Carbohydrate Polymers最新文献

Porphyran is a promising bioactive ingredient mainly composed of alternating (1→4)-α-l-galactose 6-sulfate (L6S) and (1→3)-β-d-galactose (G), with L6S units partially substituted by 3,6-anhydro-l-galactose (LA), and the O-6 position of G residues could be occasionally modified by methyl group (Me). Comprehensive research on porphyran requires efficient and precise structure characterization. In this study, a novel enzyme-glycomics strategy for porphyran structure analysis was developed. The approach involved adequately degradation of porphyran by methyl-tolerant agarase Aga86A_Wa and porphyranase Por16C_Wf. The resulting oligosaccharides were detected via UPSEC-HRMS and automatically analyzed using glycoinformatics software. The identified oligomers included (L6S-G)Me_0-1, (LA-G)_1-2, (L6S-G)(LA-G)Me_0-1, (L6S-G)₂(LA-G)Me_0-2, (L6S-G)(LA-G)₂Me_0-1. This confirms the identification of the consecutive homogeneous blocks (consisting of L6S-G or LA-G), alternating heterogeneous blocks (consisting of L6S-G and LA-G), and their methylated derivatives of porphyran. Furthermore, This method successfully distinguished the structure variations of porphyran in Porphyra from different harvest periods, species and producing areas. It provides a feasible approach for efficient and precise analyses of major and heterogeneous structure fragments of porphyran, and supports future investigations into porphyran structure-activity relationships.

Ionogels have emerged as promising candidates for flexible electronics due to their unique properties. However, the development of bio-based ionogels that simultaneously satisfy the requirements of facile fabrication, multifunctionality, and recyclability remains a significant challenge. Herein, the design and preparation of a high-performance ionogel based on lipoic acid and alkenyl xylan (LA-XEA ionogel) is reported. The bio-based ionogel featuring hierarchical dynamic covalent cross-linked double networks (HBD-CAN) via melt processing. Xylan simultaneously inhibits the closed-loop depolymerization of polymeric LA chains while functioning as a cross-linking agent in the ionogel network, resulting in improved mechanical strength. The resulting LA-XEA ionogel demonstrates remarkable properties, including exceptional stretchability (1500 %), strong skin adhesion (33 kPa), high conductivity (6.20 mS/m), excellent optical transparency (>85 %), rapid self-healing capability, and full recyclability. Significantly, LA-XEA ionogel exhibits multi-response mode to both tensile and temperature stimuli, rendering it an ideal candidate for the development of highly sensitive strain and temperature sensors. Meanwhile, LA-XEA ionogel is suitable for wearable sensors to achieve high-quality electrophysiological signal acquisition. This work provides a promising strategy for designing xylan-based ionogels.

Functional filler materials are often incorporated into films assembled from natural polymers to enhance their optical, mechanical, barrier, and preservative properties. However, the efficacy of these fillers depends on their compatibility with the surrounding polymer matrix. The application of carbon-based fillers in films is often limited by their strongly hydrophobic nature, which restricts their dispersion and interaction within hydrophilic polymer matrices. Inspired by mussel adhesion, we employed in situ dopamine self-polymerization to modify the surfaces of graphene nanosheets, which significantly improved their compatibility with hydrophilic starch matrices. The interfacial interactions of the graphene nanosheets with the starch matrix were analyzed using density functional theory (DFT) simulations. In addition, rheology and low-field nuclear magnetic resonance (LF-NMR) analyses indicated the formation of a stable three-dimensional network structure between the modified graphene fillers and the starch matrix. The formation of this network enhanced the structural integrity of the films and impeded crack propagation. As a result, the tensile strength of the composite film increased from around 14.8 to 27.9 MPa, while the water vapor and oxygen permeability were reduced by around 30 % and 40 %, respectively. This novel strategy could be extended to other biopolymers, thereby enabling the design of multifunctional, high-performance green composites for next-generation packaging and other applications.

Lytic polysaccharide monooxygenases (LPMOs) are mono‑copper-dependent enzymes that catalyze the oxidative breakdown of polysaccharides. The recently discovered AA17 family, exclusively found in oomycete genomes, plays a critical role in plant-pathogen interactions, with Phytophthora infestans AA17 (PiAA17) LPMOs shown to degrade homogalacturonan (HG). In plant cell walls, HG is methyl-esterified, but the influence of this modification on the mode-of-action of AA17 LPMOs is unknown. In this study, we established the phylogenetic distribution of the AA17 family, which diverged into six clades. Three AA17 enzymes from distinct clades were successfully heterologously produced. PiAA17C, the only one of three tested AA17 enzymes active on HG substrates, oxidatively cleaved HGs with degrees of methyl-esterification (DM) of 0, 20, and 60, but not highly methyl-esterified HG (DM92). Advanced liquid chromatographic and mass spectrometric analysis demonstrated that PiAA17C generated C4-oxidized and decarboxylated C4-oxidized oligogalacturonides. Among these products, those having internal methyl-esterified galacturonic acid (MeGalA) residues were more abundant than those with reducing end MeGalA residues. PiAA17C preferably cleaved HG between two non-methylated GalA residues, followed by cleavages involving one GalA and one MeGalA residue, with the lowest preference for cleavage between two MeGalA residues.

