Development of Quantum Sensing Technology for pH Measurement in Intracellular Microenvironments Using Fluorescent Nanodiamonds

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20507
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Yanagi Tamami 国立研究開発法人量子科学技術研究開発機構, 量子生命科学研究所, 博士研究員 (90911280)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: NVセンター / 全光学的計測 / バイオイメージング / in cells / in vivo / ex vivo

Outline of Final Research Achievements

In this project, we aimed to establish a technique for in situ measurement of pH in intracellular environments using fluorescent nanodiamonds (FNDs) to demonstrate that microenvironmental pH changes play an important role in biological system. For this purpose, we developed a less invasive ODMR measurement system and FND samples that are pH-responsive and do not prevent cellular and molecular targeting. First, we developed an all-optical T1-weighted ODMR imaging technique and succeeded in T1-based selective imaging of FNDs. We also developed FND with hydrophilic coating on the surface, which showed high biocompatibility and low nonspecific adsorption. With these results, we are now ready to detect pH changes in the intracellular microenvironment using FNDs.

Free Research Field

ナノバイオサイエンス

Academic Significance and Societal Importance of the Research Achievements

近年、細胞内の局所的なpHの変化が生命現象に重要な役割を果たすことが示唆されているが、その実証には生細胞中の局所pHをin situで観測しなければならない。QST五十嵐グループでは、FNDの表面電荷状態によってNVCの縦緩和時間T1が変化する現象を利用し、微小空間内pHのリアルタイム計測を世界で初めて実現した(Fujisaku et al., ACS Nano 2019)。本研究により生細胞中の局所pHを観測するための技術の確立に近づいたことで、細胞内物理・化学パラメータの網羅的な解析に基づく生命の本質理解に貢献できたと考えている。