Liu Tze-Hsuan, Xiao Jian-Long, Lee Chau-Hwang, Lin Jiunn-Yuan
Department of Physics, National Chung Cheng University, Chia-Yi 62102, Taiwan.
Appl Opt. 2011 Jul 1;50(19):3311-5. doi: 10.1364/AO.50.003311.
We use optical tweezers to trap a unilamellar phospholipid vesicle and measure the out-of-plane thermal fluctuations by using differential confocal microscopy. Bending moduli of the lipid membranes are calculated directly from the mean-square values of the fluctuation amplitudes. Owing to the refractive index contrast between the inner and outer solutions of the vesicle, optical tweezers trap the vesicle laterally and improve the reliability of the measured fluctuation amplitudes along the optical axis. Bending moduli of membranes in gel or fluid phases obtained by the combination of differential confocal microscopy and optical tweezers are close to those reported previously. We also obtain the bending modulus of sphingomyelin membranes in the gel phase, which was not reported previously.
我们使用光镊捕获单层磷脂囊泡，并通过差分共聚焦显微镜测量平面外热涨落。脂质膜的弯曲模量直接由涨落幅度的均方值计算得出。由于囊泡内外溶液之间的折射率差异，光镊从侧面捕获囊泡，并提高了沿光轴测量的涨落幅度的可靠性。通过差分共聚焦显微镜和光镊相结合获得的凝胶相或流体相膜的弯曲模量与先前报道的相近。我们还获得了凝胶相中鞘磷脂膜的弯曲模量，这是之前未报道过的。
