Search Results (1,472)

Candida albicans (C. albicans) is an opportunistic fungal pathogen capable of causing a wide range of infections, including mucosal and systemic candidiasis. In the oral cavity, fungi represent a minor component of the microbiome but can significantly contribute to morbidity, particularly under conditions of dysbiosis or immunosuppression. Treatment remains challenging due to increasing multidrug resistance. This study investigates the in vitro antifungal potential of Viroelixir, a standardized polyphenol blend derived from green tea and pomegranate and enriched in catechins (including epigallocatechin gallate, EGCG), ellagitannins (notably punicalagin), ellagic acid, and flavonoids, with particular focus on its potential anti-virulence mechanisms. Methods: The effect of Viroelixir on C. albicans growth was assessed using MTT assay, optical density measurements, colony formation, carbohydrate quantification, and pH variation analysis. Biofilm formation, morphological transition, ROS production, necrosis, virulence gene expression, adhesion, and host immune responses were also evaluated. Results: Viroelixir significantly inhibited C. albicans growth and reduced colony formation compared with untreated controls. The formulation also inhibited biofilm formation and markedly reduced pseudohyphal development, reaching up to 94% reduction under specific treatment conditions. Flow cytometry analysis showed an increase in dead fungal cells, reaching approximately 88% following exposure to Viroelixir at the highest tested concentration. In addition, Viroelixir reduced the transcript levels of several virulence-associated genes, including SAP1–SAP9 and EAP1. In epithelial cell co-culture models, pre-treatment of C. albicans with Viroelixir reduced fungal adhesion and attenuated epithelial inflammatory responses, including IL-6, IL-8, and hBD-2 production, and was associated with reduced activation of the TLR4-NF-κB signaling pathway. Conclusions: These findings suggest that the antifungal and anti-virulence effects observed may be associated with the polyphenolic compounds present in the Viroelixir formulation, highlighting its potential as a promising in vitro antifungal candidate against C. albicans. Full article

The use of cellulosic reinforcement fillers, including cellulose and holocellulose, in the development of sustainable biopolymer composites has become increasingly essential and continues to attract significant attention in the composite industry. This study aimed to improve the structural and morphological characteristics of the polyhydroxybutyrate (PHB) matrix by incorporating cellulosic fillers—namely, α-cellulose and holocellulose produced via a green processing method—and to evaluate the effect of hemicellulose, present in holocellulose and exhibiting compatibilizing capability, on the overall performance of PHB-based blends. For this, the PHB matrix was first dissolved in chloroform, after which the cellulosic fillers were incorporated into the PHB–chloroform mixtures at 1 wt.% to provide the best homogeneous fiber dispersion. The PHB and cellulosic filler mixtures were blended at 500 rpm with a magnetic mixer for 30 min, and the resulting composite was cast onto a Teflon plate. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to characterize the morphological and structural analysis of the obtained biopolymer-based composites. Thermogravimetric analysis (TG-DTG) was used to determine the thermal properties. The results obtained confirmed the presence of cellulosic fillers in the PHB matrix using FTIR, XRD, and SEM. In contrast to holocellulose, α-cellulose in the PHB matrix was shown to create a more organized structure. Both α-cellulose and holocellulose reinforcements were found to have similar effects on the thermal properties of the PHB matrix. Compared with neat PHB, the amount of residual char was found to be more than 36-fold in the sample containing α-cellulose and more than 41-fold in the sample containing holocellulose. Full article

This study focuses on the development and characterization of advanced composite materials based on poly(ε-caprolactone) (PCL) and poly(vinylidene fluoride) (PVDF), with or without silver nanoparticles (AgNPs), planned for peripheral nerve or bone regeneration. The complementary properties of PCL (biocompatibility and biodegradability) and PVDF (mechanical stability and piezoelectric functionality) were exploited by blending the polymers in different ratios, resulting in binary (PCL/PVDF) and ternary (PCL/PVDF/AgNPs) composites. Green-synthesized AgNPs were integrated to enhance antimicrobial activity and to support tissue repair through improved signal transmission. Functional thin films and electrospun fibres were obtained and subjected to advanced characterization techniques, including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermal analysis. The results demonstrated appropriate morphology, chemical composition, structural stability, and favourable interactions with simulated physiological media. Preliminary biocompatibility assays confirmed good cell viability, supporting the biomedical applicability of the designed scaffolds. Overall, the obtained results highlight the potential of AgNPs-functionalized PCL/PVDF binary and ternary composites as promising candidates for flexible, durable, and bioactive implants in peripheral nerve or bone regeneration. Full article

