Analytes kinetics in lateral flow membrane analyzed by cTnI monitoring using magnetic method

Cardiac Troponin I (cTnI) functionalized immunomagnetic beads in lateral flow membrane was measured to analyze the analyte kinetics of mass-transport and antibody-antigen binding reaction. A hybrid AMR/PHR (Anisotropic magnetoresistance/Planar Hall resistance) ring sensor exhibits self-balanced bridge characteristics for each branch with an additive magnetic field effect and its field sensitivity was 135 mu V/Oe for the +/- 50 Oe range. The real time monitoring of the sensor voltage for the cTnI concentrations in the range of 0.44-2.2 nM exhibits a two-step increment with time. A rapid increment in early time regime up to 50s is related with the kinetics of antibody-antigen binding reactions, and then a gradual increment is governed by the kinetics of analyte transportation. The sensor voltage variation in early time regime was equal to 70% of the total variation at 400 s. (C) 2011 Elsevier B.V. All rights reserved.