FeCo@hydrochar nanocomposites as efficient peroxymonosulfate activator for organic pollutant degradation.

Sulfate radical-based advanced oxidation processes (SR-AOPs) are renowned for their exceptional capacity to degrade refractory organic pollutants due to their wide applicability, cost-effectiveness, and swift mineralization and oxidation rates. The primary sources of radicals in AOPs are persulfate (PS) and peroxymonosulfate (PMS) ions, sparking significant interest in their mechanistic and catalytic aspects. To develop a novel nanocatalyst for SR-AOPs, particularly for PMS activation, we synthesized carbon-coated FeCo nanoparticles (NPs) using solvothermal methods based on the polyol approach. Various synthesis conditions were investigated, and the NPs were thoroughly characterized regarding their structure, morphology, magnetic properties, and catalytic efficiency. The FeCo phase was primarily obtained at [OH-] / [Metal] = 26 and [Fe] / [Co] = 2 ratios. Moreover, as the [Fe]/[Co] ratio increased, the degree of xylose carbonization to form a carbon coating (hydrochar) on the NPs also increased. The NPs exhibited a spherical morphology with agglomerates of varying sizes. Vibrating-sample magnetometer analysis (VSM) indicated that a higher proportion of iron resulted in NPs with higher saturation magnetization (up to 167.8 emu g-1), attributed to a larger proportion of FeCo bcc phase in the nanocomposite. The best catalytic conditions for degrading 100 ppm Rhodamine B (RhB) included 0.05 g L-1 of NPs, 2 mM PMS, pH 7.0, and a 20-min reaction at 25 °C. Notably, singlet oxygen was the predominant specie formed in the experiments in the SR-AOP, followed by sulfate and hydroxyl radicals. The catalyst could be reused for up to five cycles, retaining over 98% RhB degradation, albeit with increased metal leaching. Even in the first use, dissolved Fe and Co concentrations were 0.8 ± 0.3 and 4.0 ± 0.5 mg L-1, respectively. The FeCo catalyst proved to be effective in dye degradation and offers the potential for further refinement to minimize Co2+ leaching.

Development and evaluation of an anti-candida cream based on silver nanoparticles.

The ineffectiveness of azole drugs in treating Vulvovaginal Candidiasis (VVC) and Recurrent Vulvovaginal Candidiasis (RVVC) due to antifungal resistance of non-albicans Candida has led to the investigation of inorganic nanoparticles with biological activity. Silver nanoparticles (AgNPs) are important in nanomedicine and have been used in various products and technologies. This study aimed to develop a vaginal cream and assess its in vitro antimicrobial activity against Candida parapsilosis strains, specifically focusing on the synergy between AgNPs and miconazole. AgNPs were synthesized using glucose as a reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer in varying amounts (0.50, 0.25, and 0.10 g). The AgNPs were characterized using UV-Visible (UV-Vis) and Fourier-Transform Infrared (FT-IR) spectroscopies, X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Analysis (EDX). Fifty strains of Candida parapsilosis were used to evaluate the synergistic activity. AgNPs synthesized with 0.5 g SDS had an average size of 77.58 nm and a zeta potential of -49.2 mV, while AgNPs with 0.25 g showed 91.22 nm and -47.2 mV, respectively. AgNPs stabilized with 0.1 g of SDS were not effective. When combined with miconazole, AgNPs exhibited significant antifungal activity, resulting in an average increase of 80% in inhibition zones. The cream developed in this study, containing half the miconazole concentration of commercially available medication, demonstrated larger inhibition zones compared to the commercial samples.

Nano-Nutraceuticals for Health: Principles and Applications.

The use of nanotechnological products is increasing steadily. In this scenario, the application of nanotechnology in food science and as a technological platform is a reality. Among the several applications, the main use of this technology is for the development of foods and nutraceuticals with higher bioavailability, lower toxicity, and better sustainability. In the health field, nano-nutraceuticals are being used as supplementary products to treat an increasing number of diseases. This review summarizes the main concepts and applications of nano-nutraceuticals for health, with special focus on treating cancer and inflammation. Supplementary Information: The online version contains supplementary material available at 10.1007/s43450-022-00338-7.

Doped Carbon Quantum Dots/PVA Nanocomposite as a Platform to Sense Nitrite Ions in Meat.

A sensor device based on doped-carbon quantum dots is proposed herein for detection of nitrite in meat products by fluorescence quenching. For the sensing platform, carbon quantum dots doped with boron and functionalized with nitrogen (B,N-Cdot) were synthesized with an excellent 44.3% quantum yield via a one-step hydrothermal route using citric acid, boric acid, and branched polyethylenimine as carbon, boron, and nitrogen sources, respectively. After investigation of their chemical structure and fluorescent properties, the B,N-Cdot at aqueous suspensions showed high selectivity for NO2- in a linear range from 20 to 50 mmol L-1 under optimum conditions at pH 7.4 and a 340 nm excitation. Furthermore, the prepared B,N-Cdots successfully detected NO2- in a real meat sample with recovery of 91.4-104% within the analyzed range. In this manner, a B,N-Cdot/PVA nanocomposite film with blue emission under excitation at 360 nm was prepared, and a first assay detection of NO2- in meat products was tested using a smartphone application. The potential application of the newly developed sensing device containing a highly fluorescent probe should aid in the development of a rapid and inexpensive strategy for NO2- detection.