Plant Nanomaterials and Inspiration from Nature: Water Interactions and Hierarchically Structured Hydrogels

Yeast-Raised Polyamidoxime Hydrogel Prepared by Ice Crystal Dispersion for Efficient Uranium Extraction from Seawater

Uranium extraction from seawater has attracted worldwide attention due to the massive reserves of uranium. Due to the straightforward synthesis and strong affinity toward uranyl ions (UO2 2+), the amidoxime group shows promise for use in highly efficient uranium capture.  However, the low mass transfer efficiency within traditional amidoxime-based adsorbents severely limits the adsorption rate and the utilization of adsorption sites. In this work, a macroporous polyamidoxime (PAO) hydrogel is prepared by yeast-based biological foaming combined with ice crystal dispersion that effectively maintained the yeast activity. The yeast-raised PAO (Y-PAO) adsorbent has numerous bubble-like holes with an average pore diameter >100 µm. These macropores connected with the intrinsic micropores of PAO to construct efficient diffusion channels for UO2 2+ provided fast mass transporting channels, leading to the sufficient exposure of hidden binding sites. The maximum adsorption capacity of Y-PAO membrane reached 10.07 mg-U/g-ads, ≈1.54 times higher than that of the control sample. It took only eight days for Y-PAO to reach the saturation adsorption capacity of the control PAO (6.47 mg-U/g-ads, 28 days). Meanwhile, Y-PAO possessed excellent ion selectivity, good reusability, and low cost. Overall, the Y-PAO membrane is a highly promising adsorbent for use in industrial-scale uranium extraction from seawater.

Ln-MOF-Based Hydrogel Films with Tunable Luminescence and Afterglow Behavior for Visual Detection of Ofloxacin and Anti-Counterfeiting Applications

Highly selective and sensitive quantitative detection of ofloxacin (OFX) at ultralow concentrations in aqueous media and development of new afterglow materials remains a challenge. Herein, a new 2D water-stable lanthanide metal-organic framework (NIIC-2-Tb) is proposed, which exhibits high selectivity towards OFX through the luminescence quenching with the lowest detection limit (1.1 × 10-9 M) reported to date and a fast response within 6 s. In addition, the luminescent detection of OFX by NIIC-2-Tb is not affected by typical components of blood plasma and urine. The excellent sensing effect of NIIC-2-Tb is further utilized to prepare a composite functional sensing carrageenan hydrogel material for the rapid detection of OFX in meat in real time and the first discovery of impressive afterglow in MOF-based hydrogels. This study not only presents novel Ln-MOF materials and Ln-MOF-based hydrogel films for luminescent sensing of OFX, but also demonstrates color-tunable luminescent films with afterglow, which expands the application of composite luminescent materials for detection and anti-counterfeiting.

Silica nanoparticles as a waste product to alleviate the harmful effects of water stress in wheat

Drought is a threat to food security and agricultural sustainability in arid and semi-arid countries. Using wasted silica nanoparticles could minimize water scarcity. A controlled study investigated wheat plant physiological and morphological growth under tap-water irrigation (80-100, 60-80, and 40-60% field capacity). The benefits of S1: 0%, S2: 5%, and S3: 10% nanoparticle silica soil additions were studied. Our research reveals that water stress damages the physiological and functional growth of wheat plants. Plant height decreased by 8.9%, grain yield by 5.4%, and biological yield by 19.2%. These effects were observed when plants were irrigated to 40-60% field capacity vs. control. In plants under substantial water stress (40-60% of field capacity), chlorophyll a (8.04 mg g-1), b (1.5 mg g-1), total chlorophyll (9.55 mg g-1), carotenoids (2.44 mg g-1), and relative water content (54%), Electrolyte leakage (59%), total soluble sugar (1.79 mg g-1 fw), and proline (80.3 mol g-1) were highest. Plants cultivated with silica nanoparticles exhibit better morphological and physiological growth than controls. The largest effect came from maximum silica nanoparticle loading. Silica nanoparticles may increase drought-stressed plant growth and production.

Benchmarking the Humidity-Dependent Mechanical Response of (Nano)fibrillated Cellulose and Dissolved Polysaccharides as Sustainable Sand Amendments

Soil quality is one of the main limiting factor in the development of the food sector in arid areas, mainly due to its poor mechanics and lack of water retention. Soil's organic carbon is nearly absent in arid soils, though it is important for water and nutrient transport, to soil mechanics, to prevent erosion, and as a long-term carbon sink. In this study, we evaluate the potential benefits that are brought to inert sand by the incorporation of a range of, mainly, cellulosic networks in their polymeric or structured (fiber) forms, analogously to those found in healthy soils. We explore the impact of a wide range of nonfood polysaccharide-based amendments, including pulp fibers, nanocellulose, cellulose derivatives, and other readily available polysaccharide structures derived from arthropods (chitosan) or fruit peels (pectin) residues. A practical methodology is presented to form sand-polymer composites, which are evaluated for their soil mechanics as a function of humidity and the dynamics of their response to water. The mechanics are correlated to the network of polymers formed within the pores of the sandy soil, as observed by electron microscopy. The response to water is correlated to both the features of the network and the individual polysaccharides' physicochemical features. We expect this work to provide a rapid and reproducible methodology to benchmark sustainable organic amendments for arid soils.

Optimization of Water Based Drilling Fluid Properties with the SiO2/g-C3N4 Hybrid

Drilling fluids are an essential component of drilling operations in the oil and gas industry. Nanotechnology is being used to develop advanced drilling fluid additives. This study looked at the viability of synthesizing SiO2/g-C3N4 hybrid extending the Stober process followed by its addition in different concentrations to water-based drilling fluids and studying impact on the rheological and fluid loss properties of the fluids. The synthesized hybrid was analyzed using XRD, SEM, TGA, and FTIR. Subsequently, it was used to develop the water-based drilling mud formulations and subjected to measurements in accordance with API standard practices. The studies were carried out at various SiO2/g-C3N4 nanoparticle concentrations under before hot rolling (BHR) and after hot rolling (AHR) conditions. The outcomes demonstrated that the rheological and fluid loss properties were enhanced by the addition of SiO2/g-C3N4 nanoparticles, as it worked in synergy with other additives. Additionally, it was discovered that the nanoparticles improved the drilling fluid thermal stability. The experimental findings indicate a significant influence of SiO2/g-C3N4 nanoparticles on base fluid properties including rheology and fluid loss as the most remarkable, especially at higher temperatures. The significant improvements in yield point and 10 s gel strength were 55 and 42.8% under BHR and 216 and 140% under AHR conditions, respectively. Permeability plugging test (PPT) fluid loss was reduced by 69.6 and 87.2% under BHR and AHR conditions, respectively, when 0.5 lb/bbl nanoparticles were used in formulations. As a result, SiO2/g-C3N4 nanomaterial has the potential to be used as drilling fluid additive in water-based drilling fluids.

