title: An intimately bonded titanate nanotube-polyaniline-gold nanoparticle ternary composite as a scaffold for electrochemical enzyme biosensors.
abstract: In this work, titanate nanotubes (TNTs), polyaniline (PANI) and gold nanoparticles (GNPs) were assembled to form a ternary composite, which was then applied on an electrode as a scaffold of an electrochemical enzyme biosensor. The scaffold was constructed by oxidatively polymerising aniline to produce an emeraldine salt of PANI on TNTs, followed by gold nanoparticle deposition. A novel aspect of this scaffold lies in the use of the emeraldine salt of PANI as a molecular wire between TNTs and GNPs. Using horseradish peroxidase (HRP) as a model enzyme, voltammetric results demonstrated that direct electron transfer of HRP was achieved at both TNT-PANI and TNT-PANI-GNP-modified electrodes. More significantly, the catalytic reduction current of H2O2 by HRP was ∼75% enhanced at the TNT-PANI-GNP-modified electrode, compared to that at the TNT-PANI-modified electrode. The heterogeneous electron transfer rate constant of HRP was found to be ∼3 times larger at the TNT-PANI-GNP-modified electrode than that at the TNT-PANI-modified electrode. Based on chronoamperometric detection of H2O2, a linear range from 1 to 1200 μM, a sensitivity of 22.7 μA mM(-1) and a detection limit of 0.13 μM were obtained at the TNT-PANI-GNP-modified electrode. The performance of the biosensor can be ascribed to the superior synergistic properties of the ternary composite.
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province, 475004, PR China. Electronic address: liuxiaoqiang@henu.edu.cn.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province, 475004, PR China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province, 475004, PR China.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Huo
authors.affiliation: Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan Province, 475004, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Yan
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW 2109, Australia. Electronic address: Danny.Wong@mq.edu.au.
authors.forename: Danny K Y
authors.initials: DKY
authors.lastname: Wong
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques; D004566:Electrodes; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes; D015203:Reproducibility of Results; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; C416807:polyaniline; D006046:Gold; D014025:Titanium
keywords: A TNT-PANI-GNP ternary composite; Electrochemical enzyme biosensor; Horseradish peroxidase; PANI molecular wire