A novel nanocomposite based on fluorescent turn-on gold nanostars for near-infrared photothermal therapy and self-theranostic caspase-3 imaging of glioblastoma tumor cell

We demonstrated a novel nanocomposite based on fluorescent turn-on gold nanostars for simultaneous tumor targeting photothermal therapy (PTT) and feedback apoptosis imaging of the self-therapeutic effect. In this theranostic agent (AuNS@probe), gold nanostars (AuNSs) and fluorescent dye Atto 655, as a fluorophore/quencher pair, were conjugated to form intermolecular fluorescence quenching in virtue of the linkage of a caspase-3 responsive peptide. Folic acid targeting moiety facilitated the selective accumulation in cancer cells via receptor-mediated endocytosis. Upon photo irradiation, AuNS@probe demonstrated excellent photothermal effect and induced cell death with apoptosis related mechanism. The typical apoptosis-effector proteases, caspase-3, was subsequently activated and terminated intramolecular fluorescent quenching process. Obvious fluorescence recovery could be applied to precisely assess the activated caspase-3 expression and the real time therapeutic efficacy. This novel versatile nanocomposite could serve as a theranostic agent for tumor targeting PTT and also provide self-therapeutic monitoring for precise cancer therapeutic applications.