蛍光試薬用量子ドット分散ガラスビーズの作製と神経細胞イメージング

摘要

量子ドット（QD）は，明るい蛍光を発し、その発光波長を粒径や組成で制御できる．また，有機色素よりも耐光性が良いため，新規なバイオ用高輝度蛍光試薬として注目されている．蛍光性のQDは溶液法で得られるが，そのままでは不安定で劣化しやすい．そのため我々は，常温常圧で溶液反応によりガラスを合成できるゾルーゲル法を用いて，InPやCdSe等のQDを微小なガラスビーズ（粒径数十nm程度）中に分散した安定な水分散性蛍光体を作製した．QD分散ガラスビーズは，バイオ用の緩衝液中に希釈した際に，市販ポリマーコートQDよりも格段に高い安定性と耐光性を示した．さらに，このガラスビーズは食食作用で生きた培養神経細胞に導入でき，細胞形状の高分解能イメージングが可能であった．%Quantum dots (QDs) show bright photoluminescence whose emission wavelength can be controlled by their particle size and composition. Compared with organic fluorescent dyes, QDs are more resistant to light irradiation. Because of those advantages, QDs attract much interest as novel bright fluorescent reagents. Photoluminescent QDs are synthesized in solution. However, QDs in solution are not very stable and tend to degradate. Therefore, we developed techniques to incorporate multiple QDs such as CdSe and InP in a small glass bead (diameter: several tens nm) by using sol-gel method at room temperature and under atmosheric pressure. The QD-incorporating glass beads are water-dispersible and emit bright photoluminescence. When dispersed in buffer solution for biological use, the glass beads showed much higher stability and light-resistance than commercial polymer-coated QDs. It was possible to obtain high-resolution fluorescence image of living neuronal cells by introducing the glass beads in the cells by endocytosis.