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

EMILIANO N. PRIMO; FABIANA A. GUTIERREZ; MARÍA D RUBIANES; GUSTAVO A. RIVAS

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2015 vol. 82 p. 391 - 397

0013-4686

This work reports the successful application ofbamboo-like multiwalled carbon nanotubes (bCNT) noncovalently functionalizedwith calf-thymus double stranded DNA (dsDNA) as a robust platform (bCNTdsDNA)to build electrochemical biosensors. The ?model system? proposed here as aproofofconcept was an enzymatic biosensor devoted to glucose quantificationobtained by layer-by-layer self-assemby of polydiallyldimethylammonium (PDDA)and glucose oxidase (GOx) at glassy carbon electrodes (GCE) modified withbCNT-dsDNA (GCE/bCNT-dsDNA/(PDDA/GOx)n). The influence of GOx and PDDA assemblingconditions and the effect of the number of PDDA/GOx bilayers (n) on theperformance of the resulting biosensor is critically discussed. Thesupramolecular architecture was characterized by electrochemical impedancespectroscopy from the charge transfer resistance of quinone/hydroquinone andpotassium ferrocyanide/potassium ferricyanide; by cyclic voltammetry from thesurface concentration of GOx using ferrocene methanol as enzyme regenerator; byamperometry from the response of the enzymatically generated hydrogen peroxide;and by surface plasmon resonance from the changes in the plasmon resonanceangle. The analytical parameters obtained with GCE/bCNT-dsDNA/(PDDA/GOx)3 forthe amperometric quantification of glucose at 0.700 V were: sensitivity of (265±7) mAmM-1 cm-2, linear range between 0.25and 2.50 mM, detection limit of 50 uM, repeatability of 3.6% (n = 10), and negligible interference from maltose, galactose, fructoseand manose. The biosensor was successfully used for the sensitive quantificationof glucose in beverages and a medicine sample.