EDTA-Na3 functionalized Fe3O4 nanoparticles: grafting density control for MRSA eradication

Abstract

We report a synthesis strategy to simplify often cumbersome post-synthesis ligand exchange protocols and use that approach to synthesize EDTA-Na₃ (N-(trimethoxysilylpropyl)ethylenediaminetriacetate, trisodium salt) functionalized hydrophilic and biocompatible Fe₃O₄ nanoparticles. The grafting density of EDTA-Na₃ has been controlled from 0.07–0.37 μmol m⁻² by varying the time at which EDTA-Na₃ was added to the reaction. The success of EDTA-Na₃ surface functionalization has been verified using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Mössbauer spectroscopy techniques. Mössbauer spectroscopy results showed the evidence of Fe-EDTA monomer and dimer formation signifying covalent bonding between Fe ions and EDTA-Na₃. The earliest addition of EDTA-Na₃ resulted in the most stable dispersion of nanoparticles in water and phosphate buffered saline (PBS) which remained stable for more than a month. In addition, our results suggest that these nanoparticles can have useful applications in magnetic hyperthermia and eradication of methicillin-resistant Staphylococcus aureus (MRSA) bacteria in presence of an ac magnetic field.