Figure 3.

Bioactivity test: (a) SEM visualization of the surface of the mat_2_2 before its immersion in simulated body fluid (SBF) (control sample; magnification 1500×, scale bar = 100 µm) and after incubation in the SBF for 14 and 28 days (magnification 1000×, scale bar = 200 µm); (b) EDS spectra of apatite precipitates on the surface of the mat_2_2 along with calculated Ca/P atomic ratio; (c) Ca²⁺ and HPO₄²⁻ concentrations in the SBF samples collected during incubation with the mat_2_2 (control Ca²⁺ and control HPO₄²⁻ ion concentration in the fresh SBF; * statistically significant results compared to the control SBF, p < 0.05, unpaired t-test).