Abstract
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 Hz, which is due to the inhomogeneous and porous structure of the hybrid composition. The constant phase element of copolymer is 0.61 (n = 0.61), whereas, it is 0.88 (n = 0.88) for the hybrid composites, indicating a comparatively homogeneous microstructure after biomolecular functionalization. The transducer shows a linear change in charge transfer characteristic (Ret) on cTnI immunoreaction for spiked human serum in the concentration range of 1.0 pg mL−1–10.0 ng mL−1. The sensitivity of the transducer is 167.8 ± 14.2 Ω cm2 per decade, and it also exhibits high specificity and good reproducibility.
Highlights
In recent years, enormous interest has been attached to hybrid nanocomposites due to their wide applications in environmental science, energy conversion, sensing, etc. [1]
We demonstrate the electrochemical synthesis of conducting copolymer PPy-PPa over G-MWCNT hybrid film deposited on a glassy carbon electrode (GCE), as an impedance immunosensor, for ultrasensitive detection of cardiac troponin I spiked in human serum
The high value of n = 0.61 observed on PPy-PPa/G-carbon nanotubes (CNTs) compared with n = 0.44 on native G-CNTs further indicates a slight reduction in surface inhomogeneity in the polymer-modified electrode, which is later found to be nearly homogenous (n = 0.88) upon biomolecular immobilization with anti-cardiac troponin I (cTnI)
Summary
Enormous interest has been attached to hybrid nanocomposites due to their wide applications in environmental science, energy conversion, sensing, etc. [1]. Enormous interest has been attached to hybrid nanocomposites due to their wide applications in environmental science, energy conversion, sensing, etc. Theoretical and experimental reports on hybrid carbon nanostructures have brought special interest. Electronic supplementary material The online version of this article (doi:10.1007/s40820-016-0108-2) contains supplementary material, which is available to authorized users. Carbon nanomaterials, including carbon nanotubes (CNTs) and graphene, have shown great potential in
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