Stain variability in digital pathology affects both cross-center diagnostic consistency and the robustness of downstream computational analysis. In this work, we formulate stain normalization as a variational inverse problem and derive a Screened Poisson Normalization (SPN) model from the steady-state reaction–diffusion mechanism underlying histological staining. In the CIE $L^{*}{a}^{*}{b}^{*}$ space, the model couples a gradient-domain fidelity term with a chromatic anchoring term, yielding a screened Poisson equation that preserves tissue morphology while enforcing color consistency. We prove that the corresponding variational problem is well-posed in $H^1\left(\Omega \right)$ and stable with respect to perturbations of the input data. We further show that the screening term induces an intrinsic localization length ${\ell }_c\sim {\lambda }_c^{-1/2}$, so that boundary perturbations decay exponentially away from tile interfaces. Based on this locality, we develop a non-overlapping tiled DCT-based spectral solver for gigapixel whole-slide images, enabling consistent tile-wise stain normalization and seamless whole-slide reassembly without heuristic boundary blending. Experiments on multi-scanner, multi-protocol, and archival-fading pathology datasets show that SPN achieves stable stain normalization with competitive chromatic alignment and strong preservation of diagnostically relevant microstructure, particularly in full-slide and tiled reconstruction settings. Supplementary experiments on synthetic pathology-like images further support the robustness of SPN under controlled color perturbations and indicate good generalization across diverse staining variations. Full article

This paper investigates co-continuous structures in immiscible polymer blends through three-dimensional (3D) computational calculations based on a multiphase phase-field equation for fluid flow. The mathematical model describes phase separation with the Cahn–Hilliard (CH) equation and fluid motion with the incompressible Navier–Stokes (NS) equations. Both polymers are treated as Newtonian viscous fluids, and the model includes surface tension, viscosity, and volume fraction effects. A semi-implicit finite difference method (FDM) solves the CH equation, and a projection method maintains the incompressibility of the flow field. Multigrid techniques solve the nonlinear systems efficiently. In addition, a connectivity-based detection algorithm determines whether a phase forms a connected structure that reaches all boundaries of the numerical domain. The numerical results show that the morphology changes from a droplet–matrix structure to a co-continuous structure as the volume fraction increases. The interfacial area per unit volume reaches a local maximum near the transition between these two regimes. Full article

Lignin is an abundant aromatic biopolymer, but its conversion into high-performance fibers remains challenging due to intrinsically poor spinnability, structural heterogeneity, and inefficient stress transfer in lignin-rich systems. In this study, a processing and structure strategy is demonstrated to overcome these limitations by transforming industrial black-liquor kraft lignin into a spinnable and load-bearing fiber component. Kraft lignin recovered from black-liquor waste was extracted and subsequently purified using a hot-water treatment to remove inorganic impurities and thermally unstable fractions, increasing lignin purity to 95.9% through extensive deionized water purification using a water-to-lignin ratio of 300:1. The purified lignin was then blended with poly(vinyl alcohol) (PVA), wet-spun into continuous filaments, and subjected to post-spinning hot drawing to induce molecular orientation. This sequential extraction, purification, blending, spinning, and drawing approach enables stable wet spinning and the continuous formation of lignin-rich lignin/PVA filaments without filament breakage, directly addressing the primary processing bottleneck of lignin-based fibers. Molecular-level miscibility between lignin and PVA is confirmed by the presence of a single glass transition temperature at 88.3 °C, indicating the formation of a homogeneous amorphous phase. SEM observations reveal composition-dependent surface roughness and non-circular cross-sectional morphologies arising from differential coagulation and shrinkage, demonstrating that lignin actively participates in the load-bearing fiber network rather than acting as a passive filler. As a result of purification-enabled spinnability, true blend miscibility, and post-spinning hot drawing, fibers with a lignin-to-PVA composition of 40:60 achieve a maximum tensile strength of 2.8 GPa, approaching the performance range of commercial high-strength polymer fibers. This work establishes a clear relationship between material structure, processing strategy, and resulting properties, highlighting the potential of industrial lignin waste as a sustainable precursor for advanced fiber applications. Full article

