Rapid and sensitive detection of nano-fluidically trapped protein biomarkers

In this work, we demonstrate the label-free and ultrasensitive detection of troponin-T, cardiac biomarker using nanoporous membrane integrated on a microelectrode sensor platform. The nanoporous membrane allows for spatial confinement of the protein molecules. Antigen interaction with thiol immobilized antibody perturbs the electrical double layer. Charge perturbations are recorded as impedance change at low frequency using the principle of electrochemical impedance spectroscopy (EIS). The measured impedance change is used to quantitatively determine the concentration of troponin-T in tested sample. We have shown that sensitivity of sensor for troponin-T to be 1pg/mL. The accuracy and reliability of this sensor was tested by comparing the experimental troponin-T concentration values with a commercially available electrochemiluminescence assay measured with Roche Elecsys analyzer. Using this technique we were successful in detecting protein biomarkers in whole blood, human serum, and ionic buffers. This technology provides a robust analytical platform for rapid and sensitive detection of protein biomarkers, thus establishing this technology as an ideal candidate for biomarker screening in clinical settings.