2015 Fiscal Year Annual Research Report
N-heterocyclic carbene-modified gold nanoparticles for biosensing
| Project/Area Number |
26288023
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| Research Institution | Nagoya University |
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Principal Investigator |
CRUDDEN Cathleen 名古屋大学, トランスフォーマティブ生命分子研究所, 客員教授 (10721029)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | gold nanoparticle / N-heterocyclic carbene / gold nanocluster / bio-imaging |
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| Outline of Annual Research Achievements |
(i) Nanoparticles. We have been able to prepare several NHC-stabilized nanoparticles. Specifically, we have prepared nanoparticles stabilized by bidentate NHCs. These NHC-modified nanoparticles have been tested for thermal stability and show excellent results. We are currently testing all nanoparticles with thiols that will mimic biological thiols. Collaborations are in place for the testing of photoaccoustic properties for the coming year.
(ii) Nanoclusters. We have examined several different methods for the preparation of nanoclusters. We prepared Au nanoclusters stabilized by thiols and stabilized by phosphines and found that the phosphine-stabilized nanoclusters could be exchanged for carbenes. The most stable and well-characterized nanoclusters are those that have an Au11 core, and thus are relatively small. These clusters are currently being studied by the Tsukuda group at the University of Tokyo, world experts in the preparation and analysis of gold clusters.
We have also succeeded in making clusters from a bottom up approach, using NHC-Au-X starting materials, where X can be another NHC or a halide. After considerable experimentation, we found that a mixture of the charged (NHC)2Au+ and NHC-Au-Cl gave the best results. Cluster formation was initiated by reduction with NaBH4 and the clusters purified using bioanalytical techniques including centrifugation and ultrafiltration. In order to investigate the exact number of gold atoms and NHCs, we have given these clusters to the Tsukuda group for in depth profiling by mass spectrometry.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Progress-to-date has been very good. As noted above, we have made progress in the synthesis of stable nanoparticles functionalized by a variety of different NHCs. We are in the process of testing the stability of the NHC-functionalized nanoparticles. It has already been determined that NHC-protected nanoparticles with long alkyl chains have good thermal stability, and their stability against various reagents is in the process of being tested. Unfortunately since the alkyl chains render these nanoparticles dispersible in organic solvents such as toluene but insoluble in water we will have to prepare another type of nanoparticle with long alkyl chains containing terminal hydroxyl or carboxyl groups in order to properly test stability under biological conditions, and to do biosensing.
In the case of nanoclusters, we do have carboxyl-terminated nanoclusters that are dispersible in water and will test these for biological stability as described below. We had initial difficulties with the purification and analysis of these materials since our lab is not fully equipped with the instrumentation required for these tasks. However, the biology groups at our Institute have kindly permitted us to use many of there instrumentations and so we have been able to purify these unique nanoclusters. In addition, we have employed the characterization tools (TEM etc) from the Itami Erato team in order to better understand the nanoparticles and nanoclusters we have prepared.
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| Strategy for Future Research Activity |
In year three, we will fully characterize the nanoparticles and nanoclusters prepared thus far in our group. Water dispersible nanoparticles will be prepared, and along with the already dispersible nanoclusters, these will be tested for stability under high salt conditions, aqueous conditions, and in the presence of biological nucleophiles. Initially, we will just employ nanoparticles themselves injected into tissue samples, and eventually we plan to attach targeting agents to observe specific tumors in the body. In addition to the in vivo work, we will also more fully characterize the nanoclusters, including attempting crystallization such that the structure can be solved by single crystal X-ray crystallography. Finally, we will adjust the synthetic conditions and the structure of the N-heterocyclic carbenes to obtain the most stable nanoclusters suitable for in vivo imaging.
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| Causes of Carryover |
研究に従事してした博士研究員の退職により、当初予定していた研究使用額に差が生じたため
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| Expenditure Plan for Carryover Budget |
研究用の試薬、器具の購入に使用する予定である。また生体イメージングへの応用研究に向け、抗体の購入やナノ粒子の精製為に利用する
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[Journal Article] Iterative protecting group-free cross-coupling leading to chiral multiply arylated structures2016
Author(s)
Cathleen M. Crudden, Christopher Ziebenhaus, Jason P. G. Rygus, Kazem Ghozati,Phillip J. Unsworth, Masakazu Nambo, Samantha Both, Marieke Hutchinson, Veronique S. Laberge, Yuuki Maekawa, Daisuke Imao
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Journal Title
Nature Communications
Volume: 7
Pages: 1-7
DOI
Peer Reviewed / Int'l Joint Research
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[Presentation] Mild, Easy Deposition Method for the Production of Highly Ordered, Ultra Stable NHC-based Films on Gold2015
Author(s)
Crudden CM, Horton JH, Narouz M, Smith C, McLean AB, Drevniok B, Zenkina OV, Ebralidze II, Kraatz HB, She Z, Saunders L, Li Z, Alashred A, Munro K, Baddeley CJ, Larrea CR, Mosey NP.
Organizer
98th Canadian Society for Chemistry conference
Place of Presentation
Ottawa, Canada
Year and Date
2015-06-13 – 2015-06-17
Invited
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