Carbohydrate Polymers最新文献

Polysaccharide-based metal-organic frameworks have attracted widespread attention due to their combination of the biocompatibility and flexibility of polysaccharides. Cyclodextrin are interesting bio-ligands in the construction of polysaccharide-based MOFs. Conventional methods for preparing cyclodextrin metal-organic frameworks (CD-MOFs) are often time-consuming and inefficient. In this study, cost-effective and environmentally friendly α- and β-CD-MOFs were successfully synthesized using a hydrothermal method, with optimized incubation time and solvent ratios. The materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and N₂ adsorption/desorption measurements. The CO₂ adsorption mechanism was also examined using Fourier transform infrared spectroscopy (FTIR). The results demonstrated excellent thermal and cycling stability of the materials. The CO₂ uptake capacities of α- and β-CD MOF-K were 10.8 and 11.2 cm³/g, respectively. Additionally, the CD-MOFs showed strong selectivity for CO₂ over N₂. Given the straightforward operational procedures, safety characteristics, and mild reaction conditions of CD-MOFs, it is reasonable to conclude that they are promising candidates for use as CO₂ adsorption materials.

Acellular cellulose-based biomaterials hold promising potential for treating bladder injuries. However, the compromised cellular state surrounding the wound impedes the complete reconstruction of the bladder. This necessitates the development of a bio-instructive cellulose-based biomaterial that actively controls cell behavior to facilitate effective bladder regeneration. To develop such an advanced cell-free scaffold, a bacterial cellulose (BC) substrate is elaborately modified through layer-by-layer assembly of heparin and collagen (H/C), followed by glutaraldehyde crosslinking, resulting in a biomimetic nanofibrous scaffold with optimized mechanical properties and reduced salt crystal deposition. Critically, the scaffold is functionalized with anti-CD29 antibodies, enabling selective in situ capture of urine-derived stem cells (USCs) without compromising their viability. The (H/C)-modified BC scaffold exhibits exceptional swelling and extracellular matrix-like architecture, which mirrors the natural bladder environment. Fluorescent immunostaining confirms uniform antibody grafting, confirming the efficacy of this modified biomaterial in attracting and retaining USCs. Overall, this study introduces a BC-based scaffold that has been innovatively modified with CD29, enabling the selective capture of USCs from urine. This innovative acellular biomaterial represents a promising acellular strategy to address the challenges posed by compromised cellular conditions during bladder reconstruction, offering a novel avenue for regenerative bladder therapies.

Drug-resistant bacterial infections represent a critical global public health challenge, driven largely by the misuse and overuse of antibiotics. Tackling the growing threat of bacterial resistance necessitates the development of innovative antibacterial agents that function independently of traditional antibiotics. In this study, novel antibacterial nano-micelles were rationally designed by conjugating quaternized chitosan with the photosensitizer chlorin e6. These nano-micelles promoted the solubility and stability of chlorin e6 while maintaining robust singlet oxygen generation under 660 nm laser irradiation. The positively charged nano-micelles facilitated strong electrostatic interactions with bacterial surfaces, promoting efficient adhesion and enabling effective photodynamic antibacterial activity mediated by singlet oxygen. In vitro experiments revealed that the nano-micelles exhibited instant and prolonged antibacterial effects, effectively suppressing bacterial proliferation without inducing resistance and disrupting mature biofilms. Furthermore, in conjunction with laser treatment, nano-micelles exhibited remarkable in vivo antibacterial efficacy, significantly accelerating the healing of skin wounds infected with Methicillin-resistant Staphylococcus aureus while maintaining favorable biocompatibility. These findings highlight the potential of the nano-micelles as a promising non-antibiotic antibacterial formulation, offering a powerful strategy to combat drug-resistant bacterial infections and paving the way for their clinical application in infection management.

In this study, corn starch esters were obtained by a novel methodology using oleic acid as an esterifying agent and L(+)-tartaric acid as both catalyst and esterifying agent. The degree of substitution (DS) was determined along the reaction time to control the level of substitution achieved (up to 0.33), while all the other reaction parameters were maintained constant. Several techniques were applied to characterize the starch esters obtained, namely, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), differential scanning calorimetry (DSC), proton nuclear magnetic resonance spectroscopy (H NMR), polarized light microscopy, and X-ray diffraction (XRD). The incorporation of ester groups causes a gradual decrease in the crystallinity and thermal stability of the substituted starches. The hydrophobicity of the samples increases significantly as a function of the DS obtained. ¹H NMR analysis and solubility in dimethylsulfoxide (DMSO) indicate that the L(+)-tartaric acid is involved as a catalyst and an esterifying agent that crosslinks starch chains. The materials obtained are promising for use in various applications such as emulsifiers, surface coating materials, flavoring agents in the food industry, and biomedical applications for bone fixation and replacements, among others, meriting future studies.

