Effects of Hydroxyapatite Morphology on MC3T3-E1 Osteoblast-Like Cells

Hydroxyapatite (HA) whiskers have been used to reinforce HA ceramics, polyethylene and polyetheretherketone for new orthopaedic biomaterials. While the mechanical advantages of HA whiskers are promising, the effects of the whisker morphology on cellular behavior has not been investigated. Therefore, the overall objective of this study was to investigate the initial attachment, proliferation and differentiation of MC3T3-E1 osteoblast-like cells plated on HA powder and whisker substrates. MC3T3-E1 osteoblast-like cells were cultured in vitro on powder compacts prepared from HA powder or whiskers. The substrates were characterized chemically and physically to ensure that the only difference between them was the native powder morphology. A combination of biochemical assays and microscopy showed that cells cultured on HA whisker substrates exhibited greater initial attachment and spreading compared to the HA powder. Additionally, cells cultured on both HA powder and whisker substrates reached confluence within 14 days, nearing or exceeding levels of activity seen with a control substrate consisting of tissue culture plastic. No difference was observed in the proliferation rate of cells on HA whisker vs. powder substrates. Therefore, HA whiskers were concluded to be at least as biocompatible as a more conventional equiaxed powder.