Optical Trapping of Nanoparticles in X-Ray Photodynamic Therapy
A radioluminescent material converts ionizing radiation, such as X-rays, into lower energy photons. The use of radioluminescent nanoparticles has been proposed to enhance the efficacy of photodynamic therapy (PDT) in cancer treatments. During a typical treatment, a molecular specie, called photosensitizer, absorbs visible energy to produce reactive oxygen species, which determine cellular death due to the resulting oxidative stress. The required visible energy has a low penetration depth through the tissues, which limits this approach to superficial treatments. Contrarily, X-rays allow for deep penetration through the tissues. Both gold and lanthanide-doped nanoparticles have been proven to absorb efficiently X-rays, with the latter being also able to convert the high energy radiation into visible light for PDT. The use of lanthanide-doped nanoparticles for X-ray PDT (X-PDT) is limited by the high mobility of the nanoparticles, which results into the necessity to find a way to guide the therapy and force the nanoparticles to stay into the zone under treatment until its completion. This possibility is also interesting in view of the perspective easier removal of the trapped particles, which reduces the risk of their unwanted accumulation into organs. This project aims to investigate the use of hybrid gold/radioluminescent nanosystems for cancer treatment by combining X-PDT and optical trapping. Gold nanoparticles can be efficiently trapped and moved with a focused beam, which makes interesting the combination of gold and radioluminescent nanoparticles into hybrid nanosystems. These novel nano-drugs will be tested for developing new and more selective techniques for cancer treatments.