Ca no3 2

The Ti-6Al-7Nb alloy (BIMO Metals, Wrocław, Poland) was anodized in 0.1 M Ca(H₂PO₂)₂ solution (Alfa Aesar, Kandel, Germany) with 150 g/dm³ Ca₃(PO₄)₂ (Avantor, Gliwice, Poland) particles at 350 V. The current density applied during the anodization process was 150 mA/cm². The sample possessed a cylindrical shape with a diameter of 9.5 mm and a height of 5 mm. The procedure of surface pretreatment and anodization was described in our previous paper [29 (link)]. Next, an additional sol-gel coating was formed on the previously anodized sample according to the following procedure: 1 M KH₂PO₄ with 0.67 M Ca(NO₃)₂ (Sigma Aldrich, Poznań, Poland) in aqueous solution was prepared, and then, NH₃ aq. (Alfa Aesar, Kandel, Germany) was added to adjust the pH to 10. The solution was mixed for 48 h (aging), and then, the anodized sample was coated using the dip coating technique at a dipping and pulling speed of 0.2 cm/min. The sample was then dried at room temperature and heat treated for 30 min in a furnace at 660 °C with a controlled ramp rate (10 °C/min) in the air condition. The sample was treated in the furnace at 660 °C for 2 h, followed by cooling down to ambient temperature (in the furnace).

The reagents used in this study for CoFe₂O₄ synthesis are: CoCl₂•6H₂O (ACS reagent, 99% Sigma-Aldrich, St. Louis, MO, USA), FeCl₂•6H₂O (Fisher Scientific, laboratory reagent grade, Waltham, MA, USA), NaOH (ROTH 98%, Carl Roth, Karlsruhe, Germany), carboxymethyl cellulose (CMC) (Sigma-Aldrich, St. Louis, MO, USA). The materials used in the synthesis of the CoFe₂O₄@HaP nanocomposite are: Ethanol (99.8% ROTH, Carl Roth, Karlsruhe, Germany), Hexadecyltrimethylammonium bromide (CTAB, Sigma Aldrich, St. Louis, MO, USA), H₃PO₄ (85% ROTH, Carl Roth, Karlsruhe, Germany), NH₄OH (25% CHIM REACTIV SRL, Bucharest, Romania), Ca(NO₃)₂ (Sigma-Aldrich, St. Louis, MO, USA).

The reactants MnCl ₂·4H ₂O, Ca(NO ₃) ₂, La(NO ₃) ₃, KMnO ₄ and KOH were purchased from Sigma Aldrich Co., Madrid, Spain.

MnCl₂, KMnO₄, (NH₄)₂HPO₄, Ca(NO₃)₂, K₂SO₄, NaCl, citric acid monohydrate, glutathione, glucose, saccharose, glycine, methionine, lysine, cysteine, tryptophan, methionine, deionized water, and human serum, were obtained from Sigma-Aldrich, St. Louis, MO, USA.

A schematic diagram of the fabrication process for WCP and SrWCP is shown in Figure 1A. The amount of reactants used is summarized in Table S1. In brief, 5 L of Ca(NO₃)₂ (Sigma-Aldrich, China) and Sr(NO₃)₂ (Sigma-Aldrich, China) was added to an equal volume of (NH₄)₂HPO₄ solution (Chengdu Kelong Chemical Reagent Co., Ltd, China) under a continuous stirring rate of 500 rpm and a temperature of 40 °C. The pH of the mixed solution was continuously monitored by a pH meter and adjusted to 8.5 by adding aqueous ammonia. After ageing for 24 h, the solution was washed 3 times with distilled water, dried at 120 °C for 24 h and crushed into powder. The bioceramics were then synthesized by the microwave-assisted H₂O₂ foaming method and then sintered at 1100 °C for 2 h at a rate of 5 °C/min increment to 1100 °C. The surface of the two bioceramics was further modified in an aqueous system containing 1 mol/L nitric acid and deionized water (pH = 4.0). The system was transferred into a Teflon-lined stainless-steel autoclave (KH-100 mL, Changyi Co. Ltd, China) at 180 ℃ for 12 h. The obtained WCP and SrWCP bioceramics were washed, dried and shaped into cylinders (diameter 3 × 4 mm³) for implantation and into discs (diameter 14 × 2 mm³) for in vitro tests after sterilization by γ-ray irradiation.