MDPI Acta Medica Okayama 2076-3417 14 23 2024 Preparation of Nano- and Microparticles Obtained from Polymerization Reaction and Their Application to Surface Coating of Woody Materials 11326 EN Toshinori Shimanouchi Department of Environmental Chemistry and Materials, Okayama University, Daichi Hirota Department of Environmental Chemistry and Materials, Okayama University, Masafumi Yoshida Department of Environmental Chemistry and Materials, Okayama University, Kazuma Yasuhara Division of Materials Science, Nara Institute of Science and Technology (NAIST) Yukitaka Kimura Department of Environmental Chemistry and Materials, Okayama University, A surface coating of polymer particles of different hydrophobicity and wide-ranged size is helpful for the surface modification of materials such as woody thin board (WTB) derived from biomass. A preparation method for polymer particles was, in this study, proposed using a capillary-type flow system. Under hydrothermal conditions, the refinement of dispersed oil droplets in water (O/W emulsions) and the polymerization reaction could be simultaneously advanced, and polymer particles of polystyrene (PS), polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA), and poly-L-lactic acid (PLLA) with a particle size of about 100 nm could be synthesized. The coating of polymer particles gave an improved effect on the water repellency of WTBs due to the hydrophobicity of polymer particles and an alteration of surface roughness, and it also provided long-term stability (more than 6 years). No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2076-3417 13 12 2023 Hydrothermal Preparation of Faceted Vesicles Made of Span 40 and Tween 40 and Their Characterization 6893 EN Toshinori Shimanouchi Department of Environmental Chemistry and Materials, Okayama University Yui Komori Department of Environmental Chemistry and Materials, Okayama University Kazuki Toramoto Department of Environmental Chemistry and Materials, Okayama University Keita Hayashi National Institute of Technology, Nara College Kazuma Yasuhara Division of Materials Science, Nara Institute of Science and Technology (NAIST) Ho-Sup Jung Center for Food and Bioconvergence, Department of Food Science and Biotechnology, Seoul National University Yukitaka Kimura Department of Environmental Chemistry and Materials, Okayama University The Span 40 (sorbitan monooleate)/Tween 40 (polyoxyethylene sorbitan monolaurate) system gives faceted vesicles with angular surfaces, rather than spherical vesicles. Herein, a continuous and facile preparation method, based on the subcritical water-assisted emulsification and solvent diffusion, was presented to yield faceted vesicles with two major and minor axes (Type A) and vesicles closer to a polyhedron (Type B). Type A, rather than Type B, vesicles were likely to be formed. From the measurements concerning & zeta;-potential, membrane fluidity, and the polarization environment of the membranes, faceted vesicles could be obtained at 0.25 wt% of the surfactant concentration. The phase-separated behavior of Span 40 and Tween 40 within vesicle membranes could explain the structural feature of faceted vesicles and calcein leakage behavior. The significant advantage is that Type A vesicles would be utilized as alternative drug carriers for others with low encapsulation efficiency, although the present technical limitations cause difficulty in the selective formation of Type A and B vesicles and the selection of adequate solvent to accelerate the solvent diffusion step. No potential conflict of interest relevant to this article was reported.

