Nanoprobe-Enhanced, Split Aptamer-Based Electrochemical Sandwich Assay for Ultrasensitive Detection of Small Molecules

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 a...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2015-08, Vol.87 (15), p.7712-7719
Main Authors: Zhao, Tao, Liu, Ran, Ding, Xiaofan, Zhao, Juncai, Yu, Haixiang, Wang, Lei, Xu, Qing, Wang, Xuan, Lou, Xinhui, He, Miao, Xiao, Yi
Format: Article
Language:English
Subjects:
Affinity
Aptamers, Nucleotide - chemistry
Assaying
Binding
Binding sites
Bioassays
Biosensing Techniques - methods
Cocaine - analysis
Electrochemical Techniques
Equivalence
Ligands
Limit of Detection
Molecules
Nanoparticles
Nanostructure
Nanostructured materials
Platforms
Sensitivity analysis
Small Molecule Libraries - analysis
Strategy
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Summary: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.
ISSN:0003-2700
1520-6882
DOI:10.1021/acs.analchem.5b01178