Starch biosynthesis is a pivotal determinant of barley grain quality and yield, yet its regulatory mechanisms remain incompletely characterized. This study identifies HvERF72, an AP2-domain transcription factor, as a key regulator of starch biosynthesis and granule initiation in barley grains. Comparative analyses of CRISPR/Cas9-generated HvERF72 knockout mutants revealed enhanced B-type granule formation and elevated total starch content, whereas overexpression lines exhibited contrasting phenotypes, including reduced starch accumulation and suppressed B-type granule initiation. Transcriptional profiling at 15 DAF indicated significant upregulation of critical starch biosynthesis genes (HvAGPL1, HvAGPS1, HvSS2a, HvSBEI, HvSBEIIb, and HvGBSSI) in mutants, while overexpression lines showed downregulation of these genes. Mechanistic investigation demonstrated that HvERF72 directly binds to GCC-box motifs in the promoter regions of HvSS2a and HvSBEI, repressing their transcription. These findings establish HvERF72 as dual-function regulator that modulates starch biosynthesis and B-type granule initiation, providing novel molecular targets for optimizing starch yield and industrial quality in barley breeding programs.

Current clinical therapeutic protocols for diabetic foot ulcers (DFUs) remain inadequate due to their low response to therapeutic drugs and high recurrence rates. The normal healing process of diabetic wounds is frequently disrupted by factors such as microbial infections and elevated reactive oxygen species (ROS) levels. In this study, we developed a gel patch that can accelerate wound re epithelialization and scavenge ROS and antibacterial. To provide a dependable biological framework for wound tissue regeneration, this patch incorporates two components analogous to the extracellular matrix: snail glycosaminoglycan and gelatin. The multifunctional patch exhibited potent antibacterial activity, eliminating over 99.9 % of Staphylococcus aureus and Escherichia coli, and reduced reactive oxygen species (ROS) levels in oxidative stress-induced cells by 80 %. In a diabetic wound infection model, the patch inhibited bacterial colonization, accelerated re-epithelialization by two-fold, and lowered inflammatory markers, highlighting its dual antimicrobial and pro-healing effects. The patch demonstrated a precisely synchronized gradual degradation and controlled drug release profile, which aligned with the spatiotemporal dynamics of wound healing progression. In summary, this innovative approach presented a facile, safe, and highly efficient therapeutic strategy for the management of DFUs.

Zhou et al. (https://doi.org/10.1016/j.carbpol.2025.123917) employed fungal-derived chitosan to synthesize guanidinium-functionalized chitosan (GCS) and aldehyde-modified chitosan (ACS) for Schiff-base hydrogel formation. For completeness, it would be valuable to clarify whether ACS might undergo any self-crosslinking or self-gelation under the conditions used, and to discuss its specific suitability as the aldehyde donor within the Schiff-base network. This comment underscores the importance of a more precise structural definition of ACS, especially concerning its function in the Schiff-base reaction. A thorough structural characterization-ideally via comprehensive NMR analysis-will verify the degree of modification and clarify its exact role in the crosslinking mechanism.

In recent years, coalbed methane (CBM) has received considerable attention because of its clean and efficient features. However, CBM reservoirs are typically characterized by low formation pressures, which pose significant challenges during drilling by causing substantial drilling fluid loss. Foam drilling fluids, characterized by low density and reduced hydrostatic pressure, have emerged as a viable solution to this problem. This study investigates the formulation and performance of high-performance foam drilling fluids, employing alkyl polyglucoside (APG) as the foaming agent and cellulose nanofibers (CNFs) as stabilizers. Three distinct types of CNFs were evaluated for their foam-stabilizing capabilities, i.e., mechanically treated CNFs (M-CNFs), TEMPO-oxidized CNFs (T-CNFs), and lignin-containing CNFs (L-CNFs). The results showed that T-CNFs exhibited superior foam stability compared to M-CNFs and L-CNFs. The synergistic interaction between APG and T-CNFs led to reduced surface tension, smaller foam bubbles, thicker and more viscous liquid films, and enhanced electrostatic repulsion between bubbles, resulting in enhanced foam stability. Moreover, the T-CNF-stabilized Pickering foam drilling fluid demonstrated excellent rheological and filtration properties. This study not only offers valuable insights into the development of efficient and sustainable foam drilling fluids using biomass-derived nanomaterials but also contributes to advancing environmentally friendly CBM exploration technologies.

The proliferation of electronic devices has led to a substantial increase in non-degradable electronic waste (e-waste), posing significant environmental challenges. Consequently, biodegradable natural polymers have garnered considerable attention as sustainable alternatives to conventional non-degradable materials in electronic applications. Bacterial cellulose (BC), a natural polymer characterized by abundant hydroxyl groups and a three-dimensional (3D) nanonetwork structure, exhibits exceptional properties including high purity, superior mechanical strength, excellent water retention capacity, non-toxicity, renewability, and complete biodegradability. These unique attributes, coupled with its distinctive structural features, render BC as a promising green matrix material for developing functional composites in eco-friendly electronic devices. This review provides a systematic analysis of various eco-friendly composite materials derived from BC, covering conductive, piezoelectric, magnetoelectric, and thermoelectric composites. Additionally, the fabrication methodologies for BC-based composites, including in-situ chemical synthesis, ex-situ incorporation, and biosynthesis techniques, are comprehensively analyzed. Furthermore, the applications of BC-based composites was explored in diverse fields such as sensors, energy storage systems (batteries and supercapacitors), and energy harvesting devices (nanogenerators). Finally, we deliver a critical evaluation of the current challenges and future research directions for BC-based composites in the development of sustainable electronic devices.