Study of the biosensor based on platinum nanoparticles supported on carbon nanotubes and sugar-lectin biospecific interactions for the determination of glucose

Highly sensitive electrochemical platform based on Pt nanoparticles supported on carbon nanotubes (Pt-nano-CNTs) and sugar-lectin biospecific interactions is developed for the direct electrochemistry of glucose oxidase (GOD). Firstly, Pt-nano-CNTs nanocomposites were prepared in the presence of carbon nanotubes (CNTs), and then the mixture was cast on a glassy carbon electrode (GCE) using chitosan as a binder. Thereafter, concanavalin A (Con A) was adsorbed onto the precursor film by the electrostatic force between positively charged chitosan and the negatively charged Con A. Finally, the multilayers of Con A/GOD films were prepared based on biospecific affinity of Con A and GOD via layer-by-layer (LBL) self-assembly technique. The electrochemical behavior of the sensor was studied using cyclic voltammetry and chronoamperometry. The electrochemical parameters of GOD in the film were calculated with the results of the electron transfer coefficient (a) and the apparent heterogeneous electron transfer rate constant (k(s)) as 0.5 and 5.093 s(-1). respectively. Experimental results show that the biosensor responded linearly to glucose in the range from 1.2 x 10(-6) to 2.0 x 10(-3) M, with a detection limit of 4.0 x 10(-7) M under optimized conditions. (C) 2011 Elsevier Ltd. All rights reserved.