Yu Ogawa

French National Centre for Scientific Research | CNRS · Centre de Recherches sur les Macromolécules Végétales

Peptides and nucleic acids with programmable sequences are widely explored for the production of tunable, self‐assembling functional materials. Herein we demonstrate that the primary sequence of oligosaccharides can be designed to access materials with tunable shapes and properties. Synthetic cellulose‐based oligomers were assembled into 2D or 3D r...

Peptides and nucleic acids with programmable sequences are widely explored for the production of tunable, self‐assembling functional materials. Herein we demonstrate that the primary sequence of oligosaccharides can be designed to access materials with tunable shapes and properties. Synthetic cellulose‐based oligomers were assembled into 2D or 3D r...

A mechanistic understanding of the principles governing the hierarchical organization of supramolecular polymers offers a paradigm for tailoring synthetic molecular architectures at the nano to micrometric scales. Herein, the unconventional crystal growth mechanism of a supramolecular polymer of superbenzene(coronene)-diphenylalanine conjugate (Cr-...

Molecular weight information is essential for comprehending the chemical and physical properties of cellulose. However, traditional methods used to analyze high-molecular-weight cellulose are often unsuitable for cellulose oligomers. In this study, we emphasize the influence of molecular weight distribution on the determination of molecular weight...

Xylans are the most abundant plant heteropolysaccharides and can account for over one-third of the content of cell walls in biomass. Xylans crystallize from dilute aqueous solution into crystal hydrates. Since lignin is closely associated with xylans in cell walls, we investigated the effect of residual lignin on crystal formation. We used β-(1 → 4...

Hydrothermal treatment between 150 °C and 230 °C is widely used in wood processing, from the steam treatment of timber for better dimensional stability and durability to the pretreatment for enzymatic saccharification and chemical pulping. Understanding the ultrastructural changes of wood cell walls through hydrothermal treatments is crucial for co...

Phosphoric acid is widely used for the swelling and hydrolysis of cellulose. The detailed description of molecular interactions between cellulose and phosphoric acid is essential for understanding and controlling these processes. Here, to obtain structural insights into the swelling behavior, we investigated the structural evolution of cellulose sw...

There has been a resurgence of studies on xylan particles describing various properties and exploring new applications. The aim of this study was to analyze xylan hydrate crystals in the wet state and after air-drying using state-of-art imaging techniques in order to assess the impact of water on both crystallinity and particle morphology. Xylan fr...

Understanding the defect structure is fundamental to correlating the structure and properties of materials. However, little is known about the defects of soft matter at the nanoscale beyond their external morphology. We report here on the molecular-level structural details of kink defects of cellulose nanocrystals (CNCs) based on a combination of e...

Accurate determination of molecular weight is crucial for understanding the chemical and physical properties of cellulose. However, traditional methods for analyzing high-molecular-weight cellulose are often unsuitable for cellulose oligomers. In this study, we emphasize how the molecular weight distribution affect the accuracy of four characteriza...

Amylose, a mostly linear homopolymer of glucosyl units extracted from native starch granules, can form a large variety of so-called V-type host–guest complexes when cocrystallized with small hydrophobic molecules. Several allomorphs are known that contain six-, seven-, or eight-fold amylose single helices, the guest molecules being located in the h...

Structural color is poorly known in plants relative to animals. In fruits, only a handful of cases have been described, including in Viburnum tinus where the blue color results from a disordered multilayered reflector made of lipid droplets. Here, we examine the broader evolutionary context of fruit structural color across the genus Viburnum. We ob...

Choanoflagellates are primitive protozoa used as models for animal evolution. They express a large variety of multi-domain proteins contributing to adhesion and cell communication, thereby providing a rich repertoire of molecules for biotechnology. Adhesion often involves proteins adopting a β-trefoil fold with carbohydrate-binding properties there...

Polysaccharides are the most abundant class of biopolymers, holding an important place in biological systems and sustainable material development. Their spatial organization and intra- and intermolecular interactions are thus of great interest. However, conventional single crystal crystallography is not applicable since polysaccharides crystallize...

One main challenge to utilize cellulose-based fibers as the precursor for carbon fibers is their inherently low carbon yield. This study aims to evaluate the use of keratin in chicken feathers, a byproduct of the poultry industry generated in large quantities, as a natural charring agent to improve the yield of cellulose-derived carbon fibers. Kera...

Cellulose is a polysaccharide that displays chirality across different scales, from the molecular to the supramolecular level. This feature has been exploited to generate chiral materials. To date, the mechanism of chirality transfer from the molecular level to higher-order assemblies has remained elusive, partially due to the heterogeneity of cell...

