Trends in early mineralization of murine calvarial osteoblastic cultures: a Raman microscopic study

The elucidation of early mineralization of bone is of great interest to the medical world. A clearer understanding of the initial bone formation processes can lead to information regarding the treatment and prevention of bone disorders and fractures and the manufacture of prosthetics. We exploited the mineralizing capabilities of bone cell cultures (osteoblast cultures) to monitor the earliest composition changes during mineral formation using Raman spectroscopy. We observed the first mineralization in 8-day-old osteoblasts and identified the mineral species as one that is very similar to that found in fetal bone tissue, a lightly carbonated apatite. Raman spectra show that carbonation, an indicator of bone maturity, appears at the first detectable stage of mineralization in osteoblasts, and increases over time. We also isolated single osteoblasts by growing them on fused-silica microscope slides. Not only did these cells exhibit abnormal growth patterns, but they also expressed a mineral composition different to a carbonated apatite. Raman spectra of this mineral species have spectral characteristics comparable to those of beta-tricalcium phosphate. Copyright (C) 2002 John Wiley Sons, Ltd.