Coronavirus disease 2019 (COVID-19) has spread rapidly and led to over 5 million deaths to date globally. Due to the successively emerging mutant strains, therapeutics and prevention against the causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are urgently needed. Prevention of SARS-CoV-2 infection in public and hospital areas is essential to reduce the frequency of infections. Silver nanoparticles (AgNPs) with virucidal effects have been reported. Therefore, we investigated the virucidal activity and safety of ten types of AgNPs with different surface modifications and particle sizes, in cells exposed to SARS-CoV-2 in vitro. The AgNPs could effectively inhibit the activity of SARS-CoV-2, and different surface modifications and particle sizes conferred different virucidal effects, of which 50-nm BPEI showed the strongest antiviral effect. We concluded that the efficacy of each type of AgNP type was positively correlated with the corresponding potential difference (R² = 0.82). These in vitro experimental data provide scientific support for the development of therapeutics against COVID-19, as well as a research basis for the development of broad-spectrum virucides. Given the increasing acquired resistance of pathogens against conventional chemical and antibody-based drugs, AgNPs may well be a possible solution for cutting off the route of transmission, either as an external material or a potential medicine.

Three-dimensional structured illumination microscopy (3D-SIM) doubles the spatial resolution along all dimensions and is used widely in cellular imaging. However, its temporal resolution is constrained by the need for sequential plane-by-plane movement of the sample using a piezo stage for imaging, which often increases the acquisition time to several seconds per volume. To address this limitation, we develop 3D multiplane SIM (3D-MP-SIM), which simultaneously detects multiplane images and reconstructs them using synergistically evolved reconstruction algorithms. Compared with conventional 3D-SIM imaging, 3D-MP-SIM achieves an approximately eightfold increase in the temporal resolution of volumetric super-resolution imaging, with lateral and axial spatial resolutions of about 120 and 300 nm, respectively. The rapid acquisition substantially reduces motion artefacts during the imaging of dynamic structures, such as late endosomes, in live cells. Moreover, we demonstrate the capabilities of 3D-MP-SIM via high-speed time-lapse volumetric imaging of the endoplasmic reticulum at rates of up to 11 volumes per second. We also show the feasibility of dual-colour imaging by observing rapid and close interactions among intra- and intercellular organelles in 3D space. These results highlight the potential of 3D-MP-SIM for explaining dynamic behaviours and interactions at the subcellular level and in three dimensions.