Cubosome nanoparticles for enhanced delivery of mitochondria anticancer drug elesclomol and therapeutic monitoring via sub-cellular NAD(P)H multi-photon fluorescence lifetime imaging

Elesclomol (ELC) is an anticancer drug inducing mitochondria cytotoxicity through reactive oxygen species. Here, for the first time, we encapsulate the poorly water soluble ELC in monoolein-based cubosomes stabilized with Pluronic F127. Cellular uptake and nanocarrier accumulation close to the mitochondria with sub-micrometer distance is identified via three-dimensional (3D) confocal microscopy and edge-to-edge compartment analysis. To monitor the therapeutic effect of the ELC nanocarrier, we apply for the first time, label-free time-lapse multi-photon fluorescence lifetime imaging microscopy (MP-FLIM) to track NAD(P)H cofactors with sub-cellular resolution on live cells exposed to an anticancer nanocarrier. Improved in vitro cytotoxicity is verified when loading the pre-complexed ELC with copper (ELC-Cu). Importantly, for equivalent copper concentration, cubosomes loaded with ELC-Cu show higher cytotoxicity compared to the free drug. The novel nanocarrier shows promising features for systemic ELC-Cu administration, and furthermore we establish the MP-FLIM technique for the assessment of anticancer drug delivery systems.