[16a-2C-1~9] 4.2 Bio- and Medical Photonics

▲ [16a-2C-7] Visualization of lipid rafts in an artificial monolayer membrane by using slit-scanning Raman microscopy

〇Jun Ando^1,2,3,4, Masanao Kinoshita^5,6, Jin Cui^5,7, Hiroyuki Yamakoshi^2,4, Kosuke Dodo^1,2,4, Katsumasa Fujita^1,2,3, Michio Murata^5,7, Mikiko Sodeoka^1,2,4 (1.AMED-CREST, AMED, 2.ERATO Sodeoka Live Cell Chemistry PJ, 3.Dept. Applied Physics, Osaka Univ., 4.RIKEN, 5.ERATO Lipid Active Structure PJ, 6.Dept. Chem, Kyushu Univ., 7.Dept. Chem, Osaka Univ.)

キーワード：Raman microscopy,Lipid raft,Alkyne-tag

We utilized slit-scanning Raman microscopy to observe lipid rafts in an artificial monolayer membrane. Lipid raft is a specific micro-domain in a membrane, enriched in sphingomyelin (SM) and cholesterol (chol). It has been though to have important biological functions in a cell. As a model of lipid raft, artificial ternary membrane of SM/PC/chol has been widely investigated. Phase separation of this membrane has been visualized by fluorescently labeled lipid, however, these probes are often excluded from raft-like ordered domain in membrane due to the steric effect of the bulky fluorophore on lipid packing. We focused on Raman scattering microscopy to directly observe SM in a membrane. To specifically observe SM, we synthesized the analogue of SM modified with diyne moiety, which shows distinct scattering signal at Raman silent region of lipid molecules with minimal disturbance on the original property of SM. We performed Raman imaging of diyne-SM/DOPC/chol ternary monolayer membrane on a substrate by using slit-scanning Raman microscopy. Raman intensity distribution, reconstructed by the peak height of diyne, visualized heterogeneous distribution of diyne-SM, forming micrometer-sized domains. High spatial resolution of our system allows us to analyze lipid distribution inside of the domain, where the dinye-SM was enriched in the central area of the domain rather than the peripheral area.