A Facile Structural Isomerization‐Induced 3D Spatial D‐A Interlocked Network for Achieving NIR‐II Phototheranostic Agents

Abstract

The performances of second near-infrared (NIR-II) organic phototheranostic agents (OPTAs) depend on both molecular structure and molecular packing when used as nanoparticles (NPs). Herein, we proposed a facile structural isomerization-induced 3D spatial donor (D)-acceptor (A) interlocked network for achieving NIR-II OPTAs. Two isomers, 4MNVDPP and 6MNVDPP were synthesized and formulated into NPs. 6MNVDPP, which has a larger electrostatic potential difference, exhibits a compact 3D spatial D-A interlocked network in the crystal form, while 4MNVDPP forms 2D D-D type J-aggregates. Thus, 6MNVDPP NPs show red-shifted NIR absorption and larger molar extinction coefficient than 4MNVDPP NPs. Thanks to the typical NIR-II emission, superior photothermal-stability, high photothermal conversion efficiency (89 %) and reactive oxygen species production capacity, 6MNVDPP NPs exhibit outstanding NIR-II tiny capillary vasculature/tumor imaging ability and synergistic photothermal/photodynamic anti-cancer effect in vivo.