TY - JOUR AU - Singal, Shobhita AU - Srivastava, Avanish K. AU - Rajesh, Rajesh PY - 2016/09/15 Y2 - 2024/03/28 TI - Electrochemical Impedance Analysis of Biofunctionalized Conducting Polymer-Modified Graphene-CNTs Nanocomposite for Protein Detection JF - Nano-Micro Letters JA - Nano-Micro Lett VL - 9 IS - 1 SE - Articles DO - 10.1007/s40820-016-0108-2 UR - https://www.nmlett.org/index.php/nml/article/view/365 SP - 7 AB - <p>We report an electrodeposited poly(pyrrole-co-pyrrolepropylic acid) copolymer modified electroactive graphene-carbon nanotubes composite deposited on a glassy carbon electrode to detect the protein antigen (cTnI). The copolymer provides pendant carboxyl groups for the site-specific covalent immobilization of protein antibody, anti-troponin I. The hybrid nanocomposite was used as a transducer for biointerfacial impedance sensing for cTnI detection. The results show that the hybrid exhibits a pseudo capacitive behaviour with a maximum phase angle of 49° near 1&nbsp;Hz, which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61 (<em>n</em>&nbsp;=&nbsp;0.61), whereas, it is 0.88 (<em>n</em>&nbsp;=&nbsp;0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic (<em>R</em> <sub>et</sub>) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0&nbsp;pg&nbsp;mL<sup>−1</sup>–10.0&nbsp;ng&nbsp;mL<sup>−1</sup>. The sensitivity of the transducer is 167.8&nbsp;±&nbsp;14.2&nbsp;Ω&nbsp;cm<sup>2</sup> per decade, and it also exhibits high specificity and good reproducibility.</p> ER -