In the era of increasing generation of various waste streams, the possibility of utilizing them as secondary resources is of utmost importance and fully corresponds to the goals of the circular economy. Industrial residues from the pulp and paper industry, such as biomass combustion ash (FARP) and sludge from industrial wastewater treatment (PPWS), together with natural zeolite as a modifying additive, represent valuable sources enabling their integrated valorization. The present study aims to investigate the potential for their reuse through the development of sustainable material blends. A comprehensive analysis of the chemical composition and morphology of the obtained mixtures was carried out using inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate a tendency for the formation of mineral matrices dominated by calcium–sulfur–oxygen (Ca–S–O) phases, with the presence of calcium sulfate and aluminosilicate structures. The blends are associated with the formation of stable crystalline structures exhibiting potential pozzolanic activity. In this way, carbon is captured and fixed in a stable mineral form. The obtained results suggest the potential of these blends for use in low-carbon systems focused on waste valorization and carbon retention. The materials may be suitable for applications in construction, soil remediation, and environmental technologies, contributing to closing the resource loop “from farm to table and back again”. Full article

Ocular infections and inflammation represent a clear risk to eye health, but standard eye masks often lack the necessary therapeutic features. Moreover, most existing studies employ a blended electrospinning approach, which leads to an inhomogeneous spatial distribution of the therapeutic agents. However, using the coaxial technique can address these limitations. This study develops a coaxial electrospun nanofibrous eye mask with dual antibacterial and antioxidant functions, aiming to provide an innovative ocular treatment tool for eye care. Generally, a core-shell structured bilayer polycaprolactone-polylysine/polyvinyl alcohol-resveratrol (PCL-PLs/PVA-RSV) membrane is successfully prepared by coaxial electrospinning, where the core is resveratrol-loaded PVA and the shell is PLs-loaded PCL. Results show uniform fiber morphology, favorable hydrophilicity, and potential for sustained release due to core-shell design. The membrane significantly inhibits the growth of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli); at the same time, it exhibits excellent free radical scavenging ability and good component biocompatibility, achieving slow release of the two drugs and long-term antioxidant effect. This multifunctional platform offers a synergistic approach to combating microbial infection and oxidative stress, showing great potential for eye care. Full article

Polymer blends constitute a strategy for tailoring the properties of commercial polymers, leading to the development of materials designed for specific applications. In this work, the effect of the mixing sequence of the reactive compatibilizer styrene–acrylonitrile functionalized with epoxy groups (SAN-g-Epoxy) on the performance of poly(butylene terephthalate) (PBT)/acrylonitrile–butadiene–styrene (ABS) blends was investigated. PBT/ABS blends (60/40 wt%) were prepared by reactive extrusion in a twin-screw extruder followed by injection molding, incorporating five parts per hundred resin (phr) of SAN-g-Epoxy through different mixing sequences, aiming to understand how the processing order influences interfacial reactions, morphology, and the final properties of the material. The results indicated that SAN-g-Epoxy promotes reactive compatibilization between PBT and ABS, as evidenced by a significant increase in torque and complex viscosity, as well as by an increase in the intensity of the carbonyl band in the Fourier transform infrared spectroscopy (FTIR) spectra. By scanning electron microscopy (SEM), the presence of the compatibilizer resulted in a pronounced morphological refinement of the dispersed ABS phase, reducing the average particle size from approximately 4.34 µm to about 0.47–0.54 µm. Among the processing strategies, the route (PBT/SAN-g-Epoxy) + ABS exhibited the best mechanical performance under impact, reaching 206.7 J/m. However, the simultaneous mixing sequence PBT/ABS/SAN-g-Epoxy showed the best balance of properties, with gains of 203% in impact strength, 8.8% in elastic modulus, and 40.1% in heat deflection temperature (HDT) compared to neat PBT. The results indicate that PBT can be improved and tailored for engineering applications. Full article

