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Comparison of amorphous TCP nanoparticles to micron‐sized α‐TCP as starting materials for calcium phosphate cements
Author(s) -
Brunner Tobias J.,
Bohner Marc,
Dora Claudio,
Gerber Christian,
Stark Wendelin J.
Publication year - 2007
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30809
Subject(s) - amorphous solid , materials science , amorphous calcium phosphate , chemical engineering , calcium , nanoparticle , transmission electron microscopy , cement , phosphate , mineralogy , composite material , nanotechnology , chemistry , metallurgy , organic chemistry , engineering
Abstract The development of degradable bone cements with a mineral composition similar to natural bone was investigated using highly reactive calcium phosphate phases as starting materials. Mixtures of XRD‐amorphous, glassy tricalcium phosphate (amorphous‐TCP) nanoparticles of 25–60 nm size and micron sized, milled α‐TCP were set by hydration with sodium phosphate buffer and investigated for possible application as single component calcium phosphate cements (CPCs). Isothermal calorimetry allowed a precise tracking of the setting process. Amorphous‐TCP nanoparticles converted into calcium deficient hydroxyapatite with cement setting times below 12 min. The total energy release by the material during hardening corroborated the importance of high specific surface area and phase composition, that is, amorphous state of the nanometric starting material as repeatedly suggested earlier. The phase composition of the resulting CPCs was characterized by X‐ray diffraction before and after setting. The morphology was investigated by nitrogen adsorption, scanning, and transmission electron microscopy and revealed the formation of highly porous calcium deficient hydroxyapatite with specific surface areas of up to 160 m 2 g −1 after setting. In contrast to the very fast reaction time and highest specific surface area, the mechanical stability of the resulting CPC is still insufficient and requires further improvement. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2007