Multifunctional Tetracycline-Loaded Silica-Coated Core-Shell Magnetic Nanoparticles: Antibacterial, Antibiofilm, and Cytotoxic Activities.

In the current study, the physicochemical and biological properties of tetracycline-loaded core-shell nanoparticles (Tet/Ni 0.5 Co 0.5 Fe 2 O 4 /SiO 2 and Tet/CoFe 2 O 4 /SiO 2 ) were investigated. The antibacterial activity of nanoparticles alone and in combination with tetracycline was investigated against a number of Gram-positive and Gram-negative bacteria for determining minimum inhibitory concentration (MIC) values. The MIC of Tet/Ni 0.5 Co 0.5 Fe 2 O 4 /SiO 2 nanoparticles turned out to be significantly higher than that of Tet/CoFe 2 O 4 /SiO 2 nanoparticles. Furthermore, Tet/Ni 0.5 Co 0.5 Fe 2 O 4 /SiO 2 nanoparticles exhibited potent antibiofilm activity against pathogenic bacteria compared to Tet/CoFe 2 O 4 /SiO 2 nanoparticles. The drug delivery potential of both carriers was assessed in vitro up to 124 h at different pH levels and it was found that the drug release rate was increased in acidic conditions. The cytotoxicity of nanoparticles was evaluated against a skin cancer cell line (melanoma A375) and a normal cell line (HFF). Our findings showed that Tet/Ni 0.5 Co 0.5 Fe 2 O 4 /SiO 2 had greater cytotoxicity than CoFe 2 O 4 /SiO 2 against the A375 cell line, whereas both synthesized nanoparticles had no significant cytotoxic effects on the normal cell line. Nonetheless, the biocompatibility of nanoparticles was assessed in vivo and the interaction of nanoparticles with the kidney was scrutinized up to 14 days. The overall results of the present study implied that the synthesized multifunctional magnetic nanoparticles with drug delivery potential, anticancer activity, and antibacterial activity are promising for biomedical applications.