Studying Variations in Bone Composition at Nano-Scale Resolution: A Preliminary Report

Bone has a hierarchical structure extending from the micrometer to the nanometer scale. We report here the first analysis of non-human primate osteonal bone obtained using a spectrometer coupled to an AFM microscope (AFM-IR), with a resolution of 50–100 nm. Average spectra correspond to those observed with conventional FTIR spectroscopy. The following validated FTIR parameters were calculated based on intensities observed in scans covering ~60 µm from the osteon center: mineral content (1030/1660 cm⁻¹), crystallinity (1030/1020 cm⁻¹), collagen maturity (1660/1690 cm⁻¹), and acid phosphate content (1128/1096 cm⁻¹). A repeating pattern was found in most of these calculated IR parameters corresponding to the reported inter- and intra-lamellar spacing in human bone, indicating that AFM-IR measurements will be able to provide novel compositional information on the variation in bone at the nanometer level.