Cellulose nanocrystals and cellulose nanofibrils based hydrogels for biomedical applications

Recent progress of multifunctional nanocellulose-based pharmaceutical materials: A review

In the pharmaceutical industry, ongoing research and development focus on discovering new drug formulations that align with regulatory approvals. Recently, innovative drug delivery systems have been used to maximize therapeutic efficacy with a precision of sustained drug delivery in the disease management system. Nanocellulose (NCs) synthesized from abundant cellulose, have attracted wide attention for potential pharmaceutical applications due to their unique properties, such as biocompatibility, high surface area-to-volume ratio, extensive drug loading and binding capacity, controlled drug release efficiency, strength, and availability with various treatments and modification ability. Nevertheless, research on nanocarriers (NCs) in the pharmaceutical field faces several limitations and challenges. Key areas requiring further exploration include chemical consumption, energy intensity, effluent management, recovery processes from acid hydrolysis, reaction times, ecotoxicology, and overall development progress. This overview provides the applications of emerging nanocellulose. It gives a clue on the synthesis of sustainable NCs related to their different sources, pre- and post-modifications of NCs, and key properties in pharmaceutical sectors. Furthermore, it gives an overview of the current advancements, life cycle analysis, biosafety, and key property performance with a summary of challenges and future perspectives.

Facile Design of Multiscale Cellulose-Enhanced Hydrogel Electrolytes for Flexible Zn-Ion Capacitors in Wearable Electronics

Flexible solid-state supercapacitors show significant potential for wearable electronics; however, achieving simultaneous mechanical robustness and high ionic conductivity remains challenging. In this work, a polyacrylamide (PAM)/cellulose nanocrystal (CNC)-based hydrogel electrolyte loading with carboxymethyl cellulose (CMC) is engineered to address this limitation (PAM/CNC-CMC-Zn2+). Incorporating CNC improved the mechanical properties of hydrogels, while subsequently adding CMC-Na enriched with hydrophilic groups (─OH and ─COO-) into PAM/CNC hydrogels disrupted hydrogen-bond networks within the ZnSO4 electrolyte, thereby optimizing Zn2+ solvation sheath structure. This modification suppressed corrosion currents and minimized side reactions. The hydrogel demonstrated outstanding mechanical properties, including a tensile strength of 0.22 MPa, high stretchability (1452.1%), and remarkable fracture toughness (0.98 MJ m-3). The zinc-ion capacitors (Zn // PAM/CNC-CMC-Zn2+ // AC) demonstrate exceptional electrochemical performance, achieving a significant specific capacitance of 151.4 F g⁻¹ at 0.5 A g⁻¹, coupled with a remarkable power density of 1150 W kg⁻¹ (at 10.9 Wh kg⁻¹). Notably, the device exhibits outstanding performance stability, maintaining its functionality under mechanical folding and retaining its efficiency after 10 000 long charge-discharge cycles. These multiscale cellulose-based design highlights the hydrogel electrolyte's dual functionality in balancing mechanical adaptability and electrochemical efficiency, offering a potential solution for next-generation wearable energy storage systems.

Recent Advances in Modeling Tissues Using 3D Bioprinted Nanocellulose Bioinks

Bioprinting creates 3D tissue models by depositing cells encapsulated in biocompatible materials. These 3D printed models can better emulate physiological conditions in comparison with traditional 2D cell cultures or animal models. Such models can be produced from human cells, possessing human genetics and replicating the 3D microenvironment found in vivo. Many different types of biocompatible materials serve as bioinks, including gelatin methacryloyl (GelMA), alginate, fibrin, and gelatin. Nanocellulose has emerged as a promising addition to these materials. Nanocellulose─composed of cellulose chain bundles with lateral dimensions ranging from a few to several tens of nanometers─possesses key properties for 3D bioprinting applications. It can form biocompatible hydrogels, which have excellent physical properties, and its structure resembles collagen, making it useful for modeling tissues with high collagen content such as bone, cartilage, sink, and muscle. Here we review some of the recent advances in the use of nanocellulose in bioinks for the creation of bone, cartilage, skin, and muscle tissue specific models and identify areas for future progress.

Nanocellulose-hydrogel hybrids: A review on synthesis and applications in agriculture, food packaging and water remediation

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NC-HHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.

Plant-derived biomass-based hydrogels for biomedical applications

Hydrogels made of plant-derived biomass have gained popularity in biomedical applications because they are frequently affordable, readily available, and biocompatible. Finding the perfect plant-derived biomass-based hydrogels for biomedicine that can replicate essential characteristics of human tissues in regard to structure, function, and performance has proved to be difficult. In this review, we summarize some of the major contributions made to this topic, covering basic ideas and different biomass-based hydrogels made of cellulose, hemicellulose, and lignin. Also included is an in-depth discussion regarding the biosafety and toxicity assessments of biomass-based hydrogels. Finally, this review also highlights important scientific debates and major obstacles regarding biomass-based hydrogels for biomedical applications.

Enhancing performance of in-situ synthesized biocompatible shape memory polyurethane acrylate by cellulose nanocrystals

This study presents the development of biocompatible and biodegradable nanocomposites utilizing renewable cellulose nanocrystals (CNCs) in polycaprolactone (PCL)-based polyurethane acrylates (PUA) through in situ polymerization. First, CNCs were derived from cotton linter via acid hydrolysis; then functionalized with 3-methacryloxypropyltrimethoxysilane to produce silane-modified CNCs (S-CNCs). CNCs offered uniform dispersion in PUA up to 2 wt% loading, resulting in significant property enhancements, including ∼60 % increase in tensile strength and ∼25 % increase in Young's modulus. Despite the chemical interaction of S-CNCs with PUA, they tended to agglomerate beyond 0.5 wt% loading due to the promotion of chemical interactions between S-CNC particles at higher concentrations. Despite this, comparable improvements (e.g. ∼50 % in tensile strength and ∼25 % in Young's modulus) were observed at just 0.5 wt% S-CNC loading. Both neat PUA and PUA nanocomposites demonstrated exceptional shape memory properties, with shape fixity exceeding 95 % and shape recovery approaching 100 %. However, S-CNCs also halved the shape recovery time compared to neat PUA, a critical advancement for time-sensitive applications. Meanwhile, the biocompatibility of PUA was largely preserved in the presence of the nanoparticles, particularly for S-CNC.

From waste to wonder: Biomass-derived nanocellulose and lignin-based nanomaterials in biomedical applications

Cellulose and lignin, as the most abundant biomass resources in nature, have been widely utilized in conventional industry. While their high-value potential remained underexplored for decades, recent advancements in nanotechnology and processing techniques have revealed their unique physicochemical properties, biocompatibility, and optical characteristics at the nanoscale, sparking significant interest in biomedical applications. Nanocellulose (NC), characterized by its high surface area, superior mechanical strength, and excellent biocompatibility, holds great promise in drug delivery, wound dressing, and tissue engineering. Similarly, lignin nanoparticles (LNPs) and lignin-based carbon quantum dots (L-CQDs), known for their multi-functionality, low toxicity, and outstanding fluorescence properties, emerge as sustainable alternatives for bio-imaging and bioanalytical detection. This review provides an overview of the hierarchical structure of biomass resources, details the preparation methods of cellulose- and lignin-based nanomaterials, and highlights their advancements in biomedical applications. Furthermore, it addresses the challenges and limitations associated with the clinical applications of these nanomaterials, offering insights and guidance for future research and development.

