Transformation from calcium sulfate to calcium phosphate in biological environment
Journal
Journal of Materials Science: Materials in Medicine
Journal Volume
32
Journal Issue
12
Date Issued
2021
Author(s)
Abstract
The formation of a nano-apatite surface layer is frequently considered a measure of bioactivity, especially for non-phosphate bioceramics. In the present study, strontium-doped calcium sulfate, (Ca,Sr)SO4, was used to verify the feasibility of this measure. The (Ca,Sr)SO4 specimen was prepared by mixing 10% SrSO4 by weight with 90% CaSO4·?H2O powder by weight. A solid solution of (Ca,7.6%Sr)SO4 was then produced by heating the powder mixture at 1100 °C for 1 h. The resulting (Ca,Sr)SO4 specimen was readily degradable in phosphate solution. A newly formed surface layer in the form of flakes was formed within one day of specimen immersion in phosphate solution. Structural and microstructure–compositional analyses indicated that the flakes were composed of octacalcium phosphate (OCP) crystals. An amorphous interface containing OCP nanocrystals was found between the newly formed surface layer and the remaining (Ca,Sr)SO4 specimen. The specimen was also implanted into a rat distal femur bone defect. In addition to new bone, fibrous tissue and inflammatory cells were found to interlace the (Ca,Sr)SO4 specimen. The present study indicated that a more comprehensive evaluation is needed to assess the bioactivity of non-phosphate bioceramics. [Figure not available: see fulltext.] ? 2021, The Author(s).
Subjects
Bioactivity
Bioceramics
Bone
Calcium phosphate
Calcium sulfate
Amorphous interfaces
Biological environments
Compositional analysis
Distal femurs
Nano-apatites
Octacalcium phosphate
Phosphate crystals
Phosphate solutions
Powder mixtures
Surface layers
Strontium compounds
Type
journal article