3D-Printed Inherently Antibacterial Contact Lens-Like Patches Carrying Antimicrobial Peptide Payload for Treating Bacterial Keratitis

Delivery of therapeutic agents through contact lenses-like patches is a promising strategy to achieve significant bioavailability with negligible eye drainage. The present study investigates the preparation and 3D printing of mucoadhesive gelatin methacryloyl (GelMA)/chitosan methacryloyl (ChiMA) hydrogels to fabricate them as contact lens-like patches (CLP) loaded with antimicrobial peptide, S100A12 (AMP) for treating bacterial keratitis (BK). Extrusion technology is used to print the patches layer by layer to form a hemispherical scaffold suitable for eyewear, and 3D-printed CLP is crosslinked using Irgacure 2959 under UV light. The results from the in vivo experiment conducted on Pseudomonas aeruginosa-infected BK rabbit model after the treatment with AMP-loaded CLP have shown a significant decrease in bacterial load when plated for CFU. The newly developed delivery system containing AMP has great potential to overcome the treatment challenges of multidrug resistance (MDR) in bacteria and eliminate the frequent dosing associated with eye drops. The presence of chitosan in the formulation provides a synergetic effect on the AMP in disrupting bacterial biofilms. The ease of using 3D printing will open new avenues for optimizing the dosage depending on the severity of the BK in the patients, which can be used as personalized medicine.

From Nature-Sourced Polysaccharide Particles to Advanced Functional Materials

Polysaccharides constitute over 90% of the carbohydrate mass in nature, which makes them a promising feedstock for manufacturing sustainable materials. Polysaccharide particles (PSPs) are used as effective scavengers, carriers of chemical and biological cargos, and building blocks for the fabrication of macroscopic materials. The biocompatibility and degradability of PSPs are advantageous for their uses as biomaterials with more environmental friendliness. This review highlights the progresses in PSP applications as advanced functional materials, by describing PSP extraction, preparation, and surface functionalization with a variety of functional groups, polymers, nanoparticles, and biologically active species. This review also outlines the fabrication of PSP-derived macroscopic materials, as well as their applications in soft robotics, sensing, scavenging, water harvesting, drug delivery, and bioengineering. The paper is concluded with an outlook providing perspectives in the development and applications of PSP-derived materials.

Ionic Conductive Cellulose-Based Hydrogels with Superior Long-Lasting Moisture and Antifreezing Features for Flexible Strain Sensor Applications

Nowadays, wearable devices derived from flexible conductive hydrogels have attracted enormous attention. Nevertheless, the utilization of conductive hydrogels in practical applications under extreme conditions remains a significant challenge. Herein, a series of inorganic salt-ion-enhanced conductive hydrogels (HPE-LiCl) consisting of hydroxyethyl cellulose, hydroxyethyl acrylate, lithium chloride, and ethylene glycol/water binary solvent were fabricated via a facile one-pot method. Apart from outstanding self-adhesion, high stretchability, and remarkable fatigue resistance, the HPE-LiCl hydrogels possessed especially excellent antifreezing and long-lasting moisture performances, which could maintain satisfactory flexibility and electric conductivity over extended periods of time, even in challenging conditions such as extremely low temperatures (as low as -40 °C) and high temperatures (as high as 80 °C). Consequently, the HPE-LiCl-based sensor could timely and accurately monitor various human motion signals even in adverse environments and after long-term storage. Hence, this work presents a facile strategy for the design of long-term reliable hydrogels as smart strain sensors, especially used in extreme environments.

Recent advances in photo-crosslinkable methacrylated silk (Sil-MA)-based scaffolds for regenerative medicine: A review

Silks fibroin can be chemically modified through amino acid side chains to obtain methacrylated silk (Sil-MA). Sil-MA could be processed into a variety of scaffold forms and combine synergistically with other biomaterials to form composites vehicle. The advent of Sil-MA material has enabled impressive progress in the development of various scaffolds based on Sil-MA type to imitate the structural and functional characteristics of natural tissues. This review highlights the reasonable design and bio-fabrication strategies of diverse Sil-MA-based tissue constructs for regenerative medicine. First, we elucidate modification methodology and characteristics of Sil-MA. Next, we describe characteristics of Sil-MA hydrogels, and focus on the design approaches and formation of different types of Sil-MA-based hydrogels. Thereafter, we present an overview of the recent advances in the application of Sil-MA based scaffolds for regenerative medicine, including detailed strategies for the engineering methods and materials used. Finally, we summarize the current research progress and future directions of Sil-MA in regenerative medicine. This review not only delineates the representative design strategies and their application in regenerative medicine, but also provides new direction in the fabrication of biomaterial constructs for the clinical translation in order to stimulate the future development of implants.

Lignin Modification for Enhanced Performance of Polymer Composites

The biopolymer lignin, which is heterogeneous and abundant, is usually present in plant cell walls and gives them rigidity and strength. As a byproduct of the wood, paper, and pulp manufacturing industry, lignin ranks as the second most prevalent biopolymer worldwide, following cellulose. This review paper explores the extraction, modification, and prospective applications of lignin in various industries, including the enhancement of thermosetting and thermoplastic polymers, biomedical applications such as vanillin production, fuel development, carbon fiber composites, and the creation of nanomaterials for food packaging and drug delivery. The structural characteristics of lignin remain undefined due to its origin, separation, and fragmentation processes. This comprehensive overview encompasses state-of-the-art techniques, potential applications, diverse extraction methods, chemical modifications, carbon fiber utilization, and the extraction of vanillin. Moreover, the review focuses on the utilization of lignin-modified polymer blends across multiple manufacturing sectors, providing insights into the advantages and limitations of this innovative approach for the development of environmentally friendly materials.

Metal-organic gels: recent advances in their classification, characterization, and application in the pharmaceutical field

Metal-organic gels (MOGs) are a type of functional soft substance with a three-dimensional (3D) network structure and solid-like rheological behavior, which are constructed by metal ions and bridging ligands formed under the driving force of coordination interactions or other non-covalent interactions. As the homologous substances of metal-organic frameworks (MOFs) and gels, they exhibit the potential advantages of high porosity, flexible structure, and adjustable mechanical properties, causing them to attract extensive research interest in the pharmaceutical field. For instance, MOGs are often used as excellent vehicles for intelligent drug delivery and programmable drug release to improve the clinical curative effect with reduced side effects. Also, MOGs are often applied as advanced biomedical materials for the repair and treatment of pathological tissue and sensitive detection of drugs or other molecules. However, despite the vigorous research on MOGs in recent years, there is no systematic summary of their applications in the pharmaceutical field to date. The present review systematically summarize the recent research progress on MOGs in the pharmaceutical field, including drug delivery systems, drug detection, pharmaceutical materials, and disease therapies. In addition, the formation principles and classification of MOGs are complemented and refined, and the techniques for the characterization of the structures/properties of MOGs are overviewed in this review.

