A simple, low-cost, and reproducible method for creating materials with even silver nanoparticles (AgNP) dispersion was established. Chitosan nanofibers with silica phase (CS/silica) were synthesized by an electrospinning technique to obtain highly porous 3D nanofiber scaffolds. Silver nanoparticles in the form of a well-dispersed metallic phase were synthesized in an external preparation step and embedded in the CS/silica nanofibers by deposition for obtaining chitosan nanofibers with silica phase decorated by silver nanoparticles (Ag/CS/silica). The antibacterial activity of investigated materials was tested using Gram-positive and Gram-negative bacteria. The results were compared with the properties of the nanocomposite without silver nanoparticles and a colloidal solution of AgNP. The minimum inhibitory concentration (MIC) of obtained AgNP against Staphylococcus aureus (S. aureus) ATCC25923 and Escherichia coli (E. coli) ATCC25922 was determined. The physicochemical characterization of Ag/CS/silica nanofibers using various analytical techniques, as well as the applicability of these techniques in the characterization of this type of nanocomposite, is presented. The resulting Ag/CS/silica nanocomposites (Ag/CS/silica nanofibers) were characterized by small angle X-ray scattering (SAXS), X-ray diffraction (XRD), and atomic force microscopy (AFM). The morphology of the AgNP in solution, both initial and extracted from composite, the properties of composites, the size, and crystallinity of the nanoparticles, and the characteristics of the chitosan fibers were determined by electron microscopy (SEM and TEM).

Humans are chronically exposed to airborne particulate matter and environmental microplastics through food, water, and consumer products. These anthropogenic pollutants may accumulate in human tissues, but their distribution and chemical identity remain poorly understood. In this study, we analyzed samples of human brain, liver, thyroid, kidney, heart, skeletal muscle, and lung tissue collected post-mortem to assess the presence and composition of micro- and nanoplastics (MNPs). Tissue samples were digested using hydrogen peroxide (30% H₂O₂) and processed via alumina filtration. The retained residues and filtrates were characterized using optical microscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), dynamic light scattering (DLS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and optical photothermal infrared (O-PTIR) microscopy. Our analysis revealed a wide range of inorganic particles (primarily aluminosilicates and carbonates) and synthetic polymers, including polyethylene terephthalate (PET), polystyrene (PS), polyacrylonitrile (PAN), and cellulose derivatives. Notably, PS, PET, and PAN nanoparticles (<0.02 µm) were detected in the filtrates, indicating their potential to cross biological barriers and accumulate at the nanoscale. The thyroid, kidney, and brain tissues showed the highest levels of microplastic contamination, with up to 40.4 MP/g (wet weight) detected. These findings confirm the heterogeneous organ-specific accumulation of environmental polymers and highlight the potential of human autopsy tissues as biomonitors for environmental plastic exposure. The application of advanced spectroscopic techniques enables precise identification of polymeric contaminants and supports further research on their environmental origins and pathways of human exposure.

Exopolymeric substances (EPS) can determine plant-microorganism interactions and have great potential as bioactive compounds. The different amounts of EPS obtained from cultures of three endophytic Fusarium culmorum strains with different aggressiveness—growth promoting (PGPF), deleterious (DRMO), and pathogenic towards cereal plants—depended on growth conditions. The EPS concentrations (under optimized culture conditions) were the lowest (0.2 g/L) in the PGPF, about three times higher in the DRMO, and five times higher in the pathogen culture. The EPS of these strains differed in the content of proteins, phenolic components, total sugars, glycosidic linkages, and sugar composition (glucose, mannose, galactose, and smaller quantities of arabinose, galactosamine, and glucosamine). The pathogen EPS exhibited the highest total sugar and mannose concentration. FTIR analysis confirmed the β configuration of the sugars. The EPS differed in the number and weight of polysaccharidic subfractions. The EPS of PGPF and DRMO had two subfractions and the pathogen EPS exhibited a subfraction with the lowest weight (5 kDa). The three EPS preparations (ethanol-precipitated EP, crude C, and proteolysed P) had antioxidant activity (particularly high for the EP-EPS soluble in high concentrations). The EP-EPS of the PGPF strain had the highest antioxidant activity, most likely associated with the highest content of phenolic compounds in this EPS.