ACE2 and acidosis disorder: These results show that ACE2 expression was induced by acidic‐related pH conditions and attenuated by CaCO3‐NPs, which not only uncovers the mechanism by which acidic pH promotes SARS‐CoV‐2 infection but also suggests that CaCO3‐NPs are a potential antidote to prevent SARS‐CoV‐2 infection in acidosis patients (Figure 4G).