Au/Fe/Au trilayer nanodiscs as theranostic agents for magnet-guided photothermal, chemodynamic therapy and ferroptosis with photoacoustic imaging

Abstract

Image-guided phototheranostics, including photothermal therapy and photoacoustic imaging using plasmonic nanoparticles, has attracted attention due to its remarkable photothermal conversion effects. In particular, considering the several benefits of biocompatibility, unique plasmon resonance, and tunable optical properties, gold nanoparticles of various shapes have been widely utilized as phototheranostic agents. However, applications in the near-infrared window have been limited due to the tendency of anisotropic gold nanoparticles to transform into spherical shapes under repetitive laser irradiation, which cause a shift in the localized surface plasmon resonance peak and reduces photothermal stability. To address these limitations, we introduce an Fe layer between Au nanodiscs to synthesize Au/Fe/Au trilayer uniform structured nanodiscs (AuFeAuNDs) using nanoimprint lithography. This approach aims to improve photostability and endow a magnetic targeting ability, enabling more accurate spatiotemporal regulation. The AuFeAuNDs primarily function as photothermal therapy agents and also serve as chemodynamic agents via the Fenton reaction specifically within the tumor microenvironment, which induces ferroptosis. Moreover, the AuFeAuNDs trigger immunogenic cell death following photothermal therapy. This study demonstrates applications of magnetic-targeted AuFeAuNDs for photoacoustic imaging-guided, spatiotemporal-controlled photothermal therapy, chemodynamic therapy, and immune modulation to bolster anti-tumor immune responses in cancer treatment.