Tumor targeting in situ aggregation of nanoparticle-to-nanoparticle strategy to simultaneously induce ferroptosis and immunogenic cell death using complementary heparin and protamine molecules

Antibody-drug conjugate (ADC)-based tumor-targeting therapies have demonstrated clinical success in selective drug delivery for cancer treatment. However, the effectiveness of these strategies is hindered by the low amount of loaded payload, lack of sustained efficacy, and insufficient therapeutic performance. In this study, we introduce a novel in situ aggregation-based targeting system using two combinable nanoparticles (NP) that leverage the biocompatible and specific interaction between complementary protamine and heparin molecules. To demonstrate it, we developed protamine-based nanoparticles (PPNC NP) containing cytotoxic negatively charged curcumin (NCur), and heparin-based nanoparticles (HDFe NP) encapsulating doxorubicin and Fe³⁺. The NP-NP treatment successfully formed aggregates at targeted tumor sites. Our findings demonstrate that the initial administration of PPNC NP effectively targets the tumor and the subsequent administration of complementary HDFe NPs results in their significant accumulation in the tumor tissue, directed by the ‘guidance effect’ of PPNC NPs. This sequence of events promotes the formation of in situ aggregates within the tumor tissue, leading to prolonged nanoparticle accumulation, ferroptosis and immunogenic cell death (ICD). In conclusion, our study demonstrates the effectiveness of a biocompatible and in situ aggregating nanoparticle-nanoparticle system as a solution for overcoming the limitations of current nanoparticle-based delivery systems.