Advances in the biosensors for lactate and pyruvate detection for medical applications: A review

This review analyzes electrochemical biosensors for the determination of lactate (lactic acid) and pyruvate (pyruvic acid) concentrations in liquid samples, especially in the blood serum. The biosensor systems for the simultaneous determination of both substances and commercial variants of the biosensors are presented, and the biosensors for medical diagnostics are highlighted. The information concerning the necessity of separate and simultaneous determination of lactate and pyruvate, as well as lactate to pyruvate ratio, is given; the traditional methods for the determination of these substances are briefly described. Lactate dehydrogenase and lactate oxidase are shown to be most commonly used in the biosensors for lactate detection. Pyruvate oxidase and living cells are used in the biosensors for pyruvate detection. Different methods of the enzymes immobilization are presented, as well as strategies for enhancement of the biosensor sensitivity. An additional requirement for practical applications is the biosensor resistance to electroactive interferents, inhibitors, biofouling, and electrode passivation; thus, the variants of solving these problems in the biosensors for lactate and pyruvate detection are analyzed.