title: Functionalized ZnO nanorod-based selective magnesium ion sensor for intracellular measurements.
abstract: ZnO nanorods were grown on a silver-coated tip of a borosilicate glass capillary (0.7 μm in tip diameter) and used as selective potentiometric sensor of intracellular free Mg(2+). To functionalize the ZnO nanorods for selectivity of Mg(2+), a polymeric membrane with Mg(2+)-selective ionophores were coated on the surface of the ZnO nanorods. These functionalized ZnO nanorods exhibited a Mg(2+)-dependent electrochemical potential difference versus an Ag/AgCl reference microelectrode within the concentration range from 500 nM to 100 mM. Two types of cells, human adipocytes and frog oocytes, were used for the intracellular Mg(2+) measurements. The intracellular concentration of free Mg(2+) in human adipocytes and frog oocytes were 0.4-0.5 and 0.8-0.9 mM, respectively. Such type of nanoelectrode device paves the way to enable analytical measurements in single living cells and to sense other bio-chemical species at the intracellular level.
authors.affiliation: Department of Science and Technology, Campus Norrköping, Bredgatan 34, Linköping University, SE-60174 Norrköping, Sweden. muhas@itn.liu.se
authors.forename: Muhammad H
authors.initials: MH
authors.lastname: Asif
authors.forename: Syed M Usman
authors.initials: SM
authors.lastname: Ali
authors.forename: Omer
authors.initials: O
authors.lastname: Nur
authors.forename: Magnus
authors.initials: M
authors.lastname: Willander
authors.forename: Ulrika H
authors.initials: UH
authors.lastname: Englund
authors.forename: Fredrik
authors.initials: F
authors.lastname: Elinder
mesh_terms: D017667:Adipocytes / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002413:Cations, Divalent / Q000032:analysis; D055664:Electrochemical Techniques; D005260:Female; D006801:Humans; D007424:Intracellular Fluid / Q000737:chemistry*; D008274:Magnesium / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D009865:Oocytes / Q000737:chemistry; D014982:Xenopus laevis; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D008274:Magnesium; D015034:Zinc Oxide