Nanocellulose-based porous materials: Regulation and pathway to commercialization in regenerative medicine

We review the recent progress that have led to the development of porous materials based on cellulose nanostructures found in plants and other resources. In light of the properties that emerge from the chemistry, shape and structural control, we discuss some of the most promising uses of a plant-based material, nanocellulose, in regenerative medicine. Following a brief discussion about the fundamental aspects of self-assembly of nanocellulose precursors, we review the key strategies needed for material synthesis and to adjust the architecture of the materials (using three-dimensional printing, freeze-casted porous materials, and electrospinning) according to their uses in tissue engineering, artificial organs, controlled drug delivery and wound healing systems, among others. For this purpose, we map the structure-property-function relationships of nanocellulose-based porous materials and examine the course of actions that are required to translate innovation from the laboratory to industry. Such efforts require attention to regulatory aspects and market pull. Finally, the key challenges and opportunities in this nascent field are critically reviewed.

Graft onto approaches for nanocellulose-based advanced functional materials

The resurgence of cellulose as nano-dimensional 'nanocellulose' has unlocked a sustainable bioeconomy for the development of advanced functional biomaterials. Bestowed with multifunctional attributes, such as renewability and abundance of its source, biodegradability, biocompatibility, superior mechanical, optical, and rheological properties, tunable self-assembly and surface chemistry, nanocellulose presents exclusive opportunities for a wide range of novel applications. However, to alleviate its intrinsic hydrophilicity-related constraints surface functionalization is inevitably needed to foster various targeted applications. The abundant surface hydroxyl groups on nanocellulose offer opportunities for grafting small molecules or macromolecular entities using either a 'graft onto' or 'graft from' approach, resulting in materials with distinctive functionalities. Most of the reviews published to date extensively discussed 'graft from' modification approaches, however 'graft onto' approaches are not well discussed. Hence, this review aims to provide a comprehensive summary of 'graft onto' approaches. Furthermore, insight into some of the recently emerging applications of this grafted nanocellulose including advanced nanocomposite formulation, stimuli-responsive materials, bioimaging, sensing, biomedicine, packaging, and wastewater treatment has also been reviewed.

A study across scales to unveil microstructural regimes in the multivalent metal driven self-assembly of cellulose nanocrystals

Understanding the behaviour of self-assembled systems, from nanoscale building blocks to bulk materials, is a central theme for the rational design of high-performance materials. Herein, we revealed, at different length scales, how the self-assembly of TEMPO-oxidised cellulose nanocrystals (TOCNCs) into rod fractal gels is directed by the complexation of Fe3+ ions on the surface of colloidal particles. Different specificities in Fe3+ binding on the TOCNC surface and conformational changes of the nanocellulose chain were unveiled by paramagnetic NMR spectroscopy. The macroscopic properties of systems presenting different concentrations of TOCNCs and Fe3+ ions were investigated by rheology and microscopy, demonstrating the tunability of the self-assembly of cellulose nanorods driven by Fe3+ complexation. Near-atomistic coarse-grained molecular dynamics simulations were developed to gain microscopic insight into the behaviour of this colloidal system. We found that the formation of different self-assembled architectures is driven by metal-nanocellulose complexation combined with the attenuation of electrostatic repulsion and water structuration around cellulose, leading to different microstructural regimes, from isolated nanorods to disconnected rod fractal clusters and rod fractal gels. These findings lay the foundation to unlock the full potential of cellulose nanocrystals as sustainable building blocks to develop self-assembled materials with defined structural control for a range of advanced applications.

Accelerating Cellulose Nanocrystal Assembly into Chiral Nanostructures

Cellulose nanocrystal (CNC) suspensions self-assembled into chiral nematic liquid crystals. This property has enabled the development of versatile optical materials with fascinating properties. Nevertheless, the scale-up production and commercial success of chiral nematic CNC superstructures face significant challenges. Fabrication of chiral nematic CNC nanostructures suffers from a ubiquitous pernicious trade-off between uniform chiral nematic structure and rapid self-assembly. Specifically, the chiral nematic assembly of CNCs is a time-consuming, spontaneous process that involves the organization of particles into ordered nanostructures as the solvent evaporates. This review is driven by the interest in accelerating chiral nematic CNC assembly and promoting a long-range oriented chiral nematic CNC superstructure. To start this review, the chirality origins of CNC and CNC aggregates are analyzed. This is followed by a summary of the recent advances in stimuli-accelerated chiral nematic CNC self-assembly procedures, including evaporation-induced self-assembly, continuous coating, vacuum-assisted self-assembly, and shear-induced CNC assembly under confinement. In particular, stimuli-induced unwinding, alignment, and relaxation of chiral nematic structures were highlighted, offering a significant link between the accelerated assembly approaches and uniform chiral nematic nanostructures. Ultimately, future opportunities and challenges for rapid chiral nematic CNC assembly are discussed for more innovative and exciting applications.

Polysaccharides and Structural Proteins as Components in Three-Dimensional Scaffolds for Breast Cancer Tissue Models: A Review

Breast cancer is the most common cancer among women, and even though treatments are available, efficiency varies with the patients. In vitro 2D models are commonly used to develop new treatments. However, 2D models overestimate drug efficiency, which increases the failure rate in later phase III clinical trials. New model systems that allow extensive and efficient drug screening are thus required. Three-dimensional printed hydrogels containing active components for cancer cell growth are interesting candidates for the preparation of next generation cancer cell models. Macromolecules, obtained from marine- and land-based resources, can form biopolymers (polysaccharides such as alginate, chitosan, hyaluronic acid, and cellulose) and bioactive components (structural proteins such as collagen, gelatin, and silk fibroin) in hydrogels with adequate physical properties in terms of porosity, rheology, and mechanical strength. Hence, in this study attention is given to biofabrication methods and to the modification with biological macromolecules to become bioactive and, thus, optimize 3D printed structures that better mimic the cancer cell microenvironment. Ink formulations combining polysaccharides for tuning the mechanical properties and bioactive polymers for controlling cell adhesion is key to optimizing the growth of the cancer cells.

