Hierarchically collapsible nanoactuator modulates mitochondrial ferroptosis-bioenergetic homeostasis cascade to decouple ischemic stroke.

Ischemic stroke, a life-altering cerebrovascular emergency triggered by prolonged cerebral hypoperfusion, remains a therapeutic enigma. Current interventions struggle with ischemia-reperfusion injury; restoring blood flow unleashes reactive oxygen species (ROS), driving secondary neuronal damage and functional loss. Ischemia-induced mitochondrial dysfunction heightens oxidative stress and hastens neuronal death. We address oxidative-stress-driven neuronal injury by engineering a hierarchically collapsible nanoactuator suppressing mitochondrial ferroptosis and restoring cellular energy homeostasis. The nanoactuator integrates a diselenide-crosslinked shell conjugated with a mitochondrial-targeting peptide, enabling blood-brain barrier penetration and mitochondrial delivery. Its collapsible core, composed of an ATP-gadolinium coordination polymer encapsulating a ferroptosis inhibitor, enables MRI-guided tracking and ROS-responsive drug release. In damaged mitochondria, the nanoactuator replenishes ATP, restores membrane potential, reduces ROS levels, and alleviates ferroptosis. Intravenous administration in a transient middle cerebral artery occlusion (tMCAO) mouse model demonstrated robust multi-mechanistic neuroprotection. This hierarchical nanoactuator platform offers a strategy for ischemic stroke and related neurodegenerative diseases.