Monitoring of oxygen concentration in biological tissues is essential for understanding cellular metabolism, mitochondrial function, and tissue regeneration. Mitochondrial dysfunction is linked to a wide range of metabolic and degenerative diseases, yet current diagnostic approaches lack the capability to continuously measure oxygen and metabolite dynamics in vivo. This work introduces an implantable electrochemical sensor platform developed for real-time monitoring of tissue oxygen tension to support diagnosis and study of mitochondria-related disorders. The research encompasses device design, fabrication, preclinical validation, and clinical testing within a translational framework. A complementary lactate sensor further extends the platform’s diagnostic capabilities, establishing groundwork for future metabolic monitoring technologies.