Fig. 6. Internal printing.

a–c Illustration of the internal printing of silver within a primary part printed with porous silica cages. First, a block of silica cages without additional functionalization is printed (a). The block is immersed in a solution of silver nitrate and photoinitiators. A light pattern in the shape of slabs is then projected onto this block (b), resulting in the localized reduction of Ag⁺ ions into Ag⁰ (c). d Photograph of the resulting block of silica cages exhibiting three slabs of metallic silver. Backscattered electron-based SEM image (e) and EDS map (f) of a silver slab embedded in the porous silica matrix.