TY - JOUR
T1 - Mode of interaction of two fluorinated-hydrogenated hybrid amphiphiles with dipalmitoylphosphatidylcholine (DPPC) at the air-water interface
AU - Hoda, Kazuki
AU - Kawasaki, Hideya
AU - Yoshino, Norio
AU - Chang, Chien Hsiang
AU - Morikawa, Yoko
AU - Sugihara, Gohsuke
AU - Shibata, Osamu
N1 - Funding Information:
This work (OS) was supported by Grant-in-aid for Scientific Research 17310075 from the Japan Society for Promotion of Science and by Grant 17650139 from the Ministry of Education, Science and Culture, Japan, which are gratefully acknowledged. We also thank Mr. H. Nakahara (Kyushu University, JSPS Research Fellowships for Young Scientists) for helpful and stimulating discussions about this manuscript. This work was also supported in part by funds from the Central Research Institute of Fukuoka University and from the advanced Material Institute of Fukuoka University.
PY - 2006/11/1
Y1 - 2006/11/1
N2 - Two-component Langmuir monolayers formed on 0.02 M Tris buffer solution (pH 7.4) with 0.13 M NaCl at 298.2 K were investigated for two different fluorinated-hydrogenated hybrid amphiphiles (F6PH5PPhNa and F8PH5PPhNa or F6 and F8, respectively) with DPPC. Surface pressure (π), surface potential (ΔV) and dipole moment (μ⊥) as a function of molecular surface area (A) were measured by employing the Whilhelmy method and an ionizing electrode method. From the A- and ΔV-XF6 (or XF8) curves, partial molecular surface area (PMA) and apparent partial molecular surface potential (APSP) were determined as a function of surface mole fraction (XFn) at discrete surface pressures. Then, the behavior of occupied surface areas and surface potentials of the respective components could be made clearer. Compressibility (Cs), elasticity (Cs- 1), and excess Gibbs energy (ΔG(ex)) as a function of XF6 (or XF8) were estimated at definite pressures. These physico-chemical parameters were found to reflect the mechanical strength of monolayer films formed. The regular solution theory being applied to ΔG(ex), the activity coefficients (f) as well as the interaction parameter (Ip) between DPPC and two hybrid amphiphiles in the binary monolayers were evaluated. Ip values thus obtained indicated that F8 molecules interact more strongly with DPPC molecules than F6. Moreover, in order to better understand the morphological monolayer state, Langmuir-Blodgett (LB) films made from DPPC and fluorinated-hydrogenated hybrid amphiphiles were examined by atomic force microscopy (AFM). The miscibility of the two components in the monolayer state is evidenced by these thermodynamic quantities and AFM observations. Furthermore, AFM images demonstrated that F8 could more effectively disperse the ordered domains of DPPC than F6.
AB - Two-component Langmuir monolayers formed on 0.02 M Tris buffer solution (pH 7.4) with 0.13 M NaCl at 298.2 K were investigated for two different fluorinated-hydrogenated hybrid amphiphiles (F6PH5PPhNa and F8PH5PPhNa or F6 and F8, respectively) with DPPC. Surface pressure (π), surface potential (ΔV) and dipole moment (μ⊥) as a function of molecular surface area (A) were measured by employing the Whilhelmy method and an ionizing electrode method. From the A- and ΔV-XF6 (or XF8) curves, partial molecular surface area (PMA) and apparent partial molecular surface potential (APSP) were determined as a function of surface mole fraction (XFn) at discrete surface pressures. Then, the behavior of occupied surface areas and surface potentials of the respective components could be made clearer. Compressibility (Cs), elasticity (Cs- 1), and excess Gibbs energy (ΔG(ex)) as a function of XF6 (or XF8) were estimated at definite pressures. These physico-chemical parameters were found to reflect the mechanical strength of monolayer films formed. The regular solution theory being applied to ΔG(ex), the activity coefficients (f) as well as the interaction parameter (Ip) between DPPC and two hybrid amphiphiles in the binary monolayers were evaluated. Ip values thus obtained indicated that F8 molecules interact more strongly with DPPC molecules than F6. Moreover, in order to better understand the morphological monolayer state, Langmuir-Blodgett (LB) films made from DPPC and fluorinated-hydrogenated hybrid amphiphiles were examined by atomic force microscopy (AFM). The miscibility of the two components in the monolayer state is evidenced by these thermodynamic quantities and AFM observations. Furthermore, AFM images demonstrated that F8 could more effectively disperse the ordered domains of DPPC than F6.
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U2 - 10.1016/j.colsurfb.2006.07.019
DO - 10.1016/j.colsurfb.2006.07.019
M3 - Article
C2 - 16962292
AN - SCOPUS:33750044599
VL - 53
SP - 37
EP - 50
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
SN - 0927-7765
IS - 1
ER -