Cobalt-incorporated Chlorapatite: Preparation by Molten Salt Method, Anti-oxidation and Cytocompatibility

doi:10.15541/jim20220040

Abstract

Abstract:

Orthopedic surgery and postoperative inflammation are easy to induce oxidative stress, which hinders the process of bone repair. Bioactive ceramics have excellent osteogenic properties, but lack the ability to resist oxidative stress. Therefore, it is of great significance to develop a bioactive ceramic material with antioxidant function. Here, cobalt-incorporated chloroapatite (Co-MS-TCP) was prepared by a molten salt method, in which the mixture of lithium chloride and potassium chloride was used as a molten salt system, and β-phase tricalcium phosphate (TCP) and cobalt chloride hexahydrate (CoCl₂∙6H₂O) were used as raw material and cobalt source, respectively. The antioxidant ability of Co-MS-TCP was determined by catalyzing H₂O₂ clearance. The cytocompatibility and anti-oxidation of Co-MS-TCP were further evaluated by analyzing the changes of cell viability and intracellular reactive oxygen species (ROS). Results showed that Co-MS-TCP with controllable cobalt content can be prepared by a molten salt method with changing the addition amount of CoCl₂∙6H₂O source. The scavenging capacity of H₂O₂ increased with the increase of cobalt content in chlorapatite, and more than 90% of H₂O₂ could be scavenged within 6 h due to the catalytic activity of Co-MS-TCP. Furthermore, cell experiments confirmed the cytocompatibility and antioxidative property of Co-MS-TCP. 3% Co-MS-TCP at a concentration of 1.5 mg·mL^-1 could still ensure the survival rate of bone marrow mesenchymal stem cells and chondrocytes to be higher than 85%, and 3% Co-MS-TCP can also significantly reduce the content of intracellular ROS for the H₂O₂-stimulated cells. Therefore, molten salt method is an effective way to prepare cobalt-incorporated bioactive ceramics with antioxidative property, which also provides a promising strategy for the development of functional bioactive ceramics with high catalytic activity and biocompatibility.

Key words: bioactive ceramics, molten salt method, cobalt, anti-oxidation

CLC Number:

TQ174

SHU Chaoqin, ZHU Min, ZHU Yufang. Cobalt-incorporated Chlorapatite: Preparation by Molten Salt Method, Anti-oxidation and Cytocompatibility[J]. Journal of Inorganic Materials, 2022, 37(11): 1225-1235.

Figures/Tables 13

Fig. 1 XRD patterns of Co-MS-TCP powders prepared by molten salt method with different holding time The color figure can be obtained from online edition

Fig. 2 SEM images of β-TCP powders before and after molten salt treatment with different holding time (A1-A2) β-TCP; (B1-B2) 0 h Co-MS-TCP; (C1-C2) 0.5 h Co-MS-TCP; (D1-D2) 1 h Co-MS-TCP; (E1-E2) 2 h Co-MS-TCP; (F1-F2) 3 h Co-MS-TCP

Fig. 3 H2O2 scavenging effect of (A) MS-TCP and (B) Co-MS-TCP powders prepared by molten salt method with different holding time *** p<0.001

Fig. 4 XRD patterns of Co-MS-TCP powders prepared by molten salt method with different cobalt salt additions

Fig. 5 SEM images of Co-MS-TCP powders prepared by molten salt method with different cobalt salt additions (A1, A2) MS-TCP; (B1, B2) 1% Co-MS-TCP; (C1, C2) 3% Co-MS-TCP; (D1, D2) 5% Co-MS-TCP

Fig. 6 Contents and valence state of cobalt in Co-MS-TCP on H2O2 scavenging ability (A) H2O2 scavenging effect of Co-MS-TCP powders with different cobalt contents; (B) XPS spectra of cobalt in 3% Co-MS-TCP powder; (C, D) Cobalt contents in MS-TCP, 1% Co-MS-TCP, 3% Co-MS-TCP, and 5% Co-MS-TCP powders determined by (C) ICP-AES and (D) XRF methods. *p<0.05, **p<0.01, ***p<0.001. The color figures can be obtained from online edition

Fig. 7 Releases of (A) Ca, (B) P and (C) Co ions from β-TCP, MS-TCP and 3% Co-MS-TCP powders in Tris-HCl buffer The color figures can be obtained from online edition

Fig. 8 SEM images of (A1, A2) β-TCP, (B1, B2) MS-TCP and (C1, C2) 3% Co-MS-TCP after soaking in SBF for 7 d and (D) their corresponding FT-IR spectra The color figure can be obtained from online edition

Fig. 9 Cell viabilities of MS-TCP and 3% Co-MS-TCP powders with different concentrations on (A) cartilage cells and (B) bone marrow mesenchymal stem cells **p<0.01, *** p<0.001; The color figures can be obtained from online edition

Fig. 10 Images of intracellular ROS staining fluorescence in cartilage cells stimulated by H2O2 treatment with powders (A) Blank, (B) β-TCP, (C) MS-TCP, (D) 3% Co-MS-TCP and (E) corresponding fluorescence intensity statistics ***p<0.001; The color figures can be obtained from online edition

Fig. 11 Images of intracellular ROS staining fluorescence in bone marrow mesenchymal stem cells stimulated by H2O2 treatment with powders (A) Blank, (B) β-TCP, (C) MS-TCP, (D) 3% Co-MS-TCP and (E) Corresponding fluorescence intensity statistics. * p<0.05, ** p<0.01 The color figures can be obtained from online edition

Fig. 12 Calcein AM and PI fluorescence images of cartilage cells treated with different powders((A) Blank; (B) β-TCP; (C) MS-TCP; (D) 3% Co-MS-TCP; (A1-D1) Cells without H2O2 stimulation; (A2-D2) Cells stimulated with H2O2 showing live (green) and death (red) cells) The color figures can be obtained from online edition

Fig. 13 Calcein AM and PI fluorescence images of bone marrow mesenchymal stem cells treated with powders (A) Blank; (B) β-TCP; (C) MS-TCP; (D) 3% Co-MS-TCP; (A1-D1) Cells without H2O2 stimulation; (A2-D2) Cells stimulated with H2O2 showing live (green) and death (red) cells The color figures can be obtained from online edition

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