Nanoparticles: their potential use in antibacterial photodynamic therapy

Photodynamic therapy (PDT) has been proposed as a new technique to inactivate microorganisms as it does not lead to the selection of mutant resistant strains; a clear benefit compared to antibiotic treatment. PDT has also attracted the interest of nanotechnology as the effectiveness of the treatment can be greatly enhanced by the use of nanoparticles. In the last decade, different approaches to the combination of nanoparticles and PDT have been investigated in relation to the antimicrobial applications of the technique. One use of the nanoparticles is to improve the delivery of photosensitiser to the bacteria; others use the nanoparticles to improve the inactivation kinetics. A different approach utilises nanoparticles as a photosensitiser. In this review these diverse types of interactions will be described.