An aptamer-based fluorometric zearalenone assay using a lighting-up silver nanocluster probe and catalyzed by a hairpin assembly
An enzyme-free fluorometric assay is described for the determination of zearalenone (ZEN). The method combines (a) catalyzed hairpin assembly (CHA), (b) ultrahigh fluorescent light-up G-rich DNA sequences in proximity to silver nanoclusters (Ag NCs), and (c) the use of aptamers (Apt). In the presence of ZEN, the inhibit sequence (Inh) is released from the aptamer-trigger sequence (Apt-T) via the binding of ZEN and the aptamer of Apt-T. The free Apt-T acts as a switch that opens the hairpins H1 and H2 to generate H1-H2 complex. The released Apt-T is available to trigger the next round of CHA between H1 and H2. Finally, the hybridization between H1 and the Ag NCs probe (P) causes the G-rich sequence to be in close proximity to the dark Ag NCs encapsulated by P. This leads to highly efficient lighting up of the Ag NCs and the production of amplified fluorescence with excitation/emission peaks at 575/628 nm. Under the optimized conditions, a linear correlation was observed with concentrations ranging from 1.3 pg mL−1 to 100 ng mL−1, and the limit of detection was 0.32 pg mL−1 (at S/N = 3). The method was successfully validated by analyzing maize and beer for levels of ZEN after a simple sample preparation procedure.
KeywordsFungaltoxin Catalyzed hairpin assembly Guanine-rich DNA Fluorescence Template Nanoprobe Wide analytical range Beer analysis Maize analysis
This work was supported by the National Key Research and Development Program of China (No.2017YFC1200903, No.2017YFC1200905), the National Natural Science Foundation of China (No.81773482), the National Key R&D Program of China (grant number 2018YFC1602500) and the Key Research and Development Program of Tianjin (No.18YFZCNC01260).
Compliance with ethical standards
Conflict of interest
The authors declare no competing financial interest.
- 6.Sun Y, Hu X, Zhang Y, Yang J, Wang F, Wang Y, Deng R, Zhang G (2014) Development of an immunochromatographic strip test for the rapid detection of zearalenone in corn. J Agric Food Chem 62:16–21Google Scholar
- 11.Wang YK, Zou Q, Sun JH, Wang HA, Sun X, Chen ZF, Yan YX (2015) Screening of single-stranded DNA (ssDNA) aptamers against a zearalenone monoclonal antibody and development of a ssDNA-based enzyme-linked oligonucleotide assay for determination of zearalenone in corn. J Agric Food Chem 63:36–41Google Scholar
- 13.Xu W, Qing Y, Chen S, Chen J, Qin Z, Qiu J, Li C (2017) Electrochemical indirect competitive immunoassay for ultrasensitive detection of zearalenone based on a glassy carbon electrode modified with carboxylated multi-walled carbon nanotubes and chitosan. Microchim Acta 184:3339–3347CrossRefGoogle Scholar
- 17.Chen J, Ji X, Tinnefeld P, He Z (2016) Multifunctional dumbbell-shaped DNA-Templated selective formation of fluorescent silver Nanoclusters or copper nanoparticles for sensitive detection of biomolecules. ACS Appl Mater Interfaces 8:86–94Google Scholar
- 26.Wang Y, Gan N, Zhou Y, Li TH, Hu FT, Cao YT, Chen YJ (2017) Novel label-free and high-throughput microchip electrophoresis platform for multiplex antibiotic residues detection based on aptamer probes and target catalyzed hairpin assembly for signal amplification. Biosens Bioelectron 97:100–106CrossRefGoogle Scholar
- 28.Zhang P, Liu H, Li XC, Ma SZ, Men S, Wei H, Cui JJ, Wang HN (2017) A label-free fluorescent direct detection of live Salmonella typhimurium using cascade triple trigger sequences-regenerated strand displacement amplification and hairpin template-generated-scaffolded silver nanoclusters. Biosens Bioelectron 87:1044–1049CrossRefGoogle Scholar