Fig. 5

Effects of nanoparticles on the neutralization of extracellular pseudo virus. The nanoparticle preparations were incubated with pseudotyped SARS-CoV-2 lentivirus expressing green fluorescent protein (GFP) at 37 °C for 1 h. The mixtures were then added to (A) ACE2-expressing H1975 cells (H1975-ACE2), (B) 293T cells (293T-ACE2), or (C) BEAS-2B cells (BEAS-2B-ACE2). Assay for viral infection was done by detecting the GFP-expressing cells as described in the Materials and Methods. The overexpression of ACE2 in H1975-ACE2 cells, 293T-ACE2 cells, and BEAS-2B-ACE2 cells was determined by Western blot and shown in the left panels. The expression of GFP was evaluated using microscopy. BF, bright field. The percent inhibition (%) was calculated as 1-(GFP signal in the presence of nanoparticles)/(GFP signal in the absence of nanoparticles) × 100. Data points represent the mean of three independent experiments ± SD. *p < 0.05 and ***p < 0.001. Scale bar = 200 μm