title: DNA electrochemical biosensor based on thionine-graphene nanocomposite.
abstract: A novel protocol for development of DNA electrochemical biosensor based on thionine-graphene nanocomposite modified gold electrode was presented. The thionine-graphene nanocomposite layer with highly conductive property was characterized by scanning electron microscopy, transmission electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. An amino-substituted oligonucleotide probe was covalently grafted onto the surface of the thionine-graphene nanocomposite by the cross-linker glutaraldehyde. The hybridization reaction on the modified electrode was monitored by differential pulse voltammetry analysis using an electroactive intercalator daunomycin as the indicator. Under optimum conditions, the proposed biosensor exhibited high sensitivity and low detection limit for detecting complementary oligonucleotide. The complementary oligonucleotide could be quantified in a wide range of 1.0 × 10(-12) to 1.0 × 10(-7)M with a good linearity (R(2)=0.9976) and a low detection limit of 1.26 × 10(-13)M (S/N=3). In addition, the biosensor was highly selective to discriminate one-base or two-base mismatched sequences.
authors.affiliation: College of Sciences, Shanghai University, Shanghai 200444, PR China; State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Limei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: College of Sciences, Shanghai University, Shanghai 200444, PR China. Electronic address: luoliqw@yahoo.com.cn.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China. Electronic address: wangzx@ciac.jl.cn.
authors.forename: Zhenxin
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D020137:Base Pair Mismatch; D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D004247:DNA / Q000032:analysis* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D055664:Electrochemical Techniques; D006108:Graphite; D057230:Limit of Detection; D053761:Nanocomposites; D015345:Oligonucleotide Probes / Q000235:genetics; D010640:Phenothiazines; D012680:Sensitivity and Specificity
chemical_list: D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D015345:Oligonucleotide Probes; D010640:Phenothiazines; C030325:anthrax toxin; D006108:Graphite; D004247:DNA; C009469:thionine