Engineering a Carbolong Nanoplatform for Piezoelectric Immunotherapy

Piezoelectric dynamic therapy utilizes the acoustic-electric conversion of piezoelectric materials under ultrasound (US) to generate abundant reactive oxygen species (ROS) to kill tumor cells, offering an attractive protocol for tumor therapy. However, traditional piezoelectric sonosensitizers generally exhibit wide band gaps, resulting in suboptimal charge separation, low ROS generation efficiency, and insufficient induction of immunogenic cell death (ICD), which limits their therapeutic efficacy. In this study, we report a narrow-band gap piezoelectric nanoplatform engineered from porphyrin-osmapentalyne hybrids (P-OsPT). By strategically coupling anti-Hückel carbolong electron acceptor (A) with a Hückel-compliant porphyrin electron donor (D), a pronounced A-D-A architecture is established. The incorporation of osmium within the carbolong framework facilitates a d_π-p_π conjugation system, which not only significantly narrows the band gap and provides efficient channels for intraparticle charge transport but also imparts piezoelectric properties to the material. Under US irradiation, P-OsPT nanoparticles (NPs) achieve efficient acoustic-electric conversion, resulting in high ROS generation efficiency. In vitro and in vivo studies demonstrate that P-OsPT NPs-mediated piezoelectric immunotherapy can effectively kill tumor cells while inducing ICD, resulting in activation of immune response and inhibition of tumor metastasis. This study highlights the potential of carbolong complexes as a versatile platform for piezoelectric immunotherapy.