Cells and Materials


Knowledge of the phase, composition, and crystallite size and perfection of the mineral in normal and abnormally calcified tissues provides insight into the mechanism by which this mineral was deposited. These data also can be used to develop rational therapies for pathological conditions characterized by abnormal mineral deposition. As illustrated in this review, coupling of an optical microscope with a Fourier transform infrared (FT-IR) spectrophotometer permits the mapping at 20 μm spatial resolution of changes in mineral characteristics (content, particle size, composition) in the growth plate, in bone biopsies, in mineralizing cell culture systems, and in soft tissue calcifications. Based on the infrared properties of apatitic compounds, and comparisons with x-ray diffraction data, correlations have been established from which mineral parameters can be determined. The validity of these spectral correlations has been demonstrated by independent measurements of mineral content (ash weight), and crystal particle size (dark field electron microscopy).