Abstract
We report a discovery that personal glucose meters (PGMs) can give a dose-dependent response to nicotinamide coenzymes, such as the reduced form of nicotinamide adenine dinucleotide (NADH). We have developed methods that take advantage of this discovery to perform one-step homogeneous assays of many non-glucose targets that are difficult to recognize by DNAzymes, aptamers, or antibodies, and without the need for conjugation and multiple steps of sample dilution, separation, or fluid manipulation. The methods are based on the target-induced consumption or production of NADH through cascade enzymatic reactions. Simultaneous monitoring of the glucose and L-lactate levels in human plasma from patients with diabetes is demonstrated and the results are comparable to those from current standard test methods. Since a large number of commercially available enzymatic assay kits utilize NADH in their detection, this discovery will allow the transformation of almost all of these clinical lab tests into POC tests that use a PGM.