title: A sensitive and label-free impedimetric biosensor based on an adjunct probe.
abstract: A highly sensitive and label-free impedimetric biosensor is achieved based on an adjunct probe attached nearby the capture probe. In this work, the adjunct probe was co-assembled on the surface of gold electrode with the capture probe hybridized with the reporter probe, and then 6-mercapto-1-hexanol was employed to block the nonspecific binding sites. When target DNA was added, the adjunct probe functioned as a fixer to immobilize the element of reporter probe displaced by the target DNA sequences and made the reporter probe approach the electrode surface, leading to effective inhibition of charge transfer. The increase in charge transfer resistance is related to the quantity of the target DNA in a wide range. The linear range for target DNA with specific sequences was from 0.1 nM to 0.5 μM with a good linearity (R=0.9988) and a low detection limit of 6.3 pM. This impedimetric biosensor has the advantages of simplicity, sensitivity, good selectivity, and large dynamic range.
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
authors.forename: Xi Yuan
authors.initials: XY
authors.lastname: Zhang
authors.forename: Long Yin
authors.initials: LY
authors.lastname: Zhou
authors.forename: Hong Qun
authors.initials: HQ
authors.lastname: Luo
authors.forename: Nian Bing
authors.initials: NB
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D058266:Dielectric Spectroscopy; D004566:Electrodes; D000441:Hexanols / Q000737:chemistry; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: C503488:6-mercapto-1-hexanol; D000441:Hexanols; D015345:Oligonucleotide Probes; D013438:Sulfhydryl Compounds; D004247:DNA