Uptake of Nanoparticles as a Model System for Viruses under the Presence of Chloroquine.

In the context of fighting SARS-CoV-2 infection, chloroquine and its derivatives have been suggested as treatments. It has been argued that the therapeutic effect is based on the modulation of viral uptake and fate. Similarities to the endocytosis of nanoparticles (NPs) are used here to recapitulate the effect of chloroquine on this process. The possibilities and limits of this approach are discussed. In particular, it is demonstrated that the uptake of NPs can be diminished in the presence of toxic chloroquine concentrations. Chloroquine further reduced acidification of endosomes/lysosomes, which may interfere with the optical readout of fluorescence-labeled NPs. Furthermore, depending on the system used, chloroquine can either increase or decrease transfection upon particle-based DNA delivery.