Researchers developed a fully bioresorbable sensor that continuously tracked deep-tissue lactate for more than 10 days in animal models, according to a Jul. 27 report.
In a study published in Nature Communications, the team designed and evaluated an electrochemical sensor made from biodegradable materials intended for continuous monitoring of lactate levels within deep tissues. The device used a flexible adhesive substrate composed of poly(ethylene glycol) diacrylate and peptide double-network hydrogel to adhere to wet tissues while maintaining flexibility. Chitosan and genipin were incorporated to strengthen adhesion and enhance the stability of the enzyme-containing sensing layer.
The detection system featured molybdenum/molybdenum oxide electrodes, with a hydrogel loaded with lactate dehydrogenase and nicotinamide adenine dinucleotide immobilized on the working electrode. This allowed selective detection of lactate via an enzyme-assisted proton-intercalation mechanism. The sensors were tested for sensitivity, selectivity, mechanical stability, biodegradability, biocompatibility, and resistance to interference both in laboratory settings and in animal subjects.
Testing was conducted on rabbits, pigs, and rats under scenarios such as systemic hypoxia, localized hypoxia, epilepsy, myocardial ischemia, cerebral ischemia, septic shock, long-term hindlimb monitoring, bioresorption studies, and biocompatibility testing. A Bluetooth-enabled external module transmitted real-time data from the implantable sensor; validation was performed using commercial sensors on sampled fluids or arterial blood measurements from a blood gas analyzer.
The results showed that the sensor provided stable operation in wet biological environments with strong tissue adhesion. It demonstrated linear response at physiologically relevant concentrations up to 30 mM with high selectivity against interferents like glucose or urea. The device retained sensitivity after repeated bending or vibration cycles and remained functional for over 10 days in vivo. In systemic hypoxia experiments with rabbits as well as models of ischemia or septic shock across species tested, it detected changes in local tissue lactate before conventional indicators such as pulse rate or oxygen saturation changed significantly.
Although the technology operated effectively without retrieval surgery due to its gradual biodegradation—hydrogel degrading by 16 weeks and electrodes dissolving over 32 weeks—the study did not include human trials. Researchers said further investigation is needed regarding clinical safety and effectiveness, since many animal experiments involved only three independent tests.
