Strontium incorporation into biomimetic carbonated calcium-deficient hydroxyapatite coated carbon cloth: Biocompatibility with human primary osteoblasts

Abstract

It has already been shown that sono-electrodeposition can be used to coat activated carbon fiber cloth (ACC) with calcium phosphates (CaP) and we recently demonstrated that cathodic polarization at-1 V / Hg/Hg2SO4 was the best parameter to obtain a carbonated calcium deficient hydroxyapatite (CDA) coating with optimal uniformity and homogeneity. In the present study, we investigated whether this technique was suitable to dope this carbonated CDA coating by partial substitution with another bivalent cation such as strontium. We show here that a strontium-substituted carbonated CDA coating can be produced and quantitatively controlled up to at least 10 at.%. In this range we demonstrate that the presence of strontium does not modify either the textural or the structural properties of the carbonated CDA. Owing to the well-known effect of both carbonated CDA and strontium in bone formation, the biocompatibility of ACC coated or not with carbonated CDA or with strontium substituted carbonated CDA was tested using primary human osteoblasts. Our data revealed a positive and dose-dependent effect of strontium addition on osteoblast activity and proliferation. In conclusion, we show here that electrodeposition at-1 V is a suitable and easy process to incorporate cations of biological interest into CaP coating.

In vivo effectiveness of carbonated calcium‐deficient hydroxyapatite‐coated activated carbon fiber cloth on bone regeneration

“…We show here that the apposition of a patch consisting of CF cloth at the surface of a bone defect accelerates cortical bone healing and that carbonated calcium‐deficient apatite (CDA) coating of the fibers optimizes this effect. These results are consistent with our previous works in which we demonstrated the feasibility to perform a homogeneous and uniform coating of CDA at the surface of ACC material 22,23 and that this CDA coating improves ACC biocompatibility toward primary human osteoblasts 24 …”

“…These results are consistent with our previous works in which we demonstrated the feasibility to perform a homogeneous and uniform coating of CDA at the surface of ACC material 22,23 and that this CDA coating improves ACC biocompatibility toward primary human osteoblasts. 24 Acceleration of bone defect reconstruction in the presence of the patches was assessed by coupling different complementary techniques of analysis that is micro CT scan, MRI, and histology, which all confirmed the positive effect of both materials at Day 7 and 14. CDA coated ACC was the most efficient material, providing with the highest effect on bone cortical reconstruction.…”

“…Prior to coating, ACC was washed for 12 h in boiling distilled water using a Soxhlet® extractor, and dried at 70°C under vacuum. Carbonated CDA coating was carried out using a sono‐electrodeposition process at cathodic polarization (−1 V/Hg/Hg 2 SO 4 ) and 70°C for 6 h. The ACC characteristics (architecture, morphology, microtexture, structure, multi‐scale porosity, elemental composition, and surface chemistry), as well as the coating ones (thickness, morphology, crystallographic structure, chemical composition of the CaP phase) are detailed in our previous studies 22–24 . Patches of ACC and ACC/CDA were cut and adjusted to bone defect size (10 × 4 mm) and sterilized by dry heat at 180°C for 2 h.…”

“…22,23 We selected a combination of biocompatible ACC and biomimetic coating of carbonated calcium-deficient hydroxyapatite (CDA) whose biocompatibility was validated with human primary osteoblasts. 24 In the present work, we hypothesized that patches of ACC, uncoated or coated with CDA, could have a beneficial effect on cortical bone regeneration by simple apposition at the surface of a bone defect. To test this hypothesis, ACC and ACC/CDA patches were prepared and placed at the surface of cortical defects drilled in rat femurs.…”

“…Our previous studies demonstrated the possibility to coat different CaP phases on ACC surface by sono-electrodeposition with a total control of process [22,23]. We selected a combination of biocompatible ACC and biomimetic coating of carbonated calcium-deficient hydroxyapatite (CDA) whose biocompatibility was validated with human primary osteoblasts [24].…”