title: A sensitive amperometric immunosensor for alpha-fetoprotein based on carbon nanotube/DNA/Thi/nano-Au modified glassy carbon electrode.
abstract: A novel amperometric immunosensor for the determination of alpha-fetoprotein (AFP) was constructed using films of multi-wall carbon nanotubes/DNA/thionine/gold nanoparticles (nano-Au). Firstly, multiwall carbon nanotubes (MWCNT) dispersed in poly(diallydimethlammonium chloride) (PDDA) were immobilized on the nano-Au film which was electrochemically deposited on the surface of glassy carbon electrode. Then a negatively charged DNA film was absorbed on the positively charged PDDA. Subsequently, thionine was attached to the electrode via the electrostatic interaction between thionine and the DNA. Finally, the nano-Au was retained on the thionine film for immobilization of AFP antibody (anti-AFP). The modification process was characterized by cyclic voltammetry (CV) and scanning electron microscope (SEM). The factors possibly influenced the performance of the proposed immunosensors were studied in detail. Under optimal conditions, the proposed immunosensor exhibited good electrochemical behavior to AFP in a two concentration ranges: 0.01-10.0 and 10.0-200.0 ng/mL with a relatively low detection limit of 0.04 ng/mL at three times the background noise. Moreover, the selectivity, repeatability and stability of the proposed immunosensor were acceptable.
authors.affiliation: Key Laboratory on Luminescence and Real-Time Analysis, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Xiao-Qi
authors.initials: XQ
authors.lastname: Ran
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Ya-Qin
authors.initials: YQ
authors.lastname: Chai
authors.forename: Cheng-Lin
authors.initials: CL
authors.lastname: Hong
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Qian
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002021:Buffers; D002138:Calibration; D002244:Carbon / Q000737:chemistry; D002417:Cattle; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010640:Phenothiazines / Q000737:chemistry; D015203:Reproducibility of Results; D012996:Solutions; D013696:Temperature; D013997:Time Factors; D000509:alpha-Fetoproteins / Q000276:immunology*
chemical_list: D002021:Buffers; D037742:Nanotubes, Carbon; D010640:Phenothiazines; D012996:Solutions; D000509:alpha-Fetoproteins; D002244:Carbon; D006046:Gold; D004247:DNA; C427203:calf thymus DNA; C009469:thionine