Cahpo4 2h2o

The melt-quench route was used to produce BGs from analytical grade reagents, such as CaCO₃ (Honeywell Fluka, Dreieich, Germany), NaCO₃ (Honeywell Fluka), K₂CO₃ (Alfa Aesar, Dreieich, Germany), CaHPO₄·2H₂O (Acros Organics, Geel, Belgium), ZnO (Sigma-Aldrich, Steinheim, Germany), and commercial-grade Belgian quartz sand (SiO₂). The glasses were melted in Pt crucibles for 1.5 h at 1420 °C before being casted in graphite molds and annealed for 1 h at 520 °C. The melting process was then repeated to ensure homogeneity. The glasses were crushed and milled to produce fine particles using a Jaw Crusher (Retsch, Haan, Germany) and a planetary ball mill (Retsch), respectively. Furthermore, the BGs underwent a heat treatment process for glass sintering for 1.5 h at 690 °C at a heating rate of 2 °C/min. This process aimed to replicate the heat treatment during the production of 3D scaffolds. The sintered materials were ground into fine powder and sieved to 100 microns. The compositions of experimental glasses are shown in Table 1. The morphology of the glass particles was examined with a scanning electron microscope (SEM, Auriga, Carl-Zeiss, Jena, Germany) using a voltage of 1.5 kV. The approximate particle size was obtained by measuring around 200 particles from SEM pictures using ImageJ (U.S. National Institutes of Health, Bethesda, MD, USA).

45S5-BG was prepared following the melt-quench route using analytical grade reagents, namely, NaCO₃ (Honeywell Fluka, Steinheim, Germany), CaCO₃ (Honeywell Fluka, Steinheim, Germany), CaHPO₄·2H₂O (Acros Organics, Geel, Belgium), and commercial grade Belgian quartz sand (SiO₂). The reagents were mixed together in a platinum crucible, heated up to 1400 °C for 1 h and quenched rapidly in water. The glass frits were crushed with a Jaw Crusher (Retsch, Haan, Germany) and ground into fine powder with a planetary ball mill (Retsch, Haan, Germany) with absolute ethanol (VWR Chemicals, Radnor, PA, USA) as milling medium. The powder was subsequently sintered at 1050 °C for 2 h, ground and sieved to obtain particles less than 125 µm. The morphology of the final granules was characterized by a polygonal shape with average size of 66 ± 19 µm as depicted in Figure 2 (SEM Auriga, Carl-Zeiss, Jena, Germany). The average size was estimated from scanning electron microscopy (SEM) images using the software ImageJ (National Institutes of Health Bethesda, MD, USA).

The glasses were produced from mixtures of analytical grade reagents, namely, NaCO₃ (Honeywell Fluk, Steinheim, Germany), K₂CO₃ (Alfa Aesar, Erlenbachweg, Germany), CaCO₃ (Honeywell Fluka), CaHPO₄·₂H₂O (Acros Organics, Geel, Belgium), MgO (Sigma-Aldrich, Steinheim, Germany) and commercial-grade Belgian quartz sand (SiO₂). The batches were melted in Pt crucibles at 1420 °C for 1.5, followed by casting in graphite molds and annealing at 520 °C for 1 h. Subsequently, the glasses were crushed and ground to powders with a planetary ball mill (Retsch, Haan, Germany) and sintered at 690 °C for 1.5 h. Morphological characterization of the granules was done with scanning electron microscopy at 1.5 kV (SEM, Auriga, Carl-Zeiss, Jena, Germany).
For ion release measurements, 75 mg of glass particles were immersed in 50 mL of SBF as described in previous studies [73 (link)] and incubated in an orbital shaker at 37 °C and 90 rpm agitation. After different incubation times, the SBF supernatant was filtered and analyzed with an inductively coupled plasma optical emissions spectrometer (ICP-OES, PerkinElmer Optima 5300 DV, Shelton, CT, USA) to obtain the concentration of ions released from the glasses.