Appl. Nano, Volume 6, Issue 1 (March 2025) – 5 articles

Nanotechnology offers effective solutions for removing contaminants and harmful bacteria from polluted water. This study synthesized copper nanoparticles using a carbohydrate-based bioflocculant derived from Proteus mirabilis AB 932526.1. The bioflocculant is a natural polymer that facilitates the aggregation of particles, enhancing the efficiency of the nanoparticle synthesis process. Characterization of the bioflocculant and copper nanoparticles was conducted using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, Ultraviolet-Visible Spectroscopy, X-ray Diffraction, and Transmission Electron Microscopy techniques to assess their properties, flocculation efficiency, and antibacterial characteristics. The optimal flocculation efficiency of 80% was achieved at a copper nanoparticle concentration of 0.4 mg/mL, while a concentration of 1 mg/mL resulted in a lower efficiency of 60%. The effects of biosynthesized copper nanoparticles on human-derived embryonic renal cell cultures were also investigated, demonstrating that they are safe at lower concentrations. The copper nanoparticles effectively removed staining dyes such as safranin (90%), carbol fuchsine (88%), methylene blue (91%), methyl orange (93%), and Congo red (94%), compared to a blank showing only 39% removal. Furthermore, when compared to both chemical flocculants and bioflocculants, the biosynthesized copper nanoparticles exhibited significant nutrient removal efficiencies for nitrogen, sulfur, phosphate, and total nitrates in coal mine and Vulindlela domestic wastewater. Notably, these biosynthesized copper nanoparticles demonstrated exceptional antibacterial activity against both Gram-positive and Gram-negative bacteria. Full article

Self-emulsifying drug delivery systems (SEDDS) consist of isotropic mixtures of oils, surfactants, and solvents that after dispersion emulsify in the aqueous media of the gastrointestinal tract (GIT). SEDDS can deliver hydrophobic drugs, which could enhance their oral bioavailability by protecting them from precipitation and degradation. However, it is important to find the appropriate ratio of their excipients to produce emulsions with the desirable physicochemical characteristics. In this sense, Design of Experiments (DoE) approaches such as central composite design (CCD) and Box–Behnken design (BBD) can reduce the number of experiments necessary to determine the best composition and preparation process of a SEDDS formulation. Therefore, this article aims to discuss drug delivery through SEDDS and how DoE approaches can aid researchers in achieving product quality specifications and optimizing the formulation preparation processes. For this, the most recent and relevant papers were analyzed. This review is expected to guide future research directions for more rational development of SEDDS. Full article

Baru nut oil (Dipteryx alata Vogel) is a lipidic extract from a species endemic to the Cerrado biome, renowned for its antioxidant potential. This study aimed to develop a nanoemulsion containing baru nut oil (BNON) using lecithin and polysorbate 80, and to evaluate its antioxidant activity and cytotoxicity. The physicochemical properties of BNON were characterized, and its cytotoxicity was assessed in human erythrocytes and keratinocytes. Antioxidant activity was evaluated using the DPPH method and inhibition of AAPH-induced hemolysis. BNON exhibited a droplet size of 530.1 ± 20.48 nm, a polydispersity index of 0.496 ± 0.057, and a zeta potential of −35.7 ± 2.19 mV. Free baru nut oil showed no cytotoxicity to keratinocytes or erythrocytes within the concentration ranges tested (1.0–0.031 mg/mL and 0.8–0.006 mg/mL, respectively). In contrast, BNON displayed cytotoxic effects on keratinocytes and erythrocytes only at the highest tested concentration. Atomic force microscopy analysis of erythrocytes from the hemolysis assay revealed normal morphology for cells treated with free oil at 0.8 mg/mL, whereas cells treated with BNON at the same concentration exhibited a slightly widened concave center. Free oil at 0.8 mg/mL significantly protected erythrocytes from AAPH-induced hemolysis, while BNON did not. However, BNON (5 mg/mL) demonstrated free radical scavenging activity, quantified at 0.0074 mg Trolox equivalents/mg via the DPPH assay. These findings suggest that baru nut oil has potential as an antioxidant product, although further optimization of the nanoformulation is required. Full article

DNA encoding the 16S rRNA of bacteria is a type of nanometer-sized information storage that can be used to characterize bacterial communities in soils. Reading this molecular ’nano-archive’ is not only of interest for characterizing recent local ecological conditions but can also provide valuable information about human impacts on soils in the past. This is of great interest for archaeology and for understanding the ecological consequences of past human activities on recent ecological conditions. Powerful sequencing methods such as the Illumina process allow many different DNA sequences to be determined in parallel and provide very efficient data sets that reflect the composition of soil bacterial communities in topsoil layers as well as in translocated and covered soils of archaeological sites such as settlements, burials or workplaces. Here, a brief overview of recent developments in the use of these molecular nano-archives for the study of archaeological soil samples is given using typical examples. Full article

Pollution of freshwater by synthetic organic dyes is a major concern due to their high toxicity and mutagenicity. In this study, the degradation of Congo red (CR) and malachite green (MG) dyes was investigated using nanostructured Gd₂O₃. It was prepared using the coprecipitation method, using gadolinium nitrate and concentrated formic acid, with subsequent calcination at 600 °C. Its morphology corresponds to hollow porous microspheres with a size between 0.5 and 7.5 μm. The optical bandgap energy was determined by using the Tauc method, giving 4.8 eV. The degradation of the dyes was evaluated by UV-vis spectroscopy, which revealed that dissociative adsorption (in the dark) played a key role. It is explained by the cleavage and fragmentation of the organic molecules by hydroxyl radicals (^•OH), superoxide radicals (^•${\mathrm{O}}_2^{-}$) and other reactive oxygen species (ROS) produced on the surface of Gd₂O₃. For CR, the degradation percentage was ~56%, through dissociative adsorption, while UV light photocatalysis increased it to ~65%. For MG, these values were ~78% and ~91%, respectively. The difference in degradation percentages is explained in terms of the isoelectric point of solid (IEPS) of Gd₂O₃ and the electrical charge of the dyes. FTIR and XPS spectra provided evidence of the role of ROS in dye degradation. Full article