Pyrene functionalized single-walled carbon nanotubes as precursors for high performance biosensors

Abstract

The attachment of biotin to nanotube modified electrodes by formation of π-stacking interactions using a biotinylated pyrene derivative is reported. The specific anchoring of biological macromolecules via avidin bridges was investigated using biotinylated glucose oxidase (GOX-B) as model enzyme. Further studies focus the possibility of the electropolymerization of pyrene derivatives. Four types of biotin-SWCNT modified electrodes were investigated: (1) deposits of biotin-pyrene functionalized nanotubes (B-SWCNTs); (2) deposits of regular nanotubes, functionalized by incubation in a biotin-pyrene solution; (3) the latter configuration and subsequent electropolymerization of the adsorbed biotin-pyrene; and (4) deposits of regular nanotubes subsequently modified by electropolymerization of a pyrene-biotin monomer (2 mM). The nanotubes deposits were characterized by SEM imaging and the electropolymerization of the pyrene derivatives were investigated using cyclic voltammetry. These types of biotin-SWCNT modified electrodes were tested due to their capacity to immobilize biotinylated biomolecules (GOX-B) via avidin bridges and their performances in glucose detection were examined using amperometry. The best configuration (3) was obtained with SWCNT coatings modified by specific adsorption and electropolymerization of biotin-pyrene. A maximum current density of 584 μA cm −2 could be realized with a sensitivity of 37 mA M −1 cm −2 for a linear range between 5 μM and 13 mM.