Fig. 1. (a) Scheme for the synthesis of NAs. Gold seeds are synthesized in the presence of PSS and assembled in controlled aggregates with poly(l-lysine) (PL). The aggregates are employed as templates for the formation of the silica nanocapsules. (b) Typical wide-area TEM image of NAs. Scale bar: 200 nm. Inset: zoomed-in image of one NA. (c) Size distribution of USNPs (upper) and NAs (bottom) based on at least 100 particles imaged by TEM.
