Efficacy of Tobramycin Conjugated to Superparamagnetic Iron Oxide Nanoparticles in Treating Cystic Fibrosis Infections

Cystic fibrosis (CF) is an inherited childhood-onset life-shortening disease. It is characterized by increased respiratory production, leading to airway obstruction, chronic lung infection and inflammatory reactions. The most common bacteria causing persisting infections in people with CF isPseudomonas aeruginosa. Superparamagnetic Fe3O4iron oxide nanoparticles (NPs) conjugated to the antibiotic (tobramycin), guided by a gradient of the magnetic field or subjected to an oscillating magnetic field, show promise in improving the drug delivery across the mucus andP. aeruginosabiofilm to the bacteria. The question remains whether tobramycin needs to be released from the NPs after the penetration of the mucus barrier in order to act upon the pathogenic bacteria. We used a zero-length 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) crosslinking agent to couple tobramycin, via its amine groups, to the carboxyl groups on Fe3O4NPs capped with citric acid. The therapeutic efficiency of Fe3O4NPs attached to the drug versus that of the free drug was investigated inP. aeruginosaculture.