title: Biotinylation of ZnO nanoparticles and thin films: a two-step surface functionalization study.
abstract: This study reports ZnO nanoparticles and thin film surface modification using a two-step functionalization strategy. A small silane molecule was used to build up a stabilizing layer and for conjugation of biotin (vitamin B7), as a specific tag. Biotin was chosen because it is a well-studied bioactive molecule with high affinity for avidin. ZnO nanoparticles were synthesized by electrochemical deposition under oxidizing condition, and ZnO films were prepared by plasma-enhanced metal-organic chemical vapor deposition. Both ZnO nanoparticles and ZnO thin films were surface modified by forming a (3-mercaptopropyl)trimethoxysilane (MPTS) layer followed by attachment of a biotin derivate. Iodoacetyl-PEG2-biotin molecule was coupled to the thiol unit in MPTS through a substitution reaction. Powder X-ray diffraction, transmission electron microscopy, X-ray photoemission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy were used to investigate the as-synthesized and functionalized ZnO materials. The measurements showed highly crystalline materials in both cases with a ZnO nanoparticle diameter of about 5 nm and a grain size of about 45 nm for the as-grown ZnO thin films. The surface modification process resulted in coupling of silanes and biotin to both the ZnO nanoparticles and ZnO thin films. The two-step functionalization strategy has a high potential for specific targeting in bioimaging probes and for recognition studies in biosensing applications.
authors.affiliation: Divisions of Molecular Surface Physics and Nanoscience, Semiconductor Materials, and Chemistry, Department of Physics, Chemistry and Biology (IFM), Linkoping University, SE-58183 Linkoping, Sweden.
authors.forename: Linnéa
authors.initials: L
authors.lastname: SelegArd
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Khranovskyy
authors.forename: Fredrik
authors.initials: F
authors.lastname: Söderlind
authors.forename: Cecilia
authors.initials: C
authors.lastname: Vahlberg
authors.forename: Maria
authors.initials: M
authors.lastname: Ahrén
authors.forename: Per-Olov
authors.initials: PO
authors.lastname: Käll
authors.forename: Rositza
authors.initials: R
authors.lastname: Yakimova
authors.forename: Kajsa
authors.initials: K
authors.lastname: Uvdal
mesh_terms: D001360:Avidin / Q000737:chemistry*; D001710:Biotin / Q000737:chemistry*; D019921:Biotinylation; D008567:Membranes, Artificial; D053758:Nanoparticles / Q000737:chemistry*; D011721:Pyrenes / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: C529640:8-methoxypyrene-1,3,6-trisulfonic acid trisodium salt; D008567:Membranes, Artificial; D011721:Pyrenes; D001360:Avidin; D001710:Biotin; D015034:Zinc Oxide