Preparation And Properties Of A Pro-prodrug Nanosystem With Sequential Enzyme Activation And Photo-triggered Release

In recent years,researchers have proposed a new type of prodrug system-"Pro-prodrug."This pro-prodrug is capable of achieving more efficient cancer detection and targeted therapeutic performance through a two-stage action of internal activation and external photoinduced release.This paper first designed and successfully synthesized a novel enzyme-activated pro-prodrug molecule.The molecule consists of three parts:the anticancer drug methotrexate(MTX),the photolytic fluorophore bishydroxycoumarin,and the targeting group quinone propionic acid.Further,the pro-drug nanoparticles are prepared by using amphiphilic polymer,thereby reducing side effects,increasing retention time,and enhancing the killing performance of cancer cells.First,the pro-prodrug molecules were successfully prepared by ring formation reaction and displacement reaction,and all compounds were verified by ~1H NMR and mass spectrometry.The pro-prodrug nanoparticles were prepared and tested by DLS and TEM.The performance of the pro-prodrug is then tested and analyzed,including spectral performance,in vitro release,verification of release mechanism,two-photon excitation testing,and cell experiments.Before the molecule reacts with the DT-diaphorase,the fluorescence emission and photolysis reaction are quenched by the formation of a PET effect in the molecule by the quinone propionic acid group.After the pro-prodrug nanoparticles enter the cancer cells,the liposomes rupture and release the pro-prodrug molecules.The quinone propionic acid moiety specifically reacts with the overexpressed DT-diaphorase in cancer cells to form prodrug molecules,and the PET effect disappears and the fluorescence is restored,achieving the purpose of cancer detection.At the same time,the external use of light stimulation can further release the anticancer drug methotrexate,aiming at killing cancer cells.