MoS ₂ monolayer samples were synthesized on a SiO ₂ /Si wafer and transferred to Ir(111) for nano-scale characterization. The samples were extensively characterized during every step of the transfer process, and MoS ₂ on the final substrate was examined down to the atomic level by scanning tunneling microscopy (STM). The procedures conducted yielded high-quality monolayer MoS ₂ of milimeter-scale size with an average defect density of 2 × 10 ¹³ cm ^–2 . The lift-off from the growth substrate was followed by a release of the tensile strain, visible in a widening of the optical band gap measured by photoluminescence. Subsequent transfer to the Ir(111) surface led to a strong drop of this optical signal but without further shifts of characteristic peaks. The electronic band gap was measured by scanning tunneling spectroscopy (STS), revealing n-doping and lateral nano-scale variations. The combined use of STM imaging and density functional theory (DFT) calculations allows us to identify the most recurring point-like defects as S vacancies.

Background: Selenium (Se) is a vital micronutrient for maintaining homeostasis in the human body. Selenium nanoparticles (SeNPs) have demonstrated improved bioavailability compared to both inorganic and organic forms of Se. Therefore, supplementing with elemental Se in its nano-form is highly promising for biomedical applications related to Se deficiency. Purpose: The primary objective of this study was to evaluate the impact of the main gastrointestinal proteins on the physicochemical properties and stability of polymer-coated SeNPs. Methods: SeNPs functionalized with thiolated chitosan or hyaluronic acid were characterized based on their composition, morphology, size, and zeta potential. The stability of these particles was evaluated in simulated gastric and intestinal fluids. Additionally, the interaction propensity between major gastric proteins, such as pepsin and pancreatin, and functionalized SeNPs was investigated with FTIR, fluorescence quenching titrations, and in situ adsorption measurements. Results: The composition of the media, including pH and ionic strength, the chemistry of polymers, and the presence of the proteins, influence the size and zeta potential of the SeNPs. The increase in NP size due to the formation of large agglomerates, along with the decrease in zeta potential magnitude, confirmed the formation of a protein corona. Both pepsin and pancreatin showed a strong affinity to the particle surface. Based on the values of the apparent equilibrium dissociation constant this affinity was more pronounced for positively charged thiolated chitosan coated SeNPs compared to those coated with negatively charged hyaluronic acid. The polymer coated SeNPs displayed antioxidative potential, which could be very beneficial for health conditions associated with Se-deficiency. Conclusion: This study highlights the importance of exploring the characteristics of polymer-functionalized SeNPs under gastrointestinal conditions. Such investigations are important for developing nutritional supplements that can gradually release Se from SeNPs, thereby improving selenium absorption, bioavailability, and safety.

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.