論文 - 伴野　太祐

Machine learning prediction of self-assembly and analysis of molecular structure dependence on the critical packing parameter

Y Ishiwatari, T Yokoyama, T Kojima, T Banno, N Arai

Molecular Systems Design & Engineering 9 (1), 20-28 （Molecular Systems Design and Engineering）  9 （ 1 ） 20 - 28 2024年

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  2058-9689

　概要を見る

Amphiphilic molecules spontaneously form self-assembly structures depending on physical conditions such as the molecular structure, concentration, and temperature. These structures exhibit various functionalities according to their morphology. The critical packing parameter (CPP) is used to correlate self-organized structures with the chemical composition. However, accurately calculating it requires information about both the molecular shape and molecular aggregates, making it challenging to apply directly in molecular design. We aimed to predict the self-assembled structure of a molecule directly from its chemical structure and to analyze the factors influencing it using machine learning. Dissipative particle dynamics simulations were used to reproduce many self-assembly structures comprising various chemical structures, and their CPPs were calculated. Machine learning models were built using the chemical structures as input data and the CPPs as output data. As a result, both random forest and the gated recurrent unit showed high prediction accuracy. Feature importance analysis and sample size dependence revealed that the amphiphilic nature of molecules significantly influences the self-assembly structures. Additionally, selecting an appropriate molecular structure representation for each algorithm is crucial. The study results should contribute to product development in the fields of materials science, materials chemistry, and medical materials.

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Bifurcation and Transposition of the Wicking Front of Binary Solutions Infiltrating into Chromatography Paper Associated with Their Evaporation

A Aizawa, T Banno, K Asakura

Langmuir 39 (47), 16731-16739 （American Chemical Society (ACS)）  39 （ 47 ） 16731 - 16739 2023年11月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  0743-7463

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Photoinduced phase transition between vesicles and coacervates using low-molecular-weight catanionic amphiphiles

T Kojima, K Terasaka, K Asakura, T Banno

Colloids and Surfaces A: Physicochemical and Engineering Aspects 669, 131512 （Colloids and Surfaces A: Physicochemical and Engineering Aspects）  669 2023年07月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  0927-7757

　概要を見る

Amphiphiles form various molecular self-assemblies in the aqueous phase, such as vesicles and coacervates, depending on molecular properties. Recently, phase transitions between vesicles and coacervates have drawn much attention because the switching between “closed” and “open” compartments could achieve the controllability of molecular sequestrations. We expect that the photoinduced drastic change in the molecular structure of catanionic amphiphiles comprising azobenzene-containing cationic amphiphiles (Azo) and anionic sodium dodecyl sulfate causes the transition. Self-assemblies prepared by a thin-film hydration method were observed using microscopy under UV and subsequent visible-light illumination. Additionally, investigation of selectivity for molecular sequestration and assay of enzymatic reactions in the self-assemblies were conducted. Photoinduced reversible phase transitions between vesicles and coacervates occurred owing to the photoisomerization of Azo. The formed coacervates had selectivity for molecular sequestration. Additionally, the transition achieved fusion of different vesicles via coacervates. Although coacervates are generally known to facilitate enzymatic reactions, the reactions were inhibited in the presence of the formed self-assemblies due to the deactivation of enzymes. Our results represent rapid and non-invasive systems of reversible vesicle–coacervate transitions. Furthermore, the findings provide a new aspect of coacervates in which catanionic low-molecular-weight amphiphiles could act as suppressors of chemical reactions.

