Fig. 3.

Storage formulation of hACE2-containing NCs. (A) Size and zeta potential of freshly prepared solution (FS) of NCs and reconstituted solution (RS) of lyophilized NCs and NC–HA with different cryoprotectants. (B) SARS-CoV-2 pseudovirus neutralization efficiency of freshly prepared NCs, reconstituted NC-HA, and NC–cryoprotectant (equivalent NCs concentration, 10 μg/mL). (C) Neutralization ability remained of NC solution and lyophilized NC–HA–sucrose powder stored at 4 °C for 30 d. (D) Photos of lyophilized powder, reconstituted solution, and inhalable spray. (E) Scheme illustrating the usage of hACE2 NC–containing powder. All data are presented as mean ± SEM (n = 3). The data are analyzed by Tukey’s multiple comparisons test. ns, *, **, and *** indicate no statistical difference, P < 0.05, P < 0.01, and P < 0.001, respectively.