Potential of ligand-free magnetite nanoparticles prepared by electron beam physical vapor deposition in antimicrobial therapy

Magnetite nanoparticles (NPs) loaded with antibiotics can be used for targeted delivery of pharmacotherapy directly to the infected organ. In this way, they can overcome the shortcomings of traditional antimicrobial agents, but the amount of research in this area is limited, especially regarding the magnetite NPs synthesized by electron beam technology. The research aim is to study the effect of magnetite ligand-free NPs synthesized by electron beam physical vapor deposition, stabilized with polyvinylpyrrolidone and conjugated with the beta-lactam antibiotic ampicillin, on the development of reference strains of microorganisms. The NPs were synthesized by electron beam technology in vacuum, identified by standard nanotechnology methods and modified with polyvinylpyrrolidone and ampicillin. The nanocomposite’s hydrodynamic diameter, the loading and release of ampicillin, and the effect on the reference strains S. aureus ATCC 25923 and E. coli ATCC 25922 were determined. The synthesis resulted in magnetite NPs (10.7 nm) in a sodium chloride matrix. After coating and conjugation, the particle size was 190 nm. About 2% of ampicillin was loaded into them, which was completely released in 180 minutes with pseudo-second-order kinetics. The minimum inhibitory concentrations against test cultures S. aureus and E. coli were 1.24 μg/ml and 4.93 μg/ml, respectively. The advantage of the nanocomposite was a smaller amount of antibiotic as a part of this nanomaterial mass compared to the pure antibiotic required for a bacteriostatic effect. Therefore, the study reflects one of the options for combining magnetic NPs and an antibiotic that requires following efforts to create a clinically effective nanobiotic.