Image-guided in situ cancer vaccination with combination of multi-functional nano-adjuvant and an irreversible electroporation technique.

Cancer immunotherapy is a next-generation treatment strategy; however, its side effects limit its clinical translation. Here, a novel combination of a multi-functional nano-adjuvant (M-NA) prepared with an iron oxide/gold core and a cationic polymer shell via multilayer synthesis with CpG oligodeoxynucleotide (CpG-ODN) electrostatically complexed on its surface, and irreversible electroporation (IRE) technique was developed for effective image-guided in situ cancer vaccination. The M-NA can be retained long-term in the dense tumoral extracellular matrix after intratumoral injection and internalized by antigen-presenting cells (APCs). The IRE can induce immunogenic cell death. Indeed, in a mouse tumor model, the M-NA showed longer tumor retention time than free CpG-ODN. Compared with other treatments, the combined treatment significantly inhibited tumor growth with 100% survival rate for ∼60 days. The therapy induced the activation of cytotoxic lymphocytes and the maturation of APCs in vivo. This treatment could be effective in image-guided local cancer immunotherapy.