Enzymatic Synthesis of Oligo(ethylene glycol)-Bearing Cellulose Oligomers for in Situ Formation of Hydrogels with Crystalline Nanoribbon Network Structures

Bottom-Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis

Linear d-glucans are natural polysaccharides of simple chemical structure. They are comprised of d-glucosyl units linked by a single type of glycosidic bond. Noncovalent interactions within, and between, the d-glucan chains give rise to a broad variety of macromolecular nanostructures that can assemble into crystalline-organized materials of tunable morphology. Structure design and functionalization of d-glucans for diverse material applications largely relies on top-down processing and chemical derivatization of naturally derived starting materials. The top-down approach encounters critical limitations in efficiency, selectivity, and flexibility. Bottom-up approaches of d-glucan synthesis offer different, and often more precise, ways of polymer structure control and provide means of functional diversification widely inaccessible to top-down routes of polysaccharide material processing. Here the natural and engineered enzymes (glycosyltransferases, glycoside hydrolases and phosphorylases, glycosynthases) for d-glucan polymerization are described and the use of applied biocatalysis for the bottom-up assembly of specific d-glucan structures is shown. Advanced material applications of the resulting polymeric products are further shown and their important role in the development of sustainable macromolecular materials in a bio-based circular economy is discussed.

Freeze-Dryable, Stable, and Click-Reactive Nanoparticles Composed of Cello-oligosaccharides for Biomolecular Sensing

Nanoparticles have been widely used as platforms for biomolecular sensing because of their high specific surface area and attractive properties depending on their constituents and structures. Nevertheless, it remains challenging to develop nanoparticulate sensing platforms that are easily storable without aggregation and conjugatable with various ligands in a simple manner. Herein, we demonstrate that nanoparticulate assemblies of cello-oligosaccharides with terminal azido groups are promising candidates. Azidated cello-oligosaccharides can be readily synthesized via the enzyme-catalyzed oligomerization reaction. This study characterized the assembled structures of azidated cello-oligosaccharides produced during the enzymatic synthesis and revealed that the terminal azidated cello-oligosaccharides formed rectangular nanosheet-shaped lamellar crystals. The azido groups located on the nanosheet surfaces were successfully exploited for antigen conjugation via the click chemistry. The resultant antigen-conjugated nanosheets allowed for the quantitative and specific detection of a corresponding antibody, even in 10% serum, owing to the antifouling properties of cello-oligosaccharide assemblies against proteins. It was found that the functionalized nanosheets were redispersible in water after freeze-drying. This remarkable characteristic is attributed to the well-hydrated saccharide residues on the nanosheet surfaces. Moreover, the antibody detection capability did not decline after the thermal treatment of the functionalized nanosheets in a freeze-dried state. Our findings contribute to developing convenient nanoparticulate biomolecular sensing platforms.

Interfacial jamming of surface-alkylated synthetic nanocelluloses for structuring liquids

Nanocelluloses derived from natural cellulose sources are promising sustainable nanomaterials. Previous studies have reported that nanocelluloses are strongly adsorbed onto liquid-liquid interfaces with the concurrent use of ligands and allow for the structuring of liquids, that is, the kinetic trapping of nonequilibrium shapes of liquids. However, the structuring of liquids using nanocelluloses alone has yet to be demonstrated, despite its great potential in the development of sustainable liquid-based materials that are biocompatible and environmentally friendly. Herein, we demonstrated the structuring of liquids using rectangular sheet-shaped synthetic nanocelluloses with surface alkyl groups. Synthetic nanocelluloses with ethyl, butyl, and hexyl groups on their surfaces were readily prepared following our previous reports via the self-assembly of enzymatically synthesized cello-oligosaccharides having the corresponding alkyl groups. Among the alkylated synthetic nanocelluloses, the hexylated nanocellulose was adsorbed and jammed at water-n-undecane interfaces to form interfacial assemblies, which acted substantially as an integrated film for structuring liquids. These phenomena were attributed to the unique structural characteristics of the surface-hexylated synthetic nanocelluloses; their sheet shape offered a large area for adsorption onto interfaces, and their controlled surface hydrophilicity/hydrophobicity enhanced the affinity for both liquid phases. Our findings promote the development of all-liquid devices using nanocelluloses.

