In situ preparation of biomimetic thin films and their surface-shielding effect for organisms in high vacuum

• Published in: PloS one Vol. 8; no. 11; p. e78563
• Main Authors: Suzuki, Hiroshi, Takaku, Yasuharu, Ohta, Isao, Ishii, Daisuke, Muranaka, Yoshinori, Shimomura, Masatsugu, Hariyama, Takahiko
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 13.11.2013; Public Library of Science (PLoS)
• Subjects: Aedes - anatomy & histology; Aedes - physiology; Animals; Aquatic insects; Aqueous solutions; Biocompatibility; Bioengineering; Biomimetics; Chemical vapor deposition; Coated Materials, Biocompatible - chemical synthesis; Density gradients; Deposition; Fabrication; Field emission microscopy; Fourier transforms; Free surfaces; Glass substrates; High vacuum; Irradiated; Larva - anatomy & histology; Larva - physiology; Larvae; Materials science; Materials Testing; Medical research; Medicine; Membranes; Microscopy, Electron, Scanning - methods; Monomers; Physical vapor deposition; Plasma; Plasma Gases; Polymeric films; Polymerization; Polymers; Polyoxyethylene sorbitan monolaurate; Protective coatings; Scanning electron microscopy; Shielding; Sorbitan; Surface Properties; Surface stability; Surfactants; Temperature; Thin films; Transparency; Vacuum; Vapors; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0078563

Self-standing biocompatible films have yet to be prepared by physical or chemical vapor deposition assisted by plasma polymerization because gaseous monomers have thus far been used to create only polymer membranes. Using a nongaseous monomer, we previously found a simple fabrication method for a free-standing thin film prepared from solution by plasma polymerization, and a nano-suit made by polyoxyethylene (20) sorbitan monolaurate can render multicellular organisms highly tolerant to high vacuum. Here we report thin films prepared by plasma polymerization from various monomer solutions. The films had a flat surface at the irradiated site and were similar to films produced by vapor deposition of gaseous monomers. However, they also exhibited unique characteristics, such as a pinhole-free surface, transparency, solvent stability, flexibility, and a unique out-of-plane molecular density gradient from the irradiated to the unirradiated surface of the film. Additionally, covering mosquito larvae with the films protected the shape of the organism and kept them alive under the high vacuum conditions in a field emission-scanning electron microscope. Our method will be useful for numerous applications, particularly in the biological sciences.