Tatjana Kavleiskaja

Chitosan–gelatin (CG) hybrid hydrogels are widely recognized for their biocompatibility and suitability for soft tissue engineering, wound dressings, and biomedical coatings. Despite this promise, conventional CG systems often exhibit limited mechanical strength, restricted durability, and uncontrolled swelling, which can reduce their clinical relevance. In this study, we introduce an enhanced soft hydrogel platform reinforced with niobium pentoxide (Nb₂O₅) nanoparticles and chemically crosslinked using glutaraldehyde, with citric acid serving as a dissolution medium and processing aid. Three hydrogel variants (G1, G2 and G3) were prepared by adjusting nanoparticle concentration and subsequently evaluated through structural, morphological, swelling, gel-fraction, and rheological analyses. SEM imaging revealed that increasing Nb₂O₅ content produced notable architectural transitions—from smooth porous matrices to nanoparticle-distributed, heterogenous pore structures. XRD, FTIR, and Raman spectroscopy confirmed the structural retention of Nb₂O₅ and its effective interaction with the polymer network. Swelling and gel-fraction measurements demonstrated improved network stability in nanoparticle-loaded systems, with G2 providing the most desirable balance between swelling capacity (298%) and gel fraction (91%). Rheological studies further identified G2 as the most stable and elastic composition, exhibiting strong shear-thinning behavior and high structural recovery. Overall, G2 emerges as the optimal formulation for future biomedical development.

β‐Carotene is a useful compound for food fortification because it has beneficial effects on human health. However, it is insoluble in water and sensitive to light, oxygen and temperature. To increase the solubility and stability of β‐carotene, its complexation with polysaccharides is used. The study aimed to develop and optimise a new method for β‐carotene–xylan (CAR–XYL) complex fabrication. The physical and chemical properties of the resulting complexes were investigated. The β‐carotene:xylan ratios of 1:3 (w/w) and 1:5 (w/w) were concluded to be the most applicable to β‐carotene formulation. The solubility of the complexes was 36.8 and 38.3 mg/mL, respectively. The particles were small in size. Their hydrodynamic diameters were 300.4 ± 10.4 nm and 242.2 ± 2.6 nm, respectively. The thermal stability of the complexes at different temperatures for 30 min was not significantly affected by the β‐carotene:xylan ratio. However, the shelf life of β‐carotene under UV irradiation and long‐term storage under different conditions showed a tendency to decrease in β‐carotene:xylan ratios of 1:10 (w/w) and 1:20 (w/w). β‐Carotene complexed with xylan did not lose its antioxidant activity. Furthermore, for the use of the β‐carotene–xylan complexes in functional foods, the bioaccessibility of β‐carotene complexed with xylan was studied using the INFOGEST protocol. For CAR–XYL complexes fabricated at CAR:XYL ratios of 1:3 and 1:5, bioaccessibility was 54.3 ± 5.6% and 59.03 ± 3.3%, respectively.

This study presents a microfluidic approach for synthesizing tetracycline-loaded chitosan–tripolyphosphate (TPP) nanoparticles with tunable physicochemical properties for localized antibiofilm therapy. A custom-designed PDMS chip incorporating sequential micromixing chambers and a serpentine flow region enabled reproducible ionic crosslinking under controlled laminar flow, yielding quasi-spherical nanoparticles (132 ± 3 nm; PDI 0.178 ± 0.004) with a positive surface charge (+15.8 ± 0.3 mV) and 35% drug encapsulation efficiency. FTIR spectroscopy confirmed stable drug incorporation through electrostatic and hydrogen-bonding interactions. Functional assessment against Staphylococcus aureus and Escherichia coli biofilms demonstrated dose-dependent inhibition of metabolic activity and biomass accumulation. Compared to batch processing, the microfluidic approach enabled more consistent nanoparticle size distribution and improved reproducibility. These findings establish a flow-assisted nanomanufacturing platform for the production of bioactive chitosan-based carriers and highlight their potential in nanoscale therapeutic systems targeting biofilm-associated infections.

Photoactive hydrogels facilitate light-triggered photochemical processes, positioning them as innovative solutions in biomedical applications, especially in antimicrobial photodynamic therapy. This study presents a novel methylene blue-based photoactive hydrogel designed as a topical gel solution to overcome the limitations of traditional pad-based systems by offering enhanced adaptability to irregular wound surfaces, uniform photosensitizer distribution, and deeper therapeutic light penetration. This study investigated the development of hydrogels by cross-linking gelatin with glutaraldehyde (GA) and incorporating methylene blue (MB) to investigate the effects of cross-linking density, network structure, and small molecule inclusion on hydrogel properties. The results showed that while glutaraldehyde concentration influenced swelling behavior and network structure, the inclusion of MB altered these properties, particularly reducing swelling and MB retention at higher GA concentrations. Rheological and thermal analyses confirmed that higher GA concentrations made the hydrogels more rigid, with MB influencing both mechanical and thermal properties. Additionally, the hydrogels exhibited enhanced antimicrobial properties through increased reactive oxygen species production, particularly in light-activated conditions, demonstrating the potential of MB-based photoactive hydrogels for improving antimicrobial efficacy, especially against S. aureus, E. coli, and C. albicans, offering as a possible alternative to traditional antimicrobial treatments.

Nisin is an attractive alternative to chemical preservatives in the food industry. It is a cationic peptide of 34 amino acid residues that exhibits antimicrobial activity against Gram-positive bacteria. To ensure nisin stability in food matrices, new nisin-loaded ulvan particles were developed by the complexation method. The interaction of nisin with ulvan was demonstrated by FT-IR spectroscopy and differential scanning calorimetry. The encapsulation efficiency was calculated at different pH values within the range of 4.0–7.0 and was found to have the highest value at pH 7.0. The size and surface charge of particles fabricated at different concentrations of nisin and pH values were determined. Nisin-loaded ulvan particles exhibited antimicrobial activity against Gram-positive bacteria comparable to that of free nisin. Therefore, the developed complexes have the potential for application as biopreservatives in the food industry. For the first time, the potential of ulvan as a carrier of antimicrobial agent nisin was demonstrated.

Jerusalem artichoke tubers have diverse applications in the food industry as well as in biotechnology. Their suitability depends mostly on the inulin content. Seasonal fluctuations of fructan exohydrolase activity responsible for inulin degradation was investigated in the tubers of three Jerusalem artichoke cultivars. The changes of fructan exohydrolase activity positively correlated with the changes of the content of total and short fructooligosaccharides. Therefore, to extract inulin with higher degree of polymerization for biotechnological purposes, the tubers of Jerusalem artichoke should be uprooted in autumn before the level of fructan exohydrolase reaches its maximum. If short fructooligosaccharides are desirable, the tubers in late autumn or spring tubers overwintered in soil are suitable.