title: S-layer coated emulsomes as potential nanocarriers.
abstract: The present study introduces a novel nanocarrier system comprising lipidic emulsomes and S-layer (fusion) proteins as functionalizing tools coating the surface. Emulsomes composed of a solid tripalmitin core and a phospholipid shell are created reproducibly with an average diameter of approximately 300 nm using temperature-controlled extrusion steps. Both wildtype (wt) and recombinant (r) S-layer protein SbsB of Geobacillus stearothermophilus PV72/p2 are capable of forming coherent crystalline envelope structures with oblique (p1) lattice symmetry, as evidenced by transmission electron microscopy. Upon coating with wtSbsB, positive charge of emulsomes shifts to a highly negative zeta potential, whereas those coated with rSbsB become charge neutral. This observation is attributed to the presence of a negatively charged glycan, the secondary cell wall polymer (SCWP), which is associated only with wtSbsB. The present study shows for the first time the ability of recombinant and wildtype S-layer proteins to cover the entire surface of emulsomes with its characteristic crystalline lattice. Furthermore, in vitro cell culture studies reveal that S-layer coated emulsomes can be uptaken by human liver carcinoma cells (HepG2) without showing any significant cytotoxicity over a wide range of concentrations. The utilization of S-layer fusion proteins equipped in a nanopatterned fashion by identical or diverse functions may lead to further development of emulsomes in nanomedicine, especially for drug delivery and targeting.
authors.affiliation: Institute for Synthetic Bioarchitectures, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, 1190 Vienna, Austria.
authors.forename: Mehmet H
authors.initials: MH
authors.lastname: Ucisik
authors.forename: Seta
authors.initials: S
authors.lastname: Küpcü
authors.forename: Monika
authors.initials: M
authors.lastname: Debreczeny
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schuster
authors.forename: Uwe B
authors.initials: UB
authors.lastname: Sleytr
keywords: S-layer proteins; emulsomes; lipophilic drug delivery; nanocarriers