The majority of plant colours are produced by anthocyanin and carotenoid pigments, but colouration obtained by nanostructured materials (i.e. structural colours) is increasingly reported in plants. Here, we identify a multilayer photonic structure in the fruits of Lantana strigocamara and compare it with a similar structure in Viburnum tinus fruits...

Carbohydrate nanoparticles, both naturally derived and synthetic ones, have attracted scientific and industrial attention as high-performance renewable building blocks of functional materials. Electron microscopy (EM) has played a central role in investigations of their morphology and molecular structure, although the intrinsic radiation sensitivit...

Chain-folded lamellar V-amylose single crystals were prepared by adding butan-1-ol to hot dilute aqueous solutions of native amylose. The base-plane electron and X-ray diffraction patterns recorded from hydrated specimens agreed with a P212121 space group and an orthorhombic unit cell. A molecular model resulting from an exhaustive search of helix...

Significance Helicoidal architectures are widespread in nature; several species adopt this structure to produce brilliant colorations. Such chiral architectures are usually left-handed in plants, with the only exception found in the cell walls of epicarp cells of Pollia condensata , where both handednesses are observed. Here, we aim to understand t...

Nanocomposites based on components from nature, which can be recycled are of great interest in new materials for sustainable development. The range of properties of nacre-inspired hybrids of 1D cellulose and 2D clay platelets are investigated in nanocomposites with improved nanoparticle dispersion in the starting hydrocolloid mixture. Films with a...

Chitosan-cellulose composite fibers spun using a Lyocell technology are characterized by a homogeneous distribution and a close packing of the two biopolymers inside the fibrous matrix. Due to the intimate contact of cellulose and chitosan, synergistic effects can be observed during the pyrolysis of the composite fibers. In this study, the catalyti...

The molecular level description of carbohydrate assemblies is hampered by their structural complexity and the lack of suitable analytical methods. Here, we employed systematic chemical modifications to identify key non‐covalent interactions that triggered the supramolecular assembly of a disaccharide model. While some modifications disrupted the su...

The sustainable development of engineering biocomposites has been limited due to a lack of bio‐based monomers combining favorable processing with high performance. Here, the authors report a novel and fully bio‐based transparent wood biocomposite based on green synthesis of a new limonene acrylate monomer from renewable resources. The monomer is im...

A dielectric medium containing noncentrosymmetric domains can exhibit piezoelectric and second-harmonic generation (SHG) responses when an electric field is applied. Since many crystalline biopolymers have noncentrosymmetric structures, there has been a great deal of interest in exploiting their piezoelectric and SHG responses for electromechanical...

Rectangular V-amylose single crystals were prepared by adding racemic ibuprofen to hot dilute aqueous solutions of native and enzymatically-synthesized amylose. The lamellar thickness increased with increasing degree of polymerization of amylose and reached a plateau at about 7 nm, consistent with a chain-folding mechanism. The CP/MAS NMR spectrum...

A new type of polysaccharide (hemicellulose) nanocrystal, bearing the shape of an anisotropic nanoflake, emerged from a dimethyl sulfoxide (DMSO) dispersion of wood-based xylan through heat-induced crystallization. The dimensions of these xylan nanocrystals were controlled by the crystallization conditions. Sharp signals in solid-state NMR indicate...

The cellulose of the green alga Glaucocystis consists of almost pure Iα crystalline phase where the corresponding lattice b* axis parameter lies perpendicular to the cell wall surface in the multilamellar cell wall architecture, indicating that in this wall, cellulose is devoid of longitudinal twist. In contrast, when isolated from Glaucosytis cell...

We recently reported that Viburnum tinus fruit generates its metallic blue color using globular lipid inclusions embedded in its epicarpal cell walls. This protocol describes steps to visualize the lipidic nature of the nanostructure using cryo-ultramicrotomy, chloroform extraction, and transmission electron microscopy (TEM) imaging. This method is...

A carbohydrate-based fullerene derivative (AcMal7-C61) is designed, synthesized and applied to a lamellar-forming high-χ block copolymer system, poly(3-hexylthiophene)-block-peracetylated maltoheptaose (P3HT-b-AcMal7), to actualize an ordered donor/acceptor (D/A) network. A well-defined D/A lamellar structure of the P3HT-b-AcMal7:AcMal7-C61 blend w...

Drying cellulosic materials from their water-swollen state can collapse their ultrastructure and alter their macroscopic material properties such as mechanical strength and water-retention ability. However, at the single-crystal or molecular level, little is known about the deformation of cellulose upon drying. We thus investigate herein the drying...