Ion-Specific Gelation and Internal Dynamics of Nanocellulose Biocompatible Hybrid Hydrogels: Insights from Fluctuation Analysis

Hydrogels find widespread use in bioapplications for their ability to retain large amounts of water while maintaining structural integrity. In this article, we investigate hybrid hydrogels made of nanocellulose and either amino-polyethylenglycol or sodium alginates and we present two novel results: (1) the biocompatibility of the amino-containing hybrid gel synthesized using a simplified receipt does not require any intermediate synthetic step to functionalize either component and (2) the fluctuation in the second-order correlation function of a dynamic light scattering experiment provides relevant information about the characteristic internal dynamics of the materials across the entire sol-gel transition as well as quantitative information about the ion-specific gel formation. This novel approach offers significantly better temporal (tens of μs) and spatial (tens of μm) resolution than many other state-of-the-art techniques commonly used for such analyses (such as rheometry, SAXS, and NMR) and it might find widespread application in the characterization of nano- to microscale dynamics in soft materials.

Physical Cross-Linking of Cellulose Nanofibrils with Zein Particles as an Eco-Friendly Detergent

Pickering particles can self-assemble to form a rigid barrier film at the oil-water interface, effectively inhibiting droplet aggregation and stabilizing the emulsion. This essay explores the potential of Zein/TOCNF (TEMPO-oxidized cellulose nanofiber) complex aqueous dispersion as an environmentally friendly, nontoxic, versatile, and inexpensive cleaning agent based on the Pickering effect. The Zein/TOCNF complex exhibited an improvement in its surface hydrophobicity compared to that of pure TOCNF, so that it could be used as Pickering emulsion stabilizers. The Zein/TOCNF complex has better washing ability than the washing powder for the removal of the dirt from the cotton cloth, the glass, the stainless steel, the ceramic, and the plastic sheet. In addition, residual amounts of Zein/TOCNF complexes on the fabric were insignificant. Moreover, research results have shown that Zein/TOCNF complexes are feasible as a secure, cost-effective, and sustainable alternative to commercial washing cleaners.

Obtaining and Characterizing Poly(Acid Acrylic-co-Acrylamide) Hydrogels Reinforced with Cellulose Nanocrystals from Acacia farnesiana L. Willd (Huizache)

In this work, cellulose nanocrystals (CNCs) were obtained from the wood of Acacia farnesiana L. Willd (Huizache) via acid hydrolysis; then, they were used to reinforce polyacrylic acid-co-acrylamide (AAc/AAm) hydrogels synthesized in a solution process via in situ free radical photopolymerization. The nanomaterials were characterized using atomic force microscopy, dynamic light scattering (DLS), and the residual charge on the CNCs; the nanohydrogels were characterized using infrared spectroscopy, scanning electron microscopy, swelling kinetics, and Young's modulus. Soluble-grade cellulose presented 94.6% α-cellulose, 0.5% β-cellulose, and 2.7% γ-cellulose, as well as a viscosity of 8.25 cp and a degree of polymerization (DP) of 706. The CNCs averaged 180 nm in length and 20 nm in width. In the nanohydrogels, it was observed that the swelling kinetic behavior followed the Schott kinetic model, at times lower than 500 h; after that, it became linear. The results show that the hydrogel swelling capacity depended on the crosslinking agent and CNC concentration, as well as the CNC chemical and morphological properties, rather than the CNC source. The hydrogels with CNCs exhibited a decreased swelling degree compared to the hydrogels without CNCs. Young's modulus increased with CNC presence and depended on the concentration and characteristics of the CNC as a crosslinking agent.

Effects of Chemical Pretreatments of Wood Cellulose Nanofibrils on Protein Adsorption and Biological Outcomes

Wood-based nanocellulose is emerging as a promising nanomaterial in the field of tissue engineering due to its unique properties and versatile applications. Previously, we used TEMPO-mediated oxidation (TO) and carboxymethylation (CM) as chemical pretreatments prior to mechanical fibrillation of wood-based cellulose nanofibrils (CNFs) to produce scaffolds with different surface chemistries. The aim of the current study was to evaluate the effects of these chemical pretreatments on serum protein adsorption on 2D and 3D configurations of TO-CNF and CM-CNF and then to investigate their effects on cell adhesion, spreading, inflammatory mediator production in vitro, and the development of foreign body reaction (FBR) in vivo. Mass spectrometry analysis revealed that the surface chemistry played a key role in determining the proteomic profile and significantly influenced the behavior of periodontal ligament fibroblasts and osteoblast-like cells (Saos-2). The surface of TO-CNF 2D samples showed the highest protein adsorption followed by TO-CNF 3D samples. CM-CNF 2D samples adsorbed a higher number of proteins than their 3D counterparts. None of the CNF scaffolds showed toxicity in vitro or in vivo. However, carboxymethylation pretreatment negatively affected the adhesion, morphology, and spreading of both cell types. Although the CNF materials displayed clear differences in surface chemistry and proteomic profiles, both triggered the same foreign body response after being subcutaneously implanted in rats for 90 days. This observation highlights that the degradation rate of CNF scaffolds plays a central role in maintaining the foreign body response in vivo. It is imperative to comprehend the impact of chemical pretreatments of CNFs on protein adsorption and their interaction with diverse host cell types prior to the investigation of potential modifications. This knowledge is indispensable for the advancement of CNFs in regenerative applications within tissue engineering.

Polysaccharide-based biomaterials for regenerative therapy in intervertebral disc degeneration

Intervertebral disc (IVD) degeneration represents a significant cause of chronic back pain and disability, with a substantial impact on the quality of life. Conventional therapeutic modalities frequently address the symptoms rather than the underlying etiology, underscoring the necessity for regenerative therapies that restore disc function. Polysaccharide-based materials, such as hyaluronic acid, alginate, chitosan, and chondroitin sulfate, have emerged as promising candidates for intervertebral disc degeneration (IVDD) therapy due to their biocompatibility, biodegradability, and ability to mimic the native extracellular matrix (ECM) of the nucleus pulposus (NP). These materials have demonstrated the capacity to support cell viability, facilitate matrix production, and alleviate inflammation in vitro and in vivo, thus supporting tissue regeneration and restoring disc function in comparison to conventional treatment. Furthermore, polysaccharide-based hydrogels have demonstrated the potential to deliver bioactive molecules, including growth factors, cytokines and anti-inflammatory drugs, directly to the degenerated disc environment, thereby enhancing therapeutic outcomes. Therefore, polysaccharide-based materials provide structural support and facilitate the regeneration of native tissue, representing a versatile and effective approach for the treatment of IVDD. Despite their promise, challenges such as limited long-term stability, potential immunogenicity, and the difficulty in scaling up production for clinical use remain. This review delineates the potential of various polysaccharides during the fabrication of hydrogels and scaffolds for disc regeneration, guiding and inspiring future research to focus on optimizing these materials for clinical translation for IVDD repair and regeneration.

Preparation and properties of hydrogels with different forms of nanocellulose and low methoxyl pectin

Different proportions of cellulose nanofibers (CNFs)/cellulose nanocrystals (CNCs) and low methoxyl (LM) pectin were used to prepare hydrogels. By analyzing the apparent morphology, gel strength, rheological characteristics, microstructure, and interaction between cellulose and LM pectin, the characteristics of hydrogels created by the combination of different forms of nanocellulose and LM pectin were compared. At the same concentration, the strength of hydrogel formed by the combination of CNCs and LM pectin was higher than hydrogel formed by the combination of CNFs and LM pectin, which was consistent with the gel structure. The gel formed by the combination of LM pectin and CNFs had stronger viscoelasticity than the gel formed by the combination of LM pectin and CNCs. When the ratio of LM pectin to CNFs/CNCs is 0.5/0.5, a better gel network structure is formed, and the viscoelastic properties of the gel formed at this concentration under shock conditions are better protected.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01684-z.

