(Fe/Sr) Codoped Biphasic Calcium Phosphate with Tailored Osteoblast Cell Functionality

Although doped bioceramics have been widely investigated for biomedical applications, the codoped bioceramics remain mostly unexplored for bone regeneration applications. For example, the impact of codoping of Sr2+ and Fe3+ ions on the phase stability and cytocompatibility is not explored so far. In this perspective, the objective of the present study is to quantitatively understand this aspect in case of Fe/Sr codoped biphasic calcium phosphate (BCP). Following sol–gel synthesis, codoped BCP samples with Sr/Fe dopant concentrations of 2, 10, 20, 30, and 40 mol % as well as doped BCPs with single dopant (Sr or Fe) with similar compositions were calcined at 800 °C in air. Using extensive Rietveld analysis, the dopant content dependent crystallographic properties (e.g lattice parameters) and phase stability of HA/TCP are quantitatively assessed. In vitro cytocompatibility of codoped samples has been assessed using mouse osteoblast cells. An important observation is that, while singular dopant of Sr/Fe at 20 mol % or higher amount reduces cell viability significantly, osteoblast viability is not compromised to any significant extent on Sr/Fe codoped BCP, compared to undoped BCP. Our results indicate that one can tailor osteoblast functionality by controlling the codopant content. More importantly, all the codoped BCPs support cell proliferation, when single doped BCP exhibits significant reductionin cell viability, at dopant content of 10 mol % or higher. Cell morphological analysis supports extensive cell spreading on codoped BCPs. An attempt has been made to correlate the variation in cellular response with HA/TCP ratio and ion dissolution behavior. Taken together, the present work establishes unique advantage of Sr/Fe codoping approach toward realizing their bone replacement application