title: Stable protein device platform based on pyridine dicarboxylic acid-bound cubic-nanostructured mesoporous titania films.
abstract: Here we shortly report a protein device platform that is extremely stable in a buffer condition similar to human bodies. The protein device platform was fabricated by covalently attaching cytochrome c (cyt c) protein molecules to organic coupler molecules (pyridine dicarboxylic acid, PDA) that were already covalently bound to an electron-transporting substrate. A cubic nanostructured mesoporous titania film was chosen as an electron-transporting substrate because of its large-sized cubic holes (∼7 nm) and highly crystalline cubic titania walls (∼0.4 nm lattice). Binding of PDA molecules to the mesoporous titania surface was achieved by esterification reaction between carboxylic acid groups (PDA) and hydroxyl groups (titania) in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) mediator, whereas the immobilization of cyt c to the PDA coupler was carried out by the EDC-mediated amidation reaction between carboxylic acid groups (PDA) and amine groups (cyt c). Results showed that the 2,4-position isomer among several PDAs exhibited the highest oxidation and reduction peak currents. The cyt c-immobilized PDA-bound titania substrates showed stable and durable electrochemical performances upon continuous current-voltage cycling for 240 times (the final current change was less than 3%) and could detect superoxide that is a core indicator for various diseases including cancers.
authors.affiliation: Organic Nanoelectronics Laboratory, Department of Chemical Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Hwajeong
authors.initials: H
authors.lastname: Kim
authors.forename: Sung Soo
authors.initials: SS
authors.lastname: Park
authors.forename: Jooyeok
authors.initials: J
authors.lastname: Seo
authors.forename: Chang-Sik
authors.initials: CS
authors.lastname: Ha
authors.forename: Cheil
authors.initials: C
authors.lastname: Moon
authors.forename: Youngkyoo
authors.initials: Y
authors.lastname: Kim
mesh_terms: D001698:Biomedical Engineering; D003460:Crystallization; D045304:Cytochromes c / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D004583:Electrons; D004864:Equipment and Supplies; D006801:Humans; D049329:Nanostructures / Q000737:chemistry; D010084:Oxidation-Reduction; D016062:Porosity; D011506:Proteins / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry
chemical_list: D003998:Dicarboxylic Acids; D011506:Proteins; D011725:Pyridines; D013481:Superoxides; C009495:titanium dioxide; D045304:Cytochromes c; D014025:Titanium; C023666:pyridine