Characterization of protein-attached conducting polymer monolayer.
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.
Kim
Hwa-Jeong
HJ
Department of Chemistry, Pusan National University, Busan 609-735, South Korea.
Lee
Kyung-Sun
KS
Won
Mi-Sook
MS
Shim
Yoon-Bo
YB
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry; D004563:Electrochemistry; D004582:Electronics, Medical; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry
D001672:Biocompatible Materials; D011108:Polymers; D011506:Proteins; D013876:Thiophenes; D045304:Cytochromes c