The concerns regarding microplastics and nanoplastics pollution stimulate studies on the uptake and biodistribution of these emerging pollutants in vitro. Atomic force microscopy in nanomechanical PeakForce Tapping mode was used here to visualise the uptake and distribution of polystyrene spherical microplastics in human skin fibroblast. Particles down to 500 nm were imaged in whole fixed cells, the nanomechanical characterization allowed for differentiation between internalized and surface attached plastics. This study opens new avenues in microplastics toxicity research.

The problem of purifying domestic and hospital wastewater from pharmaceutical compounds is becoming more and more urgent every year, because of the continuous accumulation of chemical pollutants in the environment and the limited availability of freshwater resources. Clay adsorbents have been repeatedly proposed as adsorbents for treatment purposes, but natural clays are hydrophilic and can be inefficient for catching hydrophobic pharmaceuticals. In this paper, a comparison of adsorption properties of pristine montmorillonite (MMT) and montmorillonite modified with stearyl trimethyl ammonium (hydrophobic MMT-STA) towards carbamazepine, ibuprofen, and paracetamol pharmaceuticals was performed. The efficiency of adsorption was investigated under varying solution pH, temperature, contact time, initial concentration of pharmaceuticals, and adsorbate/adsorbent mass ratio. MMT-STA was better than pristine MMT at removing all the pharmaceuticals studied. The adsorption capacity of hydrophobic montmorillonite to pharmaceuticals decreased in the following order: carbamazepine (97%) > ibuprofen (95%) > paracetamol (63–67%). Adsorption isotherms were best described by Freundlich model. Within the pharmaceutical concentration range of 10–50 µg/mL, the most optimal mass ratio of adsorbates to adsorbents was 1:300, pH 6, and a temperature of 25 °C. Thus, MMT-STA could be used as an efficient adsorbent for deconta×ating water of carbamazepine, ibuprofen, and paracetamol.

Complexation of biopolymers with halloysite nanotubes (HNTs) can greatly affect their applicability as materials building blocks. Here we have performed a systematic investigation of fabrication of halloysite nanotubes complexes with nucleotides and genomic DNA. The binding of DNA and various nucleotide species (polyAU, UMP Na₂, ADP Na₃, dATP Na, AMP, uridine, ATP Mg) by halloysite nanotubes was tested using UV-spectroscopy. The study revealed that binding of different nucleotides to the nanoclay varied but was low both in the presence and absence of MgCl₂, while MgCl₂ facilitated significantly the binding of longer molecules such as DNA and polyAU. Modification of the nanotubes with DNA and nucleotide species was further confirmed by measurements of ζ-potentials. DNA-Mg-modified nanotubes were characterized using transmission electron (TEM), atomic force (AFM) and hyperspectral microscopies. Thermogravimetric analysis corroborated the sorption of DNA by the nanotubes, and the presence of DNA on the nanotube surface was indicated by changes in the surface adhesion force measured by AFM. DNA bound by halloysite in the presence of MgCl₂ could be partially released after addition of phosphate buffered saline. DNA binding and release from halloysite nanotubes was tested in the range of MgCl₂ concentrations (10–100 mM). Even low MgCl₂ concentrations significantly increased DNA sorption to halloysite, and the binding was leveled off at about 60 mM. DNA-Mg-modified halloysite nanotubes were used for obtaining a regular pattern on a glass surface by evaporation induced self-assembly process. The obtained spiral-like pattern was highly stable and resisted dissolution after water addition. Our results encompassing modification of non-toxic clay nanotubes with a natural polyanion DNA will find applications for construction of gene delivery vehicles and for halloysite self-assembly on various surfaces (such as skin or hair).

Lactiplantibacillus plantarum is best known for its significant adaptive potential and ability to colonize different ecological niches. Different strains of L. plantarum are widely used as probiotics. To characterize the probiotic potential of the novel L. plantarum FCa3L strain isolated from fermented cabbage, we sequenced its whole genome using the Illumina MiSeq platform. This bacterial isolate had a circular chromosome of 3,365,929 bp with 44.3% GC content and a cyclic phage phiX174 of 5386 bp with 44.7% GC content. The results of in vitro studies showed that FCa3L was comparable with the reference probiotic strain L. plantarum 8PA3 in terms of acid and bile tolerance, adhesiveness, H₂O₂ production, and acidification rate. The strain 8PA3 possessed higher antioxidant activity, while FCa3L demonstrated superior antibacterial properties. The antibiotic resistance of FCa3L was more relevant to the probiotic strain than that of 8PA3, although a number of silent antibiotic resistance genes were identified in its genome. Genomic evidence to support adhesive and antibacterial properties, biosynthesis of bioactive metabolites, and safety of FCa3L was also presented. Thus, this study confirmed the safety and probiotic properties of L. plantarum FCa3L via complete genome and phenotype analysis, suggesting its potential as a probiotic, although further in vivo investigations are still necessary.

Synthesis of silver nanoparticles using extracts from plants is an advantageous technological alternative to the traditional colloidal synthesis due to its simplicity, low cost, and the inclusion of environmentally friendly processes to obtain a new generation of antimicrobial compounds. The work describes the production of silver and iron nanoparticles using sphagnum extract as well as traditional synthesis. Dynamic light scattering (DLS) and laser doppler velocimetry methods, UV-visible spectroscopy, transmission electron microscopy (TEM) combined with energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), dark-field hyperspectral microscopy, and Fourier-transform infrared spectroscopy (FT-IR) were used to study the structure and properties of synthesized nanoparticles. Our studies demonstrated a high antibacterial activity of the obtained nanoparticles, including the formation of biofilms. Nanoparticles synthesized using sphagnum moss extracts likely have high potential for further research.

Polycations are an essential part of layer-by-layer (LbL)-assembled drug delivery systems, especially for gene delivery. In addition, they are used for other related applications, such as cell surface engineering. As a result, an assessment of the cytotoxicity of polycations and elucidation of the mechanisms of polycation toxicity is of paramount importance. In this study, we examined in detail the effects of a variety of water-soluble, positively charged synthetic polyelectrolytes on in vitro cytotoxicity, cell and nucleus morphology, and monolayer expansion changes. We have ranked the most popular cationic polyelectrolytes from the safest to the most toxic in relation to cell cultures. 3D cellular cluster formation was disturbed by addition of polyelectrolytes in most cases in a dose-dependent manner. Atomic force microscopy allowed us to visualize in detail the structures of the polyelectrolyte–DNA complexes formed due to electrostatic interactions. Our results indicate a relationship between the structure of the polyelectrolytes and their toxicity, which is necessary for optimization of drug and gene delivery systems.