## 3 Application of AIEgens in the Detection of Pesticide Residues in Fluorescence Sensors
### Detection of Pesticides by Metal-Organic Framework Sensors Based on AIEgens  
Combining AIEgens with metal-organic frameworks (MOFs) for pesticide detection can enhance selectivity and stability and enable diverse detection modes through functionalization such as fluorescence, colorimetry, and electrochemistry [89]. For example, [PERSON] et al. developed the luminescent MOF UiO-66-NH2 (A10), which effectively detects imidalcoprid (IM) and thiamethoxam (TH) by evaluating its selectivity, anti-interference capability, and fluorescence sensing mechanism (Figure 10) [76; 90]. In the presence of IM or TH, A10 forms aggregates, increasing particle sizes to 63,628.57 nm (IM) and 77,068.65 nm (TH) and altering zeta potentials to \(-\)14.39 mV (IM) and \(-\)14.31 mV (TH). The LOD for A10 are 5.57 \(\upmu\)g/L for IM and 0.98 \(\upmu\)g/L for TH. A10 also successfully detected IM and TH in real juice samples, with recoveries between 85% and 116%. This study highlights the potential of A10 for rapid and selective sensing of pesticides in environmental and food matrices. Figure 10: Structure of compound A10. (Reproduced with permission from ref. [90]. copyright 2023 Multidisciplinary Digital Publishing Institute). Figure 9: (**a**) Synthetic route of TPE-Pn; (**b**) Schematic illustration of the preparation of the dsRNA/DIN/A9 complex for enhanced co-loading of pesticides and synergistic pest control. (Reproduced with permission from ref. [28]. copyright 2023 Chinese Chemical Society). [PERSON] et al. synthesized a luminescent MOF (LMOF) in situ using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-oxidized cellulose nanofibers (TOCNF) as a template, creating TOCNF/LMOF hybrids (A11) that were fabricated into two-dimensional hybridization pads for detecting methyl-parathion (Figure 11a,b) [77; 91]. The ligand 1,2,4,5-tetrakis (4-carboxyphenyl) benzene (H4 TCPB) within the LMOF exhibits AIE properties (Figure 11c), which enhance fluorescence by restricting the rotation and vibration of the phenyl ring and inhibiting nonradiative decay pathways. This enhancement improves the interaction between the ligand and the target analyte, thus boosting the sensing capability. The detection of methyl-parathion with A11 relies on the interaction between the ligand and the pesticide, leading to fluorescence quenching through charge transfer (Figure 11d,e). This approach enables quantitative detection of pesticides through changes in fluorescence intensity and offers a practical and sustainable platform for AIEgens-based pesticide sensing using MOFs. [PERSON] et al. developed a highly luminescent nanocomposite, GSH-AuNCs@ZIF-8 (A12), by embedding glutathione-protected gold nanoclusters (GSH-AuNCs) within a MOF (ZIF-8) (Figure 12a) [78]. A12 demonstrates sensitive detection capabilities for Cu\({}^{2+}\) and OPs. The confinement effect of ZIF-8 enhances the stability of GSH-Au NCs and amplifies the AIE effect by restricting their intramolecular motion, significantly improving fluorescence performance. The detection mechanism involves a fluorescence quenching upon binding of A12 to Cu\({}^{2+}\). However, TCh can coordinate with Cu\({}^{2+}\) through sulfhydryl groups, restoring the fluorescence in the Cu\({}^{2+}\) + A12 system. OPs inhibit AChE activity, reducing TCh production and preventing fluorescence recovery, which allows for the detection of OPs (Figure 12b). As shown in Figure 12c, there is a strong linear relationship  
Figure 11: (**a**) Illustration of the porous channel of the LMOF; (**b**) Visual appearance of TOCNF and A11, including three hybrid pads (A11-1, A11-2, and A11-3) under white and UV light; (**c**) Molecular structure of the H4 TCPB ligand; (**d**) Illustration of quenching and photographs showing A11 responses at concentrations of 0, 0.2, 1, 2, and 5 mg/L under white and UV light; (**e**) Schematic representation of the sensing mechanism for methyl parathion using A11. (Reproduced with permission from ref. [77]. copyright 2024 Elsevier).