title: Nanoprobe-Enhanced, Split Aptamer-Based Electrochemical Sandwich Assay for Ultrasensitive Detection of Small Molecules.
abstract: It is quite challenging to improve the binding affinity of antismall molecule aptamers. We report that the binding affinity of anticocaine split aptamer pairs improved by up to 66-fold by gold nanoparticles (AuNP)-attached aptamers due to the substantially increased local concentration of aptamers and multiple and simultaneous ligand interactions. The significantly improved binding affinity enables the detection of small molecule targets with unprecedented sensitivity, as demonstrated in nanoprobe-enhanced split aptamer-based electrochemical sandwich assays (NE-SAESA). NE-SAESA replaces the traditional molecular reporter probe with AuNPs conjugated to multiple reporter probes. The increased binding affinity allowed us to use 1,000-fold lower reporter probe concentrations relative to those employed in SAESA. We show that the near-elimination of background in NE-SAESA effectively improves assay sensitivity by ∼1,000-100,000-fold for ATP and cocaine detection, relative to equivalent SAESA. With the ongoing development of new strategies for the selection of aptamers, we anticipate that our sensor platform should offer a generalizable approach for the high-sensitivity detection of diverse targets. More importantly, we believe that NE-SAESA represents a novel strategy to improve the binding affinity between a small molecule and its aptamer and potentially can be extended to other detection platforms.
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhao
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Liu
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Ding
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Juncai
authors.initials: J
authors.lastname: Zhao
authors.affiliation: ‡Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: Haixiang
authors.initials: H
authors.lastname: Yu
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Xu
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Wang
authors.affiliation: †Department of Chemistry, Capital Normal University, Xisanhuan North Road 105, Beijing 100048, China.
authors.forename: Xinhui
authors.initials: X
authors.lastname: Lou
authors.affiliation: §School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Miao
authors.initials: M
authors.lastname: He
authors.affiliation: ‡Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D003042:Cocaine / Q000032:analysis; D055664:Electrochemical Techniques; D057230:Limit of Detection; D054852:Small Molecule Libraries / Q000032:analysis*
chemical_list: D052157:Aptamers, Nucleotide; D054852:Small Molecule Libraries; D003042:Cocaine