Last piece of the puzzle: lead-assisted assembly of an arsenopalladate nanostar as an antitumor metallodrug

It is tough, but worth it, to break the simple and inflexible structure of high symmetry and low energy, such as the cuboid topology of polyoxopalladates (POPs). In this work, the heterometal-templated scaffold of arsenopalladates has afforded three nanocubes of [MIVPd12O8(AsO4)8]12- (M = SnIV, CeIV, and PbIV) and the long-sought nanostar of [PbIVPd15O10(AsO4)10]16-. The appropriate charge and radius of PbIV satisfied the uncommon host-guest assembly of both cubic and star archetypes simultaneously. More than that is the successful preparation of the methylphosphonate-capped [Pd15O10(MePO3)10]10- POP for the first time. According to the adjustable heterometals and heterogroups, the as-made POPs represent ideal subjects to reveal structure-dependent antitumor activity. It turns out that ROS-induced apoptosis mediated by arsenate functions is mainly responsible for the significant inhibition against cancers of different types, which heralds the design philosophy of POP-based antitumor metallodrugs of the next generation. Access to the long-sought nanostar of arsenopalladate is workable via host-guest assembly. The arsenate functions of such POP metallodrugs drive the ROS-induced apoptosis with great antitumor potential.