The influence of Sr and H3PO4 concentration on the hydration of SrCaHA bone cement

Abstract

Sr-contained calcium hydroxyapatite (SrCaHA) cement is a potential biomaterial for in vivo bone repair and surgery fixation due to its excellent biodegradability, bioactivity, biocompatibility, easily shaping and self-hardening. We had ever reported the in vitro physiochemical properties, biocompatibility and in vivo degradability of the SrCaHA cement obtained by mixing a cement powder of Ca(4)(PO(4))(2)O/CaHPO(4)/SrHPO(4) and a cement liquid of diluted H(3)PO(4) aqueous solution. In the present study, we intensively studied the influences of both Sr content and H(3)PO(4) concentration in diluted phosphoric acid aqueous solution on the setting time, hydration heat-liberation behaviours, and real-time microstructure and phase evolutions of the SrCaHA cement. The results show that both PO(4)(3-) and H(+) ions in PA solution attended the hydration reaction as reactants, and thus the increase of the PA concentration not only promoted the dissolution of Ca(4)(PO(4))(2)O but also pushed the hydration progress of SrCaHA bone cement. Sr content exhibits a remarkable retardation role on the apatite transformation of the SrCaHA cement pastes which probably attributed to its higher degree of supersaturation for yielding apatite crystals and lower transformation rate when exposed to the Sr(2+)-containing hydration system. This present results contribute to a better understanding on the hydration mechanism of the new SrCaHA cement and help to the more precisely controlling of its hydration process.

Strontium modified calcium phosphate cements – approaches towards targeted stimulation of bone turnover

“…83 In their TTCP/DCPA/DSPA cement system, Guo et al described a non-linear influence of Sr content on the mechanical properties: while an optimum composition was found at a Sr/(Sr + Ca) ratio of 0.05 with an increase of compressive strength up to 66 MPa compared to B50 MPa for the Sr-free reference cement, higher Sr content resulted in a reduced compressive strength. 83,84 A comparable optimum was described for DCPD-based cements where SrCO 3 replaced the second precursor component, CaO. 88 Here, up to 1.5% molar fraction of SrCO 3 increased the compressive strength of the set cement from B7 to B20 MPa.…”

“…For example, using the cementing reaction of DCPA/TTCP into hydroxyapatite upon mixing with phosphoric acid, DCPA can be substituted by its strontium analogue strontium hydrogen phosphate (SrHPO 4 , DSPA). In this way, Sr-substituted apatite cements with a Sr/(Sr + Ca) ratio of up to 0.1 were prepared by Guo et al 83,84 Since mixtures of DCPD and CaCO 3 can set into HA, one strategy to obtain SrHA cements is to replace CaCO 3 in the precursor by SrCO 3 . Following this approach, precursors composed of DCPD and various CaCO 3 -SrCO 3 mixtures were prepared by Tadier et al to obtain cements with up to 8 wt% Sr. 85 In contrast to the above-mentioned systems, the setting product was biphasic: the set cement was composed of a mixture of hydroxyapatite and SrCO 3 and no SrHA could be detected.…”

“…Furthermore, the transformation rate into HA or SrHA, respectively, was reduced in the presence of Sr albeit this could be partially compensated by higher phosphoric acid content in the cement liquid. 84 Cements comprising Sr phases as reactants to form SrHA tend to have prolonged setting times if SrCO 3 or DSPA is used as a Sr source. 81,83,86 Sr substitution in ACP, on the contrary, induced faster setting in SrACP/DCPA systems.…”

Synthesizing the strontium carbonate and silver doped bioceramic bone graft: Structure‐properties and cell viability

“…In some previous studies, it was also reported that CaCO 3 , SrHPO 4 and Strontium Carbonate additions increased the mechanical properties. 26,28 It was shown that increasing the amount of Sr decreased the reactivity and higher strength was reported than that of the trabecular bone via the in vitro study. 29 It was also reported that the addition of SrCO 3 into calcium phosphate-based compounds increased the mechanical properties by precipitating the formation of the SrHA.…”

Growth of strontium hydrogen phosphate/gelatin composites: a biomimetic approach

“…[5][6][7][8][9] A significant deal of attention has been paid to strontium containing hydroxyapatite cements to increase their bioactivity, biocompatibility and compressive strength. [10][11][12][13][14] The majority of previous studies devoted to the synthesis of SrHP have been focused on the hydrothermal method, 15,16 cathodic reduction 17 and solution growing. [18][19][20][21][22][23][24][25] Taher et al studied the hydrothermal synthesis of SrHP from a mixture of Li 2 CO 3 , SrCO 3 and H 3 PO 4 in water after conducting a thermal procedure at 180 1C for 6 h. 15 More recently, Zhang et al developed SrHP nano-belts without any surfactant as the template at 160 1C.…”