Elemental Composition in Female Dry Femora Using Portable X-Ray Fluorescence (pXRF): Association with Age and Osteoporosis

Bones or Stones: How Can We Apply Geophysical Techniques in Bone Research?

Some studies have used physical techniques for the assessment of bone structure and composition. However, very few studies applied multiple techniques, such as those described below, at the same time. The aim of our study was to determine the chemical and mineralogical/organic composition of bovine tibial bone samples using geophysical/geochemical reference techniques. X-ray diffraction (XRD), thermogravimetry (TG), Fourier-transform infrared spectrometry with attenuated total reflectance accessory (FTIR-ATR), inductively coupled mass spectrometry (ICP-MS) and inductively coupled optical emission spectrometry (ICP-OES) were applied to measure the organic and inorganic composition of 14 bovine bone samples. In addition, peripheral quantitative CT (QCT) was used to assess BMD in these bones. We were able to define the total composition of the studied bone samples. ICP-OES and ICP-MS techniques were used to determine the major and trace element composition. The X-ray analysis could detect inorganic crystalline compounds of bones, such as bioapatite, and its degree of ordering, indicating whether the bones belong to a younger or older individual. The total volatile content of the samples was calculated using TG and resulted in about 35 weight% (wt%). This, together with the 65 wt% total resulting from the chemical analysis (i.e., inorganic components), yielded a total approaching 100 wt%. As a large portion of the volatile content (H2O, CO2, etc.) was liberated from the organic components and, subordinately, from bioapatite, it could be concluded that the volatile-to-solid ratio of the examined bone samples was ~35:65. The FTIR-ATR analysis revealed that the organic portion consists of collagens containing amide groups, as their typical bands (OH, CH, CO, NC) were clearly identified in the infrared spectra. Numerous parameters of bone composition correlated with BMD as determined by QCT. In conclusion, we performed a complex evaluation of bovine bones to test multiple geophysical/geochemical techniques in bone research in association with QCT bone densitometry. From a medical point of view, the composition of the studied bones could be reliably examined by these methods.

Elemental analysis using portable X-ray fluorescence: Guidelines for the study of dry human bone

OBJECTIVE

X-ray fluorescence (XRF) is a non-destructive technique that measures the elemental concentration of different materials, including human bone. Recently, it began to be applied to paleopathological studies due to the development of portable devices and their relative ease of use. However, the lack of uniform procedures hampers comparability and reproducibility. This paper aims to provide guidelines for an efficient and standardized evaluation of bone elemental composition with a portable XRF (pXRF) device.

MATERIALS

This technical note is based on the application of the Thermo Scientific Niton XL3t 900 GOLDD+.

METHODS

This work includes suggestions for the choice and preparation of human bone samples, both from archaeological context and documented collections, and methodological procedures in pXRF setup, such as choice of calibration, assessment of accuracy, and analysis run time. Additionally, recommendations for data validation and statistical analysis are also included.

CONCLUSIONS

This technique has great potential in paleopathology since bone chemical variations may be associated with different pathological conditions, environmental contamination (e.g., lead), and/or administered treatments, such as mercury. Following an expected increase in the number of studies, it is essential to establish good practices that allow results from different researchers to be comparable.

SIGNIFICANCE

X-ray fluorescence is a non-destructive technique that measures small concentrations (ppm) of elements from magnesium (12Mg) through bismuth (83Bi).

LIMITATIONS

pXRF does not detect elements lighter than Mg, and its lower energy excitation penetrates less than other techniques.

SUGGESTIONS FOR FURTHER RESEARCH

Other research groups should test these guidelines and comment on their usefulness and replicability.

Assigned sex estimation with the clavicle and scapula: A study in a Portuguese reference sample

The estimation of biological sex is a critical step in the assessment of the biological profile of an anonymous skeletonized individual. In certain recovery circumstances, the most dimorphic skeletal areas, such as the pelvis, are absent or fragmented; in that case, other bones of the skeleton, including the clavicle and scapula, can be used to predict sex. The purpose of this research is to generate new models for the estimation of sex with clavicular and scapular measurements using a study-sample of 129 individuals with clavicle (65 males and 64 females) and 112 individuals with scapula (50 males and 62 females) from the Lisbon Identified Skeletal Collection (Portugal). A decision tree classifier (C4.5) and logistic regression (LR) were employed to create univariable and multivariable sex prediction models. Accuracy under cross-validation of the classification models is high (up to 93.8%), with minimal bias (<5%), particularly in the multivariable models. The proposed LR models facilitate the probabilistic estimation of biological sex, accounting for the significant overlap in the expression of sexual dimorphism.

Hydrothermal extraction and physicochemical characterization of biogenic hydroxyapatite nanoparticles from buffalo waste bones for in vivo xenograft in experimental rats

Hydroxyapatite (HA) can be used in odontology and orthopedic grafts to restore damaged bone due to its stable chemical characteristics, composition, and crystal structural affinity for human bone. A three-step hydrothermal method was used for the extraction of biogenic calcined HA from the buffalo waste bones at 700 °C (HA-700) and 1000 °C (HA-1000). Extracts were analyzed by thermogravimetric analysis, differential scanning calorimetry, X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and in vivo examination of HA xenografts for femoral lesions in experimental rats. Crystallinity, purity, and morphology patterns showed that the HA main phase purity was 84.68% for HA-700 and 88.99% for HA-1000. Spherical HA nanoparticles were present for calcined HA-700 samples in the range 57-423 nm. Rats with critical bone lesions of 3 mm in diameter in the left femur treated with calcined HA-700 nanoparticles healed significantly (p < 0.001) faster than rats treated with HA-1000 or negative controls. These findings showed that spherical biogenic HA-700 NPs with a bud-like structure have the potential to stimulate both osteoconduction and bone remodeling, leading to greater bone formation potential in vivo. Thus, the calcined biogenic HA generated from buffalo waste bones may be a practical tool for biomedical applications.