Impedimetric quantification of anti-dengue antibodies using functional carbon nanotube deposits validated with blood plasma assays

A high performance impedimetric immunosensor for the dengue virus antibody detection is presented. The setup profits from the formation of controlled and reproducible carbon nanotube (CNT) deposits on electrodes. Their easy functionalization via electrogeneration of a polypyrrole-NHS (N-hydroxysuccinimido 11-(pyrrol-1-yl) undecanoate) film enables the immobilization of the Dengue Virus 2 NS1 glycoprotein, the receptor unit, on the porous CNT layer via covalent amide coupling to provide the necessary selectivity towards Dengue NS1 antibody. All building steps of this immunosensor and the performance of this system were monitored by impedance spectroscopy and cyclic voltammetry. The resulting impedimetric dengue biosensor was tested in bovine blood plasma in addition to conventional measurements under controlled environment. After optimization, this immunosensor shows a good linearity in a wide concentration range (10⁻¹³–10⁻⁵ g mL⁻¹).