title: Where is it and how much? Mapping and quantifying elements in single cells.
abstract: The biological function of a chemical element in cells not only requires the determination of its intracellular quantity, but also the spatial distribution of its concentration. Different strategies can be employed to quantify and map the intracellular concentration of elements in single cells. The assessment of the intracellular elemental concentration, which is the relevant information, requires the measurement of cell volume. This challenging and demanding task requires combining different techniques allowing gathering of both morphological and compositional information on the same cell. Moreover, the need to analyse samples more similar to their natural state requires complex hardware equipment, and supplementary efforts in preparation protocols. Nevertheless, the response to the question: "where is it and how much?" is worth all these efforts. This review aims at providing an insight into the recent and most advanced techniques and strategies for quantifying and mapping chemical elements in single cells. We describe and discuss indirect detection techniques (label based) which make use of fluorescent dyes, and direct ones (label free), such as particle induced X-ray emission, proton backscattering spectrometry, scanning transmission ion spectrometry, nano-secondary ion mass spectrometry, X-ray fluorescence microscopy, complemented by X-ray imaging.
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40127, Italy. Stefano.iotti@unibo.it.
authors.forename: Emil
authors.initials: E
authors.lastname: Malucelli
authors.forename: Michela
authors.initials: M
authors.lastname: Fratini
authors.forename: Andrea
authors.initials: A
authors.lastname: Notargiacomo
authors.forename: Alessandra
authors.initials: A
authors.lastname: Gianoncelli
authors.forename: Lucia
authors.initials: L
authors.lastname: Merolle
authors.forename: Azzurra
authors.initials: A
authors.lastname: Sargenti
authors.forename: Concettina
authors.initials: C
authors.lastname: Cappadone
authors.forename: Giovanna
authors.initials: G
authors.lastname: Farruggia
authors.forename: Stefano
authors.initials: S
authors.lastname: Lagomarsino
authors.forename: Stefano
authors.initials: S
authors.lastname: Iotti
mesh_terms: D005456:Fluorescent Dyes; D008853:Microscopy; D012542:Scattering, Radiation; D059010:Single-Cell Analysis / Q000379:methods*; D018629:Spectrometry, Mass, Secondary Ion; D013052:Spectrometry, X-Ray Emission; D014965:X-Rays
chemical_list: D005456:Fluorescent Dyes