Targeting and manipulation of a specific organelle such as mitochondria, ribosomes, or centrioles with magnetic nanoparticles (MNPs) may promote understanding of the effects of localized distribution and movement of the organelle on cell health, function, and behavior. However, MNPs are usually endocytosed by cells and are therefore surrounded by an endosomal membrane, which prevents the MNPs from targeting other organelles (<b>Fig. 1a</b>). Here, we use a cell membrane fusogenic liposome to deliver MNPs into cytosol bypassing endocytosis (<b>Fig. 1b</b>). MNPs were coated with fusogenic liposome and then added to cells for 10 minutes. We tested 5 lipid-to-MNP ratios for coating and found a weight ratio of 0.28 was optimal for MNP delivery efficiency. Confocal microscope images showed approximately 30%, 50%, and 70% of MNPs were freed from the liposome at 0, 4, and 24 hours after liposome-coated MNP treatment. Over 80% of MNPs were separated from early endosomes at all time points, and transmission electron microscopy showed the absence of membrane structures surrounding MNPs in the cytosol, together indicating success in bypassing endocytosis. Almost 60% of the delivered MNPs colocalized with lysosomes. MNPs in cells could be moved with an external magnet. Future work will target delivered MNPS to mitochondria and control their movement and distribution within cells, to facilitate examining the effects of mitochondrial localization on cellular phenotypes.

Liposome-aided direct delivery of magnetic nanoparticles into cytosol

ACS Spring Meeting 2021

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