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Nanostraw‐Assisted Cellular Injection of Fluorescent Nanodiamonds via Direct Membrane Opening
Author(s) -
Hebisch Elke,
Hjort Martin,
Volpati Diogo,
Prinz Christelle N.
Publication year - 2021
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202006421
Subject(s) - sted microscopy , cytosol , endocytosis , electroporation , internalization , biophysics , endosome , membrane , fluorescence , cell membrane , fluorescence microscope , cell , microbiology and biotechnology , nanotechnology , chemistry , materials science , biology , laser , biochemistry , stimulated emission , physics , quantum mechanics , gene , optics , enzyme
Due to their stable fluorescence, biocompatibility, and amenability to functionalization, fluorescent nanodiamonds (FND) are promising materials for long term cell labeling and tracking. However, transporting them to the cytosol remains a major challenge, due to low internalization efficiencies and endosomal entrapment. Here, nanostraws in combination with low voltage electroporation pulses are used to achieve direct delivery of FND to the cytosol. The nanostraw delivery leads to efficient and rapid FND transport into cells compared to when incubating cells in a FND‐containing medium. Moreover, whereas all internalized FND delivered by incubation end up in lysosomes, a significantly larger proportion of nanostraw‐injected FND are in the cytosol, which opens up for using FND as cellular probes. Furthermore, in order to answer the long‐standing question in the field of nano‐biology regarding the state of the cell membrane on hollow nanostructures, live cell stimulated emission depletion (STED) microscopy is performed to image directly the state of the membrane on nanostraws. The time‐lapse STED images reveal that the cell membrane opens entirely on top of nanostraws upon application of gentle electrical pulses, which supports the hypothesis that many FND are delivered directly to the cytosol, avoiding endocytosis and lysosomal entrapment.