In this study, we investigate the impact of processing strategies on the nanoscale morphology and photophysical behavior of donor–acceptor thin films composed of the polymeric donor PBDTTTPD and the n-type acceptor PNDI(2HD)2T. The blend morphology and interfacial characteristics were systematically tuned using three distinct fabrication techniques: spin-coating, convective self-assembly, and space-confined solvent vapor annealing. Atomic force microscopy and photoluminescence spectroscopy were employed to elucidate structure–property correlations relevant to all-polymer optoelectronic systems. Films processed via convective self-assembly exhibited nanoscale features with extensive donor–acceptor intermixing, leading to the most efficient photoluminescence quenching of nearly 85%, indicative of enhanced exciton dissociation and charge transfer. In contrast, as-cast films displayed moderately mixed morphologies with approximately 81% quenching, serving as a reference state. The solvent vapor annealing method induced pronounced phase segregation and the formation of larger domains, resulting in reduced photoluminescence quenching efficiency of about 52%. These findings demonstrate that the nanoscale morphology, and consequently the photophysical response, of PBDTTTPD:PNDI(2HD)2T blends can be precisely tailored through processing, providing valuable design guidelines for all-polymer optoelectronic applications such as organic photovoltaics and field-effect transistors. Full article

Zirconia-based hybrid blends at various molecular or nanometer scales have attracted significant interest from a technological perspective. In particular, several inorganic-organic hybrids are being applied in the biomedical field. In this context, inorganic ZrO₂ and hybrids composed of ZrO₂, and polyethylene glycol (PEG) have been synthesized through the sol–gel process and characterized from both morphological and spectroscopic viewpoints to explore their potential as hybrid biomaterials. Atomic Force Microscopy (AFM) has enabled a quantitative assessment of the surface roughness of bioactive sol–gel-based materials. The findings indicated an increase in material porosity in relation to the amount of PEG present in the systems, underscoring the important role of PEG in influencing the morphological characteristics of zirconia-based blends. AFM images display the typical globular structure of PEG spread across the surface of all systems. All hybrid systems seem to be uniform, and no phase separation is evident, thereby validating that the produced materials are hybrid nanostructured ones. The simultaneous presence of both inorganic and organic phases was verified using Fourier-transform infrared spectroscopy (FT-IR). FT-IR deconvolution in 850–550 cm⁻¹ region showed that PEG progressively perturbs the Zr–O–Zr network, increasing disorder and establishing more flexible inorganic domains at high PEG content. Increasing polymer amount enhanced cell viability against NIH-3T3 cell line, while antibacterial activity decreased, with pure ZrO₂ showing the strongest inhibition against Escherichia coli (E. coli). Full article

This study investigates the effects of organic salts, including sodium citrate (SC), calcium citrate (CC), and calcium lactate (CL), on the structure–property–function relationships of thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) films for active packaging applications. TPS incorporated with organic salts was prepared via twin-screw extrusion, blended with PBAT, and further processed into blown films. The films were systematically characterized using ¹H NMR, FTIR, and SEM, together with optical, mechanical, water vapor permeability, and antimicrobial evaluations against Staphylococcus aureus. The results revealed that SC primarily modulated hydrogen-bonding interactions within the starch matrix, resulting in improved structural homogeneity, balanced mechanical properties, and the highest antimicrobial activity among all formulations. In contrast, CL and CC promoted ionic crosslinking through Ca²⁺–starch interactions, leading to increased stiffness and Young’s modulus but reduced polymer chain mobility and limited release of active species, particularly in CC-containing systems. These differences in molecular interactions were consistent with variations in film microstructure, where SC-containing films exhibited more uniform morphologies, while calcium-based systems showed denser but less permeable structures. Furthermore, films containing SC and CL at appropriate concentrations achieved a favorable balance between transparency, water vapor barrier properties, and antimicrobial performance. Overall, this study provides new mechanistic insights into how monovalent and divalent organic salts govern intermolecular interactions, microstructure, and functional performance in TPS/PBAT systems. The findings highlight the critical role of additive type and concentration in designing biodegradable active packaging materials with tunable mechanical, barrier, and antimicrobial properties. Full article

