New insights into the insecticidal mode of action of diatomite nanoparticles

BACKGROUND Diatomaceous earth (DE) is widely recognized as an effective physical insecticide due to its ability to dehydrate and kill insects. However, emerging evidence suggests that DE and similar artificial materials also induce nanotoxic effects, highlighting the need for a deeper understanding of its insecticidal mechanisms. RESULTS We examined the effects of DE nanoparticles (DNP) and DE microparticles (DMP) using red flour beetles ( Tribolium castaneum ) and fruit fly ( Drosophila melanogaster ) S2 cells. Our results demonstrate that while DMP primarily causes water loss, DNP induces significant cytotoxicity in insects. To uncover the cellular uptake mechanism underlying this nanotoxicity, we screened candidate pathways using chemical inhibitors in S2 cells and identified the involvement of clathrin‐dependent endocytosis in the DNP cytotoxicity. This finding was further validated through RNA interference in T. castaneum . CONCLUSION Our study elucidates the distinct mechanisms of DE insecticidal activity and establishes DNP as a natural nanoinsecticide with potential for sustainable pest management.