Theranostics 2020; 10(4):1572-1589. doi:10.7150/thno.40103 This issue

Research Paper

A bioceramic scaffold composed of strontium-doped three-dimensional hydroxyapatite whiskers for enhanced bone regeneration in osteoporotic defects

Rui Zhao1, Siyu Chen1, Wanlu Zhao1, Long Yang1, Bo Yuan1, Voicu Stefan Ioan2, Antoniac Vasile Iulian3, Xiao Yang1✉, Xiangdong Zhu1✉, Xingdong Zhang1

1. National Engineering Research Center for Biomaterials, Sichuan University, Chengdu, 610064, China.
2. Department of Analytical Chemistry and Environmental Engineering, University Politehnica of Bucharest, Bucharest 011061, Romania.
3. Department of Metallic Materials Science, Physical Metallurgy, University Politehnica of Bucharest, Bucharest 060042, Romania.

This is an open access article distributed under the terms of the Creative Commons Attribution License ( See for full terms and conditions.
Zhao R, Chen S, Zhao W, Yang L, Yuan B, Ioan VS, Iulian AV, Yang X, Zhu X, Zhang X. A bioceramic scaffold composed of strontium-doped three-dimensional hydroxyapatite whiskers for enhanced bone regeneration in osteoporotic defects. Theranostics 2020; 10(4):1572-1589. doi:10.7150/thno.40103. Available from

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Graphic abstract

Reconstruction of osteoporotic bone defects is a clinical problem that continues to inspire the design of new materials.

Methods: In this work, bioceramics composed of strontium (Sr)-doped hydroxyapatite (HA) whiskers or pure HA whiskers were successfully fabricated by hydrothermal treatment and respectively named SrWCP and WCP. Both bioceramics had similar three-dimensional (3D) porous structures and mechanical strengths, but the SrWCP bioceramic was capable of releasing Sr under physiological conditions. In an osteoporotic rat metaphyseal femoral bone defect model, both bioceramic scaffolds were implanted, and another group that received WCP plus strontium ranelate drug administration (Sr-Ran+WCP) was studied for comparison.

Results: At week 1 post-implantation, osteogenesis coupled blood vessels were found to be more common in the SrWCP and Sr-Ran+WCP groups, with substantial vascular-like structures. After 12 weeks of implantation, comparable to the Sr-Ran+WCP group, the SrWCP group showed induction of more new bone formation within the defect as well as at the implant-bone gap region than that of the WCP group. Both the SrWCP and Sr-Ran+WCP groups yielded a beneficial effect on the surrounding trabecular bone microstructure to resist osteoporosis-induced progressive bone loss. While an abnormally high blood Sr ion concentration was found in the Sr-Ran+WCP group, SrWCP showed little adverse effect.

Conclusion: Our results collectively suggest that the SrWCP bioceramic can be a safe bone substitute for the treatment of osteoporotic bone defects, as it promotes local bone regeneration and implant osseointegration to a level that strontium ranelate can achieve.

Keywords: calcium phosphate bioceramics, strontium, bone regeneration, osteoporosis, whiskerization.