Multifunctional Nanocomposites of Bismuth@porphyrin-Based Covalent–Organic Polymers with a Core–Shell Structure for Tumor Treatment

Versatile all-in-one nanoplatforms, which combine a variety of therapeutic and diagnostic capabilities, possess interesting physiochemical and biological characteristics, making them highly attractive in cancer-related biomedical applications. However, up to now, the precise design of nanocomposites with multiple functions has remained an ongoing challenge. Herein, this study constructed a tumor microenvironment (TME)-responsive nanocomposite therapeutic platform with a core–shell structure using bismuth (Bi) as the core and iron-porphyrin-containing covalent–organic polymers (COPs) as the shell. Under the irradiation of an 808 nm laser, Bi efficiently inhibits tumor cell growth through photothermal therapy (PTT), and porphyrin-based COPs can produce reactive oxygen species (ROS) by photodynamic therapy (PDT) under the irradiation of a 660 nm laser combined with chemodynamic therapy (CDT). Meanwhile, Bi as a green metal with good biocompatibility also has the potential for use in X-ray computed tomography (CT) imaging and near-infrared (NIR) thermal imaging. Therefore, this nanocomposite integrated multifunctional treatment pathways (PTT, PDT, and CDT) and multimodel (CT and NIR) imaging to cope with the complexity and diversity of tumor cells, effectively improving therapeutic efficacy and becoming a potential candidate for tumor diagnosis and treatment.