Scheme 2. Description of the IgA2-Loaded Nanoparticles and the Release Protocol Used in This Study^a.

^a The porous Si nanoparticles are loaded with the antibody via a vacuum infiltration procedure (left panel, top), which yields a mass loading of ~29%. The control involves a pure Eudragit enteric polymer bead containing IgA2 (left panel, middle). To prepare nanoparticles individually coated with the enteric polymer (left panel, bottom), the IgA2-loaded pSi nanoparticles are dispersed in a methanol solution of the Eudragit polymer and quickly added acidic aqueous solution of PVA (1 wt %) with rapid stirring to induce deposition of the coating. The drug release protocol is carried out over a total period of 5 h; for the first 2 h, the samples are incubated in SGF at pH 1.2 (right panel, red backdrop) followed by either FasSIF (pH 6.8) for the formulations using Eudragit L100 and Eudragit L30 D-55 or PBS (pH 7.4) for the formulations using Eudragit S100 (right panel, green backdrop).