MDPI Acta Medica Okayama 2076-3417 11 10 2021 Fibril Growth Behavior of Amyloid beta on Polymer-Based Planar Membranes: Implications for the Entanglement and Hydration of Polymers 4408 EN Toshinori Shimanouchi Graduate School of Environment and Life Science, Okayama University Miki Iwamura Graduate School of Environment and Life Science, Okayama University Shintaro Deguchi Graduate School of Environment and Life Science, Okayama University Yukitaka Kimura Graduate School of Environment and Life Science, Okayama University The design of biosensors and artificial organs using biocompatible materials with a low affinity for amyloid beta peptide (A beta) would contribute to the inhibition of fibril growth causing Alzheimer's disease. We systematically studied the amyloidogenicity of A beta on various planar membranes. The planar membranes were prepared using biocompatible polymers, viz., poly(methyl methacrylate) (PMMA), polysulfone (PSf), poly(L-lactic acid) (PLLA), and polyvinylpyrrolidone (PVP). Phospholipids from biomembranes, viz., 1,2-dioleoyl-phosphatidylcholine (DOPC), 1,2-dipalmitoyl-phosphatidylcholine (DPPC), and polyethylene glycol-graft-phosphatidyl ethanolamine (PEG-PE) were used as controls. Phospholipid- and polymer-based membranes were prepared to determine the kinetics of A beta fibril formation. Rates of A beta nucleation on the PSf- and DPPC-based membranes were significantly higher than those on the other membranes. A beta accumulation, calculated by the change in frequency of a quartz crystal microbalance (QCM), followed the order: PSf > PLLA > DOPC > PMMA, PVP, DPPC, and PEG-PE. Nucleation rates exhibited a positive correlation with the corresponding accumulation (except for the DPPC-based membrane) and a negative correlation with the molecular weight of the polymers. Strong hydration along the polymer backbone and polymer-A beta entanglement might contribute to the accumulation of A beta and subsequent fibrillation. No potential conflict of interest relevant to this article was reported.

elsevier Acta Medica Okayama 00063495 117 1 2019 Alteration of Membrane Physicochemical Properties by Two Factors for Membrane Protein Integration 99 110 EN Kaoru Nomura Bioorganic Research Institute, Suntory Foundation for Life Sciences Toshiyuki Yamaguchi Bioorganic Research Institute, Suntory Foundation for Life Sciences Shoko Mori Bioorganic Research Institute, Suntory Foundation for Life Sciences Kohki Fujikawa Bioorganic Research Institute, Suntory Foundation for Life Sciences Ken-ichi Nishiyama Department of Biological Chemistry and Food Sciences, Faculty of Agriculture, Iwate University Toshinori Shimanouchi Graduate School of Environmental Science, Okayama University Yasushi Tanimoto Graduate School of Agricultural Science, Kobe University Kenichi Morigaki Biosignal Research Center, Kobe University Keiko Shimamoto Bioorganic Research Institute, Suntory Foundation for Life Sciences After a nascent chain of a membrane protein emerges from the ribosomal tunnel, the protein is integrated into the cell membrane. This process is controlled by a series of proteinaceous molecular devices, such as signal recognition particles and Sec translocons. In addition to these proteins, we discovered two endogenous components regulating membrane protein integration in the inner membrane of Escherichia coli. The integration is blocked by diacylglycerol (DAG), whereas the blocking is relieved by a glycolipid named membrane protein integrase (MPIase). Here, we investigated the influence of these integration-blocking and integration-promoting factors on the physicochemical properties of membrane lipids via solid-state NMR and fluorescence measurements. These factors did not have destructive effects on membrane morphology because the membrane maintained its lamellar structure and did not fuse in the presence of DAG and/or MPIase at their effective concentrations. We next focused on membrane flexibility. DAG did not affect the mobility of the membrane surface, whereas the sugar chain in MPIase was highly mobile and enhanced the flexibility of membrane lipid headgroups. Comparison with a synthetic MPIase analog revealed the effects of the long sugar chain on membrane properties. The acyl chain order inside the membrane was increased by DAG, whereas the increase was cancelled by the addition of MPIase. MPIase also loosened the membrane lipid packing. Focusing on the transbilayer movement, MPIase reduced the rapid flip-flop motion of DAG. On the other hand, MPIase could not compensate for the diminished lateral diffusion by DAG. These results suggest that by manipulating the membrane lipids dynamics, DAG inhibits the protein from contacting the inner membrane, whereas the flexible long sugar chain of MPIase increases the opportunity for interaction between the membrane and the protein, leading to membrane integration of the newly formed protein. No potential conflict of interest relevant to this article was reported.