Self-healing cellulose-based hydrogels: From molecular design to multifarious applications

Self-healing cellulose-based hydrogels (SHCHs) exhibit wide-ranging potential applications in the fields of biomedicine, environmental management, energy storage, and smart materials due to their unique physicochemical properties and biocompatibility. This review delves into the molecular design principles, performance characteristics, and diverse applications of SHCHs. Firstly, the molecular structure and physicochemical properties of cellulose are analyzed, along with strategies for achieving self-healing properties through molecular design, with particular emphasis on the importance of self-healing mechanisms. Subsequently, methods for optimizing the performance of SHCHs through chemical modification, composite reinforcement, stimulus responsiveness, and functional integration technologies are discussed in detail. Furthermore, applications of SHCHs in drug delivery, tissue engineering, wound healing, smart sensing, supercapacitors, electronic circuits, anti-counterfeiting systems, oil/water separation, and food packaging are explored. Finally, future research directions for SHCHs are outlined, including the innovative development of new SHCHs, in-depth elucidation of cooperative strengthening mechanisms, a further expansion of application scope, and the establishment of intelligent systems. This review provides researchers with a comprehensive overview of SHCHs and serves as a reference and guide for future research and development.

Cotton cellulose nanofiber/chitosan scaffolds for skin tissue engineering and wound healing applications

Chitosan (CS) is a promising polymeric biomaterial for use in scaffolds forin vitroskin models and wound dressings, owing to its non-antigenic and antimicrobial properties. However, CS often exhibits insufficient physicochemical properties, mechanical strength, and bioactivity, limiting its efficacy in demanding applications. To address these challenges, cotton cellulose nanofibers (CNFs) represent a promising nanomaterial for enhancing CS-based scaffolds in tissue engineering. CNF offers superior stiffness, and mechanical properties that enhance cellular adhesion and proliferation, both crucial for effective tissue regeneration and healing. This study aimed to develop and characterize a scaffold combining cotton CNF and CS, focusing on its cytocompatibility with human fibroblasts and keratinocytes. The cotton CNF/CS scaffold was fabricated using the casting technique, and its physicochemical properties and cellular compatibility were assessedin vitro. The results demonstrated that incorporating cotton CNF significantly enhanced the stability of the CS matrix. The CS scaffold with 1000 μg ml-1of cotton CNF exhibited increased roughness and reduced rupture strain compared to the pure CS scaffold. The cotton CNF/CS scaffold effectively promoted the adhesion, viability, proliferation, migration, and collagen synthesis of skin cells. Notably, increased cell viability was observed in human fibroblasts cultured on scaffolds with higher concentrations of cotton CNF (100 and 1000 μg ml-1). Based on the findings, the cotton CNF/CS scaffold demonstrates enhanced physicochemical properties and bioactivity, making it a promising candidate for the development ofin vitrohuman skin models and wound healing dressings.

Calcium Cross-Linked Cellulose Nanofibrils: Hydrogel Design for Local and Controlled Nitric Oxide Release

Nitric oxide (NO) holds promise for wound healing due to its antimicrobial properties and role in promoting vasodilation and tissue regeneration. The local delivery of NO to target cells or organs offers significant potential in numerous biomedical applications, especially when NO donors are integrated into nontoxic viscous matrices. This study presents the development of robust cellulose nanofibril (CNF) hydrogels designed to control the release of nitric oxide (NO) generated in situ from a NO-donor molecule (S-nitrosoglutathione, GSNO) obtained from the nitrosation of its precursor molecule glutathione (GSH). CNF, efficiently isolated from sugar cane bagasse, exhibited a high aspect ratio and excellent colloidal stability in water. Although depletion forces could be observed upon the addition of GSH, this effect did not significantly alter the morphology of the CNF network at low GSH concentrations (<20 mM). Ionic cross-linking with Ca2+ resulted in nontoxic and robust hydrogels (elastic moduli ranging from 300 to 3000 Pa) at low CNF solid content. The release rate of NO from GSNO decreased in CNF from 1.61 to 0.40 mmol. L-1·h-1 when the nanofibril content raised from 0.3 to 1.0 wt %. The stabilization effect monitored for 16 h was assigned to hydrogel mesh size, which was easily tailored by modifying the concentration of CNF in the initial suspension. These results highlight the potential of CNF-based hydrogels in biomedical applications requiring a precise NO delivery.

Mupirocin-Doped α-Cellulose Nanopaper for Wound Dressing: Development, In Vitro Characterization and Antimicrobial Studies

This research aimed to develop a mupirocin-doped α-cellulose nanopaper (MDAC-NP) as a wound dressing to accelerate wound healing while limiting localized bacterial growth. The α-cellulose nanofibrils suspension was prepared by ultrasonication followed by microfluidization and subsequently doped with 0.05% w/v mupirocin to prepare nanopaper (MDAC-NP-A). The optimized batch of MDAC-NP had a porosity of 47.46 ± 0.60%, a thickness of 30 μm and a tensile strength of 0.113 MPa. The transmission electron microscopy images revealed long, slender, intertwined nanofibrillar structures and the scanning electron microscopy confirmed stable lamellar structures with tight nanofibrillar networks, giving them translucency. MDAC-NP-A had an excellent water vapor transmission rate of 2963 ± 10.26 g/m2/day, providing an optimal moist environment locally to promote wound healing. The mupirocin inclusion in the nanopapers was corroborated by the Fourier transform infrared spectroscopy and its crystallinity by X-ray diffraction, and differential scanning calorimetry results. The 100% drug release, was observed at 12 h from optimized MDAC-NP-A with a controlled release pattern. The MDAC-NP showed better antimicrobial activity, against S. aureus (41 mm) than E. coli (25 mm) and P. aeruginosa (17 mm) and was found to be better than marketed ointment. Thus, mupirocin-doped α-cellulose nanopapers emerge as a potential wound dressing for treating primary and secondary skin infections caused by external wounds.

Natural polysaccharides combined with mussel-inspired adhesion for multifunctional hydrogels in wound hemostasis and healing: A review

As naturally derived macromolecular polymers, polysaccharides have garnered significant attention in recent years as promising candidates for fabricating multifunctional hydrogels, particularly for wound healing applications, owing to their inherent biocompatibility, biodegradability, and structural diversity. However, the inherently weak skin adhesion of natural polysaccharide hydrogels has motivated the exploration of mussel-inspired catechol-based adhesion strategies to overcome this limitation. Incorporating mussel-inspired modifications into natural polysaccharides can imbue them with unique properties such as enhanced adhesion, antioxidant activity, antibacterial properties, and chelation capabilities, considerably broadening their potential for wound hemostasis and healing applications. This review comprehensively overviews recent advances in mussel-inspired polysaccharide hydrogels, focusing on the combination of natural polysaccharides, including chitosan, alginate, hyaluronic acid, cellulose, and dextran, with mussel-inspired catechol. We delve into their fabrication strategies and highlight their promising biomedical applications, with a particular emphasis on wound hemostasis and diverse wound healing processes. Mussel-inspired modification strategies for polysaccharide hydrogels are expected to remain a focal point within the fields of wound hemostasis and healing, paving the way for more impactful research endeavors.

