Precise control of apoptosis via gold nanostars for dose dependent photothermal therapy of melanoma

Precise induction and monitoring of cell apoptosis are significant for cancer treatment. This study aims to develop a gold nanoparticle (GNP)-based nanoprobe, which could simultaneously induce and monitor the apoptosis of melanoma cells in situ and realize a precise control of photothermal therapeutic dose. The GNS-TAT-Cy5 nanoprobe was obtained through the formation of Au-S bonds between GNS-TAT and Cy5-tagged caspase-3 specific peptides (Cy5-DEVD). The fluorescence of Cy5 was quenched by the GNS due to the nanosurface energy transfer effect. Upon laser irradiation, activated caspase-3 cleaved the substrate peptide and Cy5 was released from the nanoprobe, leading to a significant fluorescence turn on signal for sensitive and continuous analysis of caspase 3 activity in vitro and in vivo. Therefore, the GNS-TAT-Cy5 nanoprobe can serve as a precise theranostic platform via regulating the photothermal dose and achieved regulation and detection of apoptosis related to caspase-3 for melanoma.