TY - JOUR
T1 - Nano-imaging confirms improved apatite precipitation for high phosphate/silicate ratio bioactive glasses
AU - Jaimes, Altair T.Contreras
AU - Kirste, Gloria
AU - de Pablos-Martín, Araceli
AU - Selle, Susanne
AU - de Souza e Silva, Juliana Martins
AU - Massera, Jonathan
AU - Karpukhina, Natalia
AU - Hill, Robert G.
AU - Brauer, Delia S.
N1 - Funding Information:
D.S.B., A.P.M. and J.M.S.S. acknowledge funding by the German Research Foundation (DFG; grant numbers BR 4608/7-1, PA 3095/1-1 and WE 4051/21-1). D.S.B. and J.M. acknowledge funding for a bilateral exchange programme by the German Academic Exchange Service (DAAD) and the Academy of Finland. The authors thank Steffi Ebbinghaus, Gabi Möller and Lutz Preißer (Otto Schott Institute of Materials Research) for XRD measurements and sample preparation, respectively, Julia Prechtl and Andrea Böbenroth (Fraunhofer IMWS) for TEM and nano-CT sample preparation, Dr Harold Toms (Queen Mary University of London) for assistance with MAS NMR experiments and Lutz Berthold (Fraunhofer IMWS) for EDXS mappings.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021
Y1 - 2021
N2 - Bioactive glasses convert to a biomimetic apatite when in contact with physiological solutions; however, the number and type of phases precipitating depends on glass composition and reactivity. This process is typically followed by X-ray diffraction and infrared spectroscopy. Here, we visualise surface mineralisation in a series of sodium-free bioactive glasses, using transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDXS) and X-ray nano-computed tomography (nano-CT). In the glasses, the phosphate content was increased while adding stoichiometric amounts of calcium to maintain phosphate in an orthophosphate environment in the glass. Calcium fluoride was added to keep the melting temperature low. TEM brought to light the presence of phosphate clustering and nearly crystalline calcium fluoride environments in the glasses. A combination of analytical methods, including solid-state NMR, shows how with increasing phosphate content in the glass, precipitation of calcium fluoride during immersion is superseded by fluorapatite precipitation. Nano-CT gives insight into bioactive glass particle morphology after immersion, while TEM illustrates how compositional changes in the glass affect microstructure at a sub-micron to nanometre-level.
AB - Bioactive glasses convert to a biomimetic apatite when in contact with physiological solutions; however, the number and type of phases precipitating depends on glass composition and reactivity. This process is typically followed by X-ray diffraction and infrared spectroscopy. Here, we visualise surface mineralisation in a series of sodium-free bioactive glasses, using transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDXS) and X-ray nano-computed tomography (nano-CT). In the glasses, the phosphate content was increased while adding stoichiometric amounts of calcium to maintain phosphate in an orthophosphate environment in the glass. Calcium fluoride was added to keep the melting temperature low. TEM brought to light the presence of phosphate clustering and nearly crystalline calcium fluoride environments in the glasses. A combination of analytical methods, including solid-state NMR, shows how with increasing phosphate content in the glass, precipitation of calcium fluoride during immersion is superseded by fluorapatite precipitation. Nano-CT gives insight into bioactive glass particle morphology after immersion, while TEM illustrates how compositional changes in the glass affect microstructure at a sub-micron to nanometre-level.
U2 - 10.1038/s41598-021-98863-3
DO - 10.1038/s41598-021-98863-3
M3 - Article
AN - SCOPUS:85116348302
SN - 2045-2322
VL - 11
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 19464
ER -