Polyphosphate Copper Nanospheres Drive Mitochondrial Metabolic Reprogramming via Calcium Phase Separation for Self‐Sensitizing Cuproptosis

ABSTRACT Precise spatiotemporal control of intracellular Ca 2+ signaling remains a major bottleneck in reversing tumor glycolytic dominance and reactivating mitochondrial therapies. To overcome this limitation, we developed a polyphosphate (polyP)‐engineered nanoplatform that exploits liquid‐liquid phase separation (LLPS) to drive calcium‐mediated metabolic reprogramming. We discovered that FITC‐polyP coacervates with Ca 2+ to form biomolecular condensates that function as localized Ca 2+ signaling microdomains. By selectively activating key mitochondrial enzymes, these microdomains shift tumor cells toward a mitochondria‐dependent metabolic phenotype. Crucially, disturbing condensate formation via Ca 2+ chelation or enzymatic degradation prevents this transition, confirming polyP/Ca 2+ condensates as the indispensable master regulator of mitochondrial metabolic activation. Sustained mitochondrial reactivation creates a primed cellular state that sensitizes tumor cells to cuproptosis. This work establishes a resourceful self‐sensitizing nanoplatform that utilizes polyP‐induced phase separation to precisely reprogram tumor metabolism and activate cuproptosis, highlighting polyP‐induced LLPS as a novel strategy for targeted cancer therapy.