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Factors to control the alignment of surface-treated titanium dioxide powders to maximize performance of sunscreens

Takekawa, S; Ohara, M; Banno, T; Asakura, K

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE （International Journal of Cosmetic Science）  45 （ 1 ） 38 - 49 2023年02月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  0142-5463

　概要を見る

Objective: Titanium dioxide powders are contained in a large class of colour cosmetics and sunscreen formulas. When they are used, the formation of a uniform functional powder layer on the skin is an important factor to show their functionality, such as aesthetic and UV protection. Attempts were made to extract the factors that affect the UV shielding ability of the deposited powder layer. Methods: Seven kinds of surface treatments were conducted on nano-sized titanium dioxide powder to modify the surface characteristics. Dispersion samples were prepared by mixing these powders with liquids, such as mixed solutions of cyclopentasiloxane, isododecane, coconuts alkane and dimethicone using a disperser and a bead mill. The dispersions were applied using an applicator on cellulose triacetate film, polycarbonate film and polymethyl pentene film. Laser microscope observation and micro-gloss glossmeter analysis were carried out to assess the flatness of the deposited powder layers, and the UV shielding ability was evaluated using SPF analyser. Results: Factors whose influences on the structure and UV shielding ability of the deposited powder layer being analysed were pseudo-HLB of the powders, liquids for preparing the dispersions and material of the substrates. Higher UV shielding ability was attained when powders having pseudo-HLB at around 6 were employed independent from the kinds of liquids and substrates. Flatness of the deposited layer was found to enhance the UV shielding ability of the UV-B region, while that of the UV-A region was scarcely influenced by the flatness. Employing lower surface tension liquids for preparing the dispersions and materials exhibiting lower polar components of surface free energy as substrates tended to enhance the UV shielding ability. Conclusion: Surface treatments conducted on the powders in this study were found to change UV shielding ability, especially UV-B shielding ability, and the relation between pseudo-HLB and UV shielding ability was scarcely influenced by the kinds of liquids. Both surface tension of liquids and the polar component of surface free energy of substrates affected the UV shielding ability. It was suggested that pseudo-HLB calculated based on chemical structure becomes useful information to choose optimum surface treatment to make uniform powder alignment independent from the surrounding environment.

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Photoinduced collective motion of oil droplets and concurrent pattern formation in surfactant solution

T Kojima, H Kitahata, K Asakura, T Banno

Cell Reports Physical Science 4 (1) （Cell Reports Physical Science）  4 （ 1 ） 101222 - 101222 2023年01月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  2666-3864

　概要を見る

Collective motions are the spontaneous emergence of the ordered movement in living systems. Various constructive approaches have been attempted toward understanding the mechanism. However, few studies have been on the motion induced by biomimetic artificial systems based on molecular conversions. In this study, we report an artificial system of oil droplets in surfactant solutions, wherein collective motion and pattern formation occur concurrently, using the conversion of photoresponsive surfactants. Assembly/dispersion of multiple oil droplets and appearance/disappearance of circular patterns around them occur under UV/visible light illumination, respectively. Moreover, whether the assembled droplets move laterally or not depends on the number of droplets, which is considered analogous to biological organisms in response to population density. These phenomena occur because the photoisomerization of surfactants induces the gradient of interfacial tension, generating specific flow fields around droplets. Our results could be useful for understanding the mechanism of life motion in terms of physicochemical aspects.

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Factors to control the alignment of surface‐treated titanium dioxide powders to maximize performance of sunscreens

S Takekawa, M Ohara, T Banno, K Asakura

International Journal of Cosmetic Science 45 (1), 38-49 2023年

筆頭著者, 最終著者, 責任著者, 査読有り

Synthesis of Mannosylerythritol Lipid Analogues and their Self-Assembling Properties, Recovery Effects on Damaged Skin Cells, and Antibacterial Activity

Kondo, T; Yasui, C; Miyajima, I; Banno, T; Asakura, K; Fukuoka, T; Ushimaru, K; Koga, M; Saika, A; Morita, T; Takahashi, Y; Hayashi, C; Igarashi, M; Takahashi, D; Toshima, K

CHEMISTRY-A EUROPEAN JOURNAL （Chemistry - A European Journal）  28 （ 55 ）  2022年06月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  0947-6539