Ultraviolet (UV) assisted fabrication and characterization of lignin containing cellulose nanofibrils (LCNFs) from wood residues

This study aimed to explore the synergistic mechanism of lignin chromophore modifications via UV treatment and to analyze the effects of mechanical treatments on LCNF properties for future uses. The procedure involved two steps: first, lignin's chromophore modification via UV illumination, and then the ball milling process was proceeded for 1 h, followed by high-intensity ultrasonic for 15-135 min. Characterization included preserved lignin content percentage, FTIR, UV-vis NMR, and color analysis for UV-modified samples, and to access the influence of mechanical treatment on LCNF samples further yield, zeta potential analysis, XRD, thermogravimetric analysis, atomic force microscopy, and scanning electron microscopy were performed. LCNFs S-120 demonstrated a zeta potential of -21.7 mV, indicating enhanced stability compared to the S-135 sample (-10.95 mV). The S-120 sample also showed the highest yield (74.02 %) and TGA at 391 °C. In XRD analysis, the S-120 sample demonstrated the highest CrI 64.3 %, than the S-15 sample (48.2 %). Preserved lignin in the LCNFs led to a slight reduction in crystallinity across all samples but improved thermal stability for all the prepared LCNFs samples. The UV and ultrasonication improved the homogeneity and durability of the LCNF samples, enabling a process that may be used to industries.

Surface modification of cellulose nanocrystals for biomedical and personal hygiene applications

The increasing demand for sustainable and effective materials in biomedical and personal hygiene applications has driven the exploration of cellulose nanocrystals (CNCs) derived from biomass. These nanomaterials are highly valued for their exceptional mechanical properties, biocompatibility, and renewable nature. Researchers are exploring CNCs for advancing medical and hygiene products, but surface modification is often needed to maximize their benefits. Techniques such as chemical functionalization, physical coating, and hybridization can significantly enhance CNCs dispersibility, stability, and interaction with biological systems. This versatility makes CNCs suitable for a variety of applications, including drug delivery systems, wound dressings, and personal hygiene products. Despite their advantages, maintaining the inherent properties of CNCs while integrating new functionalities through modification poses a challenge. Understanding the impact of various modification techniques on CNC performance is crucial for optimizing their effectiveness. This review aimed to consolidate current knowledge on the surface modification of biomass-derived CNCs, offering insights into different methods and their implications for biomedical and personal hygiene applications. By highlighting advancements, challenges, and prospects, it served as a crucial resource for advancing the development and application of CNCs in these critical fields.

Batch and continuous fixed bed adsorption of copper (II) from acid mine drainage (AMD) using green and recyclable adsorbent from cellulose microcrystals (CMCs)

The CMCs are viable materials for applications in industry and process innovation for removing heavy metal ions since they may be used in static and dynamic adsorption processes. It is necessary to develop simple, low-cost water treatment methods that use organic, biodegradable polymers such as nanomaterial-modified cellulose microcrystals. The column technique was used to investigate the effects of operational parameters such as pH, bed depth, concentration and flow rate. The input concentrations of 20, 40, 80 and 120 mg L-1, feed flow rates of 5, 10, 15 and 20 mL min-1, and bed heights of 5, 7.5, 10 and 12.5 cm. Experimental findings showed that the adsorption capacity decreased with increasing flow rate and increased with bed depth and input concentration, which were among the breakthrough parameters evaluated. The optimum adsorption capacity of 258.09 ± 0.96 mg g-1 was found to be achieved with an ideal pH of 6, an initial concentration of 200 mg L-1, a contact period of 300 min, and a dosage of 5 g/200 mL. The Langmuir model best fits the adsorption of indigo carmine, whereas the pseudo-second-order model, which governs the adsorption mechanism, may be described by physisorption combined with chemisorption. From a thermodynamic perspective, the adsorption was exothermic and spontaneous. In continuous adsorption, the Yoon-Nelson and Thomas models provided a good match for the hole curve, whereas the Bohart-Adams model fitted the breakthrough curve's initial portion ((Ct/C0) <0.5) perfectly. A three-dimensional adsorbent that has been chemically modified. The chemically modified CMCs adsorbent was characterized using FTIR, SEM and TGA.

Recent trends in nanocellulose: Metabolism-related, gastrointestinal effects, and applications in probiotic delivery

Nanocellulose, a versatile and sustainable nanomaterial derived from cellulose fibers, has attracted considerable attention in various fields due to its unique properties. Similar to dietary fibers, nanocellulose is difficult to digest in the human gastrointestinal tract. The indigestible nanocellulose is fermented by gut microbiota, producing metabolites and potentially exhibiting prebiotic activity in intestinal diseases. Additionally, nanocellulose can serve as a matrix material for probiotic protection and show promising prospects for probiotic delivery. In this review, we summarize the classification of nanocellulose, including cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial nanocellulose (BNC), highlighting their distinct characteristics and applications. We discuss the metabolism-related characteristics of nanocellulose from oral ingestion to colon fermentation and introduce the prebiotic activity of nanocellulose in intestinal diseases. Furthermore, we provide an overview of commonly used nanocellulose-based encapsulation techniques, such as emulsification, extrusion, freeze drying, and spray drying, as well as the delivery systems employing nanocellulose matrix materials, including microcapsules, emulsions, and hydrogels. Finally, we discuss the challenges associated with nanocellulose metabolism, prebiotic functionality, encapsulation techniques, and delivery systems using nanocellulose matrix material for probiotics. This review will provide new insight into the application of nanocellulose in the treatment of intestinal diseases and probiotic delivery.

Biowaste rice husk derived cellulosic hydrogel incorporating industrial cotton waste nonwoven for wound dressing

Bio-wastes are organic materials achieved through biological sources. The rice crop produces a substantial amount of biowaste in the form of rice husk, which is rich in cellulose. In this research, cellulose was extracted from rice husk by alkalization and bleaching process. The rice husk extracted cellulose was further used to develop cellulose hydrogel by using the sol-gel technique. The nonwoven fabric of industrial cotton waste was developed in three different GSM (50, 100, and 150). The nonwoven fabric was incorporated in the cellulose hydrogel having three different concentrations (1 %, 2 %, and 3 %) to develop the hydrogel non-woven cotton fabric composite for sustainable wound dressing applications. Moreover, prepared rice husk extracted cellulose hydrogel loaded with AgNO3 (0.5 %, 1 %, and 1.5 %) for achieving antibacterial characteristics. The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed to confirm the existence of cellulose hydrogel layers within the cotton nonwoven composite. The developed hydrogel S12 exhibited a maximum fluid absorbency of 1281.84 % with a tensile strength of 28.6 N and elongation of 40.96 %. The results show successful rice husk extracted cellulose hydrogel formation, exhibiting structural stability, excellent exudate absorbency and moisture management, antimicrobial efficacy, and sustainability.

Applied research and recent advances in the development of flexible sensing hydrogels from cellulose: A review

Flexible wearable smart sensing materials have gained immense momentum, and biomass-based hydrogel sensors for renewable and biologically safe wearable sensors have attracted significant attention in order to meet the growing demand for sustainability and ecological friendliness. Cellulose has been widely used in the field of biomass-based hydrogel sensing materials, being the most abundant biomass material in nature. This review mainly focuses on the types of cellulose hydrogels, the preparation methods and their applications in smart flexible sensing materials. The structure-functional properties-application relationship of cellulose hydrogels and the applications of various cellulose hydrogels in flexible sensing are described in detail. Then it focuses on the methods and mechanisms of cellulose hydrogel flexible sensors preparation, and then summarizes the research of cellulose hydrogel sensors for different types of stimulus response mechanisms to pressure, pH, biomolecules, ions, temperature, humidity, and light. The applications of cellulose hydrogels as flexible sensing materials in biomedical sensing, smart wearable and environmental monitoring are further summarized. Finally, the future development trend of cellulose hydrogels is briefly introduced and the future development of cellulose hydrogel sensing materials is envisioned.

