“…Hence, various nanocarrier systems have been extensively investigated in oral delivery of biologics including PPs, vaccines and nucleic acids. According to materials of nanocarriers, there are primarily three categories of nanoparticles, such as polymeric, lipid-based and inorganic nanoparticles, some of which have demonstrated good delivery effect for PPs by oral routes ( Table 4 106 , 120 , 217 , 219 , 225 , 290 , 291 , 292 , 293 , 294 , 295 , 296 , 297 , 298 , 299 , 300 , 301 , 302 , 303 , 304 , 305 , 306 , 307 , 308 , 309 , 310 , 311 ).…”