　概要を見る

Synthesis of three types of purpose-designed mannosylerythritol lipid (MEL)-D analogues with decanoyl groups, β-GlcEL-D, α-GlcEL-D, and α-MEL-D, was accomplished utilizing our boron-mediated aglycon delivery (BMAD) methods. Their self-assembling properties, recovery effects on damaged skin cells, and antibacterial activity were evaluated. It was revealed, for the first time, that α-GlcEL-D and α-MEL-D only generated giant vesicles, indicating that slight differences in the steric configuration of an erythritol moiety and fatty acyl chains affect the ability to form vesicles. Analogue α-MEL-D exhibited significant recovery effects on damaged skin cells. Furthermore, α-MEL-D exhibited antibacterial activity as high as that for MEL-D, indicating that α-MEL-D is a promising artificial sugar-based material candidate for enhancing the barrier function of the stratum corneum, superior to a known cosmetic ingredient, and possesses antibacterial activity.

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Construction of Supramolecular Systems That Achieve Lifelike Functions

Banno T., Sawada D., Toyota T.

Materials （Materials）  15 （ 7 ） 2391 2022年04月

査読有り,  ISSN  1996-1944

　概要を見る

The Nobel Prize in Chemistry was awarded in 1987 and 2016 for research in supramolecular chemistry on the “development and use of molecules with structure-specific interactions of high selectivity” and the “design and production of molecular machines”, respectively. This confirmed the explosive development of supramolecular chemistry. In addition, attempts have been made in systems chemistry to embody the complex functions of living organisms as artificial non-equilibrium chemical systems, which have not received much attention in supramolecular chemistry. In this review, we explain recent developments in supramolecular chemistry through four categories: stimuli-responsiveness, time evolution, dissipative self-assembly, and hierarchical expression of functions. We discuss the development of non-equilibrium supramolecular systems, including the use of molecules with precisely designed properties, to achieve functions found in life as a hierarchical chemical system.

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Chemotaxis of oil droplets and their phase transition to aggregates with membrane structures in surfactant solution containing metal salts

S Nakayama, T Kojima, M Kaburagi, T Kikuchi, K Asakura, T Banno

ChemSystemsChem 4 (2), e202100035 （Wiley）  4 （ 2 ）  2022年03月

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  2570-4206

　概要を見る

The movement of supramolecular self-assemblies has been induced by the application of external stimuli that cause a shift to non-equilibrium conditions. However, few supramolecular chemical systems exist in which multiple different functions are associated with movement. Herein, we observed multiple phase transition of micrometer-sized lauronitrile oil droplets in a solution of cationic surfactants with aniline skeletons in the presence of metal ions. These dynamics include tactic motion and subsequent formation of aggregates with membrane structures, in a linear-type channel. These dynamic behaviors result from variations in the interfacial tension at the droplet surface and the chemical compositions owing to the interactions between system components. The current findings may provide a methodology for designing molecular systems in which multi-step phase transitions of supramolecular self-assemblies are coupled to movement in non-equilibrium conditions.

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Self-Assembling Properties and Recovery Effects on Damaged Skin Cells of Chemically Synthesized Mannosylerythritol Lipids

Kondo T., Yasui C., Banno T., Asakura K., Fukuoka T., Ushimaru K., Koga M., Minamikawa H., Saika A., Morita T., Takahashi D., Toshima K.

ChemBioChem （ChemBioChem）  23 （ 2 ） e202100631 2022年01月

査読有り,  ISSN  14394227

　概要を見る

Mannosylerythritol lipids (MELs), which are one of the representative sugar-based biosurfactants (BSs) produced by microorganisms, have attracted much attention in various fields in the sustainable development goals (SDGs) era. However, they are inseparable mixtures with respect to the chain length of the fatty acids. In this study, self-assembling properties and structure-activity relationship (SAR) studies of recovery effects on damaged skin cells using chemically synthesized MELs were investigated. It was revealed, for the first time, that synthetic and homogeneous MELs exhibited significant self-assembling properties to form droplets or giant vesicles. In addition, a small difference in the length of the fatty acid chains of the MELs significantly affected their recovery effects on the damaged skin cells. MELs with medium or longer length alkyl chains exhibited much higher recovery effects than that of C18-ceramide NP.