Hierarchical carbohydrate architectures serve multiple roles in Nature. Hardly any correlations between the carbohydrate chemical structures and the material properties are available due to the lack of standards and suitable analytic techniques. Therefore, designer carbohydrate materials remain highly unexplored, as compared to peptides and nucleic...

Hierarchical carbohydrate architectures serve multiple roles in Nature. Hardly any correlations between the carbohydrate chemical structures and the material properties are available due to the lack of standards and suitable analytic techniques. Therefore, designer carbohydrate materials remain highly unexplored, as compared to peptides and nucleic...

Viburnum tinus is an evergreen shrub that is native to the Mediterranean region but cultivated widely in Europe and around the world. It produces ripe metallic blue fruits throughout winter [1]. Despite its limited fleshy pulp [2], its high lipid content [3] makes it a valuable resource to the small birds [4] that act as its seed-dispersers [5]. He...

Vivid colours found in living organisms are often the result of scattering from hierarchical nanostructures, where the interplay between order and disorder in their packing defines visual appearance. In the case of Flavobacterium IR1, the complex arrangement of the cells in polycrystalline three-dimensional lattices is found to be a distinctive fin...

Pachyrhynchus sarcitis weevils are flightless weevils characterized by colored patches of scales on their dark elytra. The vivid colors of such patches result from the reflection of differently oriented 3D photonic crystals within their scales. The results show that hybrid P. sarcitis, the first filial generation of two P. sarcitis populations from...

Boronate ester cross-linked hydrogels have emerged as promising injectable scaffolds for biomedical applications given their rapid self-healing ability. For a rational design of such networks, all variables influencing their dynamic rheological properties, especially the boronic acid and the diol-containing molecule selected as molecular crosslinke...

Dynamic covalent hydrogels crosslinked by boronate ester bonds are promising materials for biomedical applications. However, little is known about the impact of the crosslink structure on the mechanical behaviour of the resulting network. Herein, we provide a mechanistic study on boronate ester crosslinking upon mixing hyaluronic acid (HA) backbone...

Air-dried samples of 20 hardwood species were saturated with water and subjected to thermal treatment in an autoclave at 200 °C for 2 hours under a saturated vapor pressure (1.6 MPa). Gelatinous layers were observed under optical microscope for Kalopanax septemlobus and Celtis sinensis samples, which were considered to be tension wood. The other 18...

Nanocellulose consisting of crystalline cellulose nanoparticles has a high potential to serve as a building block for bio-based functional materials. The intrinsic chirality of cellulose crystals provides them with high added values such as optical properties and chiral induction ability. At the nanoscale, this chirality is connected to the right-h...

As with many other bio-sourced colloids, chitin nanocrystals (ChNCs) can form liquid crystalline phases with chiral nematic ordering. In this work, we demonstrate that it is possible to finely tune the liquid crystalline behavior of aqueous ChNC suspensions. Such control was made possible by carefully studying how the hydrolysis conditions and susp...

Transmission electron microscopy (TEM) has played a significant role in the characterization of cellulosic materials, especially the so-called “nanocelluloses” (nanofibers and nanocrystals), from visualizing nanoscale morphologies to identifying crystal structures. With scientific and industrial interest in nanocelluloses rapidly increasing, this t...

Following the first electron micrographs of cotton in 1940, the development of transmission electron microscopy applied to native cellulose has been evolving in a series of successive advances. At first, faced with the weak contrast of the early images, the operators had to use specific electron-dense contrasting agents to reveal the ultrastructure...

Blue and near-ultraviolet structural colours have often been reported in understorey plants living in deep shade. While this intense blue coloration is very catchy to the eye of a human observer, there are cases in which structural colours can be hidden either by the scattered light interacting with pigments or because they are found in unexpected...

The hydrogen-bonding network in anhydrous chitosan crystal was studied using a combination of neutron crystallography and quantum chemical calculation. The locations of the hydroxyl hydrogen were directly resolved using Fourier omit maps applied to neutron diffraction data, whereas the amino hydrogen atoms were determined based on geometrical optim...

Mammalian gut microbiota are integral to host health. However, how this association began remains unclear. We show that in basal chordates the gut space is radially compartmentalized into a luminal part where food microbes pass and an almost axenic peripheral part, defined by membranous delamination of the gut epithelium. While this membrane, frame...

The bending of rod-like native cellulose crystals with degree of polymerization 40 and 160 using molecular dynamics simulations resulted in a deformation-induced local amorphization at the kinking point and allomorphic interconversion between cellulose Iα and Iβ in the unbent segments. The transformation mechanism involves a longitudinal chain slip...

