title: Enzyme-free surface plasmon resonance aptasensor for amplified detection of adenosine via target-triggering strand displacement cycle and Au nanoparticles.
abstract: Herein, we combine the advantage of aptamer technique with the amplifying effect of an enzyme-free signal-amplification and Au nanoparticles (NPs) to design a sensitive surface plasmon resonance (SPR) aptasensor for detecting small molecules. This detection system consists of aptamer, detection probe (c-DNA1) partially hybridizing to the aptamer strand, Au NPs-linked hairpin DNA (Au-H-DNA1), and thiolated hairpin DNA (H-DNA2) previously immobilized on SPR gold chip. In the absence of target, the H-DNA1 possessing hairpin structure cannot hybridize with H-DNA2 and thereby Au NPs will not be captured on the SPR gold chip surface. Upon addition of target, the detection probe c-DNA1 is forced to dissociate from the c-DNA1/aptamer duplex by the specific recognition of the target to its aptamer. The released c-DNA1 hybridizes with Au-H-DNA1 and opens the hairpin structure, which accelerate the hybridization between Au-H-DNA1 and H-DNA2, leading to the displacement of the c-DNA1 through a branch migration process. The released c-DNA1 then hybridizes with another Au-H-DNA1 probe, and the cycle starts anew, resulting in the continuous immobilization of Au-H-DNA1 probes on the SPR chip, generating a significant change of SPR signal due to the electronic coupling interaction between the localized surface plasma of the Au NPs and the surface plasma wave. With the use of adenosine as a proof-of-principle analyte, this sensing platform can detect adenosine specifically with a detection limit as low as 0.21 pM, providing a simple, sensitive and selective protocol for small target molecules detection.
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, PR China.
authors.forename: Gui-Hong
authors.initials: GH
authors.lastname: Yao
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, PR China. Electronic address: liangrp@163.com.
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Liang
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, PR China.
authors.forename: Chun-Fang
authors.initials: CF
authors.lastname: Huang
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Nanchang University, Nanchang 330031, PR China; Department of Chemical Engineering, Pingxiang College, Pingxiang 337055, PR China. Electronic address: jdqiu@ncu.edu.cn.
authors.forename: Jian-Ding
authors.initials: JD
authors.lastname: Qiu
mesh_terms: D000241:Adenosine / Q000032:analysis* / Q000097:blood; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D006046:Gold; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles; D020349:Surface Plasmon Resonance
chemical_list: D052157:Aptamers, Nucleotide; D006046:Gold; D000241:Adenosine
keywords: Aptamer; Au nanoparticles; Surface plasmon resonance; Target-triggering strand displacement cycle amplification