Surface-mediated self-assembly of click-reactive cello-oligosaccharides for fabricating functional nonwoven fabrics

Polymer fabrics are versatile materials used in various fields. Surface modification methods for hydrophobic polymer fibers have been developed to endow the materials with water wettability and functionality. Nevertheless, it remains a challenge to freely introduce functional groups to polymer fiber surfaces in a simple manner. Herein, we report the decoration of nonwoven fabric surfaces with azidated cello-oligosaccharide assemblies via molecular self-assembly. Cello-oligosaccharides with a terminal azido group were enzymatically synthesized and allowed to self-assemble in polyolefin, polyester, and vinylon nonwoven fabrics. It was found that the functional oligosaccharides formed bark-like assemblies on the nonwoven fiber surfaces, probably through heterogeneous nucleation. The hydrophilic oligosaccharide assemblies made the hydrophobic nonwoven surfaces water-wettable. Moreover, the azido group at oligosaccharide terminal was available for the post-functionalization of the modified nonwovens. In fact, an antigen was successfully conjugated to the modified nonwovens via the click chemistry. The antigen-conjugated nonwovens were useful for the specific and quantitative detection of a corresponding antibody. Our findings demonstrate the great potential of cello-oligosaccharide assembly for the functionalization of fabrics and other polymeric materials.

Distinguishing anti-PEG antibodies by specificity for the PEG terminus using nanoarchitectonics-based antibiofouling cello-oligosaccharide platforms

The conjugation of poly(ethylene glycol) (PEG) to therapeutic proteins or nanoparticles is a widely used pharmaceutical strategy to improve their therapeutic efficacy. However, conjugation can make PEG immunogenic and induce the production of anti-PEG antibodies, which decreases both the therapeutic efficacy after repeated dosing and clinical safety. To address these concerns, it is essential to analyze the binding characteristics of anti-PEG antibodies to PEG. However, distinguishing anti-PEG antibodies is still a difficult task. Herein, we demonstrate the use of antibiofouling cello-oligosaccharide assemblies tethering one-terminal methoxy oligo(ethylene glycol) (OEG) ligands for distinguishing anti-PEG antibodies in a simple manner. The OEG ligand-tethering two-dimensional crystalline cello-oligosaccharide assemblies were stably dispersed in a buffer solution and had antibiofouling properties against nonspecific protein adsorption. These characteristics allowed enzyme-linked immunosorbent assays (ELISAs) to be simply performed by cycles of centrifugation/redispersion of aqueous dispersions of the assemblies. The simple assays revealed that the specific OEG ligand-tethering assemblies could distinguish anti-PEG antibodies to detect a specific antibody that preferentially binds to the methoxy terminus of the PEG chain with 3 repeating ethylene glycol units. Furthermore, quantitative detection of the antibodies was successfully performed with high sensitivity even in the presence of serum. The detectable and quantifiable range of antibody concentrations covered those required clinically. Our findings open a new avenue for analyzing the binding characteristics of anti-PEG antibodies in biological samples.

Antibacterial Synthetic Nanocelluloses Synergizing with a Metal-Chelating Agent

Antibacterial materials composed of biodegradable and biocompatible constituents that are produced via eco-friendly synthetic strategies will become an attractive alternative to antibiotics to combat antibiotic-resistant bacteria. In this study, we demonstrated the antibacterial properties of nanosheet-shaped crystalline assemblies of enzymatically synthesized aminated cellulose oligomers (namely, surface-aminated synthetic nanocelluloses) and their synergy with a metal-chelating antibacterial agent, ethylenediaminetetraacetic acid (EDTA). Growth curves and colony counting assays revealed that the surface-aminated cellulose assemblies had an antibacterial effect against Gram-negative Escherichia coli (E. coli). The cationic assemblies appeared to destabilize the cell wall of E. coli through electrostatic interactions with anionic lipopolysaccharide (LPS) molecules on the outer membrane. The antibacterial properties were significantly enhanced by the concurrent use of EDTA, which potentially removed metal ions from LPS molecules, resulting in synergistic bactericidal effects. No antibacterial activity of the surface-aminated cellulose assemblies was observed against Gram-positive Staphylococcus aureus even in the presence of EDTA, further supporting the contribution of electrostatic interactions between the cationic assemblies and anionic LPS to the activity against Gram-negative bacteria. Analysis using quartz crystal microbalance with dissipation monitoring revealed the attractive interaction of the surface-aminated cellulose assembly with LPS Ra monolayers artificially produced on the device substrate.