Tendons are anisotropic tissues with exceptional mechanical properties, which result from their unique anisotropic structure and mechanical behavior under stress. While research has focused on replicating anisotropic structures and mechanical properties of tendons, fewer studies have examined their specific mechanical behaviors. Here, we present a simple method for creating calcium-crosslinked alginate-based double-network hydrogels that mimics tendons by exhibiting anisotropic structure, high mechanical strength and toughness, and a distinctive "toe region" when stretched. The tendon-mimicking hydrogel was fabricated using alginate/polyacrylamide double-network embedded with various mesoporous silica particles, followed by pre-stretching and fixation. Our findings show that hydrogels embedded with high aspect-ratio rod-shaped mesoporous silica microparticles and subjected to multiple pre-stretching cycles in the elastic range, exhibited the most favorable mechanical properties, including a toe region, closely resembling natural tendons. The hydrogels exhibited elastic modulus of 13.3 MPa, tensile strength of 5 MPa, and toughness of 3.5 MJ m^-3, even in its swollen state. An impact absorption test demonstrated the hydrogel's high energy dissipation and damping capacity, effectively absorbing external forces and functioning similarly to tendons. These anisotropic composite hydrogels, with their superior mechanical properties, offer considerable potential for applications in artificial tissue engineering, particularly where tendon-like mechanical characteristics are needed.

The inverse electron demand Diels-Alder (IEDDA) cycloaddition between tetrazines and strained dienophiles is recognized as a fast and specific reaction. The integrating tetrazines and strained dienophiles onto the backbone of polysaccharides yield appropriate water-soluble precursors for IEDDA cycloaddition. Due to the high specificity of the IEDDA reaction and its outstanding cytocompatibility, a range of cargos (live cells, peptides and pharmaceuticals) can be effectively encapsulated in polysaccharide solutions throughout the hydrogel formation. Within a few minutes, the interaction of aqueous solutions of tetrazine-polysaccharides with polysaccharide derivatives of dienophiles can form the hydrogel. The gelation time can be regulated by the structure of tetrazine/dienophile, degree of substitution, concentration of polysaccharide solutions, and temperature. The hydrogels are utilized in the fields of tissue engineering, cancer treatment, and wound healing. The embedding of stimuli-responsive functionalities within the hydrogel's architecture enhances the precision of its application for designated targets. This review begins by elucidating the principles of IEDDA and identifying the primary factors that influence the rate of cycloaddition. Subsequently, we discuss various strategies for integrating the reactants of IEDDA onto polysaccharides. Finally, the approaches for the fabrication of the relevant injectable hydrogels, their specific characteristics, and their implementation in different biomedical applications are elaborated.

The limited membrane permeability and bacterial resistance pose significant challenges in the management of intracellular drug-resistant bacterial infections. To overcome this issue, we developed a bacterial-targeted drug delivery system based on quaternary ammonium chitosan-modified mesoporous silica nanoparticles (MSN-NH₂-CFP@HACC) for the treatment of intracellular Methicillin-resistant Staphylococcus aureus (MRSA) infections. This system utilizes amino-functionalized mesoporous silica nanoparticles to efficiently load cefoperazone (CFP), and the nanoparticles' surface is coated with 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) to target bacteria and enhance macrophage uptake. The findings indicate that MSN-NH₂-CFP@HACC nanoparticles are efficiently internalized by macrophages, demonstrate accelerated drug release in acidic environments, and exhibit enhanced antibacterial properties, effectively suppressing the proliferation and intracellular escape of MRSA. Moreover, HACC enhances the bacterial capture ability of the nanoparticles and reduces resistance by disrupting bacterial membrane structures and inhibiting bacterial β-lactamase activity. In a murine model of MRSA bacteremia, MSN-NH₂-CFP@HACC exhibited remarkable antibacterial efficacy and significantly attenuated severe inflammatory responses. In conclusion, MSN-NH₂-CFP@HACC represent a promising antibiotic delivery system with exceptional antibacterial efficacy and favorable biocompatibility, thus presenting a novel strategy for addressing intracellular drug-resistant bacterial infections and demonstrating significant potential for clinical application.

