title: Cellular Uptake of Tile-Assembled DNA Nanotubes.
abstract: DNA-based nanostructures have received great attention as molecular vehicles for cellular delivery of biomolecules and cancer drugs. Here, we report on the cellular uptake of tubule-like DNA tile-assembled nanostructures 27 nm in length and 8 nm in diameter that carry siRNA molecules, folic acid and fluorescent dyes. In our observations, the DNA structures are delivered to the endosome and do not reach the cytosol of theGFP-expressing HeLa cells that were used in the experiments. Consistent with this observation, no elevated silencing of theGFPgene could be detected. Furthermore, the presence of up to six molecules of folic acid on the carrier surface did not alter the uptake behavior and gene silencing. We further observed several challenges that have to be considered when performingin vitroandin vivoexperiments with DNA structures: (i) DNA tile tubes consisting of 42 nt-long oligonucleotides and carrying single- or double-stranded extensions degrade within one hour in cell medium at 37 °C, while the same tubes without extensions are stable for up to eight hours. The degradation is caused mainly by the low concentration of divalent ions in the media. The lifetime in cell medium can be increased drastically by employing DNA tiles that are 84 nt long. (ii) Dyes may get cleaved from the oligonucleotides and then accumulate inside the cell close to the mitochondria, which can lead to misinterpretation of data generated by flow cytometry and fluorescence microscopy. (iii) Single-stranded DNA carrying fluorescent dyes are internalized at similar levels as the DNA tile-assembled tubes used here.
authors.affiliation: Faculty of Physics and Center for Nanoscience, Ludwig-Maximilians University, Munich 80799, Germany. samet.kocabey@physik.lmu.de.
authors.forename: Samet
authors.initials: S
authors.lastname: Kocabey
authors.affiliation: Division of Clinical Pharmacology, Department of Internal Medicine IV, Klinikum der Universität München, Munich 80336, Germany. hanna.meinl@outlook.com.
authors.forename: Hanna
authors.initials: H
authors.lastname: Meinl
authors.affiliation: Faculty of Physics and Center for Nanoscience, Ludwig-Maximilians University, Munich 80799, Germany. iainmacpherson@gmail.com.
authors.forename: Iain S
authors.initials: IS
authors.lastname: MacPherson
authors.affiliation: Baseclick GmbH, Tutzing 82327, Germany. v.cassinelli@baseclick.eu.
authors.forename: Valentina
authors.initials: V
authors.lastname: Cassinelli
authors.affiliation: Baseclick GmbH, Tutzing 82327, Germany. a.manetto@baseclick.eu.
authors.forename: Antonio
authors.initials: A
authors.lastname: Manetto
authors.affiliation: Division of Clinical Pharmacology, Department of Internal Medicine IV, Klinikum der Universität München, Munich 80336, Germany. simon.rothenfusser@med.uni-muenchen.de.
authors.forename: Simon
authors.initials: S
authors.lastname: Rothenfusser
authors.affiliation: Faculty of Physics and Center for Nanoscience, Ludwig-Maximilians University, Munich 80799, Germany. tim.liedl@physik.lmu.de.
authors.forename: Tim
authors.initials: T
authors.lastname: Liedl
authors.affiliation: Division of Clinical Pharmacology, Department of Internal Medicine IV, Klinikum der Universität München, Munich 80336, Germany. felix.lichtenegger@med.uni-muenchen.de.|Department of Internal Medicine III, Klinikum der Universität München, Munich 81377, Germany. felix.lichtenegger@med.uni-muenchen.de.
authors.forename: Felix S
authors.initials: FS
authors.lastname: Lichtenegger
keywords: DNA nanotechnology; DNA tile; cation; folate; siRNA delivery; stability