This research aims to develop a non-invasive strategy for small interfering RNA(siRNA)nasal deliv-ery based on ionic liquids(ILs)and cationic lipid(2,3-dioleoyloxy-propyl)-trimethylammonium-chloride(DOTAP).Other than the classical role of penetration enhancer,ILs also acted as superior solvents to si-multaneously load siRNA and DOTAP,forming siRNA-DOTAP-ILs(siRNA-DILs)formulations.During nasal mucosa penetration,DOTAP and ILs components self-assembled into cationic lipid nanocomplexes to load siRNA for enhanced in situ transfection.The siRNA-DILs demonstrated resistance against RNase,significant mucosa penetration,prolonged nasal retention,and satisfying gene-silencing efficacy at lower dosage.Meanwhile,DILs were also able to deliver KCa3.1-targeted siRNA effectively for the treatment of allergic rhinitis in rat model by nasal route.Thus,DILs have great potentials to deliver biological macromolecules across nasal mucosa by in situ dynamic self-assembly.