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New in vitro SPF Evaluation Method for Hydrophilic Sunscreen Samples

Ikawa K., Aizawa A., Banno T., Fujishiro M., Yahagi S., Kuroda A., Asakura K.

Journal of Oleo Science （Journal of Oleo Science）  71 （ 2 ） 321 - 331 2022年

査読有り,  ISSN  13458957

　概要を見る

A new method was developed for the in vitro sun protection factor (SPF) evaluation of sunscreen samples. A new type of substrate, a hydroxyalkyl cellulose-coated plate, was also prepared specifically for hydrophilic samples. This new substrate was required because hydrophilic samples would be unlikely to wet the surface of the standard cosmetic PMMA UV evaluation plate. A super-hydrophilic quartz plate was prepared by corona-discharge treatment before an aqueous solution of hydroxyalkyl cellulose was spread on it. A flat and uniform hydroxyalkyl cellulose film was subsequently formed through the evaporation of water. Special care was taken to inhibit the generation of spatial non-uniformity. Six hydrophilic sunscreen samples with in vivo SPF values of 56, 55, 52, 25, 15, and 4, were then applied to the prepared hydroxyalkyl cellulose-coated plate, as well as a super-hydrophilic quartz plate and a flat hydrophobic PMMA plate. The thicknesses of the applied layers were determined using a wheel-shaped wet film thickness gauge immediately after the application, and UV transmission was measured using an SPF analyzer. The value of in vitro SPF was calculated from the UV absorbance and the thickness of the layer. For two out of the six samples, PMMA plate could not be available, as the samples were unable to wet the PMMA surface. Relatively small differences were observed between the in vitro SPF values when the super-hydrophilic and hydroxyalkyl cellulose-coated plates were used. Samples exhibiting higher in vivo SPF were also associated with higher in vitro SPF values, although a linear relationship was not observed. In contrast to the super-hydrophilic plate whose half-life of the super-hydrophilicity is only approximately five days, the hydrophilicity of the hydroxyalkyl cellulose-coated plate scarcely varied during six months of storage. Finally, a simplified evaluation method was also proposed. The validity of the method was verified through a ring test where three researchers employed this method in different laboratories at three independent organizations.

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pH-Sensitive Controlled Motion of Micrometer-sized Oil Droplets in a Solution of Surfactants Containing Fumaric Acid Derivatives

M Kaburagi, T Kojima, K Asakura, T Banno

Journal of oleo science 71 (9), 1319-1326 （Journal of Oleo Science）  71 （ 9 ） 1319 - 1326 2022年

筆頭著者, 最終著者, 責任著者, 査読有り,  ISSN  1345-8957

　概要を見る

Self-propelled droplets are of considerable interest as an appropriate model for understanding the self-propulsion of objects in the fields of nonequilibrium physics and nonlinear science. Several research groups have reported the monodirectional motion of droplets, that is, chemotaxis, using stimuli-responsive materials. However, the precise control of chemotaxis remains challenging from the perspective of synthetic chemistry because chemotactic motion is primarily induced by the consumption of reactive oil or surfactants. Herein, we report a chemical system containing pH-responsive fumaric acid derivatives, in which the oil droplet exhibited positive chemotaxis over a wide pH range–from basic to acidic conditions. From the measurements of the interfacial tension between the oil and aqueous phases, it was deduced that the positive chemotaxis was due to heterogeneity in the interfacial tension of the droplet surface, which was accompanied by the production of surface-active compounds in the pH gradient in a linear-type channel.

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Synthesis of Mannosylerythritol Lipid Analogues and their Self‐Assembling Properties, Recovery Effects on Damaged Skin Cells, and Antibacterial Activity

T Kondo, C Yasui, I Miyajima, T Banno, K Asakura, T Fukuoka, ...

