-made nanoparticles to approximately 15% for the nanoparticles kept in supernatant after purification (Figure 1c), suggesting that more than 80% of as-made gold NRs have been recovered through a single circle of the purification procedure.

Bottom Line: Therefore, it is essential for the purification of anisotropic gold nanoparticles.The key point of our strategy lies in different shape-dependent solution stability between anisotropic nanoparticles and symmetric ones and selective self-assembly and subsequent precipitation can be induced by introducing ions to the as-made nanorod solution.As a result, gold nanorods of excellent purity (97% in number density) have been obtained within a short time, which has been confirmed by SEM observation and UV-vis-NIR spectroscopy respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210011, China. luxiang1966@gmail.com.

ABSTRACT
Anisotropic metal nanoparticles have been paid much attention because the broken symmetry of these nanoparticles often leads to novel properties. Anisotropic gold nanoparticles obtained by wet chemical methods inevitably accompany spherical ones due to the intrinsically high symmetry of face-centred cubic metal. Therefore, it is essential for the purification of anisotropic gold nanoparticles. This work presents a facile, low cost while effective solution to the challenging issue of high-purity separation of seed-mediated grown NIR-responsive gold nanorods from co-produced spherical and cubic nanoparticles in solution. The key point of our strategy lies in different shape-dependent solution stability between anisotropic nanoparticles and symmetric ones and selective self-assembly and subsequent precipitation can be induced by introducing ions to the as-made nanorod solution. As a result, gold nanorods of excellent purity (97% in number density) have been obtained within a short time, which has been confirmed by SEM observation and UV-vis-NIR spectroscopy respectively. Based on the experimental facts, a possible shape separation mechanism was also proposed.

No MeSH data available.


Related in: MedlinePlus