Nanoarchitectonics with Zinc-Doped Carbon Dots for Mitochondria-Targeted Repair and Regeneration Signaling Amplification in CLI Therapy

Critical limb ischemia (CLI) faces high rates of amputation and mortality. Despite advancements in surgical and endovascular interventions, their invasiveness and restricted applicability leave many CLI patients classified as "no-option" cases. Therapeutic angiogenesis strategies offer prospects for revascularization, but their efficacy remains suboptimal. Herein, we developed a nanomedicine, mitochondria-targeted zinc-doped ascorbic acid-derived carbon dots (TPP-Zn@ACDs), which simultaneously restores mitochondrial function and amplifies regenerative signaling to synergistically boost angiogenesis in ischemic limbs. TPP-Zn@ACDs integrate potent antioxidative properties of carbon dots and the pro-regenerative effects of Zn²⁺, with triphenylphosphine (TPP) and polyethylene glycol (PEG) functionalization endowing precise mitochondrial targeting and enhanced biocompatibility, thereby localizing therapeutic effects to the core of oxidative stress mitigation and regenerative signaling transduction. In vitro, TPP-Zn@ACDs improved mitochondrial function by reducing reactive oxygen species, restoring mitochondrial membrane potential and enhancing ATP production, through activation of the SIRT1/PGC-1α signaling pathway. Further, the proliferation, migration, and tube formation activities of endothelial cells were increased, while hypoxia-induced apoptosis and necrosis was inhibited effectively. Notably, leveraging mitochondrial restoration in endothelial cells, TPP-Zn@ACDs subsequently reprogrammed macrophages from an M1 pro-inflammatory phenotype to an M2 anti-inflammatory phenotype. In vivo, TPP-Zn@ACDs demonstrated remarkable therapeutic efficacy in a mouse CLI model, achieving robust blood flow recovery, increased microvascular density, and improved immune microenvironment. Together, this study proposes TPP-Zn@ACDs as a versatile engineering nanomedicine for mitochondria-targeted therapy, providing a scalable approach to breakthrough angiogenic efficacy in ischemic diseases.