title: Enhancement of dopamine sensing by layer-by-layer assembly of PVI-dmeOs and Nafion on carbon nanotubes.
abstract: In this study, carbon nanotubes (CNTs) were modified to further improve their performance in electrochemical sensing of dopamine (DA) levels. After a redox polymer, poly(vinylimidazole) complexed with Os(4, 4'-dimethyl- 2, 2-bipyridine)(2)Cl (termed PVI-dmeOs) was electrodeposited on multi-wall CNTs (MWCNTs), Nafion and PVI-dmeOs films were successfully layer-by-layer (LBL) assembled on the hydrophilic surface of the as-prepared PVI-dmeOs/CNTs nanocomposites through electrostatic interactions. The LBL assembly was proved by scanning electron microscopy (SEM), electrochemistry and UV-vis spectroscopy measurements. LBL assembly of Nafion/PVI-dmeOs films on CNTs significantly enhanced their linear sweep voltammetry (LSV) response sensitivity to DA, with a maximum enhancement for three Nafion/PVI-dmeOs film-modified MWCNTs. The LSV peak current density of (Nafion/PV I-dmeOs)(3)/CNT electrodes in response to 10 and 50 microM DA solutions was about 7.3 and 3.9 times those for bare CNTs. At the (Nafion/PV I-dmeOs)(3)/CNT electrodes, the limit of detection (LOD) (signal-to-noise ratio: 3) was 0.05 microM DA, the linear range was 0.1-10 microM DA (with a linear regression coefficient of 0.97) and the DA-sensing sensitivity was 8.15 microA cm( - 2) microM( - 1). The newly fabricated (Nafion/PV I-dmeOs)(3)/CNT electrodes may be developed as an ideal biosensor for direct and in situ measurement of DA levels.
authors.affiliation: Department of Bioengineering, Zhengzhou University, 100# Science Avenue, Zhengzhou 450001, People's Republic of China.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Cui
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Cui
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Sun
authors.forename: Kuan
authors.initials: K
authors.lastname: Zhang
authors.forename: Wei-De
authors.initials: WD
authors.lastname: Zhang
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry; D015374:Biosensing Techniques; D004298:Dopamine / Q000032:analysis*; D017097:Electric Impedance; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D016014:Linear Models; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D009992:Osmium / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005465:Fluorocarbon Polymers; D007093:Imidazoles; D037742:Nanotubes, Carbon; D009942:Organometallic Compounds; D011145:Polyvinyls; C072974:polyvinylimidazole; D009992:Osmium; C040402:perfluorosulfonic acid; D015082:2,2'-Dipyridyl; D004298:Dopamine