Abstract:
This study aims to characterize the structure and properties of crocodile bone to assess the potential
for use in biomedical applications. Crocodile bone samples obtained from Thailand (Crocodylus
siamensisi and Australia (Crocodylus porosus), being the tail and the tibia respectively, were
treated to remove organic material and the inner spongy (trabecular) material. The dense cortical
bone was used for comparative instrumental analyses. Specific comparisons were made against
bovine cortical bone and pure synthetic hydroxyapatite. The material was then analyzed using
simultaneous differential thermal analysis/thermogravimetric analysis (DT AlTGA), Fourier-
Transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). Imaging of full
bone samples was also conducted using an environmental scanning electron microscopy (ESEM).
The SEM provided valuable information through the imaging of samples, showing a marked
increase in bone porosity for crocodile material when compared to bovine samples. The crystallinity
and/or crystallite size of carbonated hydroxyapatite has been found to be lower than synthetic
apatite, with the tibia being the least crystalline of the bone types studied. The crystallinity index
(CI) is used as a measure of crystallite size and internal