Friction-reduction effect of the hierarchical surface microstructure of carrion beetle by controlling the real contact area.

The discovery and elucidation of the surface microstructure functions of living organisms are crucial to resolving issues, such as friction. We newly discovered that , a type of carrion beetle that lives on the ground surface, exhibited a hierarchical surface microstructure comprising a submicron-sized wrinkle structure on top of a micron-sized microstructure. The surface microstructure of this beetle improved wettability but did not exhibit superhydrophobicity, a well-known function of hierarchical structures, so it was expected to have a different function.

Microscopy and biomimetics: the NanoSuit® method and image retrieval platform.

This review aims to clarify a suitable method towards achieving next-generation sustainability. As represented by the term 'Anthropocene', the Earth, including humans, is entering a critical era; therefore, science has a great responsibility to solve it. Biomimetics, the emulation of the models, systems and elements of nature, especially biological science, is a powerful tool to approach sustainability problems.

Hydrophobic-hydrophilic crown-like structure enables aquatic insects to reside effectively beneath the water surface.

Various insects utilise hydrophobic biological surfaces to live on the surface of water, while other organisms possess hydrophilic properties that enable them to live within a water column. Dixidae larvae reside, without being submerged, just below the water surface. However, little is known about how these larvae live in such an ecological niche.

Effect of the Microstructures on Vulcanized Rubber Frictions.

Vulcanized rubber is widely used in a wide range of applications because of its flexibility, durability, sealing properties, and high degree of friction. However, this high degree of friction can also become an issue, as it leads to the wearing and breakage of parts. In this report, we investigated the effects of the vulcanized rubber microstructures on friction force by using simple, anisotropic microstructures.

In situ elemental analyses of living biological specimens using 'NanoSuit' and EDS methods in FE-SEM.

Energy dispersive X-ray spectroscopy (EDS) carried out alongside scanning electron microscopy (SEM) is a common technique for elemental analysis. To investigate "wet" biological specimens, complex pre-treatments are required to stabilize them under the high vacuum conditions of high-resolution SEM. These often produce unwanted artifacts.

Imaging dataset of fresh hydrous plants obtained by field-emission scanning electron microscopy conducted using a protective NanoSuit.

Although scanning electron microscopy (SEM) can generate high-resolution images of nanosized objects, it requires a high vacuum to do so, which precludes direct observations of living organisms and often produces unwanted structural changes. It has previously been reported that a simple surface modification gives rise to a nanoscale layer, termed the "NanoSuit", which can keep small animals alive under the high vacuum required for field-emission scanning electron microscopy (FE-SEM). We have previously applied this technique to plants, and successfully observed healthy petals in a fully hydrated state using SEM.

The Friction Properties of Firebrat Scales.

Friction is an important subject for sustainability due to problems that are associated with energy loss. In recent years, micro- and nanostructured surfaces have attracted much attention to reduce friction; however, suitable structures are still under consideration. Many functional surfaces are present in nature, such as the friction reduction surfaces of snake skins.

A 'NanoSuit' successfully protects petals of cherry blossoms in high vacuum: examination of living plants in an FE-SEM.

Land plants have evolved on dry land and developed surface barriers to protect themselves from environmental stresses. We have previously reported that polymerization of a natural extracellular substance (ECS) on the outer surface of animals by electron beam or plasma irradiation, can give rise to a nano-scale layer, termed the "NanoSuit", which can keep small animals alive under the high vacuum of a scanning electron microscope (SEM). In the present research, we have focused on plants, using petals of cherry blossoms, as experimental specimens and examined their behavior under high vacuum conditions.

Uphill Water Transport on a Wettability-Patterned Surface: Experimental and Theoretical Results.

In nature, there exist many functional water-controlling surfaces, such as the water-repellent surface of lotus leaves, the superhydrophobic water-adhesive surface of rose petals, the water-harvesting surface of a beetle's back, and the water-transporting surface of the legs of Ligia exotica. These natural surfaces suggest that surface chemistry and hierarchical structures are essential for controlling the water behavior. We have reported the preparation of superhydrophobic and antireflection silicon nanospike-array structures using self-organized honeycomb-patterned films as three-dimensional dry-etching masks.

A modified 'NanoSuit®' preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy.

Although field-emission scanning electron microscopy (FE-SEM) has proven very useful in biomedical research, the high vacuum required (10 to 10 Pa) precludes direct observations of living cells and tissues at high resolution and often produces unwanted structural changes. We have previously described a method that allows the investigator to keep a variety of insect larvae alive in the high vacuum environment of the electron microscope by encasing the organisms in a thin, vacuum-proof suit, the 'NanoSuit®'. However, it was impossible to protect wet tissues freshly excised from intact organisms or cultured cells.

Paclitaxel-Releasing Thin Biodegradable Film for Prevention of Bleb Avascularity Without Compromising Filtration in Rabbits.

Purpose: A honeycomb-patterned film (HPF) prevents bleb scarring and mitomycin C (MMC)-related bleb avascularity in a rabbit model of filtration surgery. In this study, we examined whether a HPF-releasing paclitaxel (PTX) can prevent bleb avascularity without compromising filtration.

Methods: Filtration surgery was performed in one eye of rabbits.

Preparation of biomimetic high adhesive superhydrophobic polymer pillar surfaces with crown-like metal microstructures.

