AgNPs incorporated in Eu(III)-doped hydroxyapatite biomaterial: Spectroscopic, cytotoxicity, and antimicrobial investigation

This study aimed to synthesize and to characterize hydroxyapatite with antimicrobial action. For the synthesis, the precursors calcium nitrate and phosphoric acid were employed; europium(III), 1 % w/w in relation to calcium(II), was used as spectroscopic probe, to investigate structural alterations. Silver nanoparticles, as antimicrobial agents, were added to the resulting material. Formation of the hydroxyapatite phase was confirmed by X-ray diffraction and vibrational spectroscopy in the infrared region. Incorporation of silver nanoparticles in the material was confirmed by electronic absorption spectroscopy in the ultraviolet–visible region, through the absorption band at approximately 400 nm. Scanning electron microscopy revealed that the material had adequate morphology to induce bone formation. The excitation, emission, and lifetime measurements of the structural probe, europium(III), showed that the hydroxyapatite unit cell had two symmetry sites. Cytotoxicity evaluation in human cells showed that the material was toxic at concentrations above 1250 μg/mL. At 2000 ppm, the material displayed antimicrobial activity against E. coli, but the maximum evaluated concentration was insufficient to verify activity against S. aureus. Therefore, hydroxyapatite bearing silver nanoparticles is a promising material for application in the medical area.