Carbohydrate Polymers最新文献

Enterovirus 71 (EV71) is recognized as a major causative agent of hand, foot, and mouth disease (HFMD), posing a significant global public health concern due to its widespread impact and resulting in a major public health issue worldwide. Despite its prevalence, current clinical therapy lacks effective antiviral agents. Fucosylated chondroitin sulfates (FCS) derived from sea cucumber exhibits a range of biological activities including potent antiviral effects. This study provides compelling evidence of the potent antiviral efficacy of FCS against EV71. To further elucidate the impact of structural variations on the anti-EV71 activity, native FCSs with diverse sulfation patterns and a varity of FCS derivatives were prepared and analyzed. Notably, this study presents the detailed structural characterization of FCSs from the sea cucumbers Holothuria scabra Jaege and Holothuria fuscopunctata. Analysis of the structure-activity relationships revealed that molecular weight, sulfated fucose branches, and sulfation pattern were all crucial factors contributing to the potent inhibitory effects of FCS against EV71. Interestingly, molecular weight emerged as the most significant structural determinant of the antiviral potency. These findings suggest the promising potential of utilizing FCS as an innovative EV71 entry inhibitor for the treatment of HFMD.

A combination of maleic acid and sodium hypophosphite as a durable press finishing agent has been reported as a safer but equally effective alternative to conventional formaldehyde-based cross-linking agents for applications in cellulose-based fiber and textile finishing. However, the mechanistic details of this system have not yet been fully elucidated to allow optimization of the conditions. Effective cross-linking treatment requires high curing temperatures of ≥160 °C, which enhances oxidative and thermal degradation of cellulose. In this work, the sequential steps of the cross-linking mechanism were investigated both with model compounds and cellulosic substrates. Extensive NMR studies on model compounds revealed several side reactions alongside the synthesis of the targeted cross-linkable moiety. As an alternative, to circumvent side reactions, a two-step procedure was used by synthesizing the cross-linker sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid in a well-defined pre-condensation reaction before application onto the cellulosic substrate. Further, the effect of the cross-linking treatment on the molecular weight distribution of cellulose was studied by gel permeation chromatography, which showed degradation due to maleic acid/sodium hypophosphite treatment. By using sodium 2-[(1,2-dicarboxyethyl)phosphinate]succinic acid and sodium hypophosphite, this degradation could be significantly limited.

Lyotropic chiral nematic cellulose nanocrystals (CNCs) have attracted significant attention and great progress has been made. Investigating their physical parameters, especially the twist elastic constant (K₂₂), is pivotal for advancing our comprehension of fundamental viscoelastic property of chiral nematic phase. In this study, we demonstrate a straightforward method to simultaneously estimate K₂₂ and helical twisting power (K_t) of chiral nematic CNCs. This method involves analyzing rheology properties and electro-response of CNCs, focusing on the rotational dynamics and structural reconfiguration of CNC tactoids under an electric field. By examining the rotation dynamics of CNC tactoids under an electric field, together with the viscosity characterization, the anisotropic dielectric susceptibility (∆χ) of chiral nematic CNC along the helix axis was determined. Subsequently, K₂₂/∆χ_n was extracted by analyzing CNC tactoid pitch evolution under an electric field, employing the de Gennes model. The K₂₂ for different concentrated CNCs is finally estimated by integrating experimental results and theory. It is shown that the chiral nematic CNCs present concentration-dependent K₂₂, ranging from 0.05 to 0.14 pN, while K_t spans from 0.06 to 0.14 pN/μm. This study offers a comprehensive understanding of the CNC fundamental viscoelastic property and opens up new avenues for K₂₂ measurement in other lyotropic liquid crystals.

