The search for new electrode materials has become one of the goals of modern electrochemistry. Obtaining electrodes with optimal properties gives a product with a wide application potential, both in analytics and various industries. The aim of this study was to select, from among the presented electrode materials (carbon and oxide), the one whose parameters will be optimal in the context of using them to create sensors. Electrochemical impedance spectroscopy and cyclic voltammetry techniques were used to determine the electrochemical properties of the materials. On the other hand, properties such as hydrophilicity/hydrophobicity and their topological structure were determined using contact angle measurements and confocal microscopy, respectively. Based on the research carried out on a wide group of electrode materials, it was found that transparent conductive oxides of the FTO (fluorine doped tin oxide) type exhibit optimal electrochemical parameters and offer great modification possibilities. These electrodes are characterized by a wide range of work and high chemical stability. In addition, the presence of a transparent oxide layer allows for the preservation of valuable optoelectronic properties. An important feature is also the high sensitivity of these electrodes compared to other tested materials. The combination of these properties made FTO electrodes selected for further research.

Core-shell structures are the most common type of composite material nanostructures due to their multifunctional properties. Silver nanoparticles show broad antimicrobial activity, but the safety of their utilization still remains an issue to tackle. In many applications, the silver core is coated with inorganic shell to reduce the metal toxicity. This article presents the synthesis of various materials based on silver and silica nanoparticles, including SiO₂@Ag, Ag@SiO₂, and sandwich nanostructures—Ag@SiO₂@Ag—and the morphology of these nanomaterials based on transmission electron microscopy (TEM), UV-Vis spectroscopy, and FT-IR spectroscopy. Moreover, we conducted the angle measurements due to the strong relationship between the level of surface wettability and cell adhesion efficiency. The main aim of the study was to determine the cytotoxicity of the obtained materials against two types of human skin cells—keratinocytes (HaCaT) and fibroblasts (HDF). We found that among all the obtained structures, SiO₂@Ag and Ag@SiO₂ showed the lowest cell toxicity and very high half-maximal inhibitory concentration. Moreover, the measurements of the contact angle showed that Ag@SiO₂ nanostructures were different from other materials due to their superhydrophilic nature. The novel approach presented here shows the promise of implementing core-shell type nanomaterials in skin-applied cosmetic or medical products.

1-Amino-, 1-ethylamino-, and 1-(diethylamino)-anthraquinone were characterized by UV–Vis spectroscopy, acid–base titration, electrochemical methods, and quantum-chemical (QM) calculations at the B3LYP/6-31 ++G^** level. Acid–base titration and the relative differences between the free energies of the basic and acidic forms of the studied species show that 1-(diethylamino)anthraquinone is the strongest base in an acetonitrile solution. Moreover, the structural differences between the B3LYP-optimized neutral and protonated anthraquinones, notably the presence or the absence of internal hydrogen bonds, account well for the sequence of the measured/calculated basicity. The basicity of the investigated compounds strongly influences their electrochemical properties in acetonitrile. Indeed, the cyclic voltammograms of 1-aminoanthraquinone and 1-(ethylamino)anthraquinone display two well-resolved reduction waves that indicate a two-step reduction process (EE mechanism). On the other hand, the electroreduction of 1-(diethylamino)anthraquinone becomes complicated by the interaction of its reduced forms with traces of water present in an acetonitrile solution (ECE mechanism). The mechanism of this reaction is proposed, and its possibility to occur is examined based on QM calculations.