Chemistry–A European Journal 28 (55), e202201733 2022年

筆頭著者, 最終著者, 責任著者, 査読有り

Pathway-Dependent Phase Transitions of Supramolecular Self-assemblies Containing Cationic Amphiphiles with Azobenzene and Disulfide Groups

Sawada D., Asakura K., Banno T.

Chemistry - A European Journal （Chemistry - A European Journal）  27 （ 55 ） 13840 - 13845 2021年10月

査読有り,  ISSN  09476539

　概要を見る

There have been several attempts to construct supramolecular chemical systems that mimic the phase transitions in living systems. However, most of these phase transitions are one-to-one and induced by one stimulus or chemical; there have been few reports on the pathway-dependent phase transition of supramolecular self-assemblies in multi-step. To induce multistep phase transitions, molecular crystals were prepared that contained a cationic amphiphile bearing azobenzene and disulfide groups. A reducing agent caused the crystals to become vesicles, and adjacent, non-touching vesicles fused under UV and subsequent visible light. Adding a reducing agent to the worm-like aggregates that were generated after UV irradiation of the original crystals resulted in the growth of sheet-like aggregates. 1H NMR and fluorescence anisotropy measurements showed that a series of phase transitions was induced by changes in the phase structures from molecular conversions of the reactive amphiphiles. The multiple pathway-dependent phase transitions of supramolecular self-assemblies can provide a methodology for developing new stimuli-responsive materials that exhibit the desirable properties under specific circumstances from a systems chemistry viewpoint.

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How to control powder alignment to maximize functionality and performance of color cosmetics and sunscreen

Takekawa S., Ohara M., Banno T., Asakura K.

Journal of Oleo Science （Journal of Oleo Science）  70 （ 8 ） 1081 - 1091 2021年

査読有り,  ISSN  13458957

　概要を見る

Control of powder alignment is essential for maximizing the functionality of color cosmetics and sunscreens. Various surface treatments were applied to nanosized titanium dioxide to modify their surface characteristics. Such modifications can be used to control the behavior of dispersions in cosmetics, enabling them to align uniformly. The powders were mixed with solvents and applied to a cellulose triacetate film. The features of powder alignment on the film were evaluated using several approaches. When the type of surface treatment changed by varying the weight ratio, there was no significant correlation between its alignment and treatment. However, when we focused on the pseudo-HLB each treated pigment, their alignments were correlated. It was confirmed that the powders subjected to the appropriate surface treatment combinations from the pseudo-HLB standpoint made it possible to align uniformly and create a smooth coating film. As a result, it has a high UV-shielding ability. The surface-treated powders in this study were found to change the UV shielding ability and surface roughness of the layer formed when they were formed by spreading the sample powder dispersion and drying of the film. It was suggested that the pseudo-HLB, which is calculated based on the chemical structure after the surface treatment process, is useful for choosing the optimum surface treatment to create a uniformly aligned pigment layer.

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pH-Tolerant giant vesicles composed of cationic lipids with imine linkages and oleic acids

Sawada D., Hirono A., Asakura K., Banno T.

RSC Advances （RSC Advances）  10 （ 56 ） 34247 - 34253 2020年09月

査読有り

　概要を見る

Giant vesicles (GVs) have attracted attention as functional materials because they can encapsulate both hydrophilic and hydrophobic compounds. For next generation functional GVs, both tolerance and stimuli-sensitivity are needed. So far, vesicles tolerant to acidic or basic conditions were generated using a mixture of cationic lipids and fatty acids. Here, to create functional GVs that are tolerant to a wide pH range but sensitively respond at below a specific pH, the behaviour of GVs composed of a cationic lipid with an imine bond and oleic acid was investigated. Even though the GVs prepared by the film swelling method were tolerant to strongly acidic conditions, GVs without oleic acid gradually shrank, accompanied by the generation of oil droplets at the same pH. 1H NMR analysis revealed that during hydration of the film, the imine bond hydrolysed to provide a cationic surfactant and an oil component in the presence of oleic acid due to its own Lewis basicity, suggesting the dissociation of oleic acid. The results of fluorescence spectroscopy using an environment-responsive probe and IR spectroscopy indicated that the GV tolerance originated from the intermolecular interactions of cationic lipids and anionic oleate. This journal is

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Cell-mimicry behaviors of micrometer-sized oil droplets in aqueous solution

Banno T., Toyota T., Asakura K.

