Simultaneous Detection of L-Lactate and D-Glucose Using DNA Aptamers in Human Blood Serum

L-lactate is a key metabolite indicative of physiological states, glycolysis pathways, and various diseases such as sepsis, heart attack, lactate acidosis, and cancer. Detection of lactate has been relying on a few enzymes that need additional oxidants. In this work, DNA aptamers for L-lactate were obtained using a library-immobilization selection method and the highest affinity aptamer reached a K-d of 0.43 mM as determined using isothermal titration calorimetry. The aptamers showed up to 50-fold selectivity for L-lactate over D-lactate and had little responses to other closely related analogs such as pyruvate or 3-hydroxybutyrate. A fluorescent biosensor based on the strand displacement method showed a limit of detection of 0.55 mM L-lactate, and the sensor worked in 90 % serum. Simultaneous detection of L-lactate and D-glucose in the same solution was achieved. This work has broadened the scope of aptamers to simple metabolites and provided a useful probe for continuous and multiplexed monitoring.

Automated summary

In this study, DNA aptamers for L-lactate were obtained through library-immobilization selection method with high affinity and selectivity. A fluorescent biosensor based on the strand displacement method was constructed, allowing simultaneous detection of lactate and glucose in the same solution. This research expands the application of aptamers to simple metabolites and provides a useful tool for continuous and multiplexed monitoring.