Formation of lens-like vesicles induced via microphase separations on a sorbitan monoester membrane with different headgroups

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 135; pp. 235 - 242
• Main Authors: Hayashi, Keita, Iwai, Hideka, Shimanouchi, Toshinori, Umakoshi, Hiroshi, Iwasaki, Tomoyuki, Kato, Ayako, Nakamura, Hidemi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2015
• Subjects: Biomaterials; Electrochemical Techniques; Hexoses - chemistry; Hydration; Hydrogen Bonding; Lipids - isolation & purification; Membranes; Membranes, Artificial; Molecular structure; Nonionic-surfactant vesicle; Phase separation; Polyethylene Glycols - chemistry; Polyoxyethylene; Polysorbates - chemistry; Self-assembled aggregate; Separation; Surface Properties; Surface-Active Agents - chemistry; Surgical implants; Vesicles; Phase separation; Self-assembled aggregate; Nonionic-surfactant vesicle
• ISSN: 0927-7765; 1873-4367
• DOI: 10.1016/j.colsurfb.2015.07.071

[Display omitted] •The difference of “headgroup” structure also related to the induction of the micro-phase separation on a vesicular membrane, resulting in the formation of a “lens”-like vesicle.•The specific domain with “small” curvature consisted mainly of Span 40 (sorbitan monopalmitate), while another domain with “large” curvature mainly of Tween 40 (polyoxyethylene (20) sorbitan monopalmitate).•The polyethylene glycol of Tween series surfactant affected the formation of the hydrogen bond network on the vesicle membrane. The microphase separation of lipid molecules on a vesicle membrane can be induced, depending on the difference in the geometric structures of their headgroups. Through cryo-transmission-electron-microscopy analysis, a lens-like vesicle was prepared by mixing 50wt% Span 40 (sorbitan monopalmitate) and 50wt% Tween 40 [polyoxyethylene (20) sorbitan monopalmitate]. Considering the molecular structures of Span 40 and Tween 40, the high-curvature region was mainly formed by Tween 40. As determined by Fourier-transform infrared spectroscopy, dielectric-dispersion analysis, and differential scanning calorimetry, a hydration layer was likely formed because polyoxyethylene conjugates with the headgroups of Tween 40. These investigations of the obtained self-assembled aggregates of nonionic surfactants with heterogeneous surfaces could contribute to the development of new types of biomaterials.