Influence of ternary divalent cations (Mg2+, Co2+, Sr2+) substitution on the physicochemical, mechanical and biological properties of carbonated hydroxyapatite scaffolds

Abstract

Substitution of ionic either anion or cation in a controlled amount into carbonated hydroxyapatite (CHA) structure is one of the efficient and safest ways in enhancing the properties of the materials. However, most of the works studied only focused on the physical and mechanical properties of single ionic substitution. For the first time, the influence of simultaneous ternary substitutions of divalent cations into porous CHA scaffolds on the physicochemical, mechanical, degradation and in vitro biological properties are investigated in the present study. Three different compositions of porous scaffolds with binary and ternary divalent cations, namely, pure CHA (S11), CoSr CHA (S21) and MgCoSr CHA (S31) were fabricated using polyurethane (PU) foam replication technique. Despite a small amount of Mg 2+ , Co 2+ and Sr 2+ added, these divalent cations had successfully substituted into the Ca 2+ site and remained as single phase B-type CHA. The produced scaffolds demonstrated open, interconnected and uniform pores. Interestingly, simultaneous ternary divalent cations substitution into CHA structure had successfully enhanced the compressive strength of the sintered scaffolds, also promoted better cell attachment and activities than the binary dopedand pure CHA scaffolds. It is important to note that the right choice of divalent cation can be the determining factor in tuning the physicochemical, mechanical and biological properties of CHA scaffolds.