4. Conclusions
In summary, the sol–gel process was used to produce Ca/P micro-grains with multi-crystalline phases, including the monoclinic Ca5P8 and the hexagonal Ca(PO4)3OH. The percentage contribution of each phase was estimated by applying the Rietveld method to XRD measurements, where the major phase fractions obtained were: Ca5P8 (47.8 wt.%), CaCO3 (36.3 wt.%), Ca(PO4)3OH (9.5 wt.%) and Ca (6.3 wt.%). The chemical ratio between Ca and P was 1.67, as verified by EDS analysis, this value being within the bioactivity range. The spherical shape (with ~ 4 μm of diameter) and homogeneous distribution of the proteins and phospholipids on the shell of the NR particles were observed by luminescent confocal microscopy. The interaction of the NR particles with the Ca/P grains was confirmed via confocal micrographs, supporting the proposed structure, i.e., that the Ca/P grains are surrounded by NR particles, as shown in Fig. 4(a). This aspect represents the novelty of this study. This system may open new horizons in relation to its use as a biomaterial for application in tissue regeneration. The results presented herein are the first step toward obtaining a bandage which promotes the controlled-release of biomaterials. The degradation of natural rubber, the release of Ca2 + ions in a simulated body fluid and the biocompatibility of the material with tissue regeneration are currently under investigation.