Author(s)

Takashi Yokoyama¹, Daisuke Yoshida¹, Hiroya Mori¹, Masaya Okabe¹, Zameer Shervani², Keijiro Taga¹, Yasushi Yamamoto¹, Ayumi Sumino³, Takehisa Dewa³, Mamoru Nango³, Masato Yamamoto⁴

¹Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya, Japan.
²Tohoku Foods Company, Sendai, Japan.
³Department of Frontier Materials, Nagoya Institute of Technology, Nagoya, Japan.
⁴Department of Chemistry, School of Arts and Sciences, Showa University, Fujiyoshida, Japan.

Morphology of dipalmitoyl phosphatidyl choline (DPPC)-cholesterol (Chol) mixed monolayer formed on water surface by dropping method was investigated using surface tension measurement (STm), Brewster angle microscopy (BAM), and fluorescence microscopy (FM). STm showed strong condensation effect of Chol in fluidic DPPC monolayer. Excess area (S_ex) from mean mixing state of DPPC and Chol was about twice larger than that by general compression method in the range from xC = 0.2 to 0.4 (xC: mole fraction of Chol). BAM and FM images showed clearly that the fluidic DPPC monolayer changed to condensed rigid monolayer due to the condensation effect of Chol. At more than xC = 0.3 DPPC-Chol mixed monolayer changed to condensed state similar to the Chol monolayer. These results support previous reports by compression method that Chol molecule demonstrates the strong condensation effect to the fluidic monolayer and also indicate that dropping method enables to form unique monolayer on the water surface.

DPPC-Chol Mixed Monolayer, Dropping Method, Surface Tension Measurement, Brewster Angle Microscopy, Fluorescence Microscopy, Condensation Effect

Yokoyama, T. , Yoshida, D. , Mori, H. , Okabe, M. , Shervani, Z. , Taga, K. , Yamamoto, Y. , Sumino, A. , Dewa, T. , Nango, M. and Yamamoto, M. (2016) MorphologicaObservation of Specific Condensation Effect of Cholesterol on Dipalmitoyl Phosphatidyl Choline (DPPC) Monolayer by Dropping Method. Journal of Biophysical Chemistry, 7, 98-109. doi: 10.4236/jbpc.2016.74009.