ALIFE 2018 - 2018 Conference on Artificial Life: Beyond AI （ALIFE 2018 - 2018 Conference on Artificial Life: Beyond AI）  30   13 - 14 2020年

査読有り

　概要を見る

In cell system, dynamic behaviors of nanometer- and micrometer-sized living tissues are induced through various chemical reaction networks accompanied with molecular conversions of key molecules. However, such hierarchy between macroscopic dynamics of cells and molecular conversions is very complicated. Here, as a tool for understanding the essence of the dynamic behavior found in cell system, two chemical systems for droplets exhibiting cell-mimicry behaviors have been described: transformation of molecular aggregates and locomotion mode of oil droplets.

Temperature-Dependent Dynamics of Giant Vesicles Composed of Hydrolysable Lipids Having an Amide Linkage

Tameyuki M., Hiranaka H., Toyota T., Asakura K., Banno T.

Langmuir （Langmuir）  35 （ 52 ） 17075 - 17081 2019年12月

査読有り,  ISSN  07437463

　概要を見る

Various amphiphiles including surfactants and lipids have been designed and synthesized to improve and create new functionalities. In particular, the emergence of cell-like behaviors of giant vesicles (GVs) composed of synthetic lipids has drawn much attention in the development of chemical models for cells. The aim of this study was to measure temperature-dependent morphological changes of GVs induced by fragmentation and subsequent growth using hydrolysable cationic lipids having an amide linkage. Results from differential scanning calorimetry, fluorescence spectroscopy using an environment-responsive probe, and confocal Raman microscopy showed that the dynamics observed were due to changes in the vesicle membrane, including variation in the lipid composition, induced by thermal stimulation.

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Start of Micrometer-Sized Oil Droplet Motion through Generation of Surfactants

Kasuo Y., Kitahata H., Koyano Y., Takinoue M., Asakura K., Banno T.

Langmuir （Langmuir）  35 （ 41 ） 13351 - 13355 2019年10月

査読有り,  ISSN  07437463

　概要を見る

Self-propelled motion of micrometer-sized oil droplets in surfactant solution has drawn much attention as an example of nonlinear life-like dynamics under far-from-equilibrium conditions. The driving force of this motion is thought to be induced by Marangoni convection based on heterogeneity in the interfacial tension at the droplet surface. Here, to clarify the required conditions for the self-propelled motion of oil droplets, we have constructed a chemical system, where oil droplet motion is induced by the production of 1,2,3-triazole-containing surfactants through the Cu-catalyzed azide-alkyne cycloaddition reaction. From the results of the visualization and analysis of flow fields around the droplet, the motion of the droplets could be attributed to the formation of flow fields, which achieved sufficient strength caused by the in situ production of surfactants at the droplet surface.

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Disruption of liquid marbles induced by host-guest interaction

Kozuka S., Banno T., Fujii S., Nakamura Y., Yusa S.

Chemistry Letters （Chemistry Letters）  48 （ 8 ） 840 - 843 2019年

査読有り,  ISSN  03667022

　概要を見る

The present work describes the preparation of host-guest complex formation-responsive liquid marbles (LMs) composed of a water droplet and hydrophobic adamantane (AD) powder. The importance of hydrophobic and hydrophilic balance to the stability of LM was demonstrated with this system. The hydrophobic AD powder formed an amphiphilic system upon formation of a host-guest complex with methyl-β-cyclodextrin (CD). Although the LM was stable for more than one hour on the water surface, it collapsed on the surface of a CD aqueous solution within a few minutes due to formation of the AD-CD complex.

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