• The petals of Eschscholzia californica (California Poppy) are robust, pliable and typically coloured intensely orange or yellow due to the presence of carotenoid pigments; they are also highly reflective at certain angles, producing a silky effect. • To understand the mechanisms behind colour enhancement and reflectivity in California Poppy, whic...

The petals of Eschscholzia californica (California poppy) are robust, pliable and typically coloured intensely orange or yellow owing to the presence of carotenoid pigments; they are also highly reflective at certain angles, producing a silky effect. To understand the mechanisms behind colour enhancement and reflectivity in California poppy, which...

We report the mechanical strength of native chitin nanofibrils. Highly crystalline α-chitin nanofibrils were purified from filaments produced by a microalgae Phaeocystis globosa, and two types of β-chitin nanofibrils were purified from pens of a squid Loligo bleekeri and tubes of a tubeworm Lamellibrachia satsuma, with relatively low and high cryst...

The successive extraction and re-adsorption of a linear β-(1 → 4) xylan extracted from microfibrillated birch pulp was investigated using solid-state CP/MAS 13C NMR spectroscopy, specific surface area measurements, and atomistic molecular dynamics (MD) simulations. The NMR spectra confirmed that when in contact with cellulose after re-adsorption, t...

Six types of CNCs with different sizes were prepared from tunicins by sulfuric acid hydrolysis and subsequent sonication in water. The size distributions of CNCs were comprehensively evaluated by turbidimetry, small angle X-ray scattering, and microscopy to predict their intrinsic viscosities. Experimental intrinsic viscosities [η] of the CNC dispe...

Amylose, a mostly linear homopolymer of α(1,4)‐D‐glucose extracted from native starch, has the ability to form crystalline inclusion compounds with a large variety of small molecules. In these crystallosolvates, the so‐called “V‐amylose” occurs in the form of single helices and the ligands can be located inside the helices, in‐between or both [Lour...

The native polymorphic structures of chitin, namely α- and β-chitin, were studied with X-ray diffraction (XRD), infrared and Raman spectroscopies, and sum-frequency generation (SFG) vibrational spectroscopy. The currently proposed model of α-chitin crystal based on X-ray and electron diffraction study has an antiparallel chain arrangement imposed b...

The deformation behaviour of cellulose nanocrystals under bending loads was investigated by using atomistic molecular dynamics (MD) simulations and finite element analysis (FEA), and compared with electron micrographs of ultrasonicated microfibrils. The linear elastic, non-linear elastic, and plastic deformation regions were observed with increasin...

The ultrastructural transformation of wood cellulose crystals by hydrothermal treatment was followed by synchrotron and standard X-ray scattering experiments. When treated at 200 °C for 2 h in the presence of an excess of water, a significant sharpening of the equatorial reflections of crystalline cellulose was observed, and the average crystallite...

The high-resolution structure of an α-chitin/hydrazine complex has been determined to reveal the molecular interactions between hydrazine molecules and chitin chains. The complexation with guest hydrazine molecules improves the crystallinity of α-chitin from the original form, so that the primary hydroxyl group is clearly located in the gt position...

We determined the crystal structure of anhydrous chitosan at atomic resolution, using X-ray fiber diffraction data extending to 1.17 Å resolution. The unit cell [a = 8.129(7) Å, b = 8.347(6) Å, c = 10.311(7) Å, space group P21 21 21 ] of anhydrous chitosan contains two chains having one glucosamine residue in the asymmetric unit with the primary hy...

Cellulose nanocrystals (CNCs) were produced from eucalyptus wood pulp using three different methods: i) classical sulphuric acid hydrolysis (CN-I), ii) acid hydrolysis of cellulose previously mercerized by alkaline treatment (MCN-II), and iii) solubilization of cellulose in sulphuric acid and subsequent recrystallization in water (RCN-II). The thre...

Alternative hydrogen-bond structures were found for cellulose II and IIII based on molecular dynamics simulations using four force fields and energy optimization based on density functional theory. All the modeling results were in support to the new hydrogen-bonding network. The revised structures of cellulose II and IIII differ with the fiber diff...

We have studied the crystal transition behaviors from hydrated chitosan to anhydrous chitosan by X-ray diffraction analyses. Hydrated chitosan prepared by deacetylation of crustacean α-chitin was subjected to the two conversion methods, hydrothermal treatment and high-humidity treatment via chitosan/monocarboxylic acid complex. The transition by hy...