Multifunctional hybrid nanopatches of graphene oxide and gold nanostars for ultraefficient photothermal cancer therapy

Multifunctional hybrid nanomaterials with enhanced therapeutic efficiency at physiologically safe dosages for externally triggered, image-guided therapy are highly attractive for nanomedicine. Here, we demonstrate a novel class of multifunctional hybrid nanopatches comprised of graphene oxide (GO) and gold nanostars for enhanced photothermal effect and image-guided therapy. The hybrid nanopatches with tunable localized surface plasmon resonance into the near-infrared therapeutic window (650-900 nm) were realized using a biofriendly method that obviates the need for toxic shape-directing agents. Internalization of the intact nanopatches into epithelial breast cancer cells was confirmed by Raman imaging, transmission electron microscopy, and inductively coupled plasma mass spectrometry. It appears that the amphipathic nature and the large surface area of the graphene oxide enable it to serve as a soft, flexible, and biocompatible intracellular carrier for the in situ grown plasmonic nanostructures and provide long-term biocompatibility with extremely low cytotoxicity. Apart from a remarkably improved photothermal effect compared to that of either of the components at very low dosages of the hybrids (10 μg/mL GO) and using a low laser power (0.75 W cm^-2), the hybrid nanopatches exhibit strong Raman scattering, making them excellent candidates for bioimaging, diagnostics, and image-guided therapy applications.