title: A novel carboxymethylcellulose-gelatin-titanium dioxide-superoxide dismutase biosensor; electrochemical properties of carboxymethylcellulose-gelatin-titanium dioxide-superoxide dismutase.
abstract: A novel highly sensitive electrochemical carboxymethylcellulose-gelatin-TiO(2)-superoxide dismutase biosensor for the determination of O(2)(•-) was developed. The biosensor exhibits high analytical performance with a wide linear range (1.5 nM to 2 mM), low detection limit (1.5 nM), high sensitivity and low response time (1.8s). The electron transfer of superoxide dismutase was first accomplished at the carboxymethylcellulose-gelatin-Pt and carboxymethylcellulose-gelatin-TiO(2)-Pt surface. The electron transfer between superoxide dismutase and the carboxymethylcellulose-gelatin-Pt wihout Fe(CN)(6)(4-/3-) and carboxymethylcellulose-gelatin-Pt, carboxymethylcellulose-gelatin-TiO(2)-Pt with Fe(CN)(6)(4-/3-) is quasireversible with a formal potential of 200 mV, 207 mV, and 200 mV vs Ag|AgCl respectively. The anodic (ks(a)) and cathodic (ks(c)) electron transfer rate constants and the anodic (α(a)) and cathodic (α(c)) transfer coefficients were evaluated: ks(a)=6.15 s(-1), α(a)=0.79, and ks(c)=1.48 s(-1) α(c)=0.19 for carboxymethylcellulose-superoxide dismutase without Fe(CN)(6)(4-/3-), ks(a)=6.77 s(-1), α(a)=0.87, and ks(c)=1 s(-1) α(c)=0.13 for carboxymethylcellulose-superoxide dismutase with Fe(CN)(6)(4-/3-), ks(a)=6.85 s(-1), α(a)=0.88, and ks(c)=0.76 s(-1) α(c)=0.1 carboxymethylcellulose-gelatin-TiO(2)-superoxide dismutase. The electron transfer rate between superoxide dismutase and the Pt electrode is remarkably enhanced due to immobilizing superoxide dismutase in carboxymethylcellulose-gelatin and TiO(2) nanoparticles tend to act like nanoscale electrodes.
authors.affiliation: Ankara University, Science Faculty, Department of Chemistry, Tandoğan, Ankara, 06100, Turkey. eemregul@yahoo.com
authors.forename: Emel
authors.initials: E
authors.lastname: Emregul
authors.forename: Ozge
authors.initials: O
authors.lastname: Kocabay
authors.forename: Burak
authors.initials: B
authors.lastname: Derkus
authors.forename: Tugrul
authors.initials: T
authors.lastname: Yumak
authors.forename: Kaan Cebesoy
authors.initials: KC
authors.lastname: Emregul
authors.forename: Ali
authors.initials: A
authors.lastname: Sınag
authors.forename: Kamran
authors.initials: K
authors.lastname: Polat
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D001921:Brain / Q000473:pathology; D001923:Brain Chemistry; D001932:Brain Neoplasms / Q000737:chemistry / Q000175:diagnosis / Q000473:pathology; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002417:Cattle; D058266:Dielectric Spectroscopy / Q000379:methods; D004566:Electrodes; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D005780:Gelatin / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry; D026082:Singlet Oxygen / Q000032:analysis*; D013482:Superoxide Dismutase / Q000737:chemistry / Q000378:metabolism*; D014025:Titanium / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; C009495:titanium dioxide; D026082:Singlet Oxygen; D005780:Gelatin; D014025:Titanium; D013482:Superoxide Dismutase; D002266:Carboxymethylcellulose Sodium