Development of Contactless and Label-free Measurement of Membrane Potential Using Dual-Comb Spectroscopy

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K19913
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 90:Biomedical engineering and related fields
• Research Institution: The University of Tokushima
• Principal Investigator: TAKANARI Hiroki 徳島大学, ポストLEDフォトニクス研究所, 准教授 (70723253)
• Co-Investigator(Kenkyū-buntansha): 江本 顕雄 徳島大学, ポストLEDフォトニクス研究所, 特任准教授 (80509662) ; 吉井 一倫 徳島大学, ポストLEDフォトニクス研究所, 特任准教授 (90582627)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: デュアルコム干渉計 / 活動電位 / 細胞膜電位 / 非標識測定 / 非標識イメージング

Outline of Final Research Achievements

Cells function physiologically via electrical activity. Contact measurement using electrodes and optical mapping using voltage-sensitive dyes are commonly used to measure the electrical activity of the cells. However, these techniques can only be used on single cells or excised organs and are not clinically applicable. We constructed a dual-comb interferometer that transmits an optical frequency comb through a sample and analyzes the interference waves with a reference optical frequency comb. As a preliminary step of the in vivo measurement, we prepared a sample with conductive thin films coated on both sides of glass to imitate a cell membrane, and applied a potential difference between the conductive films to measure the interference wave with the dual-comb interferometer. This experiment demonstrated the possibility of contactless, label-free measurement of potential changes inside and outside the cytoplasmic membranes.

Free Research Field

生体医工学

Academic Significance and Societal Importance of the Research Achievements

これまで細胞膜電位の変化は電極による接触計測や、電位感受性色素による光学マッピングによって達成されてきたが、前者は単一細胞にしか応用できず、後者は色素の毒性のため生体に直接用いることができない。このため、人体で細胞の電気的活動を直接知る方法が存在しない。我々は非生体試料ではあるが細胞膜を模したサンプルを作成し、2枚の薄膜間で電位差を生じた時に透過光の微細な位相変化が生じることを示した。今後、反射光学系での検証など改良を必要とするが、我々の研究成果が生体で応用されれば、神経や筋肉など多くの細胞の電気的活動を非接触・非標識で計測出来るようになる可能性がある。