Bamboo-like multiwalled carbon nanotubes dispersed in double stranded calf-thymus DNA as a new analytical platform for building layer-by-layer based biosensors

EMILIANO PRIMO,; F.A. GUTIERREZ; MARÍA D. RUBIANES; GUSTAVO A. RIVAS

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 182 p. 391 - 397

0013-4686

This work reports the successful application of bamboo-like multiwalled carbon nanotubes (bCNT) non-covalently functionalized with calf-thymus double stranded DNA (dsDNA) as a robust platform (bCNT-dsDNA) to build electrochemical biosensors. The ?model system? proposed here as a proof of concept wasan enzymatic biosensor devoted to glucose quantification obtained by layer-by-layer self-assemby ofpolydiallyldimethylammonium (PDDA) and glucose oxidase (GOx) at glassy carbon electrodes (GCE)modified with bCNT-dsDNA (GCE/bCNT-dsDNA/(PDDA/GOx)n). The influence of GOx and PDDAassembling conditions and the effect of the number of PDDA/GOx bilayers (n) on the performance ofthe resulting biosensor is critically discussed. The supramolecular architecture was characterized byelectrochemical impedance spectroscopy from the charge transfer resistance of quinone/hydroquinoneand potassium ferrocyanide/potassium ferricyanide; by cyclic voltammetry from the surfaceconcentration of GOx using ferrocene methanol as enzyme regenerator; by amperometry from theresponse of the enzymatically generated hydrogen peroxide; and by surface plasmon resonance from thechanges in the plasmon resonance angle. The analytical parameters obtained with GCE/bCNT-dsDNA/(PDDA/GOx)3 for the amperometric quantification of glucose at 0.700 V were: sensitivity of (265 7)mA mM1cm2, linear range between 0.25 and 2.50 103M, detection limit of 50 mM, repeatability of3.6% (n = 10), and negligible interference from maltose, galactose, fructose and manose. The biosensorwas successfully used for the sensitive quantification of glucose in beverages and a medicine sample.ã