Advancements of Biomacromolecular Hydrogel Applications in Food Nutrition and Health

Hydrogels exhibit remarkable degradability, biocompatibility and functionality, which position them as highly promising materials for applications within the food and pharmaceutical industries. Although many relevant studies on hydrogels have been reported in the chemical industry, materials, and other fields, there have been few reviews on their potential applications in food nutrition and human health. This study aims to address this gap by reviewing the functional properties of hydrogels and assessing their value in terms of food nutrition and human health. The use of hydrogels in preserving bioactive ingredients, food packaging and food distribution is delved into specifically in this review. Hydrogels can serve as cutting-edge materials for food packaging and delivery, ensuring the preservation of nutritional activity within food products, facilitating targeted delivery of bioactive compounds and regulating the digestion and absorption processes in the human body, thereby promoting human health. Moreover, hydrogels find applications in in vitro cell and tissue culture, human tissue repair, as well as chronic disease prevention and treatment. These broad applications have attracted great attention in the fields of human food nutrition and health. Ultimately, this paper serves as a valuable reference for further utilization and exploration of hydrogels in these respective fields.

Advanced Flexible Wearable Electronics from Hybrid Nanocomposites Based on Cellulose Nanofibers, PEDOT:PSS and Reduced Graphene Oxide

The need for responsible electronics is leading to great interest in the development of new bio-based devices that are environmentally friendly. This work presents a simple and efficient process for the creation of conductive nanocomposites using renewable materials such as cellulose nanofibers (CNF) from enzymatic pretreatment, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), and/or reduced graphene oxide (rGO). Different combinations of CNF, rGo, and PEDOT:PSS were considered to generate homogeneous binary and ternary nanocomposite formulations. These formulations were characterized through SEM, Raman spectroscopy, mechanical, electrical, and electrochemical analysis. The binary formulation containing 40 wt% of PEDOT:PSS resulted in nanocomposite formulations with tensile strength, Young's modulus, and a conductivity of 70.39 MPa, 3.87 GPa, and 0.35 S/cm, respectively. The binary formulation with 15 wt% of rGO reached 86.19 MPa, 4.41 GPa, and 13.88 S/cm of the same respective properties. A synergy effect was observed for the ternary formulations between both conductive elements; these nanocomposite formulations reached 42.11 S/cm of conductivity and kept their strength as nanocomposites. The 3D design strategy provided a highly conductive network maintaining the structural integrity of CNF, which generated homogenous nanocomposites with rGO and PEDOT:PSS. These formulations can be considered as greatly promising for the next generation of low-cost, eco-friendly, and energy storage devices, such as batteries or electrochemical capacitors.

Feasibility of biomass-based flexible and transparent AuNPs-acetylcellulose membrane for multifarious surface-enhanced Raman spectroscopy detection

BACKGROUND

Lignocellulosic biomass-based derivatives coupled with surface-enhanced Raman spectroscopy (SERS) technology have emerged as an appealing and indispensable tool in food safety and environmental monitoring for rapidly detecting trace contaminants like pesticide residues. The membrane material, serving as a substrate, ensures both sampling flexibility and test accuracy by directing the diffusion-adsorption process of the molecules. However, the existing membrane substrates, critical for the practical application of SERS, suffer from issues such as costly, intricate fabrication procedures, or restricted detection capabilities.

RESULTS

Herein, we present a flexible, transparent, and biodegradable cellulose acetate membrane with gold nanoparticles (AuNPs) uniformly embedded, fabricated using a simple scraping method. This membrane achieved a limit of detection (LOD) of thiram pesticide in water at 10-8 g mL-1. The unique optical transparency of the substrates allowed for in-situ detection on surfaces, with an LOD of thiram reaching 30 ng cm-2.

SIGNIFICANCE

Furthermore, SERS substrates made from corn stover-derived cellulose acetate enable the detection of various contaminants, highlighting their cost-effectiveness and eco-friendliness because of the abundance and low environmental impact of the raw materials.

Advances in the preparation and application of cellulose-based antimicrobial materials: A review

The rise of polymer materials in modern life has drawn attention to renewable, easily biodegradable, environmentally-friendly bio-based polymers. Notably, significant research has been dedicated to creating green antimicrobial functional materials for the biomedical field using natural polymer materials. Cellulose is a rich natural biomass organic polymer material. Given its favorable attributes like film-forming capability, biodegradability, and biocompatibility, it is extensively employed to tackle a wide range of challenges confronting humanity today. However, its inherent drawbacks, such as insolubility in water and most organic solvents, hygroscopic nature, difficulty in melting, and limited antimicrobial properties, continue to pose challenges for realizing the high-value applications of cellulose. Achieving multifunctionality and more efficient application of cellulose still poses major challenges. In this regard, the current development status of cellulose materials was reviewed, covering the classification, preparation methods, and application status of cellulose-based antimicrobial materials. The application value of cellulose-based antimicrobial materials in biomedicine, textiles, food packaging, cosmetics and wastewater treatment was summarised. Finally, insights were provided into the developing prospects of cellulose-based antimicrobial materials were provided.

High-Value Utilization of Cellulose: Intriguing and Important Effects of Hydrogen Bonding Interactions─A Mini-Review

Cellulose has been widely used in papermaking, textile, and chemical industries due to its diverse sources, environmental friendliness, and renewability. Recently, much more attention has been paid to converting cellulose into high-value-added products. Therefore, the extraction of nanocellulose, the dissolution of cellulose, and their applications are some of the most important research topics currently. However, cellulose's dense hydrogen bond network poses challenges for efficient extraction and dissolution, limiting its potential for functional material development. This review discusses the mechanisms of hydrogen bond disruption and weak interactions during nanocellulose extraction and cellulose dissolution. Key challenges and future research directions are highlighted, emphasizing developing efficient, ecofriendly, and cost-effective methods. Additionally, this review provides theoretical insights for constructing high-performance cellulose-based materials.

Synthesis, functionalization, and commercial application of cellulose-based nanomaterials

In recent times, cellulose, an abundant and renewable biopolymer, has attracted considerable interest due to its potential applications in nanotechnology. This review explores the latest developments in cellulose-based nanomaterial synthesis, functionalization, and commercial applications. Beginning with an overview of the diverse sources of cellulose and the methods employed for its isolation and purification, the review delves into the various techniques used for the synthesis of cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs), highlighting their unique properties and potential applications. Furthermore, the functionalization strategies employed to enhance the properties and tailor the functionalities of cellulose-based nanomaterials were discussed. The review also provides insights into the emerging commercial applications of cellulose-based nanomaterials across diverse sectors, including packaging, biomedical engineering, textiles, and environmental remediation. Finally, challenges and prospects for the widespread adoption of cellulose-based nanomaterials are outlined, emphasizing the need for further research and development to unlock their full potential in sustainable and innovative applications.

Lignin-containing cellulose nanocrystals enhanced electrospun polylactic acid-based nanofibrous mats: Strengthen and toughen

Biodegradable polylactic acid (PLA) nanofibrous mats prepared by electrospinning serve as suitable packaging materials. However, their practical applications are limited by their weak mechanical properties, poor thermal stability, and high cost. In this study, green and low-cost lignin-containing cellulose nanocrystals (LCNCs) with different lignin contents were developed and employed as reinforced materials to synergistically enhance the thermal, mechanical, and hydrophobic properties of PLA electrospun nanofibrous mats. The presence of moderate lignin improved the interfacial compatibility between the LCNCs and PLA, resulting in excellent mechanical properties of the nanofibrous mats. Compared to pure PLA mats, the tensile strength of the composites reached up to 21.0 MPa, representing a 6.6-fold increase. Its toughness was synchronously enhanced by 16 times, reaching a maximum of 3.6 MJ/m3. The maximum decomposition temperature of PLA/LCNCs electrospun nanofibrous mats increased from 339 °C to 365 °C. Furthermore, the increase in lignin in the LCNCs positively contributed to improving the hydrophobicity of the PLA/LCNCs electrospun nanofibrous mats. This bio-based strategy of LCNCs employed in the enhancement of fully bio-based PLA nanofibrous mats offers a viable approach for the advancement of packaging films.