Facile preparation of near-monodisperse oligocellulose and its elastomeric derivatives with tunable mechanical properties

Oligocellulose (OC) with low polydispersity indices has been produced in large quantities using an improved method of acid-assisted hydrolysis, in which long cellulose chains disintegrate in concentrated phosphoric acid at moderately elevated temperatures. The hydrolysis time has been reduced by three orders of magnitude without compromising the overall yield of the process or the quality of OC products. The efficient production of high-quality OCs in large quantities allows for developing OC-derived elastomeric materials. A series of OC-graft-poly(isobornyl methacrylate-random-n-butyl acrylate) [OC-g-P(IBOMA-r-BA)] elastomers have been synthesized via activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). OC-g-P(IBOMA-r-BA) elastomers have tunable molecular architectures and phase morphologies toward desirable mechanical properties and thermal stability suitable for various applications. The methodologies of the OC production and the graft-polymers synthesis in this study would help advance technologies for broader applications of bio-based elastomers.

High mechanical property and antibacterial poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/functional enzymatically-synthesized cellulose biodegradable composite

Biodegradable materials with antibacterial properties are highly promising. A novel antimicrobial nanocellulose (ECP) was synthesized in one-step by enzyme-catalyzed method to improve the mechanical and antimicrobial properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)]. The biodegradable nanocomposites were prepared by melt blending and the performance analysis results show that the nanocomposites display enhanced mechanical performances and antibacterial activities. Compared with the neat P(HB-co-HV), the P(HB-co-HV) doped with 0.5 wt%-ECP shows the highest mechanical properties with yield strength/elongation at break of 29.3 MPa, 7.63 %, respectively, an increase of 38 %/59 %, and a clear inhibition zone against Staphylococcus aureus (S. aureus) of approximately 3.0 mm. As a heterogeneous nucleation agent, ECP optimizes nucleation, and the interfacial interaction between phenol group and matrix promotes the compatibility and dispersion of ECP, resulting in superior mechanical properties of ECP-based composites. The P(HB-co-HV)/ECP nanocomposites have great potential in biomedical materials especially for the bone defect filling material.

Recent advances in enzymatic synthesis of β-glucan and cellulose

Bottom-up synthesis of β-glucans such as callose, fungal β-(1,3)(1,6)-glucan and cellulose, can create the defined compounds that are needed to perform fundamental studies on glucan properties and develop applications. With the importance of β-glucans and cellulose in high-profile fields such as nutrition, renewables-based biotechnology and materials science, the enzymatic synthesis of such relevant carbohydrates and their derivatives has attracted much attention. Here we review recent developments in enzymatic synthesis of β-glucans and cellulose, with a focus on progress made over the last five years. We cover the different types of biocatalysts employed, their incorporation in cascades, the exploitation of enzyme promiscuity and their engineering, and reaction conditions affecting the production as well as in situ self-assembly of (non)functionalised glucans. The recent achievements in the application of glycosyl transferases and β-1,4- and β-1,3-glucan phosphorylases demonstrate the high potential and versatility of these biocatalysts in glucan synthesis in both industrial and academic contexts.

Self-assembly of cellulose for creating green materials with tailor-made nanostructures

Inspired by living systems, biomolecules have been employed in vitro as building blocks for creating advanced nanostructured materials. In regard to nucleic acids, peptides, and lipids, their self-assembly pathways and resulting assembled structures are mostly encoded in their molecular structures. On the other hand, outside of its chain length, cellulose, a polysaccharide, lacks structural diversity; therefore, it is challenging to direct this homopolymer to controllably assemble into ordered nanostructures. Nevertheless, the properties of cellulose assemblies are outstanding in terms of their robustness and inertness, and these assemblies are attractive for constructing versatile materials. In this review article, we summarize recent research progress on the self-assembly of cellulose and the applications of assembled cellulose materials, especially for biomedical use. Given that cellulose is the most abundant biopolymer on Earth, gaining control over cellulose assembly represents a promising route for producing green materials with tailor-made nanostructures.

