Effects of sintering temperatures on micro-morphology, mechanical properties, and bioactivity of bone scaffolds containing calcium silicate

In order to develop biomaterials for hard bone repair, biomimetic scaffolds were prepared from a mixture of hydroxyapatite (HA), beta-tricalcium phosphate (TCP), and calcium silicate (CS) at optimal weight ratios via the sintering technique. Composites obtained had homogeneous pore distribution and open pore morphology. Depending on the amount of CS added and the sintered temperature, the porosity obtained varied in a range of 47-64%. The scaffolds flexural strength and modulus of the scaffolds were comparable to that of cancellous bone. Improved mechanical properties were achieved by introducing CS at elevated sintering temperature. Fine particles of CS are more resistant to heat than those of HA or TCP, which are larger in diameter. Integration of CS grains with the HA/TCP composite does not occur by sintering at 1250 degrees C. CS particles were mainly distributed at the composite grain boundaries, and played a role in cracking resistance. To test bioactivity in vitro, the scaffolds were immersed in phosphate buffered saline for 3 weeks, and then assessed for apatite forming ability. Apatite did not form on the scaffolds sintered at 1050 and 1150 degrees C, but it did in those sintered at 1250 degrees C. The new biomaterials produced are suitable to prepare scaffolds, which may be used for long bone tissue engineering.