Fe3O4@Ag and Ag@Fe3O4 Core–Shell Nanoparticles for Radiofrequency Shielding and Bactericidal Activity

Radiofrequency (RF) shielding is a type of electromagnetic (EM) shielding that prevents RF EM radiation from entering a building. Electrostatic fields, radio waves, and medical equipment can be insulated by multifunctional composites consisting of unique core–shell heterostructures; such materials are in high demand, given the rapid improvements in medical electronics and their expanding clinical applications, which represent a serious challenge of EM pollution in clinical settings. In order to avoid malfunction, the electronics in critical care devices in hospitals must be shielded from radiation. In order to create a material that can block radio waves while still utilizing RF to disinfect the surface, we built core–shell nanostructures to encase critical medical electronics. In this work, we discuss a polymer composite that is customized to provide EM shielding while also safeguarding critical care bioelectronics. Its bactericidal function, on the other hand, prevents nosocomial dangerous microorganisms from spreading contamination. We developed a library of Fe3O4@Ag and Ag@Fe3O4 core–shell and binary heterostructures with configurable Ag or Fe3O4 shell thicknesses. These heterostructures were subsequently combined with ethylene–vinyl acetate (EVA), a thermoplastic polymer, to create flexible composites that may attenuate incident EM radiation. The protective viability (SE) of Fe3O4@Ag core–shell and Ag@Fe3O4 binary nanoparticles in EVA was −32.1 and −20 dB, respectively. Due to localized heating, the Fe3O4@Ag- and Ag@Fe3O4-based nanocomposites exhibited "self-cleaning" behavior, displaying antibacterial activity in the vicinity of a 2.4 GHz wireless fidelity source against Pseudomonas aeruginosa. Taken together, these multifunctional, adaptable composites can protect electronic gadgets from EM radiation and harness RF to render the surface antibacterial, an important attribute in clinical settings.