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Abstract: Microorganisms in biofilms are protected from environmental stressors and therefore exhibit strong resistance to conventional removal strategies, including chemical disinfectants and antibiotics. In this study, we systematically evaluated nanomaterial-based removal methods on Listeria innocua biofilms. Anisotropic magnetic particles, composed of iron oxide, and silver nanoparticles, known for their intrinsic antibacterial properties, were used to assess the potential of nanostructure-triggered biofilm disruption. We investigated how particle surface roughness and size affect biofilm removal under magnetic actuation, using both classical colony-forming unit quantification (viability assessment) and fluorescence-based detection via a reporter protein. The surface roughness and size of anisotropic magnetic particles only modestly affected biofilm disruption. Conversely, a synergistic effect was observed when anisotropic magnetic particles were grafted with silver nanoparticles. Furthermore, we used Enterococcus faecalis and Candida albicans biofilms and observed pronounced species-dependent variability of the silver-based treatments. Our results indicate that hybrid magneto–chemical strategies represent a promising and likely necessary approach for reliable and robust biofilm removal.
Keywords: bacterial biofilm, magnetomechanical detachment, anisotropic magnetic nanoparticles, silver nanoparticles
Published in DiRROS: 01.07.2026; Views: 102; Downloads: 100
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Keywords: NiO nanoparticles, sol-gel, Pechini method, biosynthesis, Eruca sativa, photocatalysis
Published in DiRROS: 22.06.2026; Views: 131; Downloads: 92
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Abstract: Plasma-activated water (PAW) enables surfactant-free synthesis of gold nanoparticles (AuNPs) at room temperature and acts as a reaction medium with tuneable reactive oxygen and nitrogen species (ROS and RNS), decoupled from the plasma discharge. Treating deionised water with an argon atmospheric-pressure plasma jet for 1–16 min increased H2O2 concentration from 0 to 8 mM, lowered pH from 7.0 to 3.5, and raised the oxidation–reduction potential from 0 to 400 mV, while maintaining negligible RNS levels. These changes directly influence Au3+ reduction and AuNP growth. At 1.00 mM [Au3+], increasing PAW activation time from 1 to 16 min shortened the reduction time tenfold and shifted the LSPR maximum from 610 to 538 nm, with particle size decreasing from 120 nm to about 80 nm. Using the most reactive PAW (16 min), decreasing [Au3+] from 1.00 to 0.10 mM reduced the mean AuNP size from 80 to 35 nm, yielding uniform, well-faceted nanoparticles. Weakly activated PAW (1–2 min) yields slower, partially incomplete reduction, broader size distributions, and more planar nanoparticles. These results establish PAW as a sustainable method for directed AuNP reduction kinetics, size, morphology, and optical response without external reducing or capping agents.
Keywords: gold nanoparticles, plasma-activated water, tunable synthesis, surfactant-free synthesis
Published in DiRROS: 28.05.2026; Views: 199; Downloads: 171
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Abstract: The thorough understanding of the interactions between nanoparticles and lipid membranes has attracted major interest over the past few decades. This spans fundamental biophysics and biomechanics, as well as medical applications, where nanoparticles could serve as potential drug carriers. The influence of the lipid phase in these interactions has been studied to markedly less extent with respect to the nanoparticle size, shape and coating, as well as the presence of electric charge in either the nanoparticles or the membranes. Seeking to gain new insights into the lipid phase, we have systematically investigated the role of the liquid-disordered, the gel-ordered, as well as the seldom-studied ripple phases in modulating the interaction strength between nanoparticles and biomimetic membranes. Supported lipid vesicles and supported lipid bilayers of different composition and amount of electric charge, as well as spherical functionalized Au nanoparticles with and without charge have formed our experimental platform. The results, obtained by quartz crystal microbalance with dissipation monitoring and complemented by atomic force microscopy, reveal a strikingly different mechanistic picture of the interactions between the various lipid phases and types of nanoparticles. We demonstrate enhanced vesicle rupture in the case of stiffer membranes, consistent with recent theoretical studies, yet supported by limited existing experimental evidence. This work advances fundamental understanding of lipid-state-driven nanoparticle–membrane interactions. Such insight is essential, as dynamic changes in bilayer rigidity, composition, and surface charge determine how membranes and nanoparticles interact.
