title: Micro- and nano-tubules built from loosely and tightly rolled up thin sheets.
abstract: Tubular structures built from amphiphilic molecules are of interest for nano-sensing, drug delivery, and structuring of oils. In this study, we characterized the tubules built in aqueous suspensions of a cholesteryl nucleoside conjugate, cholesterylaminouridine (CholAU) and phosphatidylcholines (PCs). In mixtures with unsaturated PCs having chain lengths comparable to the length of CholAU, two different types of tubular structures were observed; nano- and micro-tubules had average diameters in the ranges 50-300 nm and 2-3 μm, respectively. Using cryo scanning electron microscopy (cryo-SEM) we found that nano- and micro-tubules differed in their morphology: the nano-tubules were densely packed, whereas micro-tubules consisted of loosely rolled undulated lamellas. Atomic force microscopy (AFM) revealed that the nano-tubules were built from 4 to 5 nm thick CholAU-rich bilayers, which were in the crystalline state. Solid-state (2)H NMR spectroscopy also confirmed that about 25% of the total CholAU, being about the fraction of CholAU composing the tubules, formed the rigid crystalline phase. We found that CholAU/PC tubules can be functionalized by molecules inserted into lipid bilayers and fluorescently labeled PCs and lipophilic nucleic acids inserted spontaneously into the outer layer of the tubules. The tubular structures could be loaded and cross-linked, e.g. by DNA hybrids, and, therefore, are of interest for further development, e.g. as a depot scaffold for tissue regeneration.
authors.affiliation: Molecular Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany. arbuzova@cms.hu-berlin.de.
authors.forename: Luisa
authors.initials: L
authors.lastname: Losensky
authors.affiliation: Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Goldenbogen
authors.affiliation: Robert Koch Institute, ZBS 4, Seestr. 10, 13353 Berlin, Germany.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Holland
authors.affiliation: Robert Koch Institute, ZBS 4, Seestr. 10, 13353 Berlin, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Laue
authors.affiliation: National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
authors.forename: Anca
authors.initials: A
authors.lastname: Petran
authors.affiliation: National Institute of Research and Development for Isotopic and Molecular Technologies, Donat 67-103, RO-400293 Cluj-Napoca, Romania.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Liebscher
authors.affiliation: Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany.
authors.forename: Holger A
authors.initials: HA
authors.lastname: Scheidt
authors.affiliation: Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vogel
authors.affiliation: Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04107 Leipzig, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Huster
authors.affiliation: Theoretical Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.
authors.forename: Edda
authors.initials: E
authors.lastname: Klipp
authors.affiliation: Molecular Biophysics, Institute of Biology, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany. arbuzova@cms.hu-berlin.de.
authors.forename: Anna
authors.initials: A
authors.lastname: Arbuzova
mesh_terms: D002784:Cholesterol / Q000031:analogs & derivatives* / Q000737:chemistry; D020285:Cryoelectron Microscopy; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry*; D013499:Surface Properties; D054457:Tissue Scaffolds / Q000737:chemistry; D014529:Uridine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D010713:Phosphatidylcholines; C000610645:cholesterylaminouridine; D002784:Cholesterol; D014529:Uridine