title: A three-way junction aptasensor for lysozyme detection.
abstract: A well-designed three-way junction (TWJ) aptasensor for lysozyme detection was developed based on target-binding-induced conformational change of aptamer-complementary DNA (cDNA) as probe. A ferrocene (Fc)-tagged cDNA is partially hybridized with an anti-lysozyme aptamer to form a folded structure where there is a coaxial stacking of two helices and the third one at an acute angle. In addition, the fabrication of the sensor was achieved via the single-step method, which offered a good condition for sensing. In the absence of lysozyme, electron transfer (eT), through the coaxial two helices called "conductive path", is allowed between Fc-labeled moiety and the electrode. The binding of lysozyme to the aptamer blocks eT, leading to diminished redox signal. This aptasensor with an instinct signal attenuation factor shows a high sensitivity to lysozyme, and the response data is fitted by nonlinear least-squares to Hill equation. Detection limit is 0.2nM with a dynamic range extending to 100nM. Compared with existing electrochemical impedance spectroscopy (EIS)-based approaches, TWJ-DNA aptasensor was demonstrated to be more specific for detection and simpler for regeneration procedure.
authors.affiliation: Life and Environmental Science College, Shanghai Normal University, Guilin Road 100, Shanghai 200234, PR China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Xia
authors.forename: Siwen
authors.initials: S
authors.lastname: Gan
authors.forename: Qinghao
authors.initials: Q
authors.lastname: Xu
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Qiu
authors.forename: Peiyi
authors.initials: P
authors.lastname: Gao
authors.forename: Shasheng
authors.initials: S
authors.lastname: Huang
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D002645:Chickens; D018076:DNA, Complementary / Q000737:chemistry; D058266:Dielectric Spectroscopy / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D057230:Limit of Detection; D000075163:Metallocenes; D008958:Models, Molecular; D009113:Muramidase / Q000032:analysis*; D009690:Nucleic Acid Conformation
chemical_list: D052157:Aptamers, Nucleotide; D018076:DNA, Complementary; D005296:Ferrous Compounds; D000075163:Metallocenes; C421864:hen egg lysozyme; D009113:Muramidase; C004998:ferrocene