Electrochemical antigenic sensor for the diagnosis of chronic Q fever

Abstract

• Differential diagnosis of chronic Q fever occurs through antigen- antibody interactions. • GroEl is a higly sensitive antigen which interacts specifically with antibodies against chronic Q fever. • The developed imedimetric biosensor, based on the immobilization of GroEl antigenic protein can be easily used for the rapid diagnosis of chronic Q fever in humans. • The developed system can be modified for the detection of other biomarkers, such as antibodies against acute Q fever. In this work, we report the development of an impedimetric biosensor for the direct, quick, and easy diagnosis of chronic Q fever. The biosensor is based on highly sensitive antigens that can selectively recognize antibodies against Coxiella burnetii . The biosensor is based on the immobilization of antigens onto a gold electrode using the EDC/NHS immobilization methodology. The detection is performed by impedance spectroscopy that monitors specific frequencies which provide the maximum sensitivity for the biosensor. Q fever antibodies that are present in the sera of patients interact selectively with the biosensor antigens, thereby altering the impedance of the biosensor surfaceand generating a large impedance change within a few seconds. The biosensor allows for the specific serological detection of chronic Q fever, while the developed system can also be modified for the detection of other biomarkers, such as the ones against acute Q fever.