Activating Tumor-Selective Liquid Metal Nanomedicine through Galvanic Replacement

Abstract

Advanced chemotherapeutic strategies including prodrug and nanocatalytic medicine have significantly advanced tumor-selective theranostics, but delicate prodrug screening, tedious synthesis, low degradability/biocompatibility of inorganic components, and unsatisfied reaction activity complicate treatment efficacies. Here, the intrinsic anticancer bioactivity of liquid metal nanodroplets (LMNDs) is explored through galvanic replacement. By utilizing a mechano-degradable ligand, the resultant size of the aqueous LMND is unexpectedly controlled as small as ≈20 nm (LMND20). It is demonstrated that LMND20 presents excellent tumor penetration and biocompatibility and activates tumor-selective carrier-to-drug conversion, synchronously depleting Cu²⁺ ions and producing Ga³⁺ ions through galvanic replacement. Together with abundant generation of reactive oxygen species, multiple anticancer pathways lead to selective apoptosis and anti-angiogenesis of breast cancer cells. Compared to the preclinical/clinical anticancer drugs of tetrathiomolybdate and Ga(NO₃ )₃ , LMND20 administration significantly improves the therapeutic efficacy and survival in a BCap-37 xenograft mouse model, yet without obvious side effects.

Keywords: cancer therapy; copper depletion; drug delivery; galvanic replacement; liquid metal; nanomedicine.