Characterization of protein-attached conducting polymer monolayer

Langmuir. 2008 Feb 5;24(3):1087-93. doi: 10.1021/la701689f. Epub 2008 Jan 1.

Abstract

Cytochrome c (cyt c)-immobilized monolayers and multiple monolayers of a conducting polymer [poly(terthiophene-3-carboxylic acid) polymer (poly-TTCA)] were prepared, where the monolayer of monomer precursor was fabricated with the Langmuir-Blogett technique. Covalent immobilization of cyt c was achieved by the formation of an amide bond between the carboxylic groups of the conducting polymer and amines groups of lysine in cyt c. The monolayer of poly-TTCA and poly-TTCA/cyt c was characterized by cyclic voltammetry, XPS, EQCM, Auger electron spectra (AES), and atomic force microscopy (AFM). The immobilization of cyt c on the polymer layer reveals the direct electron-transfer processes of cyt c. Cyclic voltammetry of the poly-TTCA/cyt c-modified electrode showed a pair of reversible peaks at approximately +212/+201 mV (Epa/Epc) versus Ag/AgCl in a 0.2 M phosphate buffer solution (pH 7.0). The peak separation and the redox peak current of the poly-TTCA/cyt c-modified electrodes were gradually increased by increasing the number of poly-TTCA/cyt c layers on the electrode. The heterogeneous electron-transfer rate constant (ks) of cyt c at the poly-TTCA/cyt c-monolayer-modified electrode was estimated to be 0.874 s(-1). The method provides a novel route for the fabrication of protein (cyt c)-immobilized and/or lipid (palmitoyloleoylphosphatidic acid)-immobilized monolayers and multiple monolayers of a conducting polymer. Cyt c bonded on the conductive polymer layers was applied for bioelectronic devices with unique functionality.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biocompatible Materials / chemistry
  • Cytochromes c / chemistry
  • Electrochemistry
  • Electronics, Medical
  • Microscopy, Atomic Force
  • Polymers / chemistry*
  • Proteins / chemistry*
  • Thiophenes / chemistry

Substances

  • Biocompatible Materials
  • Polymers
  • Proteins
  • Thiophenes
  • Cytochromes c