| 研究実績の概要 |
This year we have made substantial progress in the area of NHC-stabilized nanoparticles. Our first publication appeared in Angewandte Chemie International Edition. This paper detailed our study of carboxylated NHCs as ligands for the preparation of water soluble gold nanoparticles. These nanoparticles were extensively studied and could be analyzed by polyacrylamide gel electrophoresis due to their charged nature. In basic pHs, the nanoparticles were exceptionally stable, however they aggregated under acidic pH. This aggregation was shown to be reversible. The NHC-stabilized nanoparticles were stable under a variety of biologically-relevant conditions, except thiol stability was still sub optimal. In addition to the synthetic and stability studies, in collaboration with the Yamaguchi group, we were able to test the photoacoustic properties of these nanoparticles. The nanoparticles were shown to have a linear response and even the smallest nanoparticles had a reasonable photoacoustic response.
In more recent work, we have prepared a new type of bidentate NHC, one that has a single NHC ligand and a thiol ligand on the same molecule. This compound was shown to make Au(1) nanoclusters when exposed to molecular gold, and to make highly stable nanoparticles when exposed to auric acid and reducing agents. In this work, we have prepared the first NHC-based nanoparticle that is stable to exogenous thiol. This work is very preliminary and will continue in the next funding year.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
The use of bidentate NHCs to stabilize nanoparticles has proven to be an excellent strategy and we believe will be the key to employing these nanoparticles in vivo. Synthetic issues in the previous year were overcome this year, permitting us to make two of the important structures that we needed to make, namely bidentate alkylated NHCs and bidentate NHC/thiol ligands. Both of these ligands turned out to be excellent supporting ligands for gold nanoparticles.
In addition to solving synthetic issues with regards to the preparation of the ligands, we were also able to analyze the water soluble nanoparticles with the assistance of the Itami and Higashiyama group at the Institute of Transformative Bio-Molecules.
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