Facile one-pot synthesis of the mesoporous chitosan-coated cobalt ferrite nanozyme as an antibacterial and MRI contrast agent.

Cobalt ferrite (CoFe) nanoparticles (NPs) with appropriate physicochemical and biological properties have attracted great attention for biomedical applications. In the present study, chitosan-coated mesoporous CoFe (CoFeCH) NPs were synthesized using a facile one-step hydrothermal method and fully characterized using FE-SEM, EDS, BET, FTIR spectroscopy, DLS, TGA, XRD, and VSM. The spherical, highly colloidal, and monodispersed CoFeCH NPs with an average hydrodynamic size of 177.9 nm, PDI of 0.238 and zeta potential value of -33 represented a high saturation magnetization value of 59.37 emu g -1 . N 2 adsorption-desorption analysis confirmed the mesoporous structure of CoFeCH NPs with a type IV isotherm, calculated specific surface area of 89.583 m 2 g -1 and total pore volume of 0.3668 cm 3 g -1 . CoFeCH NPs exhibited high antibacterial effects on S. aureus and E. coli , comparable with standard antibiotics, while CH-coating led to higher biocompatibility of CoFe NPs on human cells in vitro . CoFeCH NPs also showed significant peroxidase activity with a K m value of 14.37 and specific activity of 0.632 mmol min -1 . CoFeCH NPs were successfully used as a MRI contrast agent with an R 2 value of 91.3 mM -1 s -1 . The overall results indicated the high potential of synthesized CoFeCH NPs by the present method for biomedical applications, especially as an antibacterial and MRI contrast agent.