In vitro dissolution of melt‐derived 45S5 and sol‐gel derived 58S bioactive glasses

Abstract

Effects of powder type, particle size (5-20 microm; 90-300 microm; 90-710 microm), and type of dissolution medium on the dissolution behavior of bioactive glasses were investigated in vitro using melt-derived 45S5 and sol-gel derived 58S bioactive glass powders. Dissolution studies were performed in simulated body fluid and in alpha-MEM based cell culture medium at 37 degrees C under dynamic conditions (1 Hz) for periods of 30 min, 1, 2, 4, 8, 17, and 22 h. The concentrations of elements dissolved from the glasses were evaluated using inductively coupled plasma analysis. The reacted powders were analyzed for bioactivity using Fourier transform infrared spectrometry to observe the formation of a calcium phosphate layer on the surface. The non-porous surfaces of melt-derived 45S5 glass powders exhibited lower dissolution rates and rate of surface layer formation than 58S gel-glass powders. The rates of dissolution for both types of powders were lower in culture medium, compared to simulated body fluid, and increased as the particle size decreased. Thus, particle size range, glass type, and powder volume fraction can be used as a means to control the release rate of active ions that stimulate the gene expression and cellular response for tissue proliferation and repair.

Laser Spinning of Bioactive Glass Nanofibers

“…[21] This outcome is in clear agreement with previous results that relate the increase of dissolution rate of bioactive glasses with the decrease of their particle size. [28] Further analyses by TEM show that for an incubation time of 5 days, the layer of calcium phosphate presents a faint crystalline structure, since weak rings appeared in the SAED pattern for both compositions. After 10 days of incubation the crystalline structure is more pronounced.…”

The effect of serum proteins on apatite growth for 45S5 Bioglass and common sol-gel derived glass in SBF

“…On TG, crystalline calcium carbonate was found in all the TG immersed in sSBF (Figure 1d). This is previously observed when the sol-gel 58S (60 mol% SiO 2 , 36 mol% CaO and 4 mol% P 2 O 5 ) composition was immersed in culture media [24] and in SBF when the glass was in high concentration [25] and was thought to be due to the phosphate in the SBF being used up during calcium phosphate nucleation, leaving excess calcium that then reacts with carbonate in the media. This could explain large resorption pits formed by osteoclast cells on the surface of 70S30C foam scaffolds in vitro (osteoclasts would be expected to resorb calcium carbonate more rapidly than glass) [26].…”

The key Features expected from a Perfect Bioactive Glass –How Far we still are from an Ideal Composition?

“…High dissolution rate [7] that causes fast resorption and may negatively affect the balance of natural bone remodelation, leading to gap formation between the tissue and the implant material [8];…”