Role of porosity in the strength, dielectric properties, and bioactivity of hardystonite ceramic material for use in bone tissue engineering applications

This work aimed to investigate the relationship between porosity, mechanical and electrical properties, and bioactivity of dense and porous hardystonite (HT; Ca2ZnSi2O7) bioceramic. Therefore, HT nanopowders were prepared to which different proportions of space holder agent were added and sintered. The microstructure of the resulting dense and porous samples was investigated by scanning electron microscopy (SEM). The mechanical properties of all samples were measured. The bioactivity of the samples prepared after soaking in simulated body fluid (SBF) for 7 and 14 days was assessed by SEM. In addition, the relationship between the incubation duration and the electrical and dielectric properties of HT cultured in SBF solution has been examined. The SEM micrographs showed that the samples soaked in SBF for 7 days showed no bioactive behavior, thanks to the chemical stability of HT. However, prolonged soaking of the samples in SBF solution for 14 days considerably improved their bioactivity behavior. These results were related to the electrical conductivity of the samples, as the samples soaked for 7 days showed a slight decrease in their values as follows: 2.19, 2.68, 5.75, and 8.94%, while the electrical conductivity values increased for all samples soaked for 14 days by 7.35, 16.9, 19.6, and 26.5%. Importantly, a significant part of encouraging fracture healing is played by this enhanced electrical conductivity. The outcomes obtained provide hope for the future use of HT in bone tissue engineering purposes.