“…Polyelectrolyte assembly is conducted on a sacrificial template core that easily decomposes in basic or acid media without affecting the polyelectrolyte capsule. The core can be fabricated from carbonates (CaCO 3 , CdCO 3 , MnCO 3 ) or oxides (SiO 2 , TiO 2 ) [25][26][27]. The core can incorporate various materials (drugs, peptides, genes, or proteins) by preloading methods or can be dissolved once the capsules are fabricated, making room for drugs, peptides, genes, or proteins in so-called post-loading methods [28][29][30][31].…”