Strontium substituted biomimetic calcium phosphate system derived from cuttlefish bone

Abstract

Biomimetic triphasic strontium‐substituted calcium phosphate (CaP) powders were prepared by wet precipitation method at 50°C, using CaCO3, (NH2)2COH3PO4, and Sr(NO3)2 as reagents. Calcite was prepared from biogenic source (cuttlefish bone). The synthesized powders have been characterized by elemental analysis, Fourier transform infrared spectrometry, X‐ray diffraction, Rietveld refinement studies and cell viability test. Phase transformation and ion release were analyzed during 7 days of incubation in simulated body fluid at 37°C. The raw precipitated powders were composed of calcium deficient carbonated hydroxyapatite (HA), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP). After heat treatment at 1200°C β‐tricalcium phosphate (β‐TCP) was detected. Strontium substitution for calcium results in an increase of lattice parameters in HA, OCP, and β‐TCP. Sr2+ occupy the Ca(1) site in HA, Ca(3,4,7,8) sites in OCP and Ca(1,2,3,4) sites in β‐TCP. Along with Sr2+ substitution, presence of Mg2+ and Na+ ions was detected as a result of using biogenic calcium carbonate. The culture of human embryonic kidney cells indicated noncytotoxicity of the prepared CaP powders with emphasis on the cell proliferation during 3 days of culture.

Selenite Substituted Calcium Phosphates: Preparation, Characterization, and Cytotoxic Activity

“…As shown in Table 2 in addition to Ca, P and Se the presence of strontium (Sr 2+ ), magnesium (Mg 2+ ) and sodium (Na + ) ions has been detected. Using a biogenic source (cuttlefish bone) as a precursor of Ca 2+ ions results in a multi-substituted CaP system as already reported in our previous research [ 11 ]. Sr 2+ and Mg 2+ substitution level is ~0.47 and ~0.45 mol%, respectively, while the substitution level of Na + ion increase from 1.45 mol% (CaP_Se0) to final 3.49 mol% (CaP_Se10).…”

“…As a source of Ca 2+ ions, CaCO 3 was used, obtained from cuttlefish bone as described in our previous paper [ 11 ]. The non-substituted CaP_0Se system was prepared by adding urea phosphate (UPH, CO(NH 2 ) 2 -H 3 PO 4 , Sigma Aldrich, St. Louis, MO, USA) into dissolved/suspended CaCO 3 at 50 °C, while stirring was continued for 4 days followed by overnight aging at room temperature (T = 23.0 ± 0.2 °C).…”

“…Parts of the as-prepared powders were sintered at 1200 °C for 2 h. Finally, part of obtained as-prepared CaP, CaP_Se0 and CaP_Se5 powders were incubated in simulated body fluid (SBF, reagents were purchased from Sigma Aldrich, St. Louis, MO, USA) for 7 days at 37 °C. Non-substituted CaP powder obtained from synthetic CaCO 3 as described in [ 11 ] was used as control.…”

“…The elemental content of prepared CaP enriched with selenium oxyanion was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), using a PerkinElmer SCIEXT ELANR DRC-e (PerkinElmer, Concord, ON, Canada). The analyses were performed according to the manufacturer’s protocol as described in our previous paper [ 11 ].…”

“…Cells were kindly provided by prof. Inga Urlić, Faculty of Science, University of Zagreb. Non-substituted CaP powder obtained from synthetic CaCO 3 as described in [ 11 ] was used as control. Calcium phosphate powders were sterilized for 15 min under UV light and incubated with Dulbecco’s modified Eagle’s culture medium (DMEM)—high glucose (Sigma-Aldrich, St. Louis, MO, USA), supplemented with 10% fetal bovine serum (Capricorn Scientific, Ebsdorfergrund, Germany) and 1% penicillin/streptomycin (Lonza, Basel, Switzerland) at a concentration of 10 mg/mL and kept at 4 °C for 24 h. After incubation, powders were centrifuged (300× g ) for 5 min, and the supernatant was used for biocompatibility testing.…”