Enzymatic approaches for diversifying bioproducts from cellulosic biomass

Cellulosic biomass is the most abundantly available natural carbon-based renewable resource on Earth. Its widespread availability, combined with rising awareness, evolving policies, and changing regulations supporting sustainable practices, has propelled its role as a crucial renewable feedstock to meet the escalating demand for eco-friendly and renewable materials, chemicals, and fuels. Initially, biorefinery models using cellulosic biomass had focused on single-product platform, primarily monomeric sugars for biofuel. However, since the launch of the first pioneering cellulosic plants in 2014, these models have undergone significant revisions to adapt their biomass upgrading strategy. These changes aim to diversify the bioproduct portfolio and improve the revenue streams of cellulosic biomass biorefineries. Within this area of research and development, enzyme-based technologies can play a significant role by contributing to eco-design in producing and creating innovative bioproducts. This Feature Article highlights our strategies and recent progress in utilizing the biological diversity and inherent selectivity of enzymes to develop and continuously optimize sustainable enzyme-based technologies with distinct application approaches. We have advanced technologies for standalone platforms, which produce various forms of cellulose nanomaterials engineered with customized and enhanced properties and high yields. Additionally, we have tailored technologies for integration within a biorefinery concept. This biorefinery approach prioritizes designing tailored processes to establish bionanomaterials, such as cellulose and lignin nanoparticles, and bioactive molecules as part of a new multi-bioproduct platform for cellulosic biomass biorefineries. These innovations expand the range of bioproducts that can be produced from cellulosic biomass, transcending the conventional focus on monomeric sugars for biofuel production to include biomaterials biorefinery. This shift thereby contributes to strengthening the Bioeconomy strategy and supporting the achievement of several Sustainable Development Goals (SDGs) of the 2030 Agenda for Sustainable Development.

Development of starch-cellulose composite films with antimicrobial potential

This study explored the structure and performance of starch-based antibacterial films reinforced with black tea cellulose nanocrystals (BT-CNCs). The optimal addition amount of BT-CNCs is 5 % (w/w Starch). This nanocrystal-infused film, incorporating chitosan (CS), ε-polylysine (ε-PL), and zinc oxide nanoparticles (ZnONP) as antibacterial agents, exhibited a smooth, continuous surface. The addition of BT-CNCs and antibacterial agents did not change the group characteristic peaks of the film, but changed the crystallinity slightly. The films, namely St, St/CNCs, St/CNCs/CS, and St/CNCs/ε-P, maintained high light transmittance (above 80 %), except for the St/CNCs/ZnONP film, which effectively shielded UV radiation. The combined use of antibacterial agents and BT-CNCs enhanced the water and oxygen barrier properties of the film. Notably, the St/CNCs/CS film exhibited the lowest solubility (17.74 % ± 0.36) and the highest tensile strength (14.23 ± 0.16 MPa). The antibacterial efficacy of the films decreased in the order of St/CNCs/ZnONP, St/CNCs/ε-PL, and St/CNCs/CS, with a more pronounced inhibitory effect on E. coli compared to S. aureus. This study marries natural waste recycling with cutting-edge food packaging technology, setting a new benchmark for the development of sustainable packaging materials.

Bioadhesive and drug-loaded cellulose nanofiber/alginate film for healing oral mucosal wounds

Recurrent oral ulcers are common oral mucosal lesions that severely reduce patients' quality of life. Commercial mucoadhesive films are easily disrupted due to oral movement and complex wet environments, thus reducing drug utilization and even causing toxic side effects. Herein, we report a mucoadhesive film composed of Ca2+-crosslinked carboxymethylated cellulose nanofibers and alginate, in which two drugs of dexamethasone (DXM) and dyclonine hydrochloride (DYC) are loaded for the treatment of oral ulcers. The wet films have a high Young's modulus of 7.1 ± 2.6 MPa and a large strain of 53.6 ± 9.8 % and adhere to tissue strongly, which allows them to resist the deformation caused by frequent oral movement. The films also have nice durability against water and excellent biocompatibility. Moreover, the drug release was controlled at different rates. The fast release of DYC facilitates the quick relief of pain, while the slow release of DXM benefits the long-term treatment of wounds. Finally, the animal experiment demonstrates the films displayed excellent therapeutic efficacy in healing oral ulcers.

Translational applications of magnetic nanocellulose composites

Nanocellulose has emerged as a potential 'green' material owing to its inimitable properties. Furthermore, the significant development in technology has facilitated the design of multidimensional nanocellulose structures, including one-dimensional (1D: microparticles and nanofibers), two-dimensional (2D: coatings), and three-dimensional (3D: hydrogels/ferrogels) composites. In this case, nanocellulose composites blended with magnetic nanoparticles represent a new class of hybrid materials with improved biocompatibility and biodegradability. The application field of magnetic nanocellulose composites (MNCs) ranges from biomedicine and the environment to catalysis and sensing. In this review, we present the major applications of MNCs, emphasizing their innovative benefits and how they interconnect with translational applications in clinics and the environment. Additionally, we focus on the synthesis techniques and role of different additives in the fabrication of MNCs for achieving extremely precise and intricate tasks related to real-world applications. Subsequently, we reveal the recent interdisciplinary research on MNCs and discuss their mechanical, tribological, electrochemical, magnetic, and biological phenomena. Finally, this review concludes with a portrayal of computational modelling together with a glimpse of the various translational applications of MNCs. Therefore, it is anticipated that the current review will provide the readers with an extensive opportunity and a more comprehensive depiction related to the types, properties, and applications of MNCs.

Bio-Based Polyurethane-Urea with Self-Healing and Closed-Loop Recyclability Synthesized from Renewable Carbon Dioxide and Vanillin

Developing recyclable and self-healing non-isocyanate polyurethane (NIPU) from renewable resources to replace traditional petroleum-based polyurethane (PU) is crucial for advancing green chemistry and sustainable development. Herein, a series of innovative cross-linked Poly(hydroxyurethane-urea)s (PHUUs) were prepared using renewable carbon dioxide (CO2) and vanillin, which displayed excellent thermal stability properties and solvent resistance. These PHUUs were constructed through the introduction of reversible hydrogen and imine bonds into cross-linked polymer networks, resulting in the cross-linked PHUUs exhibiting thermoplastic-like reprocessability, self healing, and closed-loop recyclability. Notably, the results indicated that the VL-TTD*-50 with remarkable hot-pressed remolding efficiency (nearly 98.0%) and self-healing efficiency (exceeding 95.0%) of tensile strength at 60 °C. Furthermore, they can be degraded in the 1M HCl and THF (v:v = 2:8) solution at room temperature, followed by regeneration without altering their original chemical structure and mechanical properties. This study presents a novel strategy for preparing cross-linked PHUUs with self-healing and closed-loop recyclability from renewable resources as sustainable alternatives for traditional petroleum-based PUs.

