Plasmonic modulation of gold nanotheranostics for targeted NIR-II photothermal-augmented immunotherapy

Cancer phototheranostics in the second near-infrared window (NIR-II, 1000-1700 nm) has low tissue scattering and high permissive laser exposure. However, most of the few available theranostic agents in this spectral region suffer from thermal instability and poor programmability of absorption profiles. Here, we proposed a programmable method for the plasmonic modulation of gold nanotheranostics in the NIR-II window. By adjusting the sequences and concentrations of DNA templates, the localized surface plasmon resonance (LSPR) of gold theranostics successfully redshifts to the NIR-II window. The asprepared gold nanodumbbells (AuNDs) possess good thermal stability, strong photoacoustic (PA) signals as well as high photothermal conversion efficiency (84.9 %). After conjugation with nucleolin-targeted DNA aptamer AS1411, the obtained targeted gold nanotheranostics (denoted as Ap-AuND) could perform effective NIR-II PA imaging-guided PTT for subcutaneous 4T1 tumors. Notably, the Ap-AuND-mediated NIR-II PTT significantly suppressed tumor growth and stimulated potent host antitumor immunity, resulting in significant inhibition of both distant tumor growth and whole-body spreading of tumor cells when combined with an anti-PDL1 antibody. (C) 2020 Elsevier Ltd. All rights reserved.