Newly formed tumor vasculature is usually abnormally leaky due to the extensive angiogenesis induced by the growing tumor, which enables extravasation of particles with a diameter of less than 200 nm: this phenomenon is recognized as the enhanced permeability and retention (EPR) effect. Due to their versatility, liposomes are potential candidates to take advantage of the EPR effect and passively target tumor cells. In this study, liposomes encapsulating fluorescent dye or bearing covalently-bound fluorophores on their surface were prepared and characterized in vitro. DLS and fluorescence measurements respectively showed that they currently display a diameter of less than 200nm and a fluorescence intensity similar to that of commercially available agents. Further research aims at an in vivo observation of the EPR effect through real-time visualization of the accumulation of such liposomes.
