title: Bacterial polysaccharide levan as stabilizing, non-toxic and functional coating material for microelement-nanoparticles.
abstract: Levan, fructose-composed biopolymer of bacterial origin, has potential in biotechnology due to its prebiotic and immunostimulatory properties. In this study levan synthesized by levansucrase from Pseudomonas syringae was thoroughly characterized and used as multifunctional biocompatible coating material for microelement-nanoparticles (NPs) of selenium, iron and cobalt. Transmission electron microscopy (TEM), hydrodynamic size measurements (DLS) and X-ray photoelectron spectroscopy (XPS) showed the interaction of levan with NPs. Levan stabilized the dispersions of NPs, decreased their toxicity and had protective effect on human intestinal cells Caco-2. In addition, levan attached to cobalt NPs remained accessible as a substrate for the colon bacteria Bacteroides thetaiotaomicron. We suggest that the combination of levan and nutritionally important microelements in the form of NPs serves as a first step towards a novel "2 in 1" approach for food supplements to provide safe and efficient delivery of microelements for humans and support beneficial gut microbiota with nutritional oligosaccharides.
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. Electronic address: olesja.bondarenko@kbfi.ee.
authors.forename: Olesja M
authors.initials: OM
authors.lastname: Bondarenko
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. Electronic address: angela.ivask@kbfi.ee.
authors.forename: Angela
authors.initials: A
authors.lastname: Ivask
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. Electronic address: anne.kahru@kbfi.ee.
authors.forename: Anne
authors.initials: A
authors.lastname: Kahru
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. Electronic address: heiki.vija@kbfi.ee.
authors.forename: Heiki
authors.initials: H
authors.lastname: Vija
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia. Electronic address: tiina.titma@kbfi.ee.
authors.forename: Tiina
authors.initials: T
authors.lastname: Titma
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia; Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu, Estonia. Electronic address: meeri.visnapuu@ut.ee.
authors.forename: Meeri
authors.initials: M
authors.lastname: Visnapuu
authors.affiliation: Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu, Estonia. Electronic address: urmas.joost@ut.ee.
authors.forename: Urmas
authors.initials: U
authors.lastname: Joost
authors.affiliation: Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; Competence Center of Food and Fermentation Technologies, Akadeemia tee 15A, 12618 Tallinn, Estonia. Electronic address: ksenia.kuksina@gmail.com.
authors.forename: Ksenia
authors.initials: K
authors.lastname: Pudova
authors.affiliation: Competence Center of Food and Fermentation Technologies, Akadeemia tee 15A, 12618 Tallinn, Estonia. Electronic address: signe.adamberg@ttu.ee.
authors.forename: Signe
authors.initials: S
authors.lastname: Adamberg
authors.affiliation: Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia. Electronic address: triinu.visnapuu@ut.ee.
authors.forename: Triinu
authors.initials: T
authors.lastname: Visnapuu
authors.affiliation: Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia. Electronic address: talamae@ebc.ee.
authors.forename: Tiina
authors.initials: T
authors.lastname: Alamäe
mesh_terms: D001439:Bacteroides / Q000187:drug effects; D018938:Caco-2 Cells; D020099:Coated Materials, Biocompatible / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology; D020895:Enterocytes / Q000187:drug effects; D005630:Fructans / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D014131:Trace Elements / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D005630:Fructans; D014131:Trace Elements; C072599:levan
keywords: Bacteroides thetaiotaomicron; Caco-2 in vitro; Co, Fe and Se nanomaterial; Cobalt tetraoxide (PubChem CID: 6432046); Food supplement; Levan N (PubChem CID: 440946); Magnetic oxide (PubChem CID: 14789); Safe-by-design; Selenium (PubChem CID: 6326970)