Single molecule measurement of protein conformational fluctuations using quantum effects of light induced by a single microdroplet

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02678
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Osaka Metropolitan University (2022); Osaka City University (2019-2021)
• Principal Investigator: Sakota Kenji 大阪公立大学, 大学院理学研究科, 准教授 (80346767)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 微小液滴 / イオントラップ / 蛍光検出

Outline of Final Research Achievements

We have focused on the fact that a levitated single microdroplet behaves as a tiny optical resonator, and have tried to detect fluorescence emitted from molecules dissolved in the droplet with high sensitivity by utilizing the characteristic phenomena of whispering gallery mode resonance and excitation light resonance that occur in droplets. In order to observe the behavior of molecules dissolved in a droplet, the droplet must be stably trapped for a long period of time. To achieve this, we newly developed an ion trap and a cooled adiabatic chamber in which the trap is installed. The fluorescence from the droplet was observed using this system, and it was found that the sensitivity of fluorescence detection was improved by about two orders of magnitude compared to the previously reported system.

Free Research Field

光物理化学

Academic Significance and Societal Importance of the Research Achievements

蛍光分光は様々な分光法のなかでも最も検出感度の高い分光法の一つであり，かつ測定対象を非破壊的に観測できる手法でもある。本研究では，空間捕捉された単一微小液滴が示す特徴的な現象である励起光共鳴を利用することよって蛍光検出感度の向上を達成した。また最近，微小液滴内の化学反応がバルク溶液中の化学反応とはかなり異なることが分かってきており，高感度「その場観測」分光の発展による微小環境の詳細分析が強く望まれている。本研究で開発した手法を化学反応の追跡に利用できれば，微小環境における化学反応の特異性が何に起因しているかを明らかにするための有用なツールになり得る。