Carbohydrate Polymers最新文献

Achieving effective interfacial compatibility between hydrophilic cellulose nanofibrils (CNFs) and hydrophobic vegetable oil polymers (VOPs) remained a significant challenge. To address this issue, we developed a one-component nanocomposite (OCN) based on hyperbranched CNF-grafted VOPs. Rigid precursor initiator poly (vinylbenzyl chloride) (PVBC) was first grafted onto the CNF surface via phase-transfer catalysis, forming a branched macroinitiator (CNF-g-PVBC) with chlorine contents ranging from 4.4 to 9.1 wt%. Subsequently, vegetable oil based monomers (lauryl methacrylate, LMA) were directly grafted onto CNF-g-PVBC through sacrificing initiator-free surface-initiated atom transfer radical polymerization (SI-ATRP). Finally, a hyperbranched CNF-based one-component nanocomposite (OCN-CVOP) was successfully prepared. Nanoscale infrared spectroscopy and microscopy confirmed the highly uniform morphology of the OCN-CVOP films, highlighting the superior dispersion of CNFs within the VOP matrix. Notably, compared to pure VOPs, OCN-CVOP exhibited remarkably low glass transition temperature (∼-15 °C) and reduced viscosity, which was attributed to the hyperbranched architecture. Even at LMA contents as high as ∼70 wt%, OCN-CVOP demonstrated excellent mechanical performance, achieving a tensile strength of 3.6 ± 0.2 MPa and a toughness of 21.5 ± 2.9 MJ/m³. This innovative design successfully addressed the mechanical limitations of conventional VOPs, offering a sustainable approach for developing environmentally friendly, high-performance VOP materials with diverse application potential.

Enzymatic catalysis offers notable advantages, including exceptional catalytic efficiency, selectivity, and the ability to operate under mild conditions. However, its widespread application is hindered by the high costs associated with enzymes and cofactors. Materials-mediated immobilization technology has proven effective in the recycling of enzymes and cofactors. An optimal carrier material for protein immobilization must be non-toxic, biocompatible, and should not compromise the biological activity or structure of the enzymes. Compared to synthetic polymers, chitin is a promising carrier given its low cost, renewability, abundance of functional groups, and notable biocompatibility and biodegradability. Although numerous reviews on chitosan and other polymers for immobilization have been published, few have addressed using chitin as supports. In this review, chitin-based materials mediated enzyme immobilization, the one-step purification and immobilization of enzymes, as well as co-immobilization of enzymes and cofactors were summarized. Particularly, the significance of chitin materials in the field of enzymatic catalysis was emphasized. This study has the potential to open new avenues for immobilized biocatalysts.

In an effort to mitigate or reverse the pathological progression of early-stage osteonecrosis of the femoral head (ONFH), this study employed a promising strategy that involves the sustained delivery of osteogenic factors to augment core decompression, facilitated by the use of composite hydrogels. Specifically, a hydrogel was synthesized by blending chitosan, Pluronic F-127, and tripolyphosphate, utilizing both ionic bonding and copolymer micelle cross-linking techniques. This hydrogel demonstrated exceptional biocompatibility, temperature responsiveness, pH-dependent biodegradation, and controlled release properties. The average pore diameter of the optimal hydrogel expanded to 45 μm, accompanied by zeta potentials of +34.72 ± 4.13 mV. The loading efficiency notably surpassed 90 %, while the sustained release of recombinant human bone morphogenetic proteins 9 (rhBMP9) was observed to last over 25 days at pH = 6.0 and over 36 days at pH = 7.4. This chitosan-based hydrogel, which sustained rhBMP9 release, significantly enhanced the proliferation and migration of bone marrow mesenchymal stem cells and human umbilical vein endothelial cells and promoted osteogenesis and angiogenesis both in vitro and in vivo. Collectively, our study presents an rhBMP9-loaded chitosan-based composite hydrogel system that offers innovative avenues for the research and clinical application of advanced biomaterials in the treatment of early ONFH.