Homopolymer addition is a widely used strategy to dilate the microdomain spacing of block copolymers, yet the attainable dilation is often limited by macrophase separation in conventional blends at elevated homopolymer loading. In this work, we investigate an architectural route to suppress macrophase separation while retaining homopolymer-driven dilation: a covalently hybridized bottlebrush copolymer (CH-BBC), a copolymacromer-like bottlebrush architecture in which symmetric AB diblock side chains and A-type homopolymer side chains are covalently grafted to a common backbone. Using dissipative particle dynamics (DPD) simulations, we directly compare the phase behavior of CH-BBC melts with that of composition-matched blends of symmetric AB diblocks and A-type homopolymers. Across the explored window, CH-BBC exhibits microphase morphologies and disorder without an observable two-phase region, whereas the corresponding blends show extensive two-phase coexistence at elevated homopolymer loading. Lamellar analysis and one-dimensional density decompositions further reveal that CH-BBC enables substantially larger microphase dilation and stronger selective swelling of the A-rich domain because tethered A-type homopolymer segments preferentially occupy and dilate the A-rich domain interior while diblock A segments remain localized near interfaces. Full article

The dynamic self-assembly and phase separation of donor–acceptor blends are processes that dictate the nanoscale morphology in organic solar cells. Here, we employ a fluidics-inspired framework, integrating dissipative particle dynamics simulations with percolation theory, to investigate the morphogenesis of two non-fullerene systems: P3HT-PPerAcr and P3HT-PFTBT. We analyze monomeric and homopolymer blends, and copolymer macrostructures, focusing on how key parameters such as temperature and polymer chain flexibility govern the dynamic evolution towards percolating networks. Our simulations captured the fundamental fluidic behavior and universal scaling near the critical percolation threshold (χ_c). The critical exponent β revealed distinct universality classes dictated by system compatibility and flexibility: monomeric and flexible homopolymer blends below the critical temperature (T_c) exhibit mean field behavior (β ≈ 1). In contrast, monomeric systems above χ_c and flexible copolymers below χ_c display 3D percolation behavior (β ≈ 0.45). In the case of flexible copolymeric macromolecules, above percolation threshold a quasi-bidimensional behavior emerge with (β ≈ 0.1). Notably, semi-rigid and rigid homopolymeric and copolymeric linear architectures induce a dimensional crossover, yielding quasi-2D (β ≈ 0.14) and quasi-1D (β ≈ 0.0) morphologies. These findings establish a direct link between tunable fluidic interactions, chain dynamics, and the emergence of optimal bicontinuous percolation networks. Full article

Fe₂O₃-reinforced PMMA nanocomposites were prepared by melt blending using a twin-screw micro-extruder. Fixed Fe₂O₃ loading of 2.5 wt.% was employed, and mixing times of 6 and 12 min were used to obtain nanocomposites with different dispersion characteristics. The structural and morphological properties of the samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while their thermal degradation behavior was evaluated by differential thermal and thermogravimetric analyses (DTA/TG). The activation energies of thermal degradation were calculated using the Kissinger, Takhor, and Augis–Bennett methods. Increasing the mixing time improved nanoparticle dispersion and reduced agglomeration. The addition of Fe₂O₃ slightly decreased the characteristic degradation temperatures of PMMA, while the activation energy increased for the better-dispersed sample. The results indicate that interfacial interactions and particle dispersion play important roles in the thermal degradation behavior of PMMA/Fe₂O₃ nanocomposites. Full article