TY - JOUR
T1 - Phosphate content affects structure and bioactivity of sol-gel silicate bioactive glasses
AU - Ting, Hung-Kai
AU - Page, Sam J
AU - Poologasundarampillai, Gowsihan
AU - Chen, Shu
AU - Yu, Bobo
AU - Hanna, John V
AU - Jones, Julian R
PY - 2017/12
Y1 - 2017/12
N2 - Bioactive glasses can heal bone defects and bond with bone through formation of hydroxyl carbonate apatite (HCA) surface layer. Sol-gel derived bioactive glasses are thought to have potential for improving bone regeneration rates over melt-derived compositions. The 58S sol-gel composition (60 mol% SiO2, 36 mol% CaO, and 4 mol% P2O5) has appeared in commercial products. Here, hydroxyapatite (HA) was found to form within the 58S glass during sol-gel synthesis after thermal stabilization. The preformed HA may lead to rapid release of calcium orthophosphate, or nanocrystals of HA, on exposure to body fluid, rather than the release of separate the calcium and phosphate species. Increasing the P2O5 to CaO ratio in the glass composition reduced preformed HA formation, as observed by XRD and solid-state NMR. Instead, above 12 mol% phosphate, a phosphate glass network (polyphosphate) formed, creating co-networks of phosphate and silica. Nanopore diameter of the glass and rate of HCA layer formation in simulated body fluid (SBF) decreased when the phosphate content increased.
AB - Bioactive glasses can heal bone defects and bond with bone through formation of hydroxyl carbonate apatite (HCA) surface layer. Sol-gel derived bioactive glasses are thought to have potential for improving bone regeneration rates over melt-derived compositions. The 58S sol-gel composition (60 mol% SiO2, 36 mol% CaO, and 4 mol% P2O5) has appeared in commercial products. Here, hydroxyapatite (HA) was found to form within the 58S glass during sol-gel synthesis after thermal stabilization. The preformed HA may lead to rapid release of calcium orthophosphate, or nanocrystals of HA, on exposure to body fluid, rather than the release of separate the calcium and phosphate species. Increasing the P2O5 to CaO ratio in the glass composition reduced preformed HA formation, as observed by XRD and solid-state NMR. Instead, above 12 mol% phosphate, a phosphate glass network (polyphosphate) formed, creating co-networks of phosphate and silica. Nanopore diameter of the glass and rate of HCA layer formation in simulated body fluid (SBF) decreased when the phosphate content increased.
U2 - 10.1111/ijag.12322
DO - 10.1111/ijag.12322
M3 - Article
SN - 2041-1286
VL - 8
SP - 372
EP - 382
JO - International Journal of Applied Glass Science
JF - International Journal of Applied Glass Science
IS - 4
ER -