Structure, rheology and stability of walnut oleogels with different carboxylation degree of cellulose nanofiber

The effects of carboxylation degree (0.3-2.4 mmol/g) of cellulose nanofiber (CNF) on the microstructure and mechanical properties of edible walnut oleogels were comprehensively examined. The oleogels were well prepared by emulsion-templated approach for potential substitute of conventional saturated or trans-fats in food products. The results demonstrated that the oil-binding capacity (OBC) and textural strength of oleogels enhanced with the increase of CNF carboxyl content, while the structural strength (G' in rheological measurement) and the resistance to shear thinning was first decreased and then increased. It possibly reflected the competition on the dominant structuring mechanism by hydrogen bonding from cellulose hydroxyl groups and electrostatic interactions from -COONa function. With the combined mechanism, oleogel with low structural strength and relatively high OBC (CNF carboxyl content of 1.2 mmol/g, OBC >83 %, G' ≈ 7 × 104 Pa and firmness of 0.30 N) and oleogel with enough structural rigidity and high OBC (CNF carboxyl content of 1.8 mmol/g, OBC >89 %, G' of up to 1.7 × 105 Pa, and firmness of up to 0.66 N) were both fabricated. This reveals the feasibility of regulating oleogel structure and textual properties by using CNF as the unique oleogelator and simply changing its surface carboxyl function.

Phytic Acid-Functional Cellulose Nanocrystals and Their Application in Self-Healing Nanocomposite Hydrogels

Cellulose nanocrystals (CNCs) have garnered significant attention as a modifiable substrate because of their exceptional performances, including remarkable degradability, high tensile strength, high elastic modulus, and biocompatibility. In this article, the successful adsorption of phytic acid (PA) onto the surface of cellulose nanocrystals @polydopamine (CNC@PDA) was achieved. Taking inspiration from mussels, a dopamine self-polymerization reaction was employed to coat the surface of CNCs with PDA. Utilizing Pickering emulsion, the CNC@PDA-PA nanomaterial was obtained by grafting PA onto CNC@PDA. An environmentally friendly hydrogel was prepared through various reversible interactions using poly(acrylic acid) (PAA) and Fe3+ as raw materials with the assistance of CNC@PDA-PA. By multiple hydrogen bonding and metal-ligand coordination, nanocomposite hydrogels exhibit remarkable mechanical properties (the tensile strength and strain were 1.82 MPa and 442.1%, respectively) in addition to spectacular healing abilities (96.6% after 5 h). The study aimed to develop an innovative approach for fabricating nanocomposite hydrogels with exceptional self-healing capabilities.

Cellulose-derived raw materials towards advanced functional transparent papers

Pulp and paper are gradually transforming from a traditional industry into a new green strategic industry. In parallel, cellulose-derived transparent paper is gaining ground for the development of advanced functional materials for light management with eco-friendly, high performance, and multifunctionality. This review focuses on methods and processes for the preparation of cellulose-derived transparent papers, highlighting the characterization of raw materials linked to responses to different properties, such as optical and mechanical properties. The applications in electronic devices, energy conversion and storage, and eco-friendly packaging are also highlighted with the objective to showcase the untapped potential of cellulose-derived transparent paper, challenging the prevailing notion that paper is merely a daily life product. Finally, the challenges and propose future directions for the development of cellulose-derived transparent paper are identified.

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.

B and N Codoped Cellulose-Supported Ag-/Bi-Doped Mo(S,O)3 Trimetallic Sulfo-Oxide Catalyst for Photocatalytic H2 Evolution Reaction and 4-Nitrophenol Reduction

Cellulose plays a significant role in designing efficient and stable cellulose-based metallic catalysts, owing to its surface functionalities. Its hydroxyl groups are used as anchor sites for the nucleation and growth of metallic nanoparticles and, as a result, improve the stability and catalytic activity. Meanwhile, cellulose is also amenable to surface modifications to be more suitable for incorporating and stabilizing metallic nanoparticles. Herein, the Ag-/Bi-doped Mo(S,O)3 trimetallic sulfo-oxide anchored on B and N codoped cellulose (B-N-C) synthesized by a facile approach showed excellent stability and catalytic activity for PHER at 573.28 μmol/h H2 with 25 mg of catalyst under visible light, and 92.3% of the 4-nitrophenol (4-NP) reduction was achieved within 135 min by in situ-generated protons. In addition to B and N codoping, our use of the calcination method for B-N-C preparation further increases the structural disorders and defects, which act as anchoring sites for Ag-/Bi-doped Mo(S,O)3 nanoparticles. The Ag-/Bi-doped Mo(S,O)3@B-N-C surface active site also stimulates H2O molecule adsorption and activation kinetics and reduces the photogenerated charge carrier's recombination rate. The Mo4+ → Mo6+ electron hopping transport and the O 2p and Bi 6s orbital overlap facilitate the fast electron transfer by enhancing the electron's lifetime and photoinduced charge carrier mobility, respectively. In addition to acting as a support, B-N-C provides a highly conductive network that enhances charge transport, and the relocated electron in B-N-C activates the H2O molecule, which enables Ag-/Bi-doped Mo(S,O)3@B-N-C to have appreciable PHER performance.

Bacterial Cellulose: A Sustainable Source for Hydrogels and 3D-Printed Scaffolds for Tissue Engineering

Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for biomedical applications and has raised increasing interest, particularly in the context of 3D printing for tissue engineering and regenerative medicine applications. Bacterial cellulose can serve as an excellent bioink in 3D printing, due to its biocompatibility, biodegradability, and ability to mimic the collagen fibrils from the extracellular matrix (ECM) of connective tissues. Its nanofibrillar structure provides a suitable scaffold for cell attachment, proliferation, and differentiation, crucial for tissue regeneration. Moreover, its mechanical strength and flexibility allow for the precise printing of complex tissue structures. Bacterial cellulose itself has no antimicrobial activity, but due to its ideal structure, it serves as matrix for other bioactive molecules, resulting in a hybrid product with antimicrobial properties, particularly advantageous in the management of chronic wounds healing process. Overall, this unique combination of properties makes bacterial cellulose a promising material for manufacturing hydrogels and 3D-printed scaffolds, advancing the field of tissue engineering and regenerative medicine.

Preparation of an injectable and photocurable carboxymethyl cellulose/hydroxyapatite composite and its application in cranial regeneration

Limited bone regeneration, uncontrollable degradation rate, mismatched defect zone and poor operability have plagued the reconstruction of irregular bone defect by tissue-engineered materials. A combination of biomimetic scaffolds with hydroxyapatite has gained great popularity in promoting bone regeneration. Therefore, we designed an injectable, photocurable and in-situ curing hydrogel by methacrylic anhydride -modified carboxymethyl cellulose (CMC-MA) loading with spherical hydroxyapatite (HA) to highly simulate the natural bony matrix and match any shape of damaged tissue. The prepared carboxymethyl cellulose-methacrylate/ hydroxyapatite(CMC-MA/HA) composite presented good rheological behavior, swelling ratio and mechanical property under light illumination. Meanwhile, this composite hydrogel promoted effectively proliferation, supported adhesion and upregulated the osteogenic-related genes expression of MC3T3-E1 cells in vitro, as well as the activity of the osteogenic critical protein, Integrin α1, β1, Myosin 9, Myosin 10, BMP-2 and Smad 1 in Integrin/BMP-2 signal pathway. Together, the composite hydrogels realized promotion of bone regeneration, deformity improvement, and the enhanced new bone strength in skull defect. It also displayed a good histocompatibility and stability of subcutaneous implantation in vivo. Overall, this study laid the groundwork for future research into developing a novel biomaterial and a minimally invasive therapeutic strategies for reconstructing bone defects and contour deficiencies.