Understanding Nanocellulose-Water Interactions: Turning a Detriment into an Asset

Modern technology has enabled the isolation of nanocellulose from plant-based fibers, and the current trend focuses on utilizing nanocellulose in a broad range of sustainable materials applications. Water is generally seen as a detrimental component when in contact with nanocellulose-based materials, just like it is harmful for traditional cellulosic materials such as paper or cardboard. However, water is an integral component in plants, and many applications of nanocellulose already accept the presence of water or make use of it. This review gives a comprehensive account of nanocellulose-water interactions and their repercussions in all key areas of contemporary research: fundamental physical chemistry, chemical modification of nanocellulose, materials applications, and analytical methods to map the water interactions and the effect of water on a nanocellulose matrix.

Biomimetic Design of Double-Sided Functionalized Silver Nanoparticle/Bacterial Cellulose/Hydroxyapatite Hydrogel Mesh for Temporary Cranioplasty

A structurally stable and antibacterial biomaterial used for temporary cranioplasty with guided bone regeneration (GBR) effects is an urgent clinical requirement. Herein, we reported the design of a biomimetic Ag/bacterial cellulose/hydroxyapatite (Ag/BC@HAp) hydrogel mesh with a double-sided functionalized structure, in which one layer was dense and covered with Ag nanoparticles and the other layer was porous and anchored with hydroxyapatite (HAp) via mineralization for different durations. Such a double-sided functionalized design endowed the hydrogel with distinguished antibacterial activities for inhibiting potential infections and GBR effects that could prevent endothelial cells and fibroblasts from migrating to a defected area and meanwhile show biocompatibility to MC3T3-E1 preosteoblasts. Furthermore, it was found from in vivo experimental results that the Ag/BC@HAp hydrogel with 7-day mineralization achieved optimal GBR effects by improving barrier functions toward these undesired cells. Moreover, this BC-based hydrogel mesh showed an extremely low swelling ratio and strong mechanical strength, which facilitated the protection of soft brain tissues without gaining the risk of intracranial pressure increase. In a word, this study offers a new approach to double-sided functionalized hydrogels and provides effective and safe biomaterials used for temporary cranioplasty with antibacterial abilities and GBR effects.

Lignin-Based Materials for Additive Manufacturing: Chemistry, Processing, Structures, Properties, and Applications

The utilization of lignin, the most abundant aromatic biomass component, is at the forefront of sustainable engineering, energy, and environment research, where its abundance and low-cost features enable widespread application. Constructing lignin into material parts with controlled and desired macro- and microstructures and properties via additive manufacturing has been recognized as a promising technology and paves the way to the practical application of lignin. Considering the rapid development and significant progress recently achieved in this field, a comprehensive and critical review and outlook on three-dimensional (3D) printing of lignin is highly desirable. This article fulfils this demand with an overview on the structure of lignin and presents the state-of-the-art of 3D printing of pristine lignin and lignin-based composites, and highlights the key challenges. It is attempted to deliver better fundamental understanding of the impacts of morphology, microstructure, physical, chemical, and biological modifications, and composition/hybrids on the rheological behavior of lignin/polymer blends, as well as, on the mechanical, physical, and chemical performance of the 3D printed lignin-based materials. The main points toward future developments involve hybrid manufacturing, in situ polymerization, and surface tension or energy driven molecular segregation are also elaborated and discussed to promote the high-value utilization of lignin.

Spatioselective surface chemistry for the production of functional and chemically anisotropic nanocellulose colloids

Maximizing the benefits of nanomaterials from biomass requires unique considerations associated with their native chemical and physical structure. Both cellulose nanofibrils and nanocrystals are extracted from cellulose fibers via a top-down approach and have significantly advanced materials chemistry and set new benchmarks in the last decade. One major challenge has been to prepare defined and selectively modified nanocelluloses, which would, e.g., allow optimal particle interactions and thereby further improve the properties of processed materials. At the molecular and crystallite level, the surface of nanocelluloses offers an alternating chemical structure and functional groups of different reactivity, enabling straightforward avenues towards chemically anisotropic and molecularly patterned nanoparticles via spatioselective chemical modification. In this review, we will explain the influence and role of the multiscale hierarchy of cellulose fibers in chemical modifications, and critically discuss recent advances in selective surface chemistry of nanocelluloses. Finally, we will demonstrate the potential of those chemically anisotropic nanocelluloses in materials science and discuss challenges and opportunities in this field.

Naturally Derived Janus Cellulose Nanomaterials: Anisotropic Cellulose Nanomaterial Building Blocks and Their Assembly into Asymmetric Structures

Naturally derived cellulose nanomaterials (CNMs) with desirable physicochemical properties have drawn tremendous attention for their versatile applications in a broad range of fields. More recently, Janus amphiphilic cellulose nanomaterial particles with asymmetric structures (i.e., reducing and nonreducing ends and crystalline and amorphous domains) have been in the spotlight, offering a rich and sophisticated toolbox for Janus nanomaterials. With careful surface and interfacial engineering, Janus CNM particles have demonstrated great potential as surface modifiers, emulsifiers, stabilizers, compatibilizers, and dispersants in emulsions, nanocomposites, and suspensions. Naturally derived Janus CNM particles offer a fascinating opportunity for scaling up the production of self-standing Janus CNM membranes. Nevertheless, most Janus CNM membranes to date are constructed by asymmetric fabrication or asymmetric modification without considering the Janus traits of CNM particles. More future research should focus on the self-assembly of Janus CNM particles into bulk self-standing Janus CNM membranes to enable more straightforward and sustainable approaches for Janus membranes. This review explores the fabrication, structure-property relationship, and Janus configuration mechanisms of Janus CNM particles and membranes. Janus CNM membranes are highlighted for their versatile applications in liquid, thermal, and light management. This review also highlights the significant advances and future perspectives in the construction and application of sustainable Janus CNM particles and membranes.

Benchmarking supramolecular adhesive behavior of nanocelluloses, cellulose derivatives and proteins

One of the key steps towards a broader implementation of renewable materials is the development of biodegradable adhesives that can be attained at scale and utilized safely. Recently, cellulose nanocrystals (CNCs) were demonstrated to have remarkable adhesive properties. Herein, we study three classes of naturally synthesized biopolymers as adhesives, namely nanocelluloses (CNFs), cellulose derivatives, and proteins by themselves and when used as additives with CNCs. Among the samples evaluated, the adhesion strength was the highest for bovine serum albumin and hydroxypropyl cellulose (beyond 10 MPa). These were followed by carboxymethylcellulose and CNCs (ca. 5 MPa) and mechanically fibrillated CNFs (ca. 2 MPa), and finally by tempo-oxidized CNFs (0.2 MPa) and lysozyme (1.5 MPa). Remarkably, we find that the anisotropy of adhesion (in plane vs out of plane) falls within a narrow range across the bio-based adhesives studied. Collectively, this study benchmarks bio-based non-covalent adhesives aiming towards their improvement and implementation.