Postsynthesis Self- And Coassembly of Enzymatically Produced Fluorinated Cellodextrins and Cellulose Nanocrystals

The design of new functional materials and devices substantially relies on self-assembly of hierarchical structures. Formation of 2D platelets is known in the enzymatic synthesis of cellulose-like polymers. Here we demonstrate the feasibility of postsynthesis assembly of novel fluorinated cellodextrins. Highly ordered 2D structures of large lateral dimensions, unattainable in the polymerization process, can be formed because of postsynthesis assembly of the cellodextrins. These cellodextrins were also involved in coassembly with cellulose nanocrystals (CNCs) leading to hybrid systems. The hybrid architectures obtained depend on the content of fluorine atoms in the fluorinated cellodextrins. Monofluorinated cellodextrins coassemble with CNCs into a nanoweb, while multifluorinated cellodextrins assemble around the CNCs.

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Control of parallel versus antiparallel molecular arrangements in crystalline assemblies of alkyl β-cellulosides

HYPOTHESIS

The precise control of parallel versus antiparallel molecular arrangements in synthetic assemblies of biorelated molecules is an attractive research focus from both scientific and technological viewpoints. However, little is known about cellulose-based synthetic assemblies. We hypothesized the existence of potential parameters, such as temperature, salt concentration, salt species, and solvent species, for controlling the molecular arrangement in assemblies of alkyl β-cellulosides with different alkyl chain lengths.

EXPERIMENTAL

The self-assembly of alkyl β-cellulosides was triggered by neutralization-induced water insolubilization. The crystal structures of the cellulose moieties in the assemblies were characterized by attenuated total reflection-Fourier transform infrared absorption spectroscopy and wide-angle X-ray diffraction measurements. The morphologies of the assemblies were also characterized by scanning electron, atomic force, and transmission electron microscopy.

FINDINGS

The temperature for the self-assembly, the concentration and species of inorganic salt in the self-assembly solution, and the solvent species (namely, the addition of water-miscible organic solvents into the self-assembly solution) strongly affected the molecular arrangement of the assemblies. The observations suggested that hydrophobic effects between the alkyl groups of the alkyl β-cellulosides and/or interactions of the alkyl β-cellulosides with solvent species were potential factors for controlling the molecular arrangement.

Chemoenzymatic Synthesis of Fluorinated Cellodextrins Identifies a New Allomorph for Cellulose-Like Materials*

Understanding the fine details of the self-assembly of building blocks into complex hierarchical structures represents a major challenge en route to the design and preparation of soft-matter materials with specific properties. Enzymatically synthesised cellodextrins are known to have limited water solubility beyond DP9, a point at which they self-assemble into particles resembling the antiparallel cellulose II crystalline packing. We have prepared and characterised a series of site-selectively fluorinated cellodextrins with different degrees of fluorination and substitution patterns by chemoenzymatic synthesis. Bearing in mind the potential disruption of the hydrogen-bond network of cellulose II, we have prepared and characterised a multiply 6-fluorinated cellodextrin. In addition, a series of single site-selectively fluorinated cellodextrins was synthesised to assess the structural impact upon the addition of one fluorine atom per chain. The structural characterisation of these materials at different length scales, combining advanced NMR spectroscopy and microscopy methods, showed that a 6-fluorinated donor substrate yielded multiply 6-fluorinated cellodextrin chains that assembled into particles presenting morphological and crystallinity features, and intermolecular interactions, that are unprecedented for cellulose-like materials.

Phosphorylase-catalyzed bottom-up synthesis of short-chain soluble cello-oligosaccharides and property-tunable cellulosic materials

