Preparation and Evaluation of the Antibacterial Effect of Magnetic Nanoparticles Containing Gentamicin: A Preliminary In vitro Study

Magnetic nanoparticles (MNPs) loaded by various active compounds can be used for targeted drug delivery. Objectives: In the present study, the Fe3O4 magnetic nanoparticles that contained gentamicin were prepared and their antibacterial activities were studied. Materials and Methods: MNPs containing gentamicin (G@SA-MNPs) were prepared using sodium alginate (SA) as a surface modifier. After and before coating, the prepared MNPs were characterized using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Finally, the antibacterial effect of the MNPs was investigated by a conventional serial agar dilution method. Results: Particle size distribution analysis showed that the size of MNPs, before and after coating, was in the range of 1-18 nm and 12-40 nm, respectively. The magnetization curve of G@SA-MNPs (with saturation magnetization of 27.9 emu.g-1) confirmed ferromagnetic property. Loading gentamicin on the surface of MNPs was qualitatively verified by FTIR spectrum. Quantitative analysis measurements indicated the gentamicin loading on SA-MNPs as 56.7 ± 5.4%. The measured MICs of G@SA-MNPs for Pseudomonas aeruginosa (PTTC 1574) was 1.28 μg.mL-1. The sub-MIC (0.64 μg.mL-1) concentration of G@SA-MNPs in nutrient broth could successfully inhibit the growth of P. aeruginosa for 14 hours. Conclusions: Loading gentamicin on the SA-MNPs exhibited reasonable antibacterial effects against P. aeruginosa.