Conjugated Polymer Nanoprobes for NIR-II Imaging-Guided Photodynamic/Photothermal Synergistic Cancer Therapy

Fluorescence imaging-based combined photodynamic (PDT) and photothermal (PTT) therapy strategies have presented as an attractive technique for cancer diagnosis and treatment, offering advantages such as noninvasiveness, real-time monitoring and high antitumor efficiency. However, conventional synergistic PDT/PTT platforms often rely on complex multicomponent nanosystems, which face challenges such as batch-to-batch variability, inefficient energy transfer, and the need for multiple excitation sources. To overcome these limitations and achieve a streamlined yet multifunctional system, we rationally designed and synthesized a donor-acceptor conjugated polymer CPBTT, and further developed conjugated polymer nanoparticles CPBTT-NPs. Upon irradiation with a single 808 nm laser, the CPBTT-NPs exhibited a remarkable multifunctional response: (1) strong NIR-II fluorescence for high-resolution imaging of deep tissues; (2) generating cytotoxic reactive oxygen species (via type-I PDT pathway); (3) generating substantial localized heat for PTT. In vitro and in vivo experiments demonstrate that CPBTT-NPs effectively achieve deep-tissue tumor visualization, precise tumor accumulation and potent tumor ablation with minimal systemic toxicity. This all-in-one phototherapeutic platform thus provides a simple, reproducible, and efficient strategy for advanced imaging-guided cancer theranostics.