PLGA-GLP-1 nanoparticles conjugated to CPP, then encapsulated with HPMC-polymer and loaded with iDPP4, which formed GLP-1/iDPP4 delivery multifunctional composite system, and the system was reported to have prolonged hypoglycemic effects in DM rats (Araujo et al., 2016). The gene discussed is GLP1R; the disease is diabetes mellitus.