Simultaneous Detection of L-lactate and D-glucose Using DNA Aptamers in Human Blood Serum


L-lactate is a key metabolite indicative of physiological state, 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 other substrates. In this work, DNA aptamers for L-lactate were obtained using a library-immobilization selection method and the highest affinity aptamer reached a Kd 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 no measurable response to other closely related analogs such as pyruvate and 3-hydroxybutyrate. A fluorescent biosensor based on the strand displacement method showed a limit of detection of 0.55 mM. Simultaneous detection of L-lactate and D-glucose in the same serum solution was achieved. This work has broadened the scope of aptamers to very simple metabolites and provided a useful probe for the continuous and multiplexed monitoring.


Supplementary material

Supporting Information of the manuscript
Experimental methods, additional information on the secondary structure and sequence alignment of aptamers, calculation of dissociation constant based on the strand-displacement reaction, additional kinetic traces and selectivity data.