A structural approach in the study of bones: fossil and burnt bones at nanosize scale

Abstract

We review the different factors affecting significantly mineral structure and composition of bones.Particularly, it is assessed that micro-nano-structural and chemical properties of skeleton bones change drastically during burning; the micro-and nano-structural changes attending those phases manifest themselves, amongst others, in observable alterations to the bones colour, morphology, microstructure, mechanical strength and crystallinity.Intense changes involving the structure and chemical composition of bones also occur during the fossilization process. Bioapatite material is contaminated by an heavy fluorination process which, on a long-time scale reduces sensibly the volume of the original unit cell, mainly the a-axis of the 2 hexagonal P63/m space group. Moreover, the bioapatite suffers to a varying degree of extent by phase contamination from the nearby environment, to the point that rarely a fluorapatite single phase may be found in fossil bones here examined.TEM images supply precise and localized information, on apatite crystal shape and dimension, and on different processes that occur during thermal processes or fossilization of ancient bone.complementary to that given by X-ray Diffraction and Attenuated Total Reflection Infrared spectroscopy. We are presenting a synthesis of XRD, ATR-IR and TEM results on the nanostructure of various modern, burned and palaeontological bones.

Burned bones tell their own stories: A review of methodological approaches to assess heat-induced diagenesis

“…Later, Piga et al verified that heat (200-1000 ºC) induced alterations in human femur and teeth that were clearly observable in XRD diffractograms for different burning periods -an increase of the average crystal size was observed with temperature, especially above 800 ºC, and new inorganic phases such as CaO appeared, thus showing the potential of this technique for estimation of burning time and temperature(66). More recently, these conclusions were corroborated by the same authors, when they compared fossil and burned modern bones through a multi-technique methodology (including XRPD)(36).…”

“…For instance, it is now clear that heat-induced macroscopic changes are closely related to submicroscopic alterations triggered by heat (8,17,(28)(29)(30). Thus analytical methodologies aiming at the elemental composition and the submicroscopic structure started to be applied on burned bones to relate them with the macroscopic ones (18,29,(31)(32)(33)(34)(35)(36)(37)(38)(39). A review of the state of the art is here provided.…”

Biomaterials from human bone – probing organic fraction removal by chemical and enzymatic methods

“…intact, subject to burning events or to specic chemical handling, or even archaeological artefacts. 3,8,15,16,24,[30][31][32][33][34][35][36][37][38][39] FTIR, mainly in attenuated total reectance (ATR) mode, is a low-cost, non-destructive and rapid method for this type of analysis, that requires very small amounts of sample and yields very reliable data providing information on the chemical and structural characteristics of the bone, namely its organic components (protein and lipids), possible mineral contaminants (e.g. including uorapatite (francolite), chloroapatite, cinnabar or gypsum) or pathology-induced changes.…”

β-Tricalcium Phosphate Interferes with the Assessment of Crystallinity in Burned Skeletal Remains

“…While macroscopic alterations (e.g., surface colour) can be used to deduce an approximate temperature range [12][13][14][15], the investigation of the micro-and ultrastructural alterations of skeletal hard tissue exposed to high temperatures has proven to be crucial to get a reliable estimation of maximum temperature [8,9,13,[16][17][18][19][20][21][22][23]. The bone which has been thermally altered shows an increase in crystallinity, exhibiting larger crystals and lower lattice strains [8,9,13,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”