Evaluating various properties of nanohydroxyapatite synthesized from eggshells and dual-doped with Si⁴⁺ and Zn²⁺: An...

This study aimed to evaluate morphological, chemical and biocompatible properties of nanohydroxyapatite (N-HA) synthesized from eggshells and dual-doped with Si4+ and Zn2+.

In the current study, N-HA was synthesized from chicken eggshells using the wet chemical precipitation method and doped with Si4+ and Zn2+. The physical assessment was carried out using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) analysis, and X-ray diffraction (XRD) analysis. Crystal size was calculated using the Scherrer equation. Cytotoxicity was studied in vitro using the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) cytotoxicity assay. The optical density (OD) of each well was obtained and recorded at 570 nm for 24 h (t1), 48 h (t2), 72 h (t3), and 5 days (t4) using a microplate reader.

The results of Si-Zn-doped HA showed a high specific surface area with an irregular nano-sized spherical particle structure. The atomic percentage provided the ratio of calcium to phosphate; for non-doped HA, the atomic Ca/P ratio was 1.6, but for Si-Zn-doped HA, where Zn+2 Ca and Si + replaced 4 substituted P, the atomic ratio (Ca + Zn)/(P + Si) was 1.76. The average crystal size of Si-Zn-doped HA was 46 nm, while for non-doped HA it was 61 nm. both samples were non-toxic and statistically significantly less viable than the control group After 5 days, the mean cell viability of Si-Zn-doped HA (79.17 ± 2.18) was higher than that of non-doped HA (76.26 ± 1.71) (P = 0.091).

The MTT assay results showed that Si-Zn-doped HA is biocompatible. In addition, it showed characteristic physiochemical properties of a large surface area with interconnected porosity.