LANTHANIDE-DOPED UPCONVERSION NANOCRYSTALS: SYNTHESIS, OPTICAL TUNING AND BIOAPPLICATIONS

Abstract

THIS THESIS AIMS TO DEVELOP NOVEL LANTHANIDE-DOPED LUMINESCENT NANOMATERIALS WITH TUNABLE EMISSIONS FOR BIOIMAGING AND THERAPEUTIC APPLICATIONS. FIRSTLY, A RATIONAL DESIGN AND SYNTHESIS OF HIGHLY STABLE DOX-LOADED HAIRPIN DNA-FUNCTIONALIZED NAYF4@SIO2-AU UPCONVERSION NANOCONJUGATES WERE PRESENTED. AS-PREPARED NANOCONJUGATES EXHIBIT STRONG NIR EMISSION AND PHOTOTHERMAL EFFECT UNDER THE 980 NM EXCITATION. THESE FEATURES MAKE THE NANOCONJUGATES PROMISING AS SMART PROBES FOR DEEP-TISSUE IMAGING AND IN VIVO LIGHT-TRIGGERED DRUG DELIVERY. NEXT, A FACILE EXCHANGE-INDUCED DOPING APPROACH FOR FINE TUNING OF ENERGY MIGRATION-MEDIATED UPCONVERSION IN AQUEOUS SOLUTION WAS DEMONSTRATED. THROUGH AN EXCHANGE REACTION, AN OBVIOUS COLOR CHANGE COULD BE OBSERVED AT ROOM TEMPERATURE EVEN AFTER A SHORT PERIOD. BY DELIBERATELY TUNING THE COMPONENT AND CONCENTRATION OF ACTIVATORS, MULTICOLOR UPCONVERSION LUMINESCENCE COULD BE ACHIEVED. FINALLY, A LIGAND-ASSISTED ENERGY TRANSFER PROCESS IN THE INORGANIC-ORG