Light-triggered quenching of the 19F-MRI signal from micelle-encapsulated PERFECTA

We report the development of a fluorinated micellar nanosystem whose 19F-MRI signal can be selectively dimmed by application of an external stimulus. A photo-activatable quencher unit (ferrocene) was co-encapsulated with the superfluorinated PERFECTA probe in colloidal micelles. While pristine micelles were MRI responsive and were readily imaged (“On” state), their irradiation by light triggered the conversion of ferrocene to ferrocenium. The generation of paramagnetic ferrocenium resulted in shorter T2 relaxation time of the 19F-nuclei and fading of the MRI signal of PERFECTA (“Off” state).