Fig. 1.

Application of silica nanocapsules as fipronil nanocarriers against termite colonies in field. (1) Production of D4S2 protein in microbial cell factories. (2) Synthesis of silica nanocapsules (SNC) and poly(ethyleneimine) (PEI)-coated silica nanocapsules (SNC-PEI) using the D4S2 protein-stabilized nanoemulsions as the template. (3) Hypothetical schemes of worker termites foraging the bait toxicants, then relocating the baits into and distributing them to other termite castes (e.g., queen, king, soldiers, etc.) inside the mound. The sustained release properties of silica nanocapsules would provide sufficient time for bait distribution, hence, colony elimination. Note: the red dotted lines illustrate the movement of worker termites, and the arrow illustrates their moving direction.