title: TiO2/MWNTs nanocomposites-based electrochemical strategy for label-free assay of casein kinase II activity and inhibition.
abstract: In this paper, a novel label-free electrochemical strategy has been developed for assay of casein kinase II (CK2) activity and inhibition using TiO(2)/MWNTs nanocomposites. This detection system takes advantage of specific binding of the phosphate groups with TiO(2) nanoparticles and fast electron transfer rate of MWNTs. In this strategy, the synthesized TiO(2)/MWNTs nanocomposite was firstly deposited on the surface of a glassy carbon electrode (GCE). The presence of MWNTs not only increased the surface area of the electrode but also promoted electron-transfer reaction. In the presence of CK2, the kinase reaction resulted in the phosphorylation of peptide substrates. The phosphorylated peptides were subsequently captured to the surface of GCE modified with TiO(2)/MWNTs nanocomposite through specific binding of the phosphate groups with TiO(2) nanoparticles. Then the access of redox probe [Fe(CN)(6)](3-/4-) to electrode surface was blocked. As a result, the decrease peak currents were related to the concentrations of the CK2, providing a sensing mechanism for monitoring peptides phosphorylation. The electrochemical strategy can be employed to assay CK2 activity with a low detection limit of 0.07 U/mL. The linear range of the assay for CK2 was 0-0.5 U/mL. Furthermore, the interferences experiments of PKA and inhibition of CK2 have been also studied by using this strategy.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: He
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China. Electronic address: kmwang@hnu.edu.cn.
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Su
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Hunan University, PR China; Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Changsha 410082, PR China.
authors.forename: Genping
authors.initials: G
authors.lastname: Yan
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D047390:Casein Kinase II / Q000032:analysis* / Q000037:antagonists & inhibitors*; D055664:Electrochemical Techniques; D053768:Metal Nanoparticles / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000648:ultrastructure; D009842:Oligopeptides / Q000737:chemistry; D013379:Substrate Specificity; D014025:Titanium
chemical_list: D009842:Oligopeptides; C009495:titanium dioxide; D014025:Titanium; D047390:Casein Kinase II