A new micro-contact imprinted l-cysteine sensor based on sol-gel decorated graphite/multiwalled carbon nanotubes/gold nanoparticles composite modified sandpaper electrode

Abstract

A new ultrasensing sandpaper electrode was fabricated using micro-contact imprinting technique for the detection of several diseases manifested at acute level depletion of l-cysteine. The concerted effect of molecularly imprinted polymer@graphite/multiwalled carbon nanotubes/gold nanoparticles/sol-gel composite led to the growth of a nanometer thin film coating on the surface of sandpaper electrode. Herein, the redox electron relay was channelized in between imprinted nanocomposite and aluminum stripe attached at the modified surface. Determination of the analyte (l-cysteine) could simply be performed by measuring differential pulse anodic stripping voltammetric signal of potassium ferricyanide used as an external probe. The limits of detection [0.26-0.30 ng mL-1 (3σRSD ≤ 2.5%)] obtained were free from any cross-reactivity and false-positive complications in aqueous, blood serum, and pharmaceutical samples. The proposed sensor can be used as a practical sensor for monitoring cysteine deficiency, particularly with HIV-infected patients. © 2015 Published by Elsevier B.V.