Novel Colorimetric Aptasensor for Zearalenone Detection Based on Nontarget-Induced Aptamer Walker, Gold Nanoparticles, and Exonuclease-Assisted Recycling Amplification

Abstract

Zearalenone (ZEN) toxicity is a significant risk for human beings. Thus, it is of high importance to develop sensitive, precise, and inexpensive analytical methods for ZEN detection, especially in human serum. Here, a colorimetric aptasensor is presented for the determination of ZEN based on the nontarget-induced aptamer walker, catalytic reaction of gold nanoparticles (AuNPs), exonuclease III (Exo III) as a signal amplifier, and 4-nitrophenol as a colorimetric agent. Low amount of ZEN requirement and signal amplification are some of the distinct advantages of the proposed aptasensor. In the absence of ZEN, the aptamer (Apt) starts walking on the AuNP surface with the help of Exo III and binds to multiple complementary strands of aptamer, leading to the change of sample color from yellow to colorless. Upon the addition of ZEN, both the Apt and complementary strand exist as single-stranded DNAs on the surface of AuNPs, resulting in less access of 4-nitrophenol to the surface of AuNPs and less catalytic performance of AuNPs. In this situation, the color of the sample remains yellow (the color of 4-nitrophenol). The presented aptasensor was capable to detect ZEN in a wide linear dynamic range, 20-80 000 ng/L, with a detection limit of 10 ng/L. The prepared sensing strategy was successfully used for ZEN determination in the human serum sample.

Gold Nanoparticle-Based Colorimetric Strategies for Chemical and Biological Sensing Applications

“…Similar approaches based on the conversion of 4-nitrophenol to 4-aminophenol had been reported for the detection of other protein targets [144,145,146]. Last year, Taghdisi et al developed the amplified colorimetric aptasensor for zearalenone based on the exonuclease-aided aptamer walker and the catalytic AuNPs [147]. Without targets, the aptamer bound to complementary strands of aptamer on the AuNP surface and complementary strands would be degraded by the introduction of exonuclease, which led to the unmasking of the AuNP surface.…”

“…The representation of the detection of zearalenone based on the exonuclease III-aided aptamer walker and catalytic reaction of AuNPs. Reproduced with permission from Reference [147]. American Chemical Society, 2018.…”

Regulation Mechanism of ssDNA Aptamer in Nanozymes and Application of Nanozyme-Based Aptasensors in Food Safety

“…By validating in spiked samples, the aptasensor demonstrated high sensitivity, with LODs of 1.3, 2.6, and 3.2 nM in spiked water, serum, and milk samples, respectively, with 1 h analysis time. Subsequently, a colorimetric aptasensor for zearalenone detection was developed by integrating nontarget-induced aptamer walker, the peroxidase-like activity of AuNPs, and exonuclease-assisted recycling amplification [ 83 ]. As shown in Figure 2 D, both aptamers and the complementary strands were modified on the surface of AuNPs and hybridized with each other to form dsDNA between a portion of aptamer nucleotides and the complementary strand.…”

“…( D ) A colorimetric aptasensor for zearalenone detection based on Exo III-assisted aptamer walker and catalytic reaction of AuNPs. Reprinted with permission from reference [ 83 ]. Copyright 2018 American Chemical Society.…”

Progress on Structured Biosensors for Monitoring Aflatoxin B1 From Biofilms: A Review

“…When the targets are added, the colorimetric aptasensors can convert the target signal into a color change. To improve the sensitivity, the signal amplification strategy has been employed in increasingly more widespread applications in colorimetric biosensors for detecting low analyte concentrations (Taghdisi et al, 2018;Li C. et al, 2019). In the colorimetric aptasensor system, noble metal nanoparticles are usually applied as signal indicators due to their ability to change color when changing from a dispersion state to an aggregation state (Danesh et al, 2018;Zhang et al, 2018).…”