Mobile Magnetic Nanocatalysts for Bioorthogonal Targeted Cancer Therapy

The use of magnetic nanorobots to activate chemotherapeutic prodrugs represents a promising alternative to current chemotherapeutic treatments. Here, a hybrid nanowire (NW) for targeted bioorthogonally driven activation of the latent chemotherapeutic prodrug 5-fluoro-1-propargyl-uracil (Pro-5-FU) in in vitro and in vivo cancer models is proposed. The NWs are composed of magnetic iron (Fe) and palladium (Pd), a known bioorthogonal catalyst. In vitro tests with a cancer cell line showed no significant cytotoxic effect by the NWs. In contrast, NWs combined with Pro-5-FU lead to a significant reduction of cell viability, similarly to the one induced by its active chemotherapeutic counterpart 5-fluorouracil (5-FU). The reduction in cell viability is attributed to the catalytic activation of Pro-5-FU into 5-FU. To demonstrate their targeted therapeutic abilities, magnetic fields are used to attract the FePd NWs to a predefined area within a cultured cancer cell population, causing a local Pro-5-FU activation, and subsequent cell death in this region. As a proof of concept, NWs are injected in cancer tumor xenografts. The intraperitoneal injection of Pro-5-FU significantly retards tumour growth without causing significant side effects. This work presents a novel chemotherapeutic approach combining nanorobotics and bioorthogonal activation of prodrugs as an efficient alternative to conventional chemotherapy.