Immunotoxicity of stainless-steel nanoparticles obtained after 3D printing.

This study aims to investigate the in vitro effects of nanoparticles (NPs) produced during the selective laser melting (SLM) of 316 L stainless steel metal powder on the immune response in a human blood model. Experimental data did not reveal effect on viability of 316 L NPs for the tested doses. Functional immune assays showed a significant immunosuppressive effect of NPs. There was moderate stimulation (117%) of monocyte phagocytic activity without significant changes in phagocytic activity and respiratory burst of granulocytes. A significant dose-dependent increase in the levels of the pro-inflammatory cytokine TNF-a was found in blood cultures treated with NPs. On the contrary, IL-8 chemokine levels were significantly suppressed. The levels of the pro-inflammatory cytokine IL-6 were reduced by only a single concentration of NPs. These new findings can minimise potential health risks and indicate the need for more research in this area.

Silver-loaded poly(vinyl alcohol)/polycaprolactone polymer scaffold as a biocompatible antibacterial system.

A chronic nonhealing wound poses a significant risk for infection and subsequent health complications, potentially endangering the patient's well-being. Therefore, effective wound dressings must meet several crucial criteria, including: (1) eliminating bacterial pathogen growth within the wound, (2) forming a barrier against airborne microbes, (3) promoting cell proliferation, (4) facilitating tissue repair. In this study, we synthesized 8 ± 3 nm Ag NP with maleic acid and incorporated them into an electrospun polycaprolactone (PCL) matrix with 1.6 and 3.4 µm fiber sizes. The Ag NPs were anchored to the matrix via electrospraying water-soluble poly(vinyl) alcohol (PVA), reducing the average sphere size from 750 to 610 nm in the presence of Ag NPs. Increasing the electrospraying time of Ag NP-treated PVA spheres demonstrated a more pronounced antibacterial effect. The resultant silver-based material exhibited 100% inhibition of gram-negative Escherichia coli and gram-positive Staphylococcus aureus growth within 6 h while showing non-cytotoxic effects on the Vero cell line. We mainly discuss the preparation method aspects of the membrane, its antibacterial properties, and cytotoxicity, suggesting that combining these processes holds promise for various medical applications.

The Effects of Nature-Inspired Synthesis on Silver Nanoparticle Generation.

A wide range of methods can be used for nature-inspired metallic nanoparticle (NP) synthesis. These syntheses, however, are ongoing in the presence of diverse mixtures of different chemical compounds, and all or only a few of these contribute to resultant particle properties. Herein, the linden (Tilia sp.) inflorescence leachate and pure citric and protocatechuic acids were chosen for Ag-AgCl nanoparticle (NP) synthesis, and the resultant particles were then compared. We focused on the following four issues: (1) preparation of Ag-AgCl NPs using the Tilia sp.-based phytosynthetic protocol, (2) analytical determination of the common phenolic, nonphenolic, and inorganic profiles of three Tilia sp. types from different harvesting locations, (3) preparation of Ag-AgCl NPs using a mixture of citric and protocatechuic acids based on chromatographic evaluation, and (4) comparison of Tilia-based and organic acid-based syntheses. Our research confirms that the Tilia organic and inorganic profiles in biomasses are influenced by the harvesting location, and the three sites influenced both the morphology and final NP size. Our processing method was uniform, and this enabled great Ag-AgCl NP reproducibility for each specific biomass. We were then able to prove that the simplified organic acid-based synthesis produced even smaller NPs than Tilia-based synthesis. These findings provide better understanding of the significant influence on NP final properties resulting from other organic acids contained in the linden.

Crucial cytotoxic and antimicrobial activity changes driven by amount of doped silver in biocompatible carbon nitride nanosheets.

The use of Ag-modified nanomaterials continues to attract attention in biological contamination control, their potential cytotoxicity is often overlooked. Herein, biocompatible carbon nitride is modified with 1 and 5 wt.% Ag and effects of different nanomaterial dose and Ag content on antimicrobial activity and cytotoxicity is studied. Pure Ag nanoparticles and AgNO3 is tested for comparison, together with ten bacterial strains including pan-resistant Pseudomonas aeruginosa. Cytotoxicity is then investigated in three adherent and two suspension human cell lines, and results confirm that cancer adherent cell lines are the most immune lines and human cervical adenocarcinoma cells (HeLa) are more resilient than human lung adenocarcinoma cells (A549). The HeLa remains over 90 % viable even after 24 -h treatment with the highest concentration of 5%Ag/g-C3N4 (300 mg L-1) while A549 sustained viability only up to 100 mg L-1. Higher concentrations then induce cytotoxicity and A549 cell viability decreases. Our results show the importance of complementary testing of cytotoxicity by LIVE/DEAD assay using flow cytometry with more different human cell lines, which might be less immune to tested nanomaterials than HeLa and A549. Combined controls of new antibacterial agent activity tests then provide increased knowledge of their biocompatibility.

Ag-AgCl Nanoparticles Fixation on Electrospun PVA Fibres: Technological Concept and Progress.

Polymer-metal based material with unique 3D structure is an attractive substrate for the development of biomedical applications. A novel preparation of the composite from polymer fibres and silver nanoparticles has been designed through: (1) preparation of silver nanoparticles by phytosynthesis and (2) incorporation of these nanoparticles in a fibrous membrane prepared by electrospinning. The nanoparticle biosynthesis was performed in a pure environmental-friendly, easy, static, bottom-up in vitro regime using Tilia sp. leachate. TEM and XRD depict the formation, stabilisation and encapsulation of crystalline silver (14 ± 9 nm) nanoparticles (NPs) in one simple step with low tendency to aggregate. We achieved successful incorporation in the uniform electrospun 221 ± 24 nm poly(vinylalcohol) fibres, and this confirms the possibility of its use in the biomedical field. Both SEM with EDX and TEM analysis determined fibre uniformity with the presence of silver NPs, and ICP-AES confirmed the relatively similar metal concentration throughout the triplicate measurement of fibre structures on the 2 × 2 cm area in the following manner: 0.303 ± 0.018 wt. %, 0.282 ± 0.017 wt. %, and 0.281 ± 0.017 wt. %. Our hypothesis is based on previously verified preparation of active silver NPs and the easily prepared PVA electrospun fibres which act as a water soluble matrix. The simple methodology of incorporating biosynthetically prepared NPs in the PVA fibers highlights the effectiveness of this material, with simple release from water-soluble PVA and final activation of the prepared NPs.