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Characterization by FTIR and DSC interaction of collagen - hydroxyapatite

Abstract:

In the present work, we studied the effect of the mineral content (hydroxyapatite), on the thermal stability of the bone collagen matrix. The demineralization process was followed measuring the percentage of remaining mass and characterized by Fourier Transform Infra Red Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC), using a Calcium chelant agent (EDTA). A 52% loss of the initial weight was observed after 72 hours of treatment, associated with a decrease of the mineral content, indicated by changes in the intensity of the peaks correspondent to PO4-3 vibrations. The bone collagen's denaturalization and degradation temperatures was followed by DSC, showing an endotherm in 166° C for the untreated bone and in 113°C for the 72 hours treated bone, correspondent both to the bone collagen denaturalization temperature. The thermogram for the 12 hours demineralized exhibited a small endotherm in 250°C, corresponding to slight degradation, for the 72 hours treated bone the endotherm decreased to 230° C, correspondent to the bone collagen degradation. The above results lead us to conclude that the bone collagen triple helix losses its thermal stability when the interactions with the surrounding hydroxyapatite are eliminated. © Springer-Verlag Berlin Heidelberg 2007.