β-Cyclodextrin Polymer-Based Host–Guest Interaction and Fluorescence Enhancement of Pyrene for Sensitive Isocarbophos Detection

Abstract

The extensive use of organophosphorus pesticides in agriculture poses a high risk to human health and has boosted the demands for developing sensitive monitoring methods. Herein, we developed a facile and sensitive method for isocarbophos detection based on the remarkable fluorescence enhancement of pyrene during host–guest interaction of β-cyclodextrin polymer (β-CDP) and pyrene. The 3′-pyrene-labeled isocarbophos aptamer could be cleaved by exonuclease I to obtain free pyrene that was tagged on mononucleotides, which could enter the hydrophobic cavity of β-CDP, resulting in a prominent fluorescence enhancement. While the target isocarbophos was added, aptamer could undergo a conformational change into a hairpin complex, which prevented the cleavage and host–guest interaction because of the steric hindrance, leading to a weak fluorescence. The isocarbophos has been sensitively and selectively analyzed by detecting the system fluorescence intensity with a detection limit as low as 1.2 μg/L. In addition, we have verified the ability of our proposed method in real sample detection from fruit extract.

Multifunctional Alternating “Bitter-Sweet” Macromolecular Architecture

“…We further checked the Con A-binding ability of IC10 and found a higher recognition ability compared to its un-complexed polymer P5GC10 (Figure E). More interestingly, the Con A-bound IC10 shows a much higher autofluorescence than that of P5GC10 (Figure F), likely due to a synergistic influence of the host–guest association in the presence of protein, as reported with host–guest interactions in other luminescent polymers. , Besides, the TEM images of Con A-bound IC10 showed higher order unorganized aggregates formation (Figure G), likely due to a different mechanism of protein interactions, which requires further detailed analysis.…”

β-Cyclodextrin Polymer-Based Fluorescence Enhancement Strategy via Host–Guest Interaction for Sensitive Assay of SARS-CoV-2

“…Its high sensitivity was attributed to the outstanding fluorescence enhancement ability of β-CDP. In addition, β-CDP that we used in this work was a little electronegative [ 24 ]. The mutually repulsive force between the negatively charged aptamer and β-CDP could guarantee the low background; thus, it was also conducive to the high sensitivity.…”

“…Cyclodextrin polymer that constitutes monomer cyclodextrin through polymerization, graft copolymerization, or molecular cross-linking not only retains the characteristics of highly specific host–guest recognition of monomer cyclodextrin but also exhibits some advantages [ 23 ]. Our previous work proved that compared to cyclodextrin monomer, β-CDP holds a stronger fluorescence enhancement effect to pyrene besides retention of the highly specific host–guest identification characteristics [ 24 , 25 ]. Figure 1 showed that N protein aptamer modified by the fluorophore pyrene at its 3′-terminal could be hydrolyzed by exonuclease I (Exo I) to produce pyrene attached to a single nucleotide.…”