Exo I-Based Cyclic Digestion Coupled with Synergistic Enhancement Strategy for Integrating Dual-Mode Optical Aptasensor Platform

The improvement of dual-mode techniques was of particular interest to researchers, which might enhance the detection performance and applicability. Here, a dual-mode optical aptasensor (DO-aptasensor) platform based on the exonuclease I (Exo I) cyclic digestion and synergistic enhancement strategy was proposed for zearalenone (ZEN). Following the preparation of dumbbell-shaped signal probe, the Exo I-based cyclic digestion amplification was performed, and then the synergistic enhancement effect was carried out to achieve the Poly-HRP-based colorimetry and FAM-SGI-based fluorescence. The efficient homogeneous system was realized through the magnetic separation, while the signal interference was further eliminated by the graphene oxide (GO). The LOD values were as low as 0.067 ng mL-1 for colorimetry mode and 0.009 ng mL-1 for fluorescence mode, which had reduced 23-fold and 172-fold than ELASA by same ZEN-Apt. This promising platform gave rise to a dual-mode optical readout and improved sensitivity with the positively correlated detection. Meanwhile, the proposed DO-aptasensor also exhibited the acceptable specificity, desirable reliability and excellent practicability. This novel avenue of aptasensor platform held great potential for dual-mode optical monitoring of other targets, which might further expand the application scope of the Exo I-based signal amplification and synergistic enhancement effect.