Fig. 1: Schematic and experimental design for MV@GEL as an intranasal mask to intercept viral aerosols and entrap virus.

a The intranasal mask (MV@GEL) was composed of engineered cell-derived microsized vesicles (MV) with viral receptor and thermosensitive hydrogel with positive charges. It could be sprayed into the nasal cavity at room temperature and quickly transformed from the liquid state to the gel state at body temperature. The viral receptor of vesicles could help vesicles entrap the virus, and the thermosensitive hydrogel could prolong the retention time of vesicles in the nasal cavity. Once the negative viral aerosols were inhaled, the intranasal mask could perform the protective effect in the following steps: Step 1, the positively charged hydrogel could intercept the negatively charged viral aerosols presenting in airflow; Step 2, those viral aerosols could fuse with MV@GEL and release viruses into MV@GEL; Step 3, the embedded MV in MV@GEL could entrap those released viruses. b The protective effect of the intranasal mask was investigated from the following three aspects. 1. Mouse model: MV@GEL conferred strong protection against viral aerosol infection in the mouse nose and downstream lung; 2. Digital human nasal model: based on computerized tomography (CT) images of the human nasal cavity, computational fluid dynamics (CFD) simulation supported that viral aerosols could be intercepted in the human nasal cavity under MV@GEL protection; 3. Human respiratory tract model: connecting a realistic human nasal apparatus with human lung organoids and providing respiratory airflow by the pump, the human respiratory tract model was constructed and utilized to demonstrate the good performance of MV@GEL in protecting the lung organoids from viral aerosols.