Characterization of hap nanostructures doped with AgNp and the gamma radiation effects

•Microwave-assisted hydrothermal method can be used for the synthesis of nanohydroxyapatite.•The particle size distribution and morphology of the hydroxyapatite was found to be dependent of the size of AgNps.•Rietveld analysis of the XRD patterns indicated that the monoclinic and hexagonal crystalline phases were present in pure and AgNP doped Hap.•Gamma radiation induced a thermoluminescent signal which intensity increased with the size of the Ag nanoparticles that were added during the synthesis of hydroxyapatite. The goal of this work was to use Ag nanoparticles during the synthesis of hydroxyapatite (Hap) to modify its characteristics, and as a result, modify the TL intensity signal when the Hap:AgNps system is exposed to gamma radiation. The synthesis of the samples was carried out with the microwave-assisted hydrothermal method; AgNps with a proportion of 0.5% (wt%) with different diameters (17, 21 and 29 nm) that were added during the synthesis. To evaluate the effect of AgNps on the morphology and crystalline structure of the Hap, the techniques STEM, TEM and XRD were used. The XRD analysis showed the diffraction peaks associates with hydroxyapatite and minimal quantities of portlandite. The STEM results show that pure Hap consists of rods of up to 300 nm in length and 50 nm in width and laminar structures of up to 800 nm in length and 150 nm in width. The addition of Ag nanoparticles of 17 nm in size provokes an increase of the rod structures and a decrease of the laminar structures. Larger rod structures were observed for Hap samples with Ag nanoparticles of bigger sizes. Rietveld analysis of the XRD patterns indicated that the dominant monoclinic crystalline phase of pure Hap was diminished and an increase in hexagonal phase was observed accordingly with an increment in the Ag nanoparticle size. Finally, an increase of 61.7% of the TL intensity signal was obtained for AgNP (29 nm) doped HAp compared with pure Hap. This result makes the Hap:AgNps a possible candidate for gamma radiation dosimetry, mainly to undesirable events, such as nuclear accidents.