2‐Aminotrimesic Acid‐Functionalized Graphene Oxide‐Modified Screen‐Printed Electrodes for Sensitive Electrochemical Detection of Cardiac Marker Troponin I

An electrochemical impedance‐based immunosensor is reported for the sensitive detection of cardiac Troponin I (cTnI). The sensor is made up of the amine‐functionalized graphene oxide (GO)‐coated screen‐printed electrodes (SPEs). As a novel concept, GO is functionalized with aminotrimesic acid (1‐aminobenzene‐3,4,5‐tricarboxylic acid), which provides efficient water dispersion and desirable carboxyl functionality for subsequent biomodification with antibodies. Such a functionalized GO surface is useful to immobilize the anti‐cTnI antibodies efficiently and conveniently. The modification of antibodies is verified with spectroscopic and morphological investigations. Further, the application of the immunosensor electrodes toward the detection of cTnI is demonstrated through the measurements of Rct (charge transfer resistance) values in the presence of varying antigen concentration. The limit of detection (LOD) of the present method is 0.08 ng mL−1 with the range of detection as 0.1–100 ng mL−1. The specificity of the developed immunosensor is studied in the presence of ferritin, and bovine serum albumin (BSA). Thus, the herein proposed a new design of graphene‐based immunosensor is very convenient and offers highly selective and sensitive detection of cTnI. Graphene oxide is functionalized with aminotrimesic acid to achieve carboxyl functionality for subsequent bioimmobilization of antibodies. This bioconjugate is used to prepare screen‐printed immunoelectrodes for the electrochemical detection of cardiac Troponin I. The limit of detection of the present method is 0.08 ng mL−1 with the range of detection as 0.1–100 ng mL−1.