Synergistic Effect in Hybrid Plasmonic Conjugates for Theranostic Applications

Photothermal conversion efficiency ({\eta}) plays a crucial role in selecting suitable gold nanoparticles for photothermal therapeutic applications. The photothermal efficiency depends on the material used for the nanoparticles as well as their various parameters such as size and shape. By maximizing the light-to-heat conversion efficiency ({\eta}), one can reduce the concentration of nanoparticle drugs for photothermal cancer treatment and apply lower laser power to irradiate the tumor. In our study, we explored a new hybrid plasmonic conjugate for theranostic (therapy+diagnostic) applications. We conjugated 20 nm gold nanospheres with cyanine IR dyes, which exhibited significantly enhanced photothermal properties compared to bare nanoparticles. Moreover, the improved photothermal properties of the conjugates can be explained by the synergistic effect that results from the coupling between the metal nanosphere and organic dye.