An amperometric aptasensor for ultrasensitive detection of sulfadimethoxine based on exonuclease-assisted target recycling and new signal tracer for amplification

The risks caused by veterinary drug residues in animal foodstuffs are of great concern to the public. Accordingly, this work reported an amperometric aptasensor for highly sensitive detection of sulfadimethoxine (SDM). Functionalised fullerene (C60)-doped graphene (C60-rGO) nanohybrid was designed a...

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Bibliographic Details
Published in:Biosensors & bioelectronics 2018-10, Vol.117, p.706-712
Main Authors: You, Huan, Bai, Lijuan, Yuan, Yonghua, Zhou, Jing, Bai, Yan, Mu, Zhaode
Format: Article
Language:English
Subjects:
Animals
Aptamers, Nucleotide
Aptasensor
Biosensing Techniques - methods
Electrochemical Techniques
Exonucleases - metabolism
Food Analysis - methods
Fullerene-doped graphene
Fullerenes - chemistry
Gold - chemistry
Graphite - chemistry
Limit of Detection
Metal Nanoparticles - chemistry
Sulfadimethoxine
Sulfadimethoxine - analysis
Target recycling
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Summary:The risks caused by veterinary drug residues in animal foodstuffs are of great concern to the public. Accordingly, this work reported an amperometric aptasensor for highly sensitive detection of sulfadimethoxine (SDM). Functionalised fullerene (C60)-doped graphene (C60-rGO) nanohybrid was designed and prepared to load electroactive toluidine blue (Tb) through the π-π stacking, forming a C60-rGO-Tb nanocomposite. Furthermore, the as-prepared nanocomposite was decorated with gold nanoparticles and used for the immobilization of signal probes to form a new signal tracer, which was coupled with exonuclease-catalyzed target recycling for amplification. To construct the aptasensor, a thiolated double-stranded DNA (dsDNA) of aptamer-capture probe complex was immobilised on a gold electrode surface through strong Au-S bond. In the presence of SDM, the aptamer preferred to form an aptamer-SDM complex, which led to the dissociation of dsDNA. Then aptamer could be selectively digested by RecJf exonuclease, resulting in liberated SDM molecules to participate in the next reaction cycling and achieve signal amplification. Then, capture probes released from the cyclic processes were hybridized with the signal tracer, which could further enhance electrochemical signal responses. On the basis of cascade signal amplification strategies, the proposed aptasensor exhibited a wide linear range from 10 fg/mL to 10 ng/mL for SDM with high sensitivity, good selectivity and satisfactory stability. •Functionalized signal tracer was used to achieve signal generation and amplification.•RecJf exonuclease-assisted targets recycling was applied for further amplification.•Aptamer-based biosensor was used for ultrasensitive detection of sulfadimethoxine.
ISSN:0956-5663
1873-4235
DOI:10.1016/j.bios.2018.06.011