title: Lipid-bonded conducting polymer layers for a model biomembrane: application to superoxide biosensors.
abstract: Model biomembranes composed of poly-DATT/DGS/POPA and poly-DATT/DGS/CL were separately prepared on gold electrodes. A monolayer of 1,2-dioleoyl-sn-glycero-3-succinate (DGS) was covalently bonded onto electrochemically grown poly-(3,4-diamiono-2,2:5,2-terthiophene) (DATT) layers (thickness of approximately 300 nm; particle size of approximately 50 to 70 nm). The numbers of unit molecules of the poly-DATT layer and of the DGS immobilized onto the poly-DATT layers were 1.53 x 10(-7) and 1.56 x 10(-9) mol cm(-2), respectively, using a quartz crystal microbalance technique. The lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (POPA) and cardiolipin (CL) were formed onto the poly-DATT/DGS layer using the Langmuir-Blodgett technique. The surface characterizations of each step were investigated by SEM, AFM, and XPS analyses. Cytochrome c (cyt c) was immobilized onto these model biomembranes through the charge interaction between the positive charges of cyt c and the negative charges of phosphate groups in CL or POPA lipids. At the POPA- and CL-modified biomembranes, the formal potentials of the redox couple of the immobilized cyt c were 0.22 and 0.23 V (vs Ag/AgCl), respectively. The redox reaction of the immobilized cyt c at the POPA- and CL-modified biomembranes was quasireversible, and the electron-transfer rate constants were 0.121 s(-1) and 0.133 s(-1), respectively. The applicability of these cyt c immobilized bioimitation membranes as the biosensors was tested for the determination of superoxide.
authors.affiliation: Department of Chemistry and Center for Innovative Bio-Physio Sensor Technology, Pusan National University, Pusan 609-735, South Korea.
authors.forename: Nak-Hyun
authors.initials: NH
authors.lastname: Kwon
authors.forename: Md Aminur
authors.initials: MA
authors.lastname: Rahman
authors.forename: Mi-Sook
authors.initials: MS
authors.lastname: Won
authors.forename: Yoon-Bo
authors.initials: YB
authors.lastname: Shim
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques; D002308:Cardiolipins / Q000737:chemistry; D045304:Cytochromes c / Q000737:chemistry*; D004566:Electrodes; D004800:Enzymes, Immobilized; D020404:Glycerophospholipids / Q000737:chemistry; D006321:Heart; D006736:Horses; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D008567:Membranes, Artificial; D008954:Models, Biological; D011108:Polymers / Q000737:chemistry*; D013481:Superoxides / Q000378:metabolism*
chemical_list: C509561:1-palmitoyl-2-oleoyl-phosphatidyl-3-adenosine; D002308:Cardiolipins; D004800:Enzymes, Immobilized; D020404:Glycerophospholipids; D008051:Lipid Bilayers; D008055:Lipids; D008567:Membranes, Artificial; D011108:Polymers; D013481:Superoxides; D045304:Cytochromes c; D000241:Adenosine