A highly efficient nano-cluster artificial peroxidase and its direct electrochemistry on a nano complex modified glassy carbon electrode

Anal Sci. 2012;28(7):711-6. doi: 10.2116/analsci.28.711.

Abstract

A nano-cluster with highly efficient peroxide activity was constructed based on nafion (NF) and cytochrome c (Cyt c). UV-Vis spectrometry and transmission electron microscopy (TEM) methods were utilized for characterization of the nano-structured enzyme or artificial peroxidase (AP). The nano-cluster was composed of a Chain-Ball structure, with an average ball size of about 40 nm. The Michaelis-Menten (K(m)) and catalytic rate (k(cat)) constants of the AP were determined to be 2.5 ± 0.4 µM and 0.069 ± 0.001 s(-1), respectively, in 50 mM PBS at pH 7.0. The catalytic efficiency of the AP was evaluated to be 0.028 ± 0.005 µM(-1) s(-1), which was 39 ± 5% as efficient as the native horseradish peroxidase (HRP). The AP was also immobilized on a functional multi-wall carbon nanotube (MWNCTs)-gold colloid nanoparticles (AuNPs) nano-complex modified glassy carbon (GC) electrode. The cyclic voltammetry of AP on the nano complex modified GC electrode showed a pair of well-defined redox peaks with a formal potential (E°') of -45 ± 2 mV (vs. Ag/AgCl) at a scan rate of 0.05 V/s. The heterogeneous electron transfer rate constant (k(s)) was evaluated to be 0.65 s(-1). The surface concentration of electroactive AP on GC electrode (Γ) was 7 × 10(-10) mol cm(-2). The apparent Michaelis-Menten constant (K(m)(app)) was 0.23 nM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomimetic Materials / chemistry*
  • Biomimetic Materials / metabolism
  • Biosensing Techniques
  • Cytochromes c / metabolism
  • Electrochemistry / instrumentation
  • Electrochemistry / methods*
  • Electrodes
  • Fluorocarbon Polymers / chemistry
  • Glass / chemistry*
  • Gold / chemistry
  • Hydrogen Peroxide / analysis
  • Hydrogen-Ion Concentration
  • Kinetics
  • Limit of Detection
  • Membranes, Artificial
  • Metal Nanoparticles / chemistry
  • Nanostructures / chemistry*
  • Nanotubes, Carbon / chemistry*
  • Peroxidase / metabolism*

Substances

  • Fluorocarbon Polymers
  • Membranes, Artificial
  • Nanotubes, Carbon
  • perfluorosulfonic acid
  • Gold
  • Cytochromes c
  • Hydrogen Peroxide
  • Peroxidase