Fabrication and evaluation of interconnected porous carbonate apatite from alpha tricalcium phosphate spheres

Kunio Ishikawa, Tya Indah Arifta, Koichiro Hayashi, Kanji Tsuru

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26 Citations (Scopus)


Carbonate apatite (CO3Ap) blocks have attracted considerable attention as an artificial bone substitute material because CO3Ap is a component of and shares properties with bone, including high osteoconductivity and replacement by bone similar to autografts. In this study, we fabricated an interconnected porous CO3Ap block using α-tricalcium phosphate (TCP) spheres and evaluated the tissue response to this material in a rabbit tibial bone defect model. Interconnected porous α-TCP, the precursor of interconnected porous CO3Ap, could not be fabricated directly by sintering α-TCP spheres. It was therefore made via a setting reaction with α-TCP spheres, yielding interconnected porous calcium-deficient hydroxyapatite that was subjected to heat treatment. Immersing the interconnected porous α-TCP in Na–CO3–PO4 solution produced CO3Ap, which retained the interconnected porous structure after the dissolution–precipitation reaction. The diametral tensile strength and porosity of the porous CO3Ap were 1.8 ± 0.4 MPa and 55% ± 3.2%, respectively. Both porous and dense (control) CO3Ap showed excellent tissue response and good osteoconductivity. At 4 weeks after surgery, approximately 15% ± 4.9% of the tibial bone defect was filled with new bone when reconstruction was performed using porous CO3Ap; this amount was five times greater than that obtained with dense CO3Ap. At 12 weeks after surgery, for porous CO3Ap, approximately 47% of the defect was filled with new bone as compared to 16% for dense CO3Ap. Thus, the interconnected porous CO3Ap block is a promising artificial bone substitute material for the treatment of bone defects caused by large fractures or bone tumor resection.

Original languageEnglish
Pages (from-to)269-277
Number of pages9
JournalJournal of Biomedical Materials Research - Part B Applied Biomaterials
Issue number2
Publication statusPublished - Feb 2019

All Science Journal Classification (ASJC) codes

  • Biomaterials
  • Biomedical Engineering


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