A broad spectrum of nanomaterials has been investigated for multiple purposes in recent years. Some of these studied materials are magnetics nanoparticles (MNPs). Iron oxide nanoparticles (IONPs) and superparamagnetic iron oxide nanoparticles (SPIONs) are MNPs that have received extensive attention because of their physicochemical and magnetic properties and their ease of combination with organic or inorganic compounds. Furthermore, the arresting of these MNPs into a cross-linked matrix known as hydrogel has attracted significant interest in the biomedical field. Commonly, MNPs act as a reinforcing material for the polymer matrix. In the present review, several methods, such as co-precipitation, polyol, hydrothermal, microemulsion, and sol-gel methods, are reported to synthesize magnetite nanoparticles with controllable physical and chemical properties that suit the required application. Due to the potential of magnetite-based nanocomposites, specifically in hydrogels, processing methods, including physical blending, in situ precipitation, and grafting methods, are introduced. Moreover, the most common characterization techniques employed to study MNPs and magnetic gel are discussed.

Microorganisms have developed a resistance against some of the most conventional antibiotics. These microorganisms can be self-assembled, forming a microbial biofilm. A microbial biofilm formation is an inherent event on almost any surface, causing countless side effects on human health and the environment. Therefore, multiple scientific proposals have been developed based on renewable sources such as natural polymers. Natural polymers or biopolymers include cellulose, chitosan, starch, collagen, gelatin, hyaluronic acid, alginates, fibrin, and pectin, which are widely found in nature. The biopolymers have displayed many interesting properties, including biocompatibility and biodegradability. Nonetheless, these materials usually have no antimicrobial properties (except for the chitosan) by themselves. Therefore, antimicrobial agents have been incorporated into the natural polymeric matrix, providing an antimicrobial property to the biocomposite. Biocomposites consist of two different materials (one of natural origin) studied as biocompatible and biodegradable drug carriers of antimicrobial agents. In addition, due to the incorporation of antimicrobial agents, biocomposites can inhibit biofilm formation and bacteria proliferation on many surfaces. This review describes this using natural polymers as a platform of antimicrobial agents to form a biocomposite to eliminate or reduce biofilm formation on different surfaces.

Physical properties of the K_0.5Na_0.5NbO₃ (KNN) system doped with less than 1.3 mol% of Li⁺, La³⁺, and Ti⁴⁺ ions were studied. These samples were prepared by a mixture of oxides and carbonates using high‐energy milling and solid‐state reactions. The sample KNNLa0.75 showed an orthorhombic phase, and the rest showed a mixture of monoclinic and orthorhombic phases. Ion doping induced an increase in the grain size, and improved the ferroelectric and pyroelectric properties, decreasing leakage currents. The thermal diffusivity decreases with doping and differential scanning calorimetry measurements allowed the identification of crystalline transition temperatures from orthorhombic‒tetragonal, monoclinic‒tetragonal, and tetragonal‒cubic phases.

Microfluidic fuel cells offer a promising route for portable power generation; however, scaling paper-based systems remains challenging because capillary-driven flow can limit fuel distribution and electrochemical performance. This work investigates the experimental performance and computational fluid dynamics (CFD) behavior of air-breathing paper-based microfluidic fuel cell ($\mu$FCs) stacks powered directly by commercial tequila (35 vol.% ethanol). Single cells with electrode areas ranging from 0.5 cm × 0.5 cm to 3 cm × 3 cm were evaluated to determine the optimal design, followed by the construction of 4-cell and 6-cell series-parallel stacks. The smallest electrode (0.5 cm × 0.5 cm) achieved the highest power density (0.142 mW cm⁻²) and open-circuit voltage (0.92 V). Scaling to a 6-cell stack increased the maximum power density to 3.20 mW cm⁻² and the voltage to 1.39 V, outperforming the 4-cell configuration (1.09 mW cm⁻² and 1.07 V). Computational Fluid Dynamics simulations revealed that fuel velocity decreased from 2.8 × 10⁻² m s⁻¹ near the inlet to approximately 1.0 × 10⁻⁶ m s⁻¹ in the final cells because of porous-medium resistance, explaining the observed mass-transport limitations. The results demonstrate that tequila can be directly used as a sustainable fuel source and that optimized stack architectures significantly enhance power generation in paper-based microfluidic fuel cells.