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A simple photoelectrochemical (PEC) sensor based on non-modified nanostructured anodic TiO2 was fabricated and used for a rapid and sensitive detection of glucose. The anodic TiO2 layers were synthesized in an ethylene glycol-based solution containing NH4F (0.38 wt.%) and H2O (1.79 wt.%) via a three-step procedure carried out at the constant voltage of 40 V at 20 °C. At the applied potentials of 0.2, 0.5, and 1 V vs. saturated calomel electrode (SCE), the developed sensor exhibited a photoelectochemical response toward the oxidation of glucose, and two linear ranges in calibration plots were observed. The highest sensitivity of 0.237 µA µmol−1 cm−2 was estimated for the applied bias of 1 V. The lowest limit of detection (LOD) was obtained for the potential of 0.5 V vs. SCE (7.8 mM) with the fastest response at ~3 s. Moreover, the proposed PEC sensor exhibited relatively high sensibility, good reproducibility, and due to its self-cleaning properties, a good long-term stability. Interfering tests showed the selective response of the sensor in the presence of urea and uric acid. Real-life sample analyses were performed using an intravenous glucose solution, which confirmed the possibility of determining the concentration of analyte in such types of samples.

Effective application of the essential oils requires detailed exploration of their mechanism of action and the origin of diverse activity of their components. In this work, the influence of eucalyptol and terpinen-4-ol on artificial membranes was studied to verify whether the differences in the activity of these compounds are related to their effect on membranes. The properties of monolayers formed from structurally different lipids in the presence of terpenes were examined based on the results of the surface pressure-area measurements, penetration studies, and Brewster angle microscopy experiments. Both compounds were able to incorporate into the membrane and alter lipid/lipid interactions, making the monolayer less stable and more fluid. These effects were determined by monolayer composition (but not by its condensation per se) and the resulting rheological properties and were stronger in the presence of terpinen-4-ol. These findings confirm the hypothesis that differences in the antimicrobial potency of these terpenes are membrane-related, and membrane composition may determine their selectivity.

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