細胞機能を可視化する新奇な超分子ナノ材料の光創製

点击翻译按钮获取中文摘要

Our aim of this proposal is to develop a novel low-toxic, chemically stable, and highly-luminescent nanoparticles for single-molecule bio-sensing and -imaging using light as a resourceful tool. In this project, two types of novel fluorescent nanomaterials are prepared, which are fullerene-shelled CdSe-ZnS quantum dots and gold quantum clusters (Au25). Here, fullerene-shelled quantum dots are prepared by a photochemical method ; whereas, the quantum clusters are prepared by the alkaline reduction of gold ions within the pockets of bovine serum albumin. At first, a fullerene thiol molecule was synthesized by multi-step thermal chemical route. Subsequently, a monolayer of fullerene is prepared on the surface of QD by the tethering of the fullerene thiol to the ZnS surface through the S-S bonding. Finally, the fullerene thiol monolayer-protected QDs were immersed in excess fullerene thiol and photoactivated. We found the formation stable and thick fullerene shells on the surface of QDs, which is due to the 2+2 photocycloaddition reaction. Further, we characterized their photoluminescence properties at ensemble and single-molecule levels. The most interesting property of the fullerene-shelled QD is its ability to show suppressed blinking. While fullerene-shelled quantum dots show blinking suppression that is suitable for single-molecule bioimaging and solar energy harvesting ; bioconjugates of Au25 efficiently entered human cells and enabled us for obtaining NIR fluorescence images of live cells. The two types of fluorescent nanomaterials enabled us for establishing collaborations with four research groups in Japan. A part of this research is published in ACS Nano 6, 1601-1608, 2012.