Microstructural, electrical and biological activity in $$\mathrm{Ca}_{10}(\mathrm{PO}_4)_6(\mathrm{OH})_2-\mathrm{Ba}_{0.5}\mathrm{Sr}_{0.5}\mathrm{TiO}_3$$ Ca 10 ( PO 4 ) 6 ( OH ) 2 - Ba 0.5 Sr 0.5 TiO 3 ceramic composites designed for tissue engineering applications

Abstract

Abstract The article investigates electrically active ceramic composite of $$\mathrm{Ca}_{10}(\mathrm{PO}_4)_6(\mathrm{OH})_2$$ Ca 10 ( PO 4 ) 6 ( OH ) 2 (HAP) and $$\mathrm{Ba}_{0.5}\mathrm{Sr}_{0.5}\mathrm{TiO}_{3}$$ Ba 0.5 Sr 0.5 TiO 3 (BST) for biomedical applications. The study is a systematic blend of the materials science aspect of composites with a special focus on the dielectric and biological properties and their relationships. The article emphasized primarily extracting the dielectric constant ( $$\epsilon _r)$$ ϵ r ) of the specimens (that lay in the range of 3–65) and related them to microstructural properties like the grain size and at.% of BST. A broad outlook on the importance of $$\epsilon _r$$ ϵ r in determining the suitability of bioceramics for clinical applications is presented. Bioactivity analysis of the specimens led to probing the surface charges (that were negative), and it was found crucial to the growth of dense apatite layers. Furthermore, the cytocompatibility of the specimens displayed cell viability above 100% for Day 1, which increased substantially for Day 3. To reveal other biological properties of the composites, protein adsorption studies using bovine serum albumin (BSA) and fetal bovine serum (FBS) was carried out. Electrostatic interactions govern the adsorption, and the mathematical dependence on surface charges is linear. The protein adsorption is also linearly correlated with the $$\epsilon _r$$ ϵ r , intrinsic to the biomaterials. We delve deeper into protein–biomaterials interactions by considering the evolution of the secondary structure of BSA adsorbed into the specimens. Based on the investigations, 20 at.% HAP–80 at.% BST (20H–80B) was established as a suitable composite comprising the desired features of HAP and BST. Such explorations of electrical and biological properties are interesting for modulating the behavior of bioceramic composites. The results project the suitability of 20H–80B for designing electrically active smart scaffolds for the proposed biomedical applications and are expected to incite further clinical trials.