Topological Engineering of NIR-II Emissive Conjugated Oligomers With Unexpected Excited-State Manifolds for Efficient Phototheranostics and Cancer Immunotherapy.

Abstract

Phototheranostic agents operating in the second near-infrared (NIR-II) window hold great potential for precision cancer therapy, yet the rational regulation of excited-state processes to simultaneously optimize fluorescence and phototherapeutic performances remains a fundamental challenge. Herein, we report a topology-driven excited-state engineering strategy for constructing conjugated oligomers with tailored excited-state manifolds and multi-channel excitation dynamics. By precisely manipulating molecular topology, conjugated topological oligomers achieve enhanced light-harvesting capability and optimized exciton utilization, thereby enabling synergistic regulation of excitation dynamics. Under 808 nm laser irradiation, nanoparticles (NPs) derived from TBT-3 exhibit 2.8-fold enhanced NIR-II fluorescence brightness, 2.7-fold improved photothermal performance, and 7.5-fold increased total reactive oxygen species (ROS) generation compared with TBT-1. In vivo studies demonstrate that TBT-3 NPs enable high-resolution NIR-II fluorescence imaging and efficient tumor elimination. Moreover, TBT-3-mediated phototherapy induces immunogenic cell death and enhances antitumor immunity, leading to improved therapeutic efficacy when combined with anti-PD-1 immune checkpoint blockade. This work provides a molecular topology-based strategy for manipulating excited-state landscapes and establishes conjugated oligomers as versatile candidates for NIR-II phototheranostics and cancer immunotherapy.