Nanostraw‐Assisted Cellular Injection of Fluorescent Nanodiamonds via Direct Membrane Opening. Issue 7 (27th January 2021)

• Record Type: Journal Article
• Authors: Hebisch, Elke; Hjort, Martin; Volpati, Diogo; Prinz, Christelle N.
• Is Part Of: Small. Volume 17:Issue 7(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-27
• Subjects: cell transfection -- electroporation -- nanodiamonds -- nanostraws -- STED microscopy; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202006421
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: 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. Abstract : Nanostraws and gentle electrical pulses are used to inject nanodiamonds into living cells. This method results in five times more nanodiamonds reaching the cytosol and avoiding lysosomal entrapment, compared to when incubating cells with nanodiamonds. Live‐cell STED imaging reveals that the membrane opens entirely on top of the nanostraws, which allows for injection of large cargo directly to the cytosol.