Acute lung injury (ALI) is a complex acute respiratory illness with a high mortality rate. Reactive oxygen species (ROS) play a pivotal role in ALI, inducing cellular damage, inflammation, and oxidative stress, thereby exacerbating the severity of the injury. In this study, inspired by the "subtractive" strategy, we developed a fucoidan-based macrophage membrane bio-nanosystem, abbreviated as MF@CB, designed as an anti-inflammatory and antioxidant agent to alleviate lipopolysaccharide (LPS)-induced inflammation in ALI. MF@CB coated with macrophage membrane for effective targeting and accumulation in ALI lesions. In addition, MF@CB activates Nrf2 transcriptional activity in macrophages, inhibiting ROS synthesis at its origin while effectively removing ROS already present in the ALI. This dual-pronged approach demonstrates robust antioxidant properties and restores the macrophage antioxidant defense barrier. In the LPS-induced ALI mouse model, MF@CB significantly mitigated lung inflammatory damage by modulating lung macrophage polarization and inhibiting the over-secretion of pro-inflammatory cytokines by activated immune cells. More importantly, unlike most surface modification strategies because it remove the molecule, this approach is easier to apply and potentially safer and may provide useful insights into the development of more effective therapeutic strategies for ALI.

Biofilm formation on biological and material surfaces represents a heavy health and economic burden for both patient and society. To contrast this phenomenon, medical devices combining antibacterial and pro-wound healing abilities are a promising strategy. In the present work, Xanthan gum/Guar gum (XG/GG)-based scaffolds were tuned with thymol and Zn²⁺ to obtain wound dressings that combine antibacterial and antibiofilm properties and favour the healing process. The tuning process preserved the 3D extrusion-based printability of the XG/GG ink. Scaffolds swelling profile was assessed in PBS pH 7.4, and the resistance to compressive forces was studied using a texturometer. The scaffolds microarchitectures were analyzed by SEM, while ATR-FTIR spotlighted the chemical modifications of the customized materials. Thymol and Zn²⁺ release was analyzed in biologically relevant media, showing a burst release in the first hours. The antibacterial properties were confirmed against S. aureus, P. aeruginosa, and S. epidermidis by isothermal microcalorimetry and biofilm viable cell counting. Incorporation of hydroxypropyl-β-cyclodextrin (HPβCD) improved thymol loading (7- and 14-times higher thymol content) and enhanced the antimicrobial and antioxidant performances of the dressing, while the presence of Zn²⁺ strongly potentiated the antimicrobial activity, showing a potent antibiofilm response in both Gram-positive and Gram-negative strains of clinical concern. The thymol and Zn²⁺ combination led to a reduction of 99.95 %, 99.99 %, and 98.26 %, of biofilm formation against S. aureus, P. aeruginosa, and S. epidermidis, respectively. Furthermore, the scaffolds demonstrated good hemocompatibility, cytocompatibility, tissue integration and pro-angiogenic features in an in ovo CAM model.

Hard-to-cook (HTC) beans are characterised by extended cooking times. Although the changes in cell walls limiting hydration in HTC beans are widely investigated, the role of macro-molecules (starch and protein, which constitute >80 % of beans) are almost overlooked. This study investigates the structural changes in starch associated with the HTC quality in faba and adzuki beans stored at contrasting temperature and humidity regimes. Beans were stored at 4 °C (control) and 40 °C with relative humidity (RH) levels of 60 % and 80 %. Significant changes in starch properties were observed, particularly in beans stored at 40 °C and 80 % RH, with swelling power decreasing by 7 % and 12 % for faba and adzuki beans, respectively. Additionally, gelatinisation behaviour was negatively affected, with peak temperatures increasing for adzuki beans (from 66.64 °C to 68.46 °C) and enthalpy rising for faba beans (from 9.25 J/g to 10.64 J/g) along with an increase in relative crystallinity. Overall findings indicate that storage at elevated temperature (40 °C) under both moderate and high humidity conditions (60 % and 80 %) primarily or partially leads to developing HTC beans due to molecular rearrangement of starch at helical and crystalline levels.

Photodynamic therapy (PDT) eradicates tumor cells by the light-stimulated reactive oxygen species, which also induces lipid peroxidation (LPO) and subsequently ferroptosis, an iron-depended cell death. Ferroptosis has a tremendous therapeutic potential in cancer treatment, however, the ferroptosis efficiency is largely limited by the available iron in cells. Through hijacking the CD44-mediated iron endocytosis of hyaluronan (HA), here PDT with enhanced ferroptosis was realized by a HA@Ce6 nanogel self-assembled from HA, a photosensitizer Chlorin e6 (Ce6) and Fe³⁺ as cross-linkers. Taking advantages of HA's natural affinity towards CD44, HA@Ce6 enabled a targeted Ce6 delivery in CD44-overexpressed breast cancer cells and meanwhile enhanced iron uptake to "fuel" ferroptosis together with the light-stimulated LPO. Further, HA@Ce6 demonstrated an excellent anticancer PDT efficacy and ferroptosis induction in the murine 4 T1 xenograft model. This HA@Ce6 successfully exploited the role of HA in iron transport to sensitize ferroptosis, providing a potent strategy to facilitate the anticancer PDT.

Research on the interaction between surfactants and cellulose nanocrystals (CNC) has mainly focused on the interaction between CNC and conventional surfactants, and there are no reported studies on the interaction between CNC and gemini surfactants. The interactions between CNC and conventional surfactant (tetradecyltrimethylammonium bromide, termed as TTAB), asymmetric gemini surfactant ([C₁₄H₂₉(CH₃)₂N⁺(CH₂)₆N⁺(CH₃)₂C₆H₁₃]Br (14-6-6)) or symmetric gemini surfactant ([C₁₄H₂₉(CH₃)₂N⁺(CH₂)₆N⁺(CH₃)₂C₁₄H₂₉]Br₂ (14-6-14)) were examined. With increasing surfactant concentration, interaction of TTAB/CNC was described by three regions, i.e. electrostatic interaction, CNC induced micellization and dilution of free micelles. However, in the case of gemini surfactant/CNC, four binding regimes were observed, i.e. cooperative adsorption, CNC induced micellization, formation and dilution of free micelles. The behavior of 14-6-6/CNC was similar to 14-6-14/CNC where CNC promoted the partition of gemini surfactant to the air-water interface at high surfactant concentration, while it was inhibited at low surfactant concentration. At low CNC concentration, micellization induced by CNC and aggregation of surfactant/CNC complexes were absent. pH had a minimal impact on the binding process at low CNC concentration, but it affected the binding at higher CNC concentration. Additionally, the presence of electrolytes influenced the micellization process induced by CNC by reducing the electrostatic interactions.

Chitin is the second most abundant biopolymer in nature after cellulose and is composed of N-acetylglucosamine (GlcNAc) connected via β(1 → 4)-glycosidic bonds. Despite its prominence in nature and diverse roles in pharmaceutical and food technological applications, there is still a need to develop methods to study structure and function of chitin and its corresponding oligomers. Efforts have been made to analyse chitin oligomers by NMR spectroscopy, but spectral overlap has prevented any differentiation between the interior residues. In this study, chitin oligomers up to hexaose with natural abundance of ¹⁵N were analysed with NMR spectroscopy in aqueous solution. Different ¹H,¹⁵N-HSQC pulse sequences were evaluated to obtain the best resolution and sensitivity. Interior residues were resolved in the ¹⁵N dimension and detailed chemical shifts of amide proton and nitrogen are reported for the first time. Additionally, all oligomers were analysed for the presence of the amide cis form and its corresponding chemical shifts were assigned. This study exploits the information that can be obtained from chitin oligomers with NMR spectroscopy and depicts methods for detailed analysis of glycans containing oligomers of N-acetylglucosamine.

Fucosylated chondroitin sulfate (FCS) from Holothuria mexicana (FCS_Hm) was selected for investigation because of its intriguing branch features. Selective β-eliminative depolymerization and the bottom-up assembly were performed to unravel that FCS_Hm consisted of a {D-GlcA-β1,3-D-GalNAc_4S6S} backbone and branches of alternating Fuc_S (55 %) and D-GalNAc_S-α1,2-L-Fuc_S (45 %), the highest proportion of disaccharide branch reported to date. In branches, sulfation could occur at every free -OH site except O-3 of GalNAc, being the most complex and various structure features of natural FCS. Detailed structure-activity relationship analyses showed that FCS_Hm and its depolymerized products (>8 kDa) effectively competed with SLe^X and PSGL-1 to bind with P-sel at nano-molar level and the inhibition potency increased with Mw increasing. For the structural trisaccharide unit, di-O-sulfation of the Fuc_S (Fuc_2S4S and Fuc_3S4S) was almost 10-fold more potent than mono-O-sulfation (Fuc_4S). Unexpectedly, higher sulfation of the disaccharide-branched tetrasaccharide unit reduced inhibition. The reversal may attribute to fewer interactions with P-sel by molecular docking study. These results suggested that the specific configuration underpinned the potent inhibition, whereas the size and sulfate number of branches were not the key factors for the specific binding. dHmF4 (8.0 kDa) potently blocked the platelet-leukocyte aggregates formation, further verifying the potential value in use.