Dual‐Modal Au Nanorod@SiO 2– ICG@GO/PAA Nanohybrids for NIR Contrast Bioimaging and Synergistic CDT–PTT Cancer Therapy

ABSTRACT The integration of deep‐tissue optical imaging with programmable cancer therapy in a single nanoplatform remains challenging due to the poor photostability and aggregation‐induced quenching of clinical NIR dyes, along with the limited catalytic efficiency of conventional nanozymes. Herein, we report rationally designed plasmonic core–shell–shell nanohybrids, AuNRs@mSiO 2 –ICG@PAA and AuNRs@mSiO 2 –ICG@GO, enabling dual‐modal NIR fluorescence and two‐photon excitation imaging combined with NIR‐triggered catalytic–photothermal therapy. The architecture comprises an anisotropic gold nanorod (AuNR) core as a localized surface plasmon resonance (LSPR) generator, a mesoporous silica shell encapsulating indocyanine green (ICG), and an outer PAA or GO coating that enhances stability and suppresses dye leakage and photobleaching. Optimized plasmon–exciton coupling yields ∼2‐fold fluorescence enhancement and strong two‐photon excitation fluorescence for high‐contrast imaging. Notably, the GO‐wrapped hybrid acts as a plasmon‐activated nanozyme, exhibiting photo‐enhanced peroxidase‐like activity under 808 nm irradiation (2 W cm − 2 ) via hot‐electron transfer, accelerating H 2 O 2 conversion into hydroxyl radicals (•OH) for chemodynamic therapy (CDT). Simultaneously, efficient photothermal heating (ΔT ≈ 58°C; η = 27.5%) enables photothermal therapy (PTT). The synergistic CDT–PTT effect achieves near‐complete HeLa cell ablation (∼9% viability), establishing a new LSPR‐driven theragnostic strategy for imaging‐guided cancer treatment.