Assessments of dielectric and in-vitro biological properties of composite doped hydroxyapatite

Abstract

This study investigated the influence of specific dopant ions strontium (Sr²⁺), zinc (Zn²⁺), silver (Ag⁺), and fluoride (F⁻) on the functionality of composite doped hydroxyapatite (CD-HA) materials. A well-known optimization technique i.e., Taguchi’s design of experiments was employed to identify the ideal dopant concentrations in HA. This approach aimed to achieve a desired dielectric constant (DC), a key electrical property, while simultaneously promoting favourable biological properties for potential tissue engineering applications. Compared to undoped HA, specific CD-HA L6 (2.5Sr-5.0Zn-2.5 F) and L9 (5.0Sr-5.0Zn-2.5Ag) compositions exhibited significantly increased dielectric constants, reaching up to 145% higher values. The finding suggest that these nutrient doped HA could be beneficial in applications where electrical stimulation play a crucial role for bone growth. Further, L6 and L9 samples demonstrated nearly double the cell proliferation rate compared to undoped HA. In addition to cell material interaction, the antibacterial activity of both undoped HA and CD-HA samples against Escherichia coli and Staphylococcus aureus bacteria was conducted successfully. Notably, the L9 (5.0Sr-5.0Zn-2.5Ag) composition displayed the strongest antibacterial effect, with the largest inhibition zone against E. coli. These aforementioned findings suggested that these bio-ceramic CD-HA compositions containing 5% Sr and Zn, along with 2.5% Ag and F can be used as the potential candidates for various biomedical applications.