Keywords: supported lipid vesicles, supported lipid bilayers, gold nanoparticles, lipid phase, quartz crystal microbalance with dissipation monitoring (QCM-D), nanoparticle-membrane interactions
Published in DiRROS: 10.04.2026; Views: 291; Downloads: 204
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Abstract: Nanosized spinel-type ferrites have gained recognition as a unique class of engineered nanomaterials with promising applications, but their safety profiles remain insufficiently explored. Although iron (Fe), zinc (Zn), and manganese (Mn) are biologically relevant elements, the use of Zn- and Mn-containing ferrite nanoparticles in biomedical contexts demands careful (geno)toxicity evaluation. In this study, three ferrite nanoparticles – γFe2O3 (FeNPs), Zn0.7Fe2.3O4 (ZnNPs), and Mn0.4Fe2.6O4 (MnNPs) – synthesised through a microwave-assisted polyol route, functionalized with citric acid to improve colloidal stability, were evaluated for their potential (geno)toxic effects in an advanced in vitro 3D cell model, HepG2 spheroids. Cellular stress responses upon exposure to the particle were assessed using toxicogenomic analysis.This approach allows the identification of early molecular events that may precede overt toxicity, supporting a mechanistic understanding of adverse outcomes and facilitating the development of predictive biomarkers for hazard assessment. In the present study, the expression of selected DNA damage-responsive genes (TP53, MDM2, GADD45a, CDKN1A, OGG1, and JUNB), apoptosis-related genes (BCL2 and BAX) and oxidative stress response genes (SOD1, CAT, GPX1, GCLC, and GSR) was evaluated. The expression of the selected genes after exposure to the tested nanoparticles was analysed by qPCR primer assays (Applied Biosystems, USA) and One 48.48 Dynamic Array IFC for Gene Expression (Fluidigm, USA). After 24 and 96 hours of exposure, the spheroids were collected, and total RNA was isolated using the RNeasy Mini Kit from Qiagen (Qiagen, Germany) according to the manufacturer's instructions. 10 µg/mL etoposide served as athe positive control for the toxicogenomic analysis. RNA concentration and purity were assessed using a NanoDrop 1000 spectrophotometer (Thermo Fisher Scientific) by measuring absorbance at 260/280 nm and gele efectrophoresis (Figure 1). Reverse transcription of 1 µg total RNA per sample was performed with the High-Capacity cDNA Reverse Transcription Kit (Applied Biosystems, MA, USA) on a BIO-RAD T100 thermal cycler under conditions listed in Table 3. For preamplification, 4 µL of each of the 24 selected TaqMan assays (SM2) were pooled into a primer mix. The reaction mixture was prepared using TATAA PreAmp GrandMasterMix (Tataa Biocenter, Sweden), the primer pool, and nuclease-free water, following manufacturer instructions. Negative controls (NTC for preamplification and NTCq for qPCR) were included. Each reaction contained 8 µL of mix and 2 µL of 5× diluted cDNA, processed in a 96-deep well plate, sealed, vortexed, and centrifuged (1000 g, 1 min). Preamplification was carried out on a BIO-RAD T100 thermal cycler under conditions in Table 4. Gene expression analysis used TaqMan Universal PCR Master Mix and TaqMan Gene Expression Assays (Table 6). Preamplified samples were diluted 10× with nuclease-free water. Assays were prepared by mixing equal volumes (6 µL) of each assay with Fluidigm Assay Loading Reagent Kit – 10IFCS. The reaction premix combined DNA Sample Loading Reagent and Fast Probe Master Mix (Biotium/Roche) and was added to each diluted cDNA sample. qPCR was performed on 48.48 Dynamic Array™ IFC chips using the Fluidigm BioMark™ HD System under conditions in Table 5. Data were analysed with Fluidigm Gene Expression Analysis Software and quantGenious. Fold changes >1.5 or <0.66 were considered biologically relevant. Statistical significance between NP-exposed cells and solvent controls was assessed using ANOVA and Dunnett’s test in GraphPad Prism v9 (GraphPad Software, CA, USA).
Keywords: ferrite-based nanoparticles, HepG2 spheroids, toxicogenomics, changes in gene expression
Published in DiRROS: 24.03.2026; Views: 317; Downloads: 352
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