Cellulose-based materials are produced industrially in countless varieties via top-down processing of natural lignocellulose substrates. By contrast, cellulosic materials are only rarely prepared via bottom up synthesis and oligomerization-induced self-assembly of cellulose chains. Building up a cellulose chain via precision polymerization is promising, however, for it offers tunability and control of the final chemical structure. Synthetic cellulose derivatives with programmable material properties might thus be obtained. Cellodextrin phosphorylase (CdP; EC 2.4.1.49) catalyzes iterative β-1,4-glycosylation from α-d-glucose 1-phosphate, with the ability to elongate a diversity of acceptor substrates, including cellobiose, d-glucose and a range of synthetic glycosides having non-sugar aglycons. Depending on the reaction conditions leading to different degrees of polymerization (DP), short-chain soluble cello-oligosaccharides (COS) or insoluble cellulosic materials are formed. Here, we review the characteristics of CdP as bio-catalyst for synthetic applications and show advances in the enzymatic production of COS and reducing end-modified, tailored cellulose materials. Recent studies reveal COS as interesting dietary fibers that could provide a selective prebiotic effect. The bottom-up synthesized celluloses involve chains of DP ≥ 9, as precipitated in solution, and they form ~5 nm thick sheet-like crystalline structures of cellulose allomorph II. Solvent conditions and aglycon structures can direct the cellulose chain self-assembly towards a range of material architectures, including hierarchically organized networks of nanoribbons, or nanorods as well as distorted nanosheets. Composite materials are also formed. The resulting materials can be useful as property-tunable hydrogels and feature site-specific introduction of functional and chemically reactive groups. Therefore, COS and cellulose obtained via bottom-up synthesis can expand cellulose applications towards product classes that are difficult to access via top-down processing of natural materials.

Neutralization-Induced Self-Assembly of Cellulose Oligomers into Antibiofouling Crystalline Nanoribbon Networks in Complex Mixtures

Molecular self-assembly in solutions is a powerful strategy for fabricating functional architectures. Various bio(macro)molecules have been used as self-assembly components. However, structural polysaccharides, such as cellulose and chitin, have rarely been a research focus for molecular self-assembly, even though their crystalline assemblies potentially have robust physicochemical properties. Herein, we demonstrated the neutralization-induced self-assembly of cellulose oligomers into antibiofouling crystalline nanoribbon networks to produce physically cross-linked hydrogels. The self-assembly proceeded even in versatile complex mixtures, such as serum-containing cell culture media, in a controlled manner for 3D cell culture. The cultured cells grew into cell aggregates (spheroids), which were simply collected through natural filtration due to the mechanically crushable property of the crystalline nanoribbons through water flow by pipetting. We will show the potential of cellulose oligomers for biocompatible, crystalline soft materials.

Biocatalytic oligomerization-induced self-assembly of crystalline cellulose oligomers into nanoribbon networks assisted by organic solvents

Crystalline poly- and oligosaccharides such as cellulose can form extremely robust assemblies, whereas the construction of self-assembled materials from such molecules is generally difficult due to their complicated chemical synthesis and low solubility in solvents. Enzyme-catalyzed oligomerization-induced self-assembly has been shown to be promising for creating nanoarchitectured crystalline oligosaccharide materials. However, the controlled self-assembly into organized hierarchical structures based on a simple method is still challenging. Herein, we demonstrate that the use of organic solvents as small-molecule additives allows for control of the oligomerization-induced self-assembly of cellulose oligomers into hierarchical nanoribbon network structures. In this study, we dealt with the cellodextrin phosphorylase-catalyzed oligomerization of phosphorylated glucose monomers from ᴅ-glucose primers, which produce precipitates of nanosheet-shaped crystals in aqueous solution. The addition of appropriate organic solvents to the oligomerization system was found to result in well-grown nanoribbon networks. The organic solvents appeared to prevent irregular aggregation and subsequent precipitation of the nanosheets via solvation for further growth into the well-grown higher-order structures. This finding indicates that small-molecule additives provide control over the self-assembly of crystalline oligosaccharides for the creation of hierarchically structured materials with high robustness in a simple manner.

Mechanically robust crystalline monolayer assemblies of oligosaccharide-based amphiphiles on water surfaces

Cellulose oligomers with a terminal alkyl group at the reducing end formed mechanically robust crystalline monolayers via self-assembly against water surfaces from aqueous solutions in air.

