Fig. 3.

Synthesis and characterization of silica nanocapsules using oil-in-water nanoemulsions as a template. (A) Fipronil-loaded nanoemulsions stabilized by D4S2 protein (i); addition of tetraethoxysilane (TEOS) formed oil-core silica-shell nanocapsules (SNC) (ii); and addition of poly(ethyleneimine) (PEI) produced PEI-coated silica nanocapsules (SNC-PEI) (iii). (B) Size distribution as measured by dynamic light scattering (DLS). (C) Changes of zeta potentials. (D) Morphology of SNC and SNC-PEI as visualized by transmission electron microscopy (TEM) (scale bars are 500 nm). The arrows are drawn as an example showing the boundary of the silica shells.