## 3 Application of AIEgens in the Detection of Pesticide Residues in Fluorescence Sensors
### Detection of Pesticides by Supramolecular Assemblies Based on AIEgens  
Supramolecular assemblies of AIEgens offer advantages for pesticide detection, including high sensitivity, strong specificity, rapid response, and simple operation [92]. These sensors primarily detect pesticides based on the interaction between supramolecular assemblies of AIEgens and pesticide molecules. When pesticide molecules interact with these assemblies, they specifically bind to the AIEgens, causing a change in fluorescence signal. This fluorescence change can be used to detect the presence and concentration of pesticides. Figure 12: (**a**) Schematic diagram of the synthesis of A12; (**b**) Schematic representation of OP detection based on the Cu\({}^{2+}\) +A12 system; (**c**) Fluorescence images demonstrating detection with hydrogel A12 upon the addition of different concentrations of Cu\({}^{2+}\) (0–5 uM) and glyphosate (0–100 nM) under 300 nm UV light; RGB analysis of the fluorescent images was performed using a color recognizer app on a smartphone. (Reproduced with permission from ref. [78]. copyright 2023 Elsevier). For example, [PERSON] et al. designed and synthesized an esterase-activated AIE and ESIPT probe (A13), suitable for the sensitive ratio detection of carbaryl (Figure 13a) [79]. This probe functions as a supramolecular system where kaempfer tetraacetate interacts with esterase, resulting in fluorescence changes through supramolecular interactions. The acetate group in A13 acts as the esterase reaction site and initiates AIE + ESIPT. Esterase specifically hydrolyzes A13 into kaempfer, which exhibits AIE + ESIPT properties. Carbaryl inhibits esterase activity, reducing the generation of kaempfer, and thus enabling the ratio detection of carbaryl by measuring the fluorescence emission decrease at 415 nm and the ESIPT emission increase at 530 nm (Figure 13b,c). A13 has also been successfully used in real sample detection, presenting a new approach for constructing robust pesticide detection systems. [PERSON] et al. developed a novel supramolecular AIE fluorescent probe, LIQ-TPA-TZ@HSA (A14), for real-time detection of fipronil (FPN) (Figure 14a) [80]. A14 is created by embedding the AIE-active fluorescent compound LIQ-TPA-TZ into the binding pocket of serum albumin (HSA). Upon exposure to FPN, LIQ-TPA-TZ is released into the solution, causing fluorescence changes that facilitate detection. The AIE and intramolecular charge transfer properties of LIQ-TPA-TZ enhance the sensitivity of A14, enabling effective colorimetric analysis of FPN. Additionally, A14 can be applied to portable paper test strips for quick and convenient colorimetric determination of FPN by visual inspection (Figure 14b), offering a practical platform for pesticide detection using supramolecular fluorescent probes. [PERSON] et al. designed and synthesized a tetraphenyl ethylene derivative, TPE-4P (A15), functionalized with four pillar[5]arenes as a fluorescent chemical sensor for paraquat detection (Figure 15a) [81]. The pillar[5]arenes in A15 serve as recognition units for capturing paraquat molecules. When paraquat forms a host-guest complex with the pillar[5]arenes, the energy of the excited TPE molecules is dissipated as light radiation, resulting in strong fluorescence emission and allowing for the quantitative detection of paraquat. Additionally, the A15 solution was used to create a test paper that simplifies paraquat detection, demonstrating the excellent potential for practical applications (Figure 15b). The successful  
Figure 13: (**a**) Structure of compound A13; (**b**) Fluorescence spectra of kaempfer tetraacetate (10.00 \(\mathrm{\SIUnitSymbolMicro mL^{-1}}\)) incubated with esterase (0.60 \(\mathrm{U}\)\(\mathrm{mL^{-1}}\)) in the presence of carbaryl (0–250 \(\mathrm{\SIUnitSymbolMicro mL^{-1}}\)) at pH 7.4, showing the linear relationship between \(\mathrm{F_{530}/F_{415}}\) and the concentration of carbaryl; (**c**) Schematic representation of the activatable AIE + ESIPT probe for ratiometric sensing of carbaryl.