Disposable electrocatalytic sensor for whole blood NADH monitoring

Abstract

Monitoring nicotinamide adenine dinucleotide (NADH) is important because NADH is involved in cellular redox reactions and cellular energy production. Currently, few biosensors quantify NADH in whole blood. However, they still have limitations due to several defects, including poor repeatability, long analysis time, and their requirement of extra sample pretreatment. In this study, we developed electrocatalytic sensors using screen-printed electrodes with a redox-active monolayer 4′-mercapto-N-phenylquinone diamine formed by a self-assembled monolayer of a 4-aminothiophenol (4-ATP). We exhibited their behavior as electrocatalysts toward the oxidation of NADH in whole blood. Finally, the electrocatalytic sensors maintained stability and exhibited 3.5 µM limit of detection, with 0.0076 ± 0.0006 µM/µA sensitivity in a mouse’s whole blood. As proof of concept, a polyhexamethylene guanidine phosphate–treated mouse model was used to induce inflammatory and fibrotic responses, and NADH level was measured for 45 days. This work demonstrates the potential of electrocatalytic sensors to analyze NADH in whole blood and to be developed for extensive applications.

Recent Advances in Electrochemical Detection of Cell Energy Metabolism

“…In this case, a functional material was employed to enhance the sensitivity of the detection process [84]. Next, the NADH/NAD + redox couple was employed in the sensor designed by Lee et al [94], who introduced a two-step EC functionalization technique to address the challenges encountered in the measurement of body fluids. For NADH detection, a disposable electrocatalytic sensor was constructed based on an SPE coated with a redox-active monolayer of 4 ′ -mercapto-N-phenylquinone diamine (NPQD) formed via self-assembly of 4-aminothiophenol, as depicted in Figure 4A (upper panel).…”