In vitro evaluation of polymeric nanoparticles with a fluorine core for drug delivery triggered by focused ultrasound

Polymeric nanoparticles are being intensively investigated as drug carriers. Their efficiency could be enhanced if the drug release can be triggered using an external stimulus such as ultrasound. This approach is possible using current commercial apparatus that combine focused ultrasound with MRI to perform ultrasonic surgery. In this approach, nanoparticles made of a perfluoro-octyl bromide core and a thick polymeric (PLGA-PEG) shell may represent suitable drug carriers. Indeed, their perfluorocarbon core are detectable by 19F MRI, while their polymeric shell can encapsulate drugs. However, their applicability in ultrasound-triggered drug delivery remains to be proven. To do so, we used Nile red as a model drug and we measured its release from the polymeric shell by spectrofluorometry. In the absence of ultrasound, only a small amount of Nile red release was measured (