The development of greener nano-constructs with noteworthy biological activity is of supreme interest, as a robust choice to minimize the extensive use of synthetic drugs. Essential oils (EOs) and their constituents offer medicinal potentialities because of their extensive biological activity, including the inhibition of fungi species. However, their application as natural antifungal agents are limited due to their volatility, low stability, and restricted administration routes. Nanotechnology is receiving particular attention to overcome the drawbacks of EOs such as volatility, degradation, and high sensitivity to environmental/external factors. For the aforementioned reasons, nanoencapsulation of bioactive compounds, for instance, EOs, facilitates protection and controlled-release attributes. Nanoliposomes are bilayer vesicles, at nanoscale, composed of phospholipids, and can encapsulate hydrophilic and hydrophobic compounds. Considering the above critiques, herein, we report the in-house fabrication and nano-size characterization of bioactive oregano essential oil (Origanum vulgare L.) (OEO) molecules loaded with small unilamellar vesicles (SUV) nanoliposomes. The study was focused on three main points: (1) multi-compositional fabrication nanoliposomes using a thin film hydration–sonication method; (2) nano-size characterization using various analytical and imaging techniques; and (3) antifungal efficacy of as-developed OEO nanoliposomes against Trichophyton rubrum (T. rubrum) by performing the mycelial growth inhibition test (MGI). The mean size of the nanoliposomes was around 77.46 ± 0.66 nm and 110.4 ± 0.98 nm, polydispersity index (PdI) of 0.413 ± 0.015, zeta potential values up to −36.94 ± 0.36 mV were obtained by dynamic light scattering (DLS). and spherical morphology was confirmed by scanning electron microscopy (SEM). The presence of OEO into nanoliposomes was displayed by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy. Entrapment efficiency values of 79.55 ± 6.9% were achieved for OEO nanoliposomes. In vitro antifungal activity of nanoliposomes tested against T. rubrum strains revealed that OEO nanoliposomes exhibited the highest MGI, 81.66 ± 0.86%, at a concentration of 1.5 µL/mL compared to the rest of the formulations. In summary, this work showed that bioactive OEO molecules with loaded nanoliposomes could be used as natural antifungal agents for therapeutical purposes against T. rubrum.

Herein, we report the synthesis and characterization of metal complexes of Fe(iii), Co(ii), and Cu(ii) with SALPHEN (N,N-bis(salicylimine)-o-phenyldiammine) and their potential application as sensitizers in dye-sensitized solar cells (DSSCs).

Dopamine (DA) and uric acid (UA), which are vital components in human metabolism, cause several health problems if they are present in altered concentrations; thus, the determination of DA and UA is essential in real samples using selective sensors. In the present study, graphite carbon paste electrodes (CPE) were fabricated using ZnO/carbon quantum dots (ZnO/CQDs) and employed as electrochemical sensors for the detection of DA and UA. These electrodes were fully characterized via different analytical techniques (XRD, SEM, TEM, XPS, and EDS). The electrochemical responses from the modified electrodes were evaluated using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The results showed that the present electrode has exhibited high sensitivity towards DA, recognizing even at low concentrations (0.12 μM), and no inference was observed in the presence of UA. The ZnO/CQD electrode was applied for the simultaneous detection of co-existing DA and UA in real human urine samples and the peak potential separation between DA and UA was found to be greatly associated with the synergistic effect originated from ZnO and CQDs. The limit of detection (LOD) of the electrode was analyzed, and compared with other commercially available electrodes. Thus, the ZnO/CQD electrode was used to detect DA and UA in real samples, such as Saccharomyces cerevisiae cells.

In this study, we investigated the adsorption of CO₂ by carbon quantum dot-based ferrites (MFe₂O₄, M = Co²⁺, Ni²⁺, and Zn²⁺) in the context of industrial CO₂ emissions and global warming. The ferrites have been characterized using various analytical techniques [X-ray powder diffraction, FTIR, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS)], showing cubic spinel for CoFe₂O₄, reverse cubic spinel for NiFe₂O₄, and typical spinel for ZnFe₂O₄. A TGA study revealed a significant weight loss around 740-780 °C, indicating structural change occurred with increasing temperature. SEM and TEM images displayed spherical particles with sizes ranging from 10 to 50 nm. XPS confirmed the presence of C, O, and Fe atoms with specific cations (Co²⁺, Ni²⁺, and Zn²⁺). Electrochemical impedance Nyquist diagrams suggest a linear relationship between Z″ (ohm) and Z' (ohm) at low frequencies, but the semicircular loop obtained was significantly increased at higher frequencies. This suggests that the charge transfer resistance (R _CT) at the electrode boundaries (interface) is much higher than at low frequencies, indicating the resistance per area was 1853 Ω cm² for carbon paste electrodes (CPE)/CoFe₂O₄ and it decreased to 1652 Ω cm² for CPE/NiFe₂O₄ and 1672 Ω cm² for CPE/ZnFe₂O₄. However, improved electron transfer with lower resistance was seen due to the composite nature of the samples (CQDs@MFe₂O₄), revealing a lower resistance (1163 Ω cm²) for CQD@MFe₂O₄-CO₂ as compared to 1567 Ω cm² for MFe₂O₄. Thus, the adsorption of CO₂ was studied electrochemically, and interaction between ferrates with CO₂ was enhanced by the presence of CQDs in the samples. This is consistent with the adsorption of CO₂ with the samples as it follows the Langmuir pseudo-second-order kinetics (k = 4.9, qe = 121.93 for CQD@CoFe₂O₄, k = 2.9, qe = 156.52 for CQD@NiFe₂O₄, and k = 3.0, qe = 141.71 for CQD@ZnFe₂O₄), and the data show that the adsorption efficiency has been decreased by around 1.0% after 7-8 cycles. Lastly, density functional theory analysis demonstrated the interaction of CO₂ on the surface of the ferrites, deforming the CO₂ linearity, which leads to a subsequent C-O interaction to form carbonate.

Two new glycine-Schiff base copper(II) complexes were synthesized. Single crystal X-ray diffraction (SCXRD) allowed us to establish the structure of both complexes in the solid state. The glycine-Schiff base copper(II) complex derived from 2′-hydroxy-5′-nitroacetophenone showed a mononuclear hydrated structure, in which the Schiff base acted as a tridentate ligand, and the glycine-Schiff base copper(II) complex derived from 2′-hydroxy-5′-methylacetophenone showed a less common tetranuclear anhydrous metallocyclic structure, in which the Schiff base acted as a tetradentate ligand. In both compounds, copper(II) had a tetracoordinated square planar geometry. The results of vibrational, electronic, and paramagnetic spectroscopies, as well as thermal analysis, were consistent with the crystal structures. Both complexes were evaluated as catalysts in the olefin cyclopropanation by carbene transference, and both led to very high diastereoselectivity (greater than 98%).