Sensitive impedimetric detection of troponin I with metal-organic framework composite electrode

Metal-organic frameworks (MOFs) are promising materials for biosensing applications due to their large surface to volume ratio, easy assembly as thin films, and better biocompatibility than other nanomaterials. Their application in electrochemical biosensing devices can be realized by integrating them with other conducting materials, like polyaniline (PANI). In the present research, a composite of a copper-MOF (i.e., Cu₃(BTC)₂) with PANI has been explored to develop an impedimetric sensor for cardiac marker troponin I (cTnI). The solvothermally synthesized Cu₃(BTC)₂/PANI composite has been coated as a thin layer on the screen-printed carbon electrodes (SPE). This electroconductive thin film was conjugated with anti-cTnI antibodies. The above formed immunosensor has allowed the impedimetric detection of cTnI antigen over a clinically important concentration range of 1-400 ng mL^-1. The whole process of antigen analysis could be completed within 5 min. The detection method was specific to cTnI even in the co-presence of other possibly interfering proteins.