¹H and ¹⁹F NMR Spectroscopy and DFT calculations to Investigate Tethering of Silver Nanoparticles (AgNPs) with Ofloxacin Antibiotic for Drug Delivery

Tethering of ofloxacin to the AgNPs via intramolecular bonding, forming ofloxacin-AgNPs combinations as a synergetic antibiotic compound is proposed. The ofloxacin-AgNPs combination was chosen as prototypical of the fluoroquinolone family tethered with metallic nanoparticles. The results of ¹H and ¹⁹F NMR chemical shifts, self-diffusion, spin-spin, and spin-lattice relaxation rates of the ofloxacin-AgNPs combinations confirm the intramolecular tethering via fluorine atoms and less significant the nitrogen atoms in the ofloxacin. Moreover, spin-spin and spin-lattice relaxation rates of the protons in methyl groups increased monotonically as AgNPs concentration increased due to the ionic and molecular arrangement in the sample medium. The tethering between metallic/metallic oxide nanoparticles with fluroquinolones antimicrobial is happened because of the hydrogen and coordination bonding between the nanoparticle surface and the fluorine atom as well as with hydroxyl group in the antimicrobial agent. The tethering alters the physicochemical properties of the system such as self-diffusion, viscosity, acidity, and molecular relaxation and ionic state of the buffer solution. The molecular dynamic simulations provide detailed insight into the dynamics of ofloxacin interaction with nanoparticle in aqueous solution. The calculated and the experimental NMR, UV-Vis and the thermodynamics parameters will be used to complete and validate the proposed molecular arrangements in the solvation shells in the vicinity of the AgNPs.