High adhesive superhydrophobic polymer pillar surfaces with dispersed metallic crown-like micro structures were prepared by electroless plating on self-organized honeycomb patterned polymer films and peeling off the top layer of the metal covered honeycomb films. Thus obtained polymer pillar surfaces with metallic crown-like microstructures possessed conflicting properties of water repellency and adhesion. The adhesion property was tuned by number density of metallic crown-like microstructures which were adjusted by polymer concentration in a catalytic solution for electroless plating.

Dehydrogenative polymerization of coniferyl alcohol in artificial polysaccharides matrices: effects of xylan on the polymerization.

To elucidate the influence of wood polysaccharide components on lignin formation in vitro, models for polysaccharide matrix in wood secondary cell wall were fabricated from two types of bacterial cellulosic films, flat film (FBC) and honeycomb-patterned film (HPBC), as basic frameworks by depositing xylan onto the films. An endwise type of dehydrogenative polymerization, "Zutropfverfahren", of coniferyl alcohol was attempted in the films with/without xylan. The resultant dehydrogenation polymer (DHP) was generated inside and outside xylan-deposited films, whereas DHP was deposited only outside the films without xylan.

A 'NanoSuit' surface shield successfully protects organisms in high vacuum: observations on living organisms in an FE-SEM.

Although extremely useful for a wide range of investigations, the field emission scanning electron microscope (FE-SEM) has not allowed researchers to observe living organisms. However, we have recently reported that a simple surface modification consisting of a thin extra layer, termed 'NanoSuit', can keep organisms alive in the high vacuum (10(-5) to 10(-7) Pa) of the SEM. This paper further explores the protective properties of the NanoSuit surface-shield.

Breath Figures of Nanoscale Bricks: A Universal Method for Creating Hierarchic Porous Materials from Inorganic Nanoparticles Stabilized with Mussel-Inspired Copolymers.

High-performance catalysts and photovoltaics are required for building an environmentally sustainable society. Because catalytic and photovoltaic reactions occur at the interfaces between reactants and surfaces, the chemical, physical, and structural properties of interfaces have been the focus of much research. To improve the performance of these materials further, inorganic porous materials with hierarchic porous architectures have been fabricated.

Capillary rise on legs of a small animal and on artificially textured surfaces mimicking them.

The wharf roach Ligia exotica is a small animal that lives by the sea and absorbs water from the sea through its legs by virtue of a remarkable array of small blades of micron scale. We find that the imbibition dynamics on the legs is rather complex on a microscopic scale, but on a macroscopic scale the imbibition length seems to simply scale linearly with elapsed time. This unusual dynamics of imbibition, which usually slows down with time, is advantageous for long-distance water transport and results from repetition of unit dynamics.

Dressing living organisms in a thin polymer membrane, the NanoSuit, for high-vacuum FE-SEM observation.

Scanning electron microscopy (SEM) has made remarkable progress and has become an essential tool for observing biological materials at microscopic level. However, various complex procedures have precluded observation of living organisms to date. Here, a new method is presented by which living organisms can be observed by field emission (FE)-SEM.

The morphology and functions of articular chondrocytes on a honeycomb-patterned surface.

The present study investigated the potential of a novel micropatterned substrate for neocartilage formation. Articular chondrocytes were cultured on poly( ɛ-caprolactone) materials whose surfaces were either flat or honeycomb-patterned. The latter was prepared using a novel self-organization technique, while the former, was prepared by spin-coating.

Micropatterned culture of HepG2 spheroids using microwell chip with honeycomb-patterned polymer film.

Microwell chip culture is a promising technique for the generation of homogenous spheroids. We investigated the relationship between the structure of the bottom surface of microwell chip and the properties of HepG2 spheroid. We developed a microwell chip, the bottom surface of which consisted of a honeycomb-patterned polymer film (honeycomb film) that had a regular porous structure (HF chip).

Formation and control of line defects caused by tectonics of water droplet arrays during self-organized honeycomb-patterned polymer film formation.

This study describes the formation of macro-scale defects of the honeycomb-patterned polymer film and we discovered two types of new line defects which differ from the defects reported in the past studies. We examined the formation mechanisms of the line defects and clarified two types of formation mechanisms of the "Divergent" mode line defects and the "Convergent" mode line defects caused by the "tectonics" of water droplet arrays on polymer solutions. The regions causing the macro-scale line defects are made clear in the phase diagram represented by the radius and the density of the micro-scale water droplets.

Fabrication of gold nanoparticle-polymer composite particles with raspberry, core-shell and amorphous morphologies at room temperature via electrostatic interactions and diffusion.

Composite particles with varying morphologies composed of gold nanoparticles (Au NPs) and polymers were fabricated based on a combination of electrostatic interactions between the polymer particles and Au NPs and diffusion processes. The positively charged polymer particles were prepared from amino-terminated polystyrene (PS-NH2) and amino-terminated 1,2-polybutadiene (PB-NH2). Adsorption of citrate-stabilized Au NPs resulted in three different distribution states of Au NPs in the polymer particles, depending on the glass transition temperature (Tg) and molecular weight of the polymer.

Honeycomb-shaped surface topography induces differentiation of human mesenchymal stem cells (hMSCs): uniform porous polymer scaffolds prepared by the breath figure technique.

Polystyrene honeycomb scaffolds with different pore sizes were successfully fabricated by casting a polymer solution under humid conditions in order to investigate the effect of porous microtopography on hMSC differentiation. We have used honeycomb scaffolds to achieve the microtopography-induced differentiation of hMSCs. Honeycomb scaffolds led hMSCs to osteospecific and myospecific differentiations depending on the size of pores.

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

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.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces.

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system.