FTIR microspectroscopic analysis of human osteonal bone

Abstract

Fourier Transform Infrared Microspectroscopy (FTIRM) has been used to study the changes in mineral and matrix content and composition in replicate biopsies of nonosteoporotic human osteonal bone. Spectral maps in four orthogonal directions (in 10 microm steps) from the centers towards the peripheries of individual osteons were obtained from iliac crest biopsies of two necropsy cases. Mineral to matrix ratios, calculated from the ratio of integrated areas of the phosphate nu1,nu3 band at 900-1200 cm-1 to the amide I band at 1585-1725 cm-1, increased from the center to the periphery of the osteon. The total carbonate (based on the nu2 band at approximately 850-900 cm-1) to phosphate nu1,nu3 ratio decreased as the mineral to matrix ratio increased. Analysis of the nu2 CO32- band with a combination of second-derivative spectroscopy and curve fitting revealed a decrease in "labile" carbonate, a slight decrease in Type A and a slight increase in Type B carbonate from the center to the periphery of the osteon. Similar analysis of the components of the nu1,nu3 phosphate band with a combination of second-derivative spectroscopy and curve fitting revealed the presence of 11 major underlying moieties. These components were assigned by comparison with published frequencies for apatite and acid-phosphate containing calcium phosphates. The most consistent variations were alterations in the relative percent areas of bands at approximately 1020 and approximately 1030 cm-1, which had previously been assigned to nonstoichiometric and stoichiometric apatites, respectively. This ratio was used as an index of variation in crystal perfection throughout the osteon. This ratio decreased as the mineral to matrix ratio increased. The reproducibility of these parameters at multiple sites in multiple biopsies suggests their applicability for the analysis of mineral changes in disease.

HRTEM Study of the Mineral Phases in Human Cortical Bone

“…[2] However, existence of non-HA crystalline phase in bone minerals has also been expected; especially recent studies using Fourier transform infrared spectroscopy (FTIR) and inelastic neutron scattering and nuclear magnetic resonance (NMR) revealed lack of OH À in bone minerals. [3][4][5][6][7] Particularly, octacalcium phosphate (OCP) has been proposed as a precursor involved in bone formation. [2,8,9] The presence of OCP in bone minerals has been supported by a lot of indirect experimental evidences, [3][4][5][6][7] but OCP has not been directly identified in bone minerals.…”

“…[3][4][5][6][7] Particularly, octacalcium phosphate (OCP) has been proposed as a precursor involved in bone formation. [2,8,9] The presence of OCP in bone minerals has been supported by a lot of indirect experimental evidences, [3][4][5][6][7] but OCP has not been directly identified in bone minerals. Note that it is not easy to distinguish OCP from HA in the commonly obtained XRD pattern of bone minerals with poorly resolved diffraction peaks.…”

Synthesis and character investigation of new collagen Hydrolysate/polyvinyl alcohol/hydroxyapatite Polymer-Nano-Porous Membranes: I. Experimental design optimization in thermal and structural properties

“…2e, g, the FT-IR spectra of CH/HA and CH-PVA/HA composite materials are very similar to the spectra of real bone (Evans et al 1992;Paschalis et al 1996). The appearance of an amide I mode at 1,662 cm -1 indicates that CH/HA composites adopt a predominantly ahelical configuration and this is confirmed by the appearance of amide II mode at 1,556 cm -1 (Doyle et al 1975;Payne and Veis 1988).…”

Nano-FTIR chemical mapping of minerals in biological materials

“…It reveals relative weights of apatite species that are assigned, with the help of chemical and X-ray analyses, to Mg 2+ , F − or CO 3 2− substitution, or differing particle size, or crystal imperfections [24,31,32]. In this study we demonstrate the power of nano-FTIR to map naturally formed mineralized nanostructures.…”

“…While being assigned to phosphate as in the M. edulis case, we find that the tooth phosphate resonance is significantly broadened. Apparently this is an inhomogeneous broadening akin to what is known from classical FTIR spectra of bone [23][24][25][26][27][28][29][30][31][32]. Figure 7; SEM intensity (black), topography (grey, in nm scaled by 1/240), nano-FTIR spectra (upper two panels), and three therefrom extracted quantities: amplitude at 1020 cm −1 (red, scaled ×2500), ratio r of amplitudes at 1053 and 1022 cm −1 (green), and phase at 1080 cm −1 (blue, in rad scaled by 1/2).…”