Surface-hydrophobized cellulose nanomaterials (CNs) with high thermal degradation points are required for preparing various materials, such as epoxy nanocomposites, which possess high mechanical strength, optical transparency, and thermal stability. Amidation of carboxy groups in CNs is one possible chemical modification for hydrophilic CNs that contain abundant carboxy groups. However, achieving efficient amidation of high ratios of carboxy groups in CNs is highly challenging for industrial applications. In this study, carboxy group-containing fibrous wood pulp was subjected to amidation in heterogeneous solid/liquid systems to prepare products with high amidation ratios and high yields, while implementing cost-effective isolation and purification processes. Consequently, a partially acid-hydrolyzed wood pulp with abundant carboxy groups was first prepared. Subsequently, 88 % and 91 % of the carboxy groups in the pulp were successfully amidated using polyalkylene glycols-NH₂ and octylamine, respectively. This was achieved by utilizing 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride and N-methylmorpholine as the condensation reagent and activator, respectively, in N,N-dimethylformamide (DMF) at approximately 23 °C for 16 h. The thermal degradation point increased from 224 °C for the acid-hydrolyzed pulp to over 250 °C after amidation. The amidated pulps were then converted into transparent dispersions, consisting of amidated cellulose nanocrystals, by homogenization in an epoxy monomer/DMF mixture using high-pressure homogenization.

Phase change fibers (PCFs), incorporating with diverse phase change materials (PCMs) such as paraffin wax (PW), have been recognized as one of the effective strategies for fabricate smart thermoregulatory textiles. However, some fatal defects exist in traditional paraffin-cellulose-based PCFs, including the paraffin leakage and the low fiber strength. In this work, we herein propose a facile method to prepare uniform and stable paraffin emulsions stabilized by cellulose nanofibrils (CNFs), followed by a simple coaxial wet spinning to develop smart and robust cellulose-based PCFs for human body temperature management. Benefiting from the CNF-reinforced encapsulation, the stability of paraffin capsules and the compatibility of cellulose and paraffin are indeed promoted, thus allowing the cellulose-based PCF with excellent mechanical strength, leakage prevention, and thermal regulation. As a result, the as-prepared PCF, namely CNF₁-PE/PW with optimal 1 wt% CNF₁ loading, features a high tensile stress of 10.95 MPa at a strain of 111.2 % and a phase-change enthalpy value of 140.24 J/g with a slight paraffin leakage rate of 0.9 %. Moreover, the corresponding wearable fabric exhibits an excellent thermal storage and release recyclability even after 50 cycles. Therefore, this study provides a new idea for the development of intelligent cellulose-based phase change fiber materials.

A complex heteropolysaccharide SCP-2 named schisanan B (M_w = 1.005 × 10⁵ g/mol) was obtained from water extracts of Schisandra chinensis fruits, and its planar structure was finally deduced as a galacturonoglucan by a combination of monosaccharide compositions, methylation analysis, partial acid hydrolysis, enzymatic hydrolysis and 1D/2D-nuclear magnetic resonance spectroscopy. The conformation of SCP-2 exhibited a globular shape with branching in ammonium formate aqueous solutions. The rheological properties of SCP-2 were investigated on concentrations, temperature, pH and salts. The in vitro immunomodulatory activity assay demonstrated that SCP-2 significantly enhanced the production of nitric oxide (NO) and stimulated the secretion of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) in macrophages. Through a combination of high-resolution live-cell imaging, surface plasmon resonance, and molecular docking techniques, SCP-2 exhibited a strong binding affinity with the Toll-like receptor 4 (TLR4). Moreover, western blot analysis revealed that SCP-2 effectively induced downstream signaling proteins associated with TLR4 activation, thereby promoting macrophage activation. The evidence strongly indicates that TLR4 functions as a membrane protein target in the activation of macrophages and immune regulation induced by SCP-2.

Incorporating 5-aminosalicylic acid (5-ASA) into a colon-specific carrier is crucial for treating inflammatory bowel diseases (IBD), as it enhances therapeutic efficacy, targets the affected regions directly, and minimizes side effects. This study evaluated the impact of incorporating cellulose nanofibers (CNF) on the in vitro and in vivo biological performance of retrograded starch/pectin (RS/P) microparticles (MPs) containing 5-ASA. Using Fourier Transform Infrared (FTIR) Spectroscopy, shifts in the spectra of retrograded samples containing CNF were observed with increasing CNF proportions, suggesting the establishment of new supramolecular interactions. Liquid absorption exhibited pH-dependent behaviors, with reduced absorption in simulated gastric fluid (∼269 %) and increased absorption in simulated colonic fluid (∼662 %). Increasing CNF concentrations enhanced mucoadhesion in porcine colonic sections, with a maximum force of 3.4 N at 50 % CNF. Caco-2 cell viability tests showed biocompatibility across all tested concentrations (0.0625–2.0000 mg/mL). Evaluation of intestinal permeability in Caco-2 cell monolayers demonstrated up to a tenfold increase in 5-ASA permeation, ranging from 29 % to 48 %. An in vivo study using Galleria mellonella larvae, with inflammation induced by LPS, showed reduction of inflammation. Given the scalability of spray-drying, these findings suggest the potential of CNF-incorporated RS/P microparticles for targeted 5-ASA delivery in IBD.

