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The prevalence of bacterial infections presents a significant challenge in the medical field, demanding effective strategies to impede bacterial adhesion and growth on various surfaces. The conducted study investigates the efficacy of polyelectrolyte multilayerscomprising poly-(allylamine hydrochloride) (PAH) and alginate (ALG)embedded with zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) to inhibit bacterial adhesion on stainless-steel surfaces. Surface characterization involved zeta potential, contact angle, and roughness assessments. The effect of NP composition, size, and morphology in conjunction with polycation or polyanion terminating multilayers was evaluated against planktonic and surface-adhered Escherichia coli (E. coli) cells. Surfaces with the positively charged PAH-terminating multilayer displayed higher water contact angles (≈ 63°) than the negatively charged ALG-terminating multilayers (≈ 45°). Multilayers containing ZnO NPs showed a significant inhibition of planktonic E. coli growth, >99%. Moreover, complete growth inhibition of surface-adhered E. coli was achieved for multilayers containing both ZnO and CuO. Due to their larger specific surface area, rod-like ZnO NPs displayed higher antibacterial activity. The samples with ALG as the terminating layer showed more substantial antibacterial properties than samples with PAH as the terminating layer. Biocompatibility tests on immortalized human keratinocyte cells revealed good compatibility with multilayers incorporating NPs. In summary, this study underscores the potential of ZnO and CuO NPs within PAH/ALG multilayers for antibacterial applications without compromising their cytocompatibility. [ABSTRACT FROM AUTHOR]

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2–3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm−2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL−1). [ABSTRACT FROM AUTHOR]

The heat treatment of dental alloys prior to porcelain application/veneering has been proposed as a way to ensure sufficient oxide scale and to promote the porcelain's adherence in porcelain-fused-to-metal (PFM) fixed dental prostheses. The present study investigates the relationship between the bond strength of the dental porcelain to selective-laser-melted (SLM) titanium and the temperature of the titanium's pre-oxidation. The SLM Ti-6Al-4V substrates were airborne-particle abraded and either left to passivate in air at room temperature (control) or pre-oxidized in a furnace under vacuum conditions (10 kPa) at temperatures of 300, 600, 750, or 800 °C. The surface characteristics were determined using contact profilometry to measure the profile roughness (Ra), atomic force microscopy for the surface roughness (Sa) and Auger electron spectroscopy for the thickness of the oxide scale. Dental porcelain was applied to the metal substrates and the titanium-ceramic bond was assessed according to the ISO standard 9693-1:2012. The metal-ceramic interfaces were analyzed with scanning electron microscopy and energy-dispersive spectroscopy. The Ra and Sa values showed a strong positive correlation with the pre-oxidation temperature. The oxide scales covering the titanium surfaces thickened markedly at temperatures of 750 °C and above. However, the bond strength was negatively correlated with the pre-oxidation temperature. Room-temperature passivation in air following the airborne-particle abrasion of the SLM titanium resulted in a titanium-ceramic bond that is well above the ISO 9693-1:2012 recommended minimum value for metal-ceramic systems. Thus, no pre-oxidation of SLM titanium frameworks is necessary prior to the application/firing of porcelain. [ABSTRACT FROM AUTHOR]

Prosthetic liners are mainly used as an interface between residual limbs and prosthetic sockets to minimize physical and biological damage to soft tissue. However, the closed and moist conditions within liners and the amputee's skin provide a suitable environment for bacterial growth to cause infections. This study aimed to coat a comprehensive variant material with copper oxide nanoparticles (CuO NPs) and compare their surface analysis and antibacterial properties. These materials were covered with CuO NPs solution at a concentration of 70 μg mL -1 to achieve this purpose. After drying, their surface characteristics were analyzed by measuring zeta potential, contact angle, surface roughness, and fiber arrangement. Cu-released concentration from the coatings into the acetate buffer solution by inductively coupled plasma mass spectrometry indicated that lycra and nylon quickly released Cu ions to concentrations up to ∼0.2 μg mL -1 after 24 h, causing low metabolic activity of human bone-marrow mesenchymal stem cells (bMSC) in the indirect assay. Antibacterial activity of the coated specimens was evaluated by infecting their surfaces with the Gram-positive bacteria Staphylococcus epidermidis, reporting a significant ∼40 % reduction of metabolic activity for x-dry after 24 h; in addition, the number of viable bacterial colonies adhered to the surface of this material was reduced by ∼23 times in comparison with non-treated x-dry that were visually confirmed by scanning electron microscope. In conclusion, CuO NPs x-dry shows optimistic results to pursue further experiments due to its slow speed of Cu release and prolonged antibacterial activity, as well as its compatibility with human cells., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 Published by Elsevier Ltd.)