Electrochemical quantification of biomarker myeloperoxidase

Point of care testing (PoCT) devices permit precise and rapid detection of disease-related biomarkers contributing to an early disease diagnosis and administration of an appropriate treatment. The enzyme myeloperoxidase (MPO) is a relevant biomarker for infection and inflammation events assessment; however its direct electrochemical quantification is hindered by the limited accessibility to the iron atom in its active center. Herein, such hindrance of the MPO biomolecule is overcome using the redox mediator 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS). The charge involved in the electrochemical reduction of the MPO-oxidized ABTS is correlated with the concentration of MPO. The use of ABTS allowed for the electrochemical assessment of a wide range of MPO concentrations (10-1000 nM) including those reported for wound infections, chronic obstructive pulmonary disease and early adverse cardiac events. The developed electroanalytical approach is rapid and inexpensive, and thus suitable for implementation in PoCT devices.