A β-cyclodextrin-functionalized metal–organic framework enhances the insecticidal activity of indoxacarb by affecting amino acid metabolism in red imported fire ants

The invasion area of red imported fire ants (RIFAs) in China continues to expand due to factors such as ecological changes and human activities, and the resulting damage is becoming increasingly severe. The development of smart nanopesticides that respond to environmental stimuli response with precisely controlled release has great potential in improving insecticidal effects. In this work, a smart pH and α-amylase dual stimuli-responsive pesticide delivery system was constructed by combining mono-(6-amino-6-deoxy)-β-cyclodextrin (β-CD-NH2) with zeolitic imidazole skeleton-90 (ZIF-90) nanoparticles (IDC@ZIF-90-CD) loaded with indoxacarb. The average particle size of the prepared IDC@ZIF-90-CD was 249 nm, and the loading efficiency was 18.43%. The β-CD-NH2 coating on the surface of nanoparticles reduced the photodegradation of indoxacarb and prevented the premature release of the active ingredient. In vitro release kinetics showed that IDC@ZIF-90-CD rapidly released IDC under acidic and amylase conditions, consistent with the oral and intestinal environment of RIFAs. The results of bioactivity tests showed that IDC@ZIF-90-CD enhanced the toxicity of IDC toward RIFAs by increasing feeding and damaging intestinal cells. The mortality rate of the IDC@ZIF-90-CD-treated group was significantly higher than that of the IDC EC-treated group at 72 h. The nontargeted metabolomic results showed that IDC@ZIF-90-CD affected the metabolism of RIFAs by interfering with the metabolic pathways of six amino acids and one amino acid transport carrier, whereas IDC EC interfered with only two of these amino acid metabolic pathways. Overall, this work provides insight into the effective control of RIFA damage for sustainable pest management.