Herein, tetracycline adsorption employing magnetic chitosan (CS·Fe₃O₄) as the adsorbent is reported. The magnetic adsorbent was synthesized by the co-precipitation method and characterized through FTIR, XRD, SEM, and VSM analyses. The experimental data showed that the highest maximum adsorption capacity was reached at pH 7.0 (211.21 mg g⁻¹). The efficiency of the magnetic adsorbent in tetracycline removal was dependent on the pH, initial concentration of adsorbate, and the adsorbent dosage. Additionally, the ionic strength showed a significant effect on the process. The equilibrium and kinetics studies demonstrate that Sips and Elovich models showed the best adjustment for experimental data, suggesting that the adsorption occurs in a heterogeneous surface and predominantly by chemical mechanisms. The experimental results suggest that tetracycline adsorption is mainly governed by the hydrogen bonds and cation–π interactions due to its pH dependence as well as the enhancement in the removal efficiency with the magnetite incorporation on the chitosan surface, respectively. Thermodynamic parameters indicate a spontaneous and exothermic process. Finally, magnetic chitosan proves to be efficient in TC removal even after several adsorption/desorption cycles.

Silica nanoparticles have been widely explored in biomedical applications, mainly related to drug delivery and cancer treatment. These nanoparticles have excellent properties, high biocompatibility, chemical and thermal stability, and ease of functionalization. Moreover, silica is used to coat magnetic nanoparticles protecting against acid leaching and aggregation as well as increasing cytocompatibility. This review reports the recent advances of silica-based magnetic nanoparticles focusing on drug delivery, drug target systems, and their use in magnetohyperthermia and magnetic resonance imaging. Notwithstanding, the application in other biomedical fields is also reported and discussed. Finally, this work provides an overview of the challenges and perspectives related to the use of silica-based magnetic nanoparticles in the biomedical field.

Pseudomonas aeruginosa and Staphylococcus aureus are highly resistant microorganisms that contribute to prolonged hospital stays and increased mortality. Developing new antimicrobial agents is essential to address this global health challenge. Nanoemulsions (NE) containing essential oils (EOs) and phenolic compounds with antimicrobial activity represent a promising alternative. This study reports, for the first time, the formulation of a NE containing Cymbopogon flexuosus and eugenol (NECE) and its antimicrobial activity against P. aeruginosa and S. aureus. NECE exhibited suitable physicochemical properties (mean size < 200 nm, PDI < 0.3, and negative zeta potential) and remained stable for 90 days at 4 °C while maintaining antimicrobial activity. It showed bactericidal effects at 2.5 mg/mL against P. aeruginosa and 0.625 mg/mL against S. aureus. Moreover, NECE improved the biocompatibility of the free oil (FO) in Peripheral Blood Mononuclear Cells (PBMCs). Altogether, these findings demonstrate, for the first time, that NECE is a stable nanoemulsion with enhanced antimicrobial activity and biocompatibility, supporting its potential as a safe and effective topical strategy against wound-associated pathogens.

Anthropogenic activities and industrial development are consequences of the increase in the world population occurred in the last century. The result is more generation of waste through textile and metal-mechanic industries mainly by carrying out improper disposal, without proper treatment directly in the environment. This practice is criminal and causes irreversible damages to humans and other animals affected by the contaminants. As a result, the exploration, research, and development of new materials with “green” characteristics as well as new compounds, which is the case of magnetic nanocomposites containing graphene oxide and chitosan in their structure. The present review approaches these materials and their application in process for adsorption of metallic contaminants and dyes. The combination of these nanomaterials presents a potential and promising characteristic in the adsorption processes, demonstrating high efficiency, easy handling, and reusable capacity due their magnetic characteristic and combined properties.