Unravelling the Specificity of Laminaribiose Phosphorylase from Paenibacillus sp. YM-1 towards Donor Substrates Glucose/Mannose 1-Phosphate by Using X-ray Crystallography and Saturation Transfer Difference NMR Spectroscopy

Glycoside phosphorylases (GPs) carry out a reversible phosphorolysis of carbohydrates into oligosaccharide acceptors and the corresponding sugar 1-phosphates. The reversibility of the reaction enables the use of GPs as biocatalysts for carbohydrate synthesis. Glycosyl hydrolase family 94 (GH94), which only comprises GPs, is one of the most studied GP families that have been used as biocatalysts for carbohydrate synthesis, in academic research and in industrial production. Understanding the mechanism of GH94 enzymes is a crucial step towards enzyme engineering to improve and expand the applications of these enzymes in synthesis. In this work with a GH94 laminaribiose phosphorylase from Paenibacillus sp. YM-1 (PsLBP), we have demonstrated an enzymatic synthesis of disaccharide 1 (β-d-mannopyranosyl-(1→3)-d-glucopyranose) by using a natural acceptor glucose and noncognate donor substrate α-mannose 1-phosphate (Man1P). To investigate how the enzyme recognises different sugar 1-phosphates, the X-ray crystal structures of PsLBP in complex with Glc1P and Man1P have been solved, providing the first molecular detail of the recognition of a noncognate donor substrate by GPs, which revealed the importance of hydrogen bonding between the active site residues and hydroxy groups at C2, C4, and C6 of sugar 1-phosphates. Furthermore, we used saturation transfer difference NMR spectroscopy to support crystallographic studies on the sugar 1-phosphates, as well as to provide further insights into the PsLBP recognition of the acceptors and disaccharide products.

Self-Assembly of Cellulose Oligomers into Nanoribbon Network Structures Based on Kinetic Control of Enzymatic Oligomerization

The ability to chemically synthesize desired molecules followed by their in situ self-assembly in reaction solution has attracted much attention as a simple and environmentally friendly method to produce self-assembled nanostructures. In this study, α-d-glucose 1-phosphate monomers and cellobiose primers were subjected to cellodextrin phosphorylase-catalyzed reverse phosphorolysis reactions in aqueous solution in order to synthesize cellulose oligomers, which were then in situ self-assembled into crystalline nanoribbon network structures. The average degree-of-polymerization (DP) values of the cellulose oligomers were estimated to be approximately 7-8 with a certain degree of DP distribution. The cellulose oligomers crystallized with the cellulose II allomorph appeared to align perpendicularly to the base plane of the nanoribbons in an antiparallel manner. Detailed analyses of reaction time dependence suggested that the production of nanoribbon network structures was kinetically controlled by the amount of water-insoluble cellulose oligomers produced.

Enzymatic Synthesis of Cellulose Oligomer Hydrogels Composed of Crystalline Nanoribbon Networks under Macromolecular Crowding Conditions

Macromolecular crowding, a solution state with high macromolecular concentrations, was used to promote the crystallization-driven self-assembly of enzymatically synthesized cellulose oligomers. Cellulose oligomers were synthesized via cellodextrin phosphorylase-catalyzed enzymatic reactions in the concentrated solutions of water-soluble polymers, such as dextran, poly(ethylene glycol), and poly(N-vinylpyrrolidone). The reaction mixtures were transformed into cellulose oligomer hydrogels composed of well-grown crystalline nanoribbon networks irrespective of the polymer species. This method was successfully applied in the one-pot preparation of double network hydrogels composed of the nanoribbons and physically cross-linked gelatin molecules through the simple control of reaction temperatures, demonstrating the superior mechanical properties of the composite hydrogels. Our concept that promotes the growth of self-assembled architectures under macromolecular crowding conditions demonstrates a new avenue into developing novel hydrogel materials.

Multidimensional Self-Assembled Structures of Alkylated Cellulose Oligomers Synthesized via in Vitro Enzymatic Reactions

The self-assembly of biomolecules into highly ordered nano-to-macroscale structures is essential in the construction of biological tissues and organs. A variety of biomolecular assemblies composed of nucleic acids, peptides, and lipids have been used as molecular building units for self-assembled materials. However, crystalline polysaccharides have rarely been utilized in self-assembled materials. In this study, we describe multidimensional self-assembled structures of alkylated cellulose oligomers synthesized via in vitro enzymatic reactions. We found that the alkyl chain length drastically affected the assembled morphologies and allomorphs of cellulose moieties. The modulation of the intermolecular interactions of cellulose oligomers by alkyl substituents was highly effective at controlling their assembly into multidimensional structures. This study proposes a new potential of crystalline oligosaccharides for structural components of molecular assemblies with controlled morphologies and crystal structures.