課題番号                ：S-20-NM-0034

利用形態                ：機器利用

利用課題名（日本語）    ：表面増強ラマン散乱を利用した新規脂質分析手法の開発

Program Title (English) ：Surface Modification of Exosome Using Self-Polymerization of Dopamine and Its Detection by Surface Enhanced Raman Spectroscopy

利用者名（日本語）      ：王 晨煜

Username (English)     ：WANG CHENYU

所属名（日本語）        ：東京大学　大学院工学系研究科マテリアル工学専攻江島研究室

Affiliation (English)  ：Ejima lab, Department of Materials Engineering, The University of Tokyo

１．概要（Summary ）

Extracellular vesicles (EVs) play an important role in intercellular communication by carrying molecules between cells, both locally and systemically. Among which, exosome is an important category, of whose size believed to be in the range of 30−150 nm. All of which consist of cell-derived lipid-bilayer membranes and serve as vehicles carrying different types of cellular cargos, such as membrane lipids, cell-specific proteins, mRNA, DNA and microRNA delivering to the neighboring or distant recipient cells. Therefore, Exosomes are recognized as promising biomarkers and potential theranostic nanocarriers. We developed a simple and fast method to use polydopamine with its property of spontaneous polymerization modifying the surface of exosomes. Meanwhile, we used a surface enhanced Raman spectroscopy (SERS) to achieve the feasibility of the characterization of individual exosome.

２．実験（Experimental）

The exosomes were derived from cell culture supernatant, and isolated by size exclusive column. The isolated exosomes were resuspended in pH 7.4 Tris buffer solution, which were first coated with PDA by self-polymerization of dopamine. Then, phenolic hydroxyl groups of PDA which coated on the surface of exosomes, would reduce Au³⁺ to gold nanoparticles (AuNPs).

３．結果と考察（Results and Discussion）

Raman spectra of exosomes before and after AuNPs modification were determined and revealed the importance of AuNPs in activating SERS. As shown in Figure, the Raman spectra of bare exosomes and PDA-coated exosomes were almost flat without apparent peaks derived from exosomes being detected. When exosomes were coated with AuNPs, the signal intensity of base line remarkably increased. Under our measurement condition of Raman spectroscopy, the diameter of laser spot size was <1 μm. Therefore, the surface functionalization of exosomes with AuNPs makes it possible to further achieve Raman detection of single　exosome.

４．その他・特記事項（Others）

機器利用にあたりNIMS服部氏、李香蘭氏、竹村氏の支援を受けた。

５．論文・学会発表（Publication/Presentation）

なし

６．関連特許（Patent）

なし