Optical measurement of the deformation of giant lipid vesicles driven by a micropipet electrode.
We investigate the deformation of giant lipid vesicles driven by a micropipet electrode by use of differential confocal microscopy. This optical technique provides nanometer depth resolution without mechanical contact and hence prevents large tension or perforation of the soft membrane. For dipalmitoyl phosphatidylcholine (DPPC) membranes in the gel phase, we observed deformations of several hundreds of nanometers when the driving voltage was about 0.1 V. The voltage and frequency responses of the vesicle deformation can be explained by the balance between the electroosmotic force inside the micropipet and the membrane tension. We also used DPPC:cholesterol vesicles to check the validity of this model. In the fluid phase, however, the deformation is independent of the modulation signal because micrometer-scale thermal fluctuations dominate the membrane motion.
Lee
Chau-Hwang
CH
Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd., Nankang, Taipei 11529, Taiwan. clee@gate.sinica.edu.tw
Chang
Yu-Fen
YF
Tsai
Chia-Hsuan
CH
Wang
Po-Hsiang
PH