Single wavelength light-mediated, synergistic bimodal cancer photoablation and amplified photothermal performance by graphene/gold nanostar/photosensitizer theranostics.

Light-triggered nanotheranostics opens a fascinating but challenging avenue to achieve simultaneous and highly efficient anticancer outcomes for multimodal therapeutic and diagnostic modalities. Herein, a multifunctional phototheranostics based on a photosensitizer-assembled graphene/gold nanostar hybrid (GO/AuNS-PEG) was developed for cancer synergistic photodynamic (PDT) and photothermal therapy (PTT) as well as effective photothermal imaging. The stable and biocompatible GO/AuNS-PEG composite displayed a high photothermal conversion efficiency due to the enhanced optical absorbance of both graphene and gold nanostars in the near-infrared (NIR) range. By tuning the absorption wavelength of GO/AuNS-PEG to that of Chlorin e6 (Ce6), GO/AuNS-PEG/Ce6 completely eliminated the EMT6 xenograft tumors by the tremendous synergistic anticancer efficiency of simultaneous PDT and PTT under a single NIR laser irradiation (660nm) in vivo. The underlying mechanism may be the enhanced cytoplasmic uptake and accumulation of GO/AuNS-PEG/Ce6 and the subsequent photodestruction of the lysosomal membrane and mitochondria. Moreover, GO/AuNS-PEG/Ce6 exhibited negligible side-effects on the body and other organs. These results demonstrate that the graphene/gold nanostar nanoconstruct provides a versatile and reliable integrated platform for the photo-controlled cancer theragnostic applications.

STATEMENT OF SIGNIFICANCE: This work demonstrated the application of graphene-Au Nanostars hybridized system (denoted as GO/AuNS-PEG) in single wavelength laser induced synergistic photodynamic (PDT) and photothermal therapy (PTT) and effective cancer photothermal/fluorescence multimode imaging. GO/AuNS-PEG showed excellent biocompatibility and high dual-enhanced photothermal efficiency under the near-infrared laser irradiation that was very promise for deep tumor imaging. By combining with the photosensitizer Chlorin e6, both in vitro and in vivo data confirmed the efficient photoablation of the EMT6 tumors through the synergistic PDT and PTT effect under the activation of a single wavelength laser.