title: Controlling particle size in the Stöber process and incorporation of calcium.
abstract: The Stӧber process is commonly used for synthesising spherical silica particles. This article reports the first comprehensive study of how the process variables can be used to obtain monodispersed particles of specific size. The modal particle size could be selected within in the range 20-500 nm. There is great therapeutic potential for bioactive glass nanoparticles, as they can be internalised within cells and perform sustained delivery of active ions. Biodegradable bioactive glass nanoparticles are also used in nanocomposites. Modification of the Stӧber process so that the particles can contain cations such as calcium, whilst maintaining monodispersity, is desirable. Here, whilst calcium incorporation is achieved, with a homogenous distribution, careful characterisation shows that much of the calcium is not incorporated. A maximum of 10 mol% CaO can be achieved and previous reports are likely to have overestimated the amount of calcium incorporated.
authors.affiliation: Department of Materials, Imperial College London, UK.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Greasley
authors.affiliation: Department of Physics, University of Warwick, UK.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Page
authors.affiliation: School of Engineering & Applied Science and Aston Research Centre for Healthy Ageing, University of Aston, UK.
authors.forename: Slobodan
authors.initials: S
authors.lastname: Sirovica
authors.affiliation: Department of Materials, Imperial College London, UK.
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.affiliation: School of Engineering & Applied Science and Aston Research Centre for Healthy Ageing, University of Aston, UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Martin
authors.affiliation: Department of Materials, Imperial College London, UK; Applied Physics Department, University of Vigo, E.I.I., Lagoas-Marcosende E-36310, Vigo, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Riveiro
authors.affiliation: Department of Physics, University of Warwick, UK.
authors.forename: John V
authors.initials: JV
authors.lastname: Hanna
authors.affiliation: Department of Materials, Imperial College London, UK.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Porter
authors.affiliation: Department of Materials, Imperial College London, UK. Electronic address: julian.r.jones@imperial.ac.uk.
authors.forename: Julian R
authors.initials: JR
authors.lastname: Jones
keywords: Bioactive glass; Biodegradable; Nanoparticles; Sol–gel; Stӧber process