title: Layer-by-layer electrochemical biosensor with aptamer-appended active polyelectrolyte multilayer for sensitive protein determination.
abstract: Herein, we report two simple label-free electrochemical aptasensors for protein detection using layer-by-layer (LBL) self-assembled multilayers with ferrocene-appended poly(ethyleneimine) (Fc-PEI), carbon nanotubes (CNTs) and aptamer. In one sensing strategy, the Fc-PEI, CNTs and DNA aptamer are LBL assembled on the electrode surface via electrostatic interaction. In the presence of target, the aptamer on the outermost layer of the LBL self-assembled multilayer would catch the target on the electrode interface, which makes a barrier for electrons and inhibits the electro-transfer, resulting in the decreased DPV signals of Fc-PEI. Using this strategy, a wide detection range (0.3-165 ng ml(-1)) for model target thrombin is obtained, with a low detection limit of 0.14 ng ml(-1). In the similar sensing strategy for detection of lysozyme, a wide detection range (0.2 ng ml(-1) to 1.66 microg ml(-1)) and a low detection limit (0.17 ng ml(-1)) are obtained. These results prove that the LBL sensing strategies developed possess sensitivity, selectivity, stability and generality.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Du
authors.forename: Chaogui
authors.initials: C
authors.lastname: Chen
authors.forename: Bingling
authors.initials: B
authors.lastname: Li
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
authors.forename: Shaojun
authors.initials: S
authors.lastname: Dong
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004573:Electrolytes / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008567:Membranes, Artificial; D009113:Muramidase / Q000032:analysis* / Q000737:chemistry; D040081:Protein Array Analysis / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D004573:Electrolytes; D008567:Membranes, Artificial; D009113:Muramidase