Compositional dependence of the formation of calcium phosphate films on bioglass

TLDR

Bioglass composed of sodium carbonate, calcium carbonate, phosphorous pentoxide, and silica can bond to bone, a property that depends on controlled surface reactions. The study aimed to investigate how SiO2 content influences the formation of silica‑rich layers and calcium phosphate films on bioglass in a simulated physiological solution and to link these in‑vitro reactions to in‑vivo bonding. Researchers examined bioglass samples with varying SiO2 percentages in a simulated physiological solution, monitoring the development of silica‑rich layers and calcium phosphate films and correlating the observed surface reactions with expected bone‑bonding performance. They found that bioglasses with ~46 mol % SiO2 form silica‑rich layers and calcium phosphate films simultaneously at a fast rate, those with 46–55 mol % SiO2 form a silica‑rich layer first followed by a later calcium phosphate film, and glasses with >60 mol % SiO2 do not develop a calcium phosphate film.

Abstract

Abstract Bioglass, which has a composition of sodium carbonate, calcium carbonate, phosphorous pentoxide and silica, has been shown to bond to living bone. This ability is dependent on controlled surface reactions. Investigators with 45S5 bioglass have demonstrated that the formation of a SiO 2 ‐rich layer and a calcium phosphate film on its surface in an aqueous environment is associated with the film bonding the bioglass to bone. The objects of this research were: To study SiO 2 dependence on the formation of a silica‐rich layer and calcium phosphate films on a bioglass surface in a simulated physiological solution, and To establish a correlation between in vitro surface reactions and in vivo bonding ability. It was discovered that three types of reactions occur in a simulated physiological solution depending on bioglass composition: A calcium phosphate film and SiO 2 ‐rich layer form simultaneously and the reaction rate is fast for bioglasses which have a lower content of SiO 2 (∼46 mol% SiO 2 ). A SiO 2 ‐rich layer forms first and a calcium phosphate film develops later between the aqueous environment and the SiO 2 ‐rich layer for bioglasses whose SiO 2 content is between 46–55 mol %. A calcium phosphate film does not form for glasses whose SiO 2 content is more than 60 mol %.