Abstract: A method for detection of disease or pathogen related enzymes is shown using new electrochemical biosensors that are responsive to the reactivity of enzymes. Three components are involved: (1) a simple linker for attachment to electrode surfaces; (2) the ferrocene signal unit; and (3) a substrate that can be removed from the ferrocene molecule by enzyme activity. The highly reversible Fe2+/3+ redox couple of ferrocene is used as the electrochemical signal. A substrate is covalently attached to the ferrocene molecule that is selectively targeted and known to be cleaved by the enzyme analyte of interest. The enzyme activity removes the substrate from the ferrocene molecule, producing a new ferrocene molecule with a new redox potential compared to the parent ferrocene-substrate molecule which enables enzyme concentrations associated with disease or pathogens to be quantified.