Electroactive Biomaterials Regulate the Electrophysiological Microenvironment to Promote Bone and Cartilage Tissue Regeneration

The incidence of large bone and articular cartilage defects caused by traumatic injury is increasing worldwide; the tissue regeneration process for these injuries is lengthy due to limited self‐healing ability. Endogenous bioelectrical phenomenon has been well recognized to play an important role in bone and cartilage homeostasis and regeneration. Studies have reported that electrical stimulation (ES) can effectively regulate various biological processes and holds promise as an external intervention to enhance the synthesis of the extracellular matrix, thereby accelerating the process of bone and cartilage regeneration. Hence, electroactive biomaterials have been considered a biomimetic approach to ensure functional recovery by integrating various physiological signals, including electrical, biochemical, and mechanical signals. This review will discuss the role of endogenous bioelectricity in bone and cartilage tissue, as well as the effects of ES on cellular behaviors. Then, recent advances in electroactive materials and their applications in bone and cartilage tissue regeneration are systematically overviewed, with a focus on their advantages and disadvantages as tissue repair materials and performances in the modulation of cell fate. Finally, the significance of mimicking the electrophysiological microenvironment of target tissue is emphasized and future development challenges of electroactive biomaterials for bone and cartilage repair strategies are proposed.

Development of nanocellulose hydrogels for application in the food and biomedical industries: A review

As the most abundant and renewable natural resource, cellulose has attracted significant attention and research interest for the production of hydrogels (HGs). To address environmental issues and emerging demands, the benefits of naturally produced HGs include excellent mechanical properties and superior biocompatibility. HGs are three-dimensional networks created by chemical or physical cross-linking of linear or branched hydrophilic polymers and have high capacity for absorption of water and biological fluids. Although widely used in the food and biomedical fields, most HGs are not biodegradable. Nanocellulose hydrogels (NC-HGs) have been extensively applied in the food industry for detection of freshness, chemical additives, and substitutes, as well as the biomedical field for use as bioengineering scaffolds and drug delivery systems owing to structural interchangeability and stimuli-responsive properties. In this review article, the sources, structures, and preparation methods of NC-HGs are described, applications in the food and biomedical industries are summarized, and current limitations and future trends are discussed.

Unveiling structure and performance of tea-derived cellulose nanocrystals

In this study, cellulose was extracted from black tea residues to produce black tea cellulose nanocrystals (BT-CNCs) using an optimized acid hydrolysis method. The structure and performance of BT-CNCs were evaluated. The results showed that the optimal conditions for acidolysis of BT-CNCs included a sulfuric acid concentration of 64 %, a solid-liquid ratio of 1:18 (w/v), a hydrolysis temperature of 45 °C, and a hydrolysis time of 50 min. The optimization process resulted in a 44.8 % increase in the yield of BT-CNCs, which exhibited a crystallinity of 68.57 % and were characterized by the typical cellulose I structure. The diameters of the particles range from 5 to 45 nm, and they exhibit aggregation behavior. Notably, BT-CNCs demonstrated excellent storage stability, and the Tyndall effect occurred when exposed to a single beam of light. Although the thermal stability of BT-CNCs decreased, their primary thermal degradation temperature remained above 200 °C. The colloidal nature of BT-CNCs was identified as a non-Newtonian fluid with "shear thinning" behavior. This study introduces a novel method to convert tea waste into BT-CNCs, increasing the yield of BT-CNCs and enhancing waste utilization. BT-CNCs hold promise for application in reinforced composites, offering substantial industrial value.

DES-ultrasonication treatment of cellulose nanocrystals and the reinforcement in carrageenan biocomposite

CNCs are intensively studied to reinforce biocomposites. However, it remains a challenge to homogeneously disperse the CNC in biocomposites for a smooth film surface. Mechanochemical treatment via ultrasonication in deep eutectic solvent (DES) generated a stable dispersion of CNC before incorporation into carrageenan biocomposite. Shifted peaks of choline chloride (ChCl) methylene groups to 3.95-3.98 ppm in 1H NMR indicated a formation of eutectic mixture between the hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD) at the functional group of CH3···OH. The swelling of CNC in the DES was proven by the formation of intermolecular H-bond at a length of 2.46 Å. The use of DES contributed to a good dispersion of CNC in the solution which increased zeta potential by 43.2 % compared to CNC in deionized water. The ultrasonication amplitude and feed concentration were varied for the best parameters of a stable dispersion of CNC. The crystallinity of 1 wt% of CNC at 20 % sonication amplitude improved from 76 to 81 %. The high crystallinity of CNCDES resulted in an increase in film tensile and capsule loop strength of Carra-CNCDES by 20.7 and 19.4 %, respectively. Improved dispersion of CNCDES reduced the surface roughness of the biocomposite by 21.8 %. H-bond network in CNCDES improved the biocomposite properties for an ingenious reinforcement material.

The Development of a Bacterial Nanocellulose/Cationic Starch Hydrogel for the Production of Sustainable 3D-Printed Packaging Foils

Polymers have become an important part of everyday life, but most of the polymers currently used are petroleum-based. This poses an environmental problem, especially with respect to products that are quickly discarded. For this reason, current packaging development focuses on sustainable materials as an alternative to synthetic ones. Nanocellulose, a relatively new material derived from cellulose, has unique properties such as high strength, low density, high surface area, and good barrier properties, making it popular in various applications. Additionally, 3D printing technologies have become an important part of industrial and commercial processes, enabling the realization of innovative ideas and functionalities. The main aim of this research was to develop a hydrogel of bacterial nanocellulose with suitable rheological properties for the 3D printing of polymer foils. Three variations of bacterial nanocellulose hydrogel differing in ratios of bacterial nanocellulose to cationic starch were produced. The rheological studies confirmed the suitability of the hydrogels for 3D printing. Foils were successfully 3D-printed using a modified 3D printer. The physical-mechanical, surface, and optical properties of the foils were determined. All foils were homogeneous with adequate mechanical properties. The 3D-printed foils with the highest amount of cationic starch were the most homogeneous and transparent and, despite their rigidity, very strong. All foils were semi-transparent, had a non-glossy surface, and retained poor water wettability.

Stretchable, antifatigue, and intelligent nanocellulose hydrogel colorimetric film for real-time visual detection of beef freshness

The use of biopolymers as matrices and anthocyanins as pH-sensing indicators has generated increasing interest in freshness detection. Nevertheless, the weak mechanical properties and color stability of biopolymer-based smart packaging systems restrict their practicality. In this study, a nanocellulose hydrogel colorimetric film with enhanced stretchability, antifatigue properties, and color stability was prepared using soy hull nanocellulose (SHNC), polyvinyl alcohol (PVA), sodium alginate (SA), and anthocyanin (Anth) as raw materials. This hydrogel colorimetric film was used to detect beef freshness. The structure and properties (e.g., mechanical, thermal stability and hydrophobicity) of these hydrogel colorimetric films were characterized using different techniques. Fourier-transform infrared spectroscopy revealed the presence of hydrogen and ester bonds in the hydrogel colorimetric films, whereas scanning electron microscopy revealed the fish scale-like and honeycomb network structure of the hydrogel colorimetric films. Mechanical testing demonstrated that the SHNC/PVA/SA/Anth-2 hydrogel colorimetric film exhibited excellent tensile properties (elongation = 261 %), viscoelasticity (storage modulus of 11.25 kPa), and mechanical strength (tensile strength = 154 kPa), and the hydrogel colorimetric film exhibited excellent mechanical properties after repeated tensile tests. Moreover, the hydrogel colorimetric film had high transparency, excellent anti-UV linearity, thermal stability and hydrophobicity, and had displayed visually discernible color response to pH buffer solution and volatile NH3 by naked eyes, which was highly correlated with the TVB-N and pH values. Notably, the release of anthocyanin in distilled water decreased from 81.23 % to 19.87 %. The designed SHNC/PVA/SA/Anth hydrogel colorimetric films exhibited potential application as smart packaging film or gas-sensing labels in monitoring the freshness of meat products.