Search

In this work, a dual-signal ratiometric electrochemical aptasensor based on the hybrid chain reaction (HCR) and streptavidin-modified magnetic beads (SA-MBs) was developed to rapidly detect zearalenone (ZEN). The HCR, as a powerful signal amplification technique to imporve the signal of sonser. When the target is present, they specifically bind with ZEN-Apt and release ZEN-cDNA to trigger HCR. Simultaneously, more double-stranded DNA causes the signal of Thi to be blocked. As a result, the two signals tend to change in the opposite direction as the ZEN concentration changes. Additionally, the peak current ratio of I Thi /I Fc showed a positive correlation with the ZEN concentration. Under optimal conditions, the constructed biosensor showed an excellent linear detection range (1.0 × 10−10 mol/L to 1.0 × 10−6 mol/L), a low detection limit (4.4 × 10−11 mol/L) and high specificity for ZEN. In addition, the detection method retains the characteristics of low cost and rapid detection of electrochemical detection, while improving the detection limit and detection accuracy via SA-MBs and internal reference signal. This provides a new idea for the practical detection of ZEN. • The dual-signal ratiometric biosensor owns higher detection accuracy. • MoS 2 -Thi is used as the second signal to provide internal parameter comparison. • Synergistic effect of magnetic bead and HCR achieve the signal amplification. • This approach was desirable regarding to sensitivity, detection limit and range. [ABSTRACT FROM AUTHOR]

• Hybridization chain reaction is used to induce the swelling of PhCs-DNA hydrogel. • Optical signal of the hydrogel is regulated by the concentration of hairpin DNAs. • The visual, highly selective, and sensitive analysis of AFB1 has been achieved. • The sensor allows the analysis of AFB1 with only a laser pointer and a ruler. Herein, we have introduced hybridization chain reaction (HCR) into the photonic crystals (PhCs) hydrogel, for the first time, realizing HCR for inducing the change of the optical signal of PhCs hydrogel and using this hydrogel as a sensor for determination of the aflatoxin B1 (AFB1). By using specific sequences as the cross-linker, the extension of the cross-linker by HCR drives the swelling of the hydrogel, and the optical property of 2D PhCs array converts this swelling into a change of the Debye diffraction ring. Moreover, by further selecting the aptamer to construct the cross-linker, the hydrogel is also endowed with a unique capability for AFB1, making the hydrogel a novel sensor based on the signal amplification strategy. The results show that the designed hairpin DNAs can effectively trigger the HCR and cause the swelling of hydrogel, and the hydrogel sensor has a good determination performance and high specific recognition for AFB1. [ABSTRACT FROM AUTHOR]