Abstract
The biocompatibility, antimicrobial activity, and dielectric properties of hydroxyapatite (HA) doped with different percentages of ZnO were studied. Hydroxyapatite was developed in samples heat-treated at 900 degrees C/4 h; not affected by the addition of ZnO. The microstructure showed euhedral and subhedral hydroxyapatite crystals dispersed singly or accumulated in clusters. The biocompatibility test was im-plemented in simulated body fluid (SBF) for two weeks; a new HA layer on the soaked samples was developed. Antimicrobial and antifungal testing was conducted using agar diffusion; incorporating ZnO increased these effects. Dielectric measurements were performed at various frequencies; increasing ZnO content decreased the conductivity as the interfacial polarization increased and, hence, the concentration of Zn + 2 cations triggered the decline in conductivity. With increasing zinc concentrations, antibacterial action expanded in the inhibition zones. Dielectric relaxation spectroscopy showed that the dielectric spectra were characterized at low and intermediate frequencies by a superposition of interfacial polar-ization and conductivity contribution. At high frequencies, all dynamics lagged behind the alteration of the external electric field, which made the permittivity values independent of neither the frequency of the applied field nor the composition of the investigated samples. The conductivity spectrum showed a considerable effect of the ZnO content in the HA matrix.(c) 2022 Elsevier B.V. All rights reserved.