Direct electrochemistry and electrocatalysis of heme proteins immobilized in single-wall carbon nanotubes-surfactant films in room temperature ionic liquids

Amperometric biosensors were prepared by immobilizing heme proteins in single-wall carbon nanotubes (SWCNTs)-cetyltrimethyl ammonium bromide (CTAB) surfactant films based on 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) as nonaqueous electrolyte. The electrochemistry and electrocatalysis of protein-SWCNTs-CTAB films were investigated. A pair of well-defined and nearly reversible redox peaks was observed when the heme protein films were immersed into [bmim][PF6]. Moreover, the electrocatalytic activity of heme proteins for two model peroxides compounds (hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BuOOH)) was observed. Some electrocatalytic parameters for heme proteins were calculated. Compared with the detection results of t-BuOOH in other organic solvents, kinetic analysis in this experiment indicates that heme protein-SWCNTs-CTAB films operated in ionic liquid provide a higher affinity and sensitivity.