Use of magnetic nanoparticles as a drug delivery system to improve chlorhexidine antimicrobial activity

Nanotechnology offers new tools for developing therapies to prevent and treat oral infections, particularly biofilm-dependent disorders, such as dental plaques and endodontic and periodontal diseases. Chlorhexidine (CHX) is a well-characterized antiseptic agent used in dentistry with broad spectrum activity. However, its application is limited due to inactivation in body fluid and cytotoxicity toward human cells, particularly at high concentrations. To overcome these limitations, we synthesized nanosystems composed of aminosilane-coated magnetic nanoparticles functionalized with chlorhexidine (MNP@CHX). In the presence of human saliva, MNPs@CHX displayed significantly greater bactericidal and fungicidal activity against planktonic and biofilm-forming microorganisms than free CHX. In addition, CHX attached to MNPs has an increased ability to restrict the growth of mixed-species biofilms compared to free CHX. The observed depolarization of mitochondria in fungal cells treated with MNP@CHX suggests that induction of oxidative stress and oxidation of fungal structures may be a part of the mechanism responsible for pathogen killing. Nanoparticles functionalized by CHX did not affect host cell proliferation or their ability to release the proinflammatory cytokine, IL-8. The use of MNPs as a carrier of CHX has great potential for the development of antiseptic nanosystems.