title: Electrochemical molecular beacon biosensor for sequence-specific recognition of double-stranded DNA.
abstract: Direct recognition of double-stranded DNA (dsDNA) was crucial to disease diagnosis and gene therapy, because DNA in its natural state is double stranded. Here, a novel sensor for the sequence-specific recognition of dsDNA was developed based on the structure change of ferrocene (Fc) redox probe modified molecular beacon (MB). For constructing such a sensor, gold nanoparticles (AuNPs) were initially electrochemical-deposited onto glass carbon electrode (GCE) surface to immobilize thiolated MB in their folded states with Au-S bond. Hybridization of MB with target dsDNA induced the formation of parallel triplex DNA and opened the stem-loop structure of it, which resulted in the redox probe (Fc) away from the electrode and triggered the decrease of current signals. Under optimal conditions, dsDNA detection could be realized in the range from 350 pM to 25 nM, with a detection limit of 275 pM. Moreover, the proposed method has good sequence-specificity for target dsDNA compared with single base pair mismatch and two base pairs mismatches.
authors.affiliation: School of Life Science, Jiangsu Normal University, Xuzhou 221116, PR China. Electronic address: mxm0107@jsnu.edu.cn.
authors.forename: Xiangmin
authors.initials: X
authors.lastname: Miao
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Guo
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Xiao
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address: cesllsh@mail.sysu.edu.cn.
authors.forename: Liansheng
authors.initials: L
authors.lastname: Ling
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D000075163:Metallocenes; D009693:Nucleic Acid Hybridization
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; C051802:triplex DNA; D006046:Gold; D004247:DNA; C004998:ferrocene
keywords: Double-stranded DNA; Electrochemical sensor; Gold nanoparticles; Molecular beacon