Bio-based compounds have become the focus in the development of next-generation materials. The polyphosphated structure and availability of phytic acid has sparked an interest to understand its properties and apply it to making fire-retardant fabrics. However, its degradative effect on natural fibers sets limitations to its potential uses. In this study, we unveiled a new dimension to explore with phytic acid: cellulose fiber foams. Phytic acid enabled synergistic foaming with carboxymethyl cellulose albeit causing issues in long-term wet foam stability. Adding cellulose fibers to this mixture and drying at 160 °C produced solid foams with increased compressive strength and stiffness; comparable to foams cross-linked with the commonly used citric acid. The reduced contact area in low-density fiber networks allowed the cross-linking between phytic acid and the fiber network to mitigate structural weakening due to fiber degradation. Imaging also revealed the formation of a film encompassing fiber bonds; attributed to the strong interaction between phytic acid and carboxymethyl cellulose. Furthermore, phytic acid imparted self-extinguishing fire-retardant properties to the cellulose fiber foams measured using thermogravimetric analysis and cone calorimetry. This work showcases a simple new application for phytic acid without the use of catalysts or solvents. It serves to encourage further development of green practices to continuously challenge the industrial landscape.

Oral conditions, such as recurrent aphthous stomatitis, are chronic inflammatory disorders that significantly affect the life quality. This study aims to develop a novel buccal mucoadhesive based on methacrylate hydroxypropyl methylcellulose (M-HPMC) and methacrylate lignin (M-SLS) encapsulated with nanostructured lipid carriers (NLCs) for controlled release of alpha-pinene (α-pinene). NLCs with particle sizes of 152 ± 3 nm were prepared by using stearic acid and oleic acid as solid and liquid lipids, respectively. Following the successful synthesis of M-HPMC and M-SLS, various concentrations of α-pinene loaded NLCs (0, 18, 38, and 50 wt%) were encapsulated in M-HPMC/M-SLS hydrogel. It was demonstrated that the physiological and mechanical performances of hydrogels were changed, depending on the NLC content. Remarkably, the incorporation of 18 wt% NLC improved the compressive strength (143 ± 14 kPa) and toughness (17 ± 1 kJ/m³) of M-HPMC/M-SLS hydrogel. This nanocomposite hydrogel considerably decreased dissipated energy from 1.64 kJ/m³ to 0.99 kJ/m³, after a five-cycle compression test. The nanocomposite hydrogel exhibited controlled α-pinene release for up to 96 h which could significantly improve the antioxidant activity of M-HPMC/M-SLS matrix. Moreover, the reinforcing M-HPMC/M-SLS hydrogel with α-pinene-loaded NLCs resulted in increased adhesive strength (113.5 ± 7.5 kPa) to bovine buccal mucosa and cytocompatibility in contact with fibroblasts.

Chitosan chemical functionalization is a powerful tool to provide novel materials for additive manufacturing strategies. The main aim of this study was the employment of computer-aided wet spinning (CAWS) for the first time to design and fabricate carboxymethyl chitosan (CMCS) scaffolds. For this purpose, the synthesis of a chitosan derivative with a high degree of O-substitution (1.07) and water soluble in a large pH range allowed the fabrication of scaffolds with a 3D interconnected porous structure. In particular, the developed scaffolds were composed of CMCS fibers with a small diameter (< 60 μm) and a hollow structure due to a fast non solvent-induced coagulation. Zn²⁺ ionotropic crosslinking endowed the CMCS scaffolds with stability in aqueous solutions, pH-sensitive water uptake capability, and antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, post-printing functionalization through collagen grafting resulted in a decreased stiffness (1.6 ± 0.3 kPa) and a higher elongation at break (101 ± 9 %) of CMCS scaffolds, as well as in their improved ability to support in vitro fibroblast viability and wound healing process. The obtained results encourage therefore further investigation of the developed scaffolds as antimicrobial wound dressing hydrogels for skin regeneration.