title: Earliest stage of the tetrahedral nanochannel formation in cubosome particles from unilamellar nanovesicles.
abstract: Studies of nonequilibrium lipid polymorphism at the nanoscale contribute to the in-depth understanding of the structural pathways for formation of aqueous channels and emerging of channels-network ordering in liquid-crystalline (LC) nanovehicles. We present experimental structural evidence for the smallest tetrahedral-type lipid membrane aggregate, which involves completely formed nanochannels and occurs as an early intermediate state during the bilayer vesicle-to-cubosome particle transition. Nanovehicles are generated from a self-assembled lipid mixture and studied by means of high-resolution cryogenic transmission electron microscopy (cryo-TEM) and synchrotron radiation small-angle X-ray scattering (SAXS). The investigated lipid membrane composition allows for the stabilization of long-lived intermediates throughout the unilamellar vesicle-to-cubosome nanoparticle (NP) transformation at ambient temperature. The observed small cubosomic particles, with well-defined water channels, appear to be precursors of larger cubic membrane structures, thus confirming the theoretical modeling of nanochannel-network growth in diamond-type cubic lipid particles. The reported structural findings, highlighting that bilayer vesicle membrane packing and fusion are required for nanochanneled cubosome particle formation, are anticipated to advance the engineering of small lipid NPs with controllable channels for biomolecular loading and release.
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovskeho nam. 2, CZ-16206 Prague, Czech Republic.
authors.forename: Borislav
authors.initials: B
authors.lastname: Angelov
authors.forename: Angelina
authors.initials: A
authors.lastname: Angelova
authors.forename: Vasil M
authors.initials: VM
authors.lastname: Garamus
authors.forename: Markus
authors.initials: M
authors.lastname: Drechsler
authors.forename: Regine
authors.initials: R
authors.lastname: Willumeit
authors.forename: Rada
authors.initials: R
authors.lastname: Mutafchieva
authors.forename: Petr
authors.initials: P
authors.lastname: Štěpánek
authors.forename: Sylviane
authors.initials: S
authors.lastname: Lesieur
mesh_terms: D058608:Nanopores; D013997:Time Factors; D053835:Unilamellar Liposomes / Q000737:chemistry*
chemical_list: D053835:Unilamellar Liposomes