Starch-derived hydrophilic malto-oligosaccharides (Glc_n, where n = 1-7) conjugated to hydrophobic solanesol through click chemistry, i.e., Glc_n-b-Sol copolymers, have demonstrated significant promise in developing fully natural block co-oligomers for solid-state nanopatterning applications. This study explores in detail the solution self-assembly, lectin recognition, and pancreatic digestion of Glc₆- and Glc₇-b-Sol. Above a critical micelle concentration (CMC) of 0.3 g/L, both systems demonstrated self-assembly into diverse morphologies. Using the pyrene probe method, a polarity parameter of 1.2 was observed at 1 mM samples. Dynamic light scattering experiments, which measured autocorrelation functions and relaxation times at various angles, revealed the anisotropic and heterogeneous characteristics of the morphologies. Specifically, Glc₆-b-Sol predominantly exhibited spherical and elongated worm-like micelles with considerable heterogeneity across the entire range of concentrations studied. In contrast, Glc₇-b-Sol primarily formed stable, shorter, worm-like structures at lower concentrations, as observed by transmission electron microscopy. However, small-angle X-ray scattering showed that higher concentrations led to the formation of longer worm-like structures, with Glc₇-b-Sol forming thicker diameters. Notably, interaction with Concanavalin A above the CMC resulted in complete agglutination. Pancreatic digestion with hog pancreas α-amylase resulted in morphological alterations, with Glc₃- and Glc₄-b-Sol emerging as the primary digestion products for Glc₆- and Glc₇-b-Sol, respectively.

The treatment and monitoring of infected skin wounds present significant clinical challenges. Herein, a multifunctional poly(deep eutectic solvent) (PDES) electroactive hydrogel is developed by optimizing the components and the ratio of hydrogen donors and acceptors, achieving well wound hemostasis, wound healing, and monitoring administration performace. The PDES hydrogel dressing exhibits mechanical properties, including high toughness, fatigue resistance (over 9000 compression cycles), and superior skin adhesion (over 70 kPa). It also demonstrates good conductivity (~2.0 S/m) and a high signal-to-noise ratio (>7000:1), enabling its application as a flexible strain biosensor to monitor wound contraction signals during healing. The PDES hydrogel shows remarkable antibacterial performance (up to 99 %) and blood compatibility, achieving rapid hemostasis (within 15 s) and reducing blood loss (36 mg). Additionally, the PDES hydrogel effectively prevents skin wound infections, enhances collagen deposition, and facilitates microvascular reconstruction at the wound site, significantly improving infected wound healing (in 12 days). Consequently, this PDES hydrogel, with its superior mechanical properties, flexible sensing capabilities, and antibacterial features, is an ideal candidate for wound healing and monitoring administration.

This study introduces a novel bilayer wound dressing that integrates a quaternized chitosan-polyacrylic acid (QCs-PAA) sponge as the top layer with electrospun nanofibers containing curcumin as the bottom layer. For the first time, QCs and PAA were combined in an 80:20 ratio through freeze-drying to form a porous sponge layer with ideal structural properties, including 83 ± 6 % porosity and pore diameters of 290 ± 12.5 μm. For the bottom layer, five groups of nanofibers containing PAA, dextran, and curcumin were electrospun onto the porous sponge. All wound dressings were non-toxic and exhibited exceptional antibacterial activity against S. aureus and E. coli. All groups, particularly the QP/PD0.25Cur bilayer dressing, showed significant HaCaT cell adhesion. Angiogenesis assays confirmed a remarkable increase in blood vessel number and thickness in samples containing 0.25 w/w% curcumin, with vascular density increasing from 0.32 in the single-layer sponge to 0.54 in the QP/PD0.25Cur sample, representing a 68 % enhancement. In vivo studies demonstrated that within 14 days, wound healing was accelerated with the QP/PD0.25Cur bilayer dressing, achieving 96 % closure compared to other groups. The findings revealed that all fabricated bilayer sponge-nanofiber wound dressings, particularly the 0.25 w/w% curcumin sample, can be a suitable candidate for wound management.