An exercise degree monitoring biosensor based on electrochemiluminescent detection of lactate in sweat

An electrochemiluminescent (ECL)-based lactate (LA) biosensor is developed with luminol as signaling species. LA was oxidized under the catalysis of immobilized lactic dehydrogenase (LDH) and pyruvate oxidase (PYOD) with nicotinamide adenine dinucleotide (NAD) as coenzyme. As a result, the reaction yielded the hydrogen peroxide, which enhanced the electrochemiluminescence of luminol, which was acceptable for sensing the LA concentration. The resulting biosensor showed excellent response for lactate. A detection limit of 8.9 × 10−12 mol/L was obtained with the relative standard deviation (RSD) of 4.13% (CLA 1.34 × 10−10 mol/L, n = 6) and an average recovery of 101.3% for real sweat sample. The research suggests that the ECL-based biosensor was practicable for detecting the LA in sweat samples of athletes during the exercitation for evaluation of exercise degree.