Jerky-Inspired Fabrication of Anisotropic Hydrogels with Widely Tunable Mechanical Properties

Jerky is a type of meat product traditionally produced using a hang-drying process to achieve desirable textural properties. Inspired by the jerky processing, we present a strategy for fabricating strong alginate hydrogels with highly anisotropic structures via stretching and drying under constant stress. The tunable stretching process endowed the alginate hydrogels with adjustable mechanical properties and structural features by promoting the orientation and aggregation of the constituent polymers. At a high water content of about 80%, the tensile strength of the obtained hydrogel was increased to 20 MPa, which was 10 times higher than that of the hydrogel without the stretching process. Moreover, these hydrogels can be favorably compared with other common structural materials. This paper introduces a facile strategy to tune the structural alignment and mechanical properties of hydrogels, which will expand the applicability of the natural hydrogels formed by non-covalent interactions.

A Review of Performance Prediction Based on Machine Learning in Materials Science

With increasing demand in many areas, materials are constantly evolving. However, they still have numerous practical constraints. The rational design and discovery of new materials can create a huge technological and social impact. However, such rational design and discovery require a holistic, multi-stage design process, including the design of the material composition, material structure, material properties as well as process design and engineering. Such a complex exploration using traditional scientific methods is not only blind but also a huge waste of time and resources. Machine learning (ML), which is used across data to find correlations in material properties and understand the chemical properties of materials, is being considered a new way to explore the materials field. This paper reviews some of the major recent advances and applications of ML in the field of properties prediction of materials and discusses the key challenges and opportunities in this cross-cutting area.

Nanoscale Mechanism of Moisture-Induced Swelling in Wood Microfibril Bundles

Understanding nanoscale moisture interactions is fundamental to most applications of wood, including cellulosic nanomaterials with tailored properties. By combining X-ray scattering experiments with molecular simulations and taking advantage of computed scattering, we studied the moisture-induced changes in cellulose microfibril bundles of softwood secondary cell walls. Our models reproduced the most important experimentally observed changes in diffraction peak locations and widths and gave new insights into their interpretation. We found that changes in the packing of microfibrils dominate at moisture contents above 10-15%, whereas deformations in cellulose crystallites take place closer to the dry state. Fibrillar aggregation is a significant source of drying-related changes in the interior of the microfibrils. Our results corroborate the fundamental role of nanoscale phenomena in the swelling behavior and properties of wood-based materials and promote their utilization in nanomaterials development. Simulation-assisted scattering analysis proved an efficient tool for advancing the nanoscale characterization of cellulosic materials.

Nanochitin: Chemistry, Structure, Assembly, and Applications

Chitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability to structure into hierarchical assemblies, spanning the nano- and macroscales, imparting toughness and resistance (chemical, biological, among others) to multicomponent materials as well as adding adaptability, tunability, and versatility. Retaining the inherent structural characteristics of chitin and its colloidal features in dispersed media has been central to its use, considering it as a building block for the construction of emerging materials. Top-down chitin designs have been reported and differentiate from the traditional molecular-level, bottom-up synthesis and assembly for material development. Such topics are the focus of this Review, which also covers the origins and biological characteristics of chitin and their influence on the morphological and physical-chemical properties. We discuss recent achievements in the isolation, deconstruction, and fractionation of chitin nanostructures of varying axial aspects (nanofibrils and nanorods) along with methods for their modification and assembly into functional materials. We highlight the role of nanochitin in its native architecture and as a component of materials subjected to multiscale interactions, leading to highly dynamic and functional structures. We introduce the most recent advances in the applications of nanochitin-derived materials and industrialization efforts, following green manufacturing principles. Finally, we offer a critical perspective about the adoption of nanochitin in the context of advanced, sustainable materials.

Injectable Hydrogels Based on Inter-Polyelectrolyte Interactions between Hyaluronic Acid, Gelatin, and Cationic Cellulose Nanocrystals

The present work dealt with the development of physically cross-linked injectable hydrogels with potential applications in tissue engineering. The hydrogels were composed of a ternary mixture of a polyanion and a polyampholyte, hyaluronic acid (HA) and gelatin, respectively, bridged by cationic cellulose nanocrystals (cCNCs). A 3D network is formed by employing attractive electrostatic interactions and hydrogen bonding between these components under physiological conditions. The hydrogels demonstrated low viscosity at high stresses, enabling easy injection, structural stability at low stresses (<15 Pa), and nearly complete structure recovery within several minutes. Increasing the cCNC content (>3%) reduced hydrogel swelling and decelerated the degradation in phosphate-buffered saline as compared to that in pure HA and HA-gelatin samples. Biological evaluation of the hydrogel elutions showed excellent cell viability. The proliferation of fibroblasts exposed to elutions of hydrogels with 5% cCNCs reached ∼200% compared to that in the positive control after 11 days. Considering these results, the prepared hydrogels hold great potential in biomedical applications, such as injectable dermal fillers, 3D bioprintable inks, or 3D scaffolds to support and promote soft tissue regeneration.

Osteogenesis of Iron Oxide Nanoparticles-Labeled Human Precartilaginous Stem Cells in Interpenetrating Network Printable Hydrogel

Smart biomaterials combined with stem cell-based therapeutic strategies have brought innovation in the field of bone tissue regeneration. However, little is known about precartilaginous stem cells (PCSCs), which can be used as seed cells and incorporated with bioactive scaffolds for reconstructive tissue therapy of bone defects. Herein, iron oxide nanoparticles (IONPs) were employed to modulate the fate of PCSCs, resulting in the enhanced osteogenic differentiation potential both in vitro and in vivo. PCSCs were isolated from the ring of La-Croix extracted from polydactylism patient and identified through immunohistochemically staining using anti-FGFR-3 antibodies. Potential toxicity of IONPs toward PCSCs was assessed through cell viability, proliferation, and attachment assay, and the results demonstrated that IONPs exhibited excellent biocompatibility. After that, the effects of IONPs on osteogenic differentiation of PCSCs were evaluated and enhanced ALP activity, formation of mineralized nodule, and osteogenic-related genes expressions could be observed upon IONPs treatment. Moreover, in vivo bone regeneration assessment was performed using rabbit femur defects as a model. A novel methacrylated alginate and 4-arm poly (ethylene glycol)-acrylate (4A-PEGAcr)-based interpenetrating polymeric printable network (IPN) hydrogel was prepared for incorporation of IONPs-labeled PCSCs, where 4A-PEGAcr was the common component for three-dimensional (3D) printing. The implantation of IONPs-labeled PCSCs significantly accelerated the bone formation process, indicating that IONPs-labeled PCSCs could endow current scaffolds with excellent osteogenic ability. Together with the fact that the IONPs-labeled PCSCs-incorporated IPN hydrogel (PCSCs-hydrogels) was biosafety and printable, we believed that PCSCs-hydrogels with enhanced osteogenic bioactivity could enrich the stem cell-based therapeutic strategies for bone tissue regeneration.

Bioactive hydrogels based on polysaccharides and peptides for soft tissue wound management

Due to their inherent and tunable biomechanical and biochemical performances, bioactive hydrogels based on polysaccharides and peptides have shown attractive potential for wound management. In this review, the recent progress of bioactive hydrogels prepared by polysaccharides and peptides for soft tissue wound management is overviewed. Meanwhile, we focus on the elaboration of the relationship between chemical structures and inherent bioactive functions of polysaccharides and peptides, as well as the strategies that are taken for achieving multiple wound repairing effects including hemostasis, adhesion, wound contraction and closure, anti-bacteria, anti-oxidation, immunomodulation, molecule delivery, etc. Some innovative and important works are well introduced as well. In the end, current study limitations, clinical unmet needs, and future directions are discussed.

Direct Ink Writing of Biocompatible Nanocellulose and Chitosan Hydrogels for Implant Mesh Matrices

Direct ink writing via single or multihead extrusion is used to synthesize layer-by-layer (LbL) meshes comprising renewable polysaccharides. The best mechanical performance (683 ± 63 MPa modulus and 2.5 ± 0.4 MPa tensile strength) is observed for 3D printed structures with full infill density, given the role of electrostatic complexation between the oppositely charged components (chitosan and cellulose nanofibrils). The LbL structures develop an unexpectedly high wet stability that undergoes gradual weight loss at neutral and slightly acidic pH. The excellent biocompatibility and noncytotoxicity toward human monocyte/macrophages and controllable shrinkage upon solvent exchange make the cellular meshes appropriate for use as biomedical implants.

Recent Advances in Chemically Modified Cellulose and Its Derivatives for Food Packaging Applications: A Review

The application of cellulose in the food packaging field has gained increasing attention in recent years, driven by the desire for sustainable products. Cellulose can replace petroleum-based plastics because it can be converted to biodegradable and nontoxic polymers from sustainable natural resources. These products have increasingly been used as coatings, self-standing films, and paperboards in food packaging, owing to their promising mechanical and barrier properties. However, their utilization is limited because of the high hydrophilicity of cellulose. With the presence of a large quantity of functionalities within pristine cellulose and its derivatives, these building blocks provide a unique platform for chemical modification via covalent functionalization to introduce stable and permanent functionalities to cellulose. A primary aim of chemical attachment is to reduce the probability of component leaching in wet and softened conditions and to improve the aqueous, oil, water vapor, and oxygen barriers, thereby extending its specific use in the food packaging field. However, chemical modification may affect the desirable mechanical, thermal stabilities and biodegradability exhibited by pristine cellulose. This review exhaustively reports the research progress on cellulose chemical modification techniques and prospective applications of chemically modified cellulose for use in food packaging, including active packaging.

COCu: A Robust Self-Regenerative Hydrogel with Applicability as Both Hydrated Gel Dressing and Dry Suture for Seamless Tissue Fixation and Repair

Self-regenerative hydrogels have recently been developed, and represent a special type of self-healing hydrogels with the ability to restore a dehydrated hydrogel with physical damage. In this study, a self-regenerative hydrogel (COCu) based on two chitosan polymers assembled by slow-released Cu²⁺ is developed. The COCu hydrogel displays an excellent regeneration ability after being dehydrated and fractured. By simple hydration at room temperature, the fragments of the dehydrated gel fuse into one seamless whole, thereby preserving the mechanical properties and functionalities of the original hydrogel. The regeneration process can be conducted repeatedly after different methods of dehydration (natural volatilization, heat drying, lyophilization) and various modes of deconstruction (flakes, powder, lumpy sponge, etc.). Furthermore, the COCu hydrogel provides ultra-stretchability, and it can be stretched into thin (0.01-0.1 mm) filaments, which, when dried (dtCOCu), can be used as suture lines. Moreover, when used as a dry suture, it regenerates into the hydrogel in the presence of the tissue fluid, forming an excellent sealant to immobilize tissues and seamlessly seal wounds. The fast self-regeneration allows for its facile application as both a hydrated gel dressing and dry suture, and offers customized strategies for fixing and repair of different wounds in soft tissues.

Multiscale Mechanical Performance of Wood: From Nano- to Macro-Scale across Structure Hierarchy and Size Effects

This review describes methods and results of studying the mechanical properties of wood at all scales: from nano- to macro-scale. The connection between the mechanical properties of material and its structure at all these levels is explored. It is shown that the existing size effects in the mechanical properties of wood, in a range of the characteristic sizes of the structure of about six orders of magnitude, correspond to the empirical Hall-Petch relation. This “law” was revealed more than 60 years ago in metals and alloys and later in other materials. The nature, as well as the particular type of the size dependences in different classes of materials can vary, but the general trend, “the smaller the stronger”, remains true both for wood and for other cellulose-containing materials. The possible mechanisms of the size effects in wood are being discussed. The correlations between the mechanical and thermophysical properties of wood are described. Several examples are used to demonstrate the possibility to forecast the macromechanical properties of wood by means of contactless thermographic express methods based on measuring temperature diffusivity. The research technique for dendrochronological and dendroclimatological studies by means of the analysis of microhardness and Young’s modulus radial dependences in annual growth rings is described.

Highly Flexible and Broad-Range Mechanically Tunable All-Wood Hydrogels with Nanoscale Channels via the Hofmeister Effect for Human Motion Monitoring

Wood-based hydrogel with a unique anisotropic structure is an attractive soft material, but the presence of rigid crystalline cellulose in natural wood makes the hydrogel less flexible. In this study, an all-wood hydrogel was constructed by cross-linking cellulose fibers, polyvinyl alcohol (PVA) chains, and lignin molecules through the Hofmeister effect. The all-wood hydrogel shows a high tensile strength of 36.5 MPa and a strain up to ~ 438% in the longitudinal direction, which is much higher than its tensile strength (~ 2.6 MPa) and strain (~ 198%) in the radial direction, respectively. The high mechanical strength of all-wood hydrogels is mainly attributed to the strong hydrogen bonding, physical entanglement, and van der Waals forces between lignin molecules, cellulose nanofibers, and PVA chains. Thanks to its excellent flexibility, good conductivity, and sensitivity, the all-wood hydrogel can accurately distinguish diverse macroscale or subtle human movements, including finger flexion, pulse, and swallowing behavior. In particular, when "An Qi" was called four times within 15 s, two variations of the pronunciation could be identified. With recyclable, biodegradable, and adjustable mechanical properties, the all-wood hydrogel is a multifunctional soft material with promising applications, such as human motion monitoring, tissue engineering, and robotics materials.

A facile approach for anisotropic hydrogel with light-regulated stiffness and its application to achieve mechanical toughening

Many load-bearing tissues in nature obtain high toughness by fabricating anisotropic structures with spatially regulated composition and modulus at macroscale. This reality inspires a toughening strategy for hydrogel based on the controlling of modulus heterogeneity. Herein, a facile approach to realize light-regulated spatial modulus heterogeneity with large contrast in hydrogel is proposed. Ferric citric acid complex is used as a light-responsive ionic crosslinker, which can first stiffen an alginate/polyacrylamide hydrogel by coordinating with the alginate to form another network, then realize light-triggered softening through photoreduction of ferric ions. Based on this, a stripe-patterned hydrogel with alternating stiff and soft segments can be fabricated through photopatterning. The modulus contrast between the stiff and soft phases can be adjusted by control of several influence factors and the maximum modulus contrast reach up to 87 times. As a result, the toughness of the stripe-patterned hydrogel is enhanced by 3.5 times comparing to that hydrogel without pattern. This approach shows great potential in synthesis of smart hydrogel with light-programmable mechanical performances, and may be widely applicable for the hydrogels with functional groups that can coordinate with metal ions. This article is protected by copyright. All rights reserved.

Anisotropic cellulose nanocrystal hydrogel with multi-stimuli response to temperature and mechanical stress

Conventional hydrogels with isotropic polymer networks usually lack selective response to external stimuli and that limits their applications in intelligent devices. Herein, hydrogels with distinctive anisotropic optical characteristics combined with thermosensitivity were prepared through in situ photopolymerization. Self-assembled cellulose nanocrystals (CNCs) with chiral nematic ordered structure were embedded in polyethylene glycol derivatives/polyacrylamide polymer networks. The arrangement of CNCs showed a strong dependence on the self-assembly angle and standing time, enabling the fabrication of hydrogels with customizable CNCs arrangements. Increasing the self-assembly angle from 0° to 90° changed the CNCs arrangement from chiral nematic to symmetrical nematic order which, together with CNCs dynamic arrangement from isotropic to annealed chiral nematic phase at longer standing time, provided versatile ways to produce CNCs hydrogels with tunable anisotropic properties. In addition, the obtained hydrogel displayed reversible temperature and compression response, showing excellent promise to be used as soft mechanical stress and temperature sensors or novel anti-counterfeiting materials.

Effect of Moisture on Polymer Deconstruction in HCl Gas Hydrolysis of Wood

The HCl gas system previously used to produce cellulose nanocrystals was applied on Scots pine wood, aiming at a controlled deconstruction of its macrostructure while understanding the effect on its microstructure. The HCl gas treatments resulted in a well-preserved cellular structure of the wood. Differences in wood initial moisture content (iMC) prior to HCl gas treatment played a key role in hydrolysis rather than the studied range of exposure time to the acidic gas. Higher iMCs were correlated with a higher degradation of hemicellulose, while crystalline cellulose microfibrils were not largely affected by the treatments. Remarkably, the hydrogen-deuterium exchange technique showed an increase in accessible OH group concentration at higher iMCs, despite the additional loss in hemicelluloses. Unrelated to changes in the accessible OH group concentration, the HCl gas treatment reduced the concentration of absorbed D₂O molecules.

Lignocellulosic Materials for the Production of Biofuels, Biochemicals and Biomaterials and Applications of Lignocellulose-Based Polyurethanes: A Review

The present review is devoted to the description of the state-of-the-art techniques and procedures concerning treatments and modifications of lignocellulosic materials in order to use them as precursors for biomaterials, biochemicals and biofuels, with particular focus on lignin and lignin-based products. Four different main pretreatment types are outlined, i.e., thermal, mechanical, chemical and biological, with special emphasis on the biological action of fungi and bacteria. Therefore, by selecting a determined type of fungi or bacteria, some of the fractions may remain unaltered, while others may be decomposed. In this sense, the possibilities to obtain different final products are massive, depending on the type of microorganism and the biomass selected. Biofuels, biochemicals and biomaterials derived from lignocellulose are extensively described, covering those obtained from the lignocellulose as a whole, but also from the main biopolymers that comprise its structure, i.e., cellulose, hemicellulose and lignin. In addition, special attention has been paid to the formulation of bio-polyurethanes from lignocellulosic materials, focusing more specifically on their applications in the lubricant, adhesive and cushioning material fields. High-performance alternatives to petroleum-derived products have been reported, such as adhesives that substantially exceed the adhesion performance of those commercially available in different surfaces, lubricating greases with tribological behaviour superior to those in lithium and calcium soap and elastomers with excellent static and dynamic performance.

Plant-Based Structures as an Opportunity to Engineer Optical Functions in Next-Generation Light Management

This review addresses the reconstruction of structural plant components (cellulose, lignin, and hemicelluloses) into materials displaying advanced optical properties. The strategies to isolate the main building blocks are discussed, and the effects of fibrillation, fibril alignment, densification, self-assembly, surface-patterning, and compositing are presented considering their role in engineering optical performance. Then, key elements that enable lignocellulosic to be translated into materials that present optical functionality, such as transparency, haze, reflectance, UV-blocking, luminescence, and structural colors, are described. Mapping the optical landscape that is accessible from lignocellulosics is shown as an essential step toward their utilization in smart devices. Advanced materials built from sustainable resources, including those obtained from industrial or agricultural side streams, demonstrate enormous promise in optoelectronics due to their potentially lower cost, while meeting or even exceeding current demands in performance. The requirements are summarized for the production and application of plant-based optically functional materials in different smart material applications and the review is concluded with a perspective about this active field of knowledge.

Supramolecular Assembly of Shape Memory and Actuating Hydrogels for Programmable Shape Transformation

The deformable diversity of organisms in nature has inspired the development of bionic hydrogel actuators. However, the anisotropic structures of hydrogel actuators cannot be altered after the fabrication process, which restricts hydrogel actuators to provide complex and diverse shape deformations. Herein, we propose a dual programming method to generate numerous anisotropic structures from initial isotropic gelatin-containing hydrogels; the isotropic hydrogel blocks could be first assembled into anisotropic structures based on the coil-triple helix transition of gelatin, and then, the assembled hydrogels could further be fixed into various temporary anisotropies, so that they can produce complex and diverse deformations under the stimulation of pH. In addition, the shape programming and deformation behaviors are reversible. This dual programming method provides more potential for the application of hydrogel actuators in soft robots and bionics.

Tuning the Porosity, Water Interaction, and Redispersion of Nanocellulose Hydrogels by Osmotic Dehydration

Osmotic dehydration (OD) was introduced as a method to reproducibly tune the water content and porosity of cellulose nanofiber (CNF) hydrogels. The hierarchical porosity was followed by electron microscopy (pores with a >100 μm diameter) and thermoporosimetry (mesopores), together with mechanical testing, in hydrogels with solid contents ranging from 0.7 to 12 wt %. Furthermore, a reciprocal correlation between proton conductivity and the ratio of water bound to the nanocellulose network was established, suggesting the potential of these systems toward tunable energy materials.

Delignified wood aerogels as scaffolds coated with an oriented chitosan–cyclodextrin co-polymer for removal of microcystin-LR

Nano-porous aerogels are an advantageous approach to produce low-density materials with high surface area, particularly when using biobased materials. Frequently, most biobased aerogels are synthesized through a bottom-up approach, which requires high energy inputs to break and rebuild the raw materials, and for elimination of water. To curb this, this work focused on generating aerogels by a top-down approach through the delignification of a wood substrate while eliminating water by solvent exchange. To diversify the surface chemistry for use in water treatment, the delignified wood–nanowood-was coated with a chitosan–cyclodextrin co-polymer and tested in the capture of microcystin-LR. The generated nanowood structure had 75% porosity after coating, with up to 339% water swelling and an adsorption capacity of 0.12 mg g⁻¹ of the microcystin. This top-down technique enables the generation of low-cost aerogels by reducing steps, using a biobased self-assembled coating with hydrophobic active sites, and avoiding costly energetic input.

Herein, a preassembled chitosan-cyclodextrin was used as a versatile coating onto delignified wood as an alternative for the removal of microcystin-LR. The addition of β-cyclodextrin proved to allow the nanowood scaffold to adsorb up to 0.12 mg g⁻¹.

A multifunctional and environmentally safe superhydrophobic membrane with superior oil/water separation, photocatalytic degradation and anti-biofouling performance

Wastewater is typically complicated with spilled oil, water soluble toxic dyes and microorganisms, making it hard to be processed and causing a significant threat to the environmental safety and human health. In this paper, we demonstrate a simple solution immersion method to obtain a multifunctional cellulose-based membrane (CBM) that possesses both superhydrophobicity with a water contact angle of 163° and superior functionalities including self-cleaning, oil-water separation, anti-biofouling, and photocatalytic degradation capabilities. The achievement of separation efficiency (96%), comparatively high flux (141 L·m^-2·h^-1) and recyclable (7 times) oil/water separation performance is attributed to the robust superhydrophobicity enabled by the synergy of metal oxide (i.e., CuO) nanostructure coating and stearic acid (SA) modification. The superhydrophobic CBM also preferentially adsorbs organic dyes in aqueous solution, e.g., methylene blue (MB), promoting their efficient decomposition (about 70.3% of MB decomposed in 3 h) with high recyclability under UV irradiation. Most remarkably, the CBM exhibits superior anti-biofouling capability and persistently resists the algae adhesion in long duration (over 20 days), as a result of the self-cleaning ability as well as the antimicrobial property of CuO nanoparticles. Our finding here paves the way to use simple, cost-effective, environmentally safe, and reliable method to fabricate multifunctional materials for wastewater treatment in complex environments.

Deconstruction and Reassembly of Renewable Polymers and Biocolloids into Next Generation Structured Materials

This review considers the most recent developments in supramolecular and supraparticle structures obtained from natural, renewable biopolymers as well as their disassembly and reassembly into engineered materials. We introduce the main interactions that control bottom-up synthesis and top-down design at different length scales, highlighting the promise of natural biopolymers and associated building blocks. The latter have become main actors in the recent surge of the scientific and patent literature related to the subject. Such developments make prominent use of multicomponent and hierarchical polymeric assemblies and structures that contain polysaccharides (cellulose, chitin, and others), polyphenols (lignins, tannins), and proteins (soy, whey, silk, and other proteins). We offer a comprehensive discussion about the interactions that exist in their native architectures (including multicomponent and composite forms), the chemical modification of polysaccharides and their deconstruction into high axial aspect nanofibers and nanorods. We reflect on the availability and suitability of the latter types of building blocks to enable superstructures and colloidal associations. As far as processing, we describe the most relevant transitions, from the solution to the gel state and the routes that can be used to arrive to consolidated materials with prescribed properties. We highlight the implementation of supramolecular and superstructures in different technological fields that exploit the synergies exhibited by renewable polymers and biocolloids integrated in structured materials.

Solvent-Assisted Fractionation of Oligomeric Cellulose and Reversible Transformation of Cellulose II and IV

Oligomeric cellulose with an average degree of polymerization of 7.68 and a polydispersity of 1.04 has been fractionated using solution processes. Three fractions have been obtained through initial dissolution, subsequent crystallization, and solvent precipitation, respectively. The resulting oligocellulose fraction has an average degree of polymerization of 7.70 and a polydispersity of 1.01, respectively. Cellulose IV₂ crystals form in the oligocellulose fraction, and reversibly transform to II and back to IV using simple solvents.

Anion-Specific Water Interactions with Nanochitin: Donnan and Osmotic Pressure Effects as Revealed by Quartz Microgravimetry

The development of new materials emphasizes greater use of sustainable and eco-friendly resources, including those that take advantage of the unique properties of nanopolysaccharides. Advances in this area, however, necessarily require a thorough understanding of interactions with water. Our contribution to this important topic pertains to the swelling behavior of partially deacetylated nanochitin (NCh), which has been studied here by quartz crystal microgravimetry. Ultrathin films of NCh supported on gold-coated resonators have been equilibrated in aqueous electrolyte solutions (containing NaF, NaCl, NaBr, NaNO₃, Na₂SO₄, Na₂SO₃, or Na₃PO₄) at different ionic strengths. As anticipated, NCh displays contrasting swelling/deswelling responses, depending on the ionic affinities and valences of the counterions. The extent of water uptake induced by halide anions, for instance, follows a modified Hofmeister series with F^- producing the highest swelling. In marked contrast, Cl^- induces film dehydration. We conclude that larger anions promote deswelling such that water losses increase with increasing anion valence. Results such as the ones reported here are critical to ongoing efforts designed to dry chitin nanomaterials and develop bio-based and sustainable materials, including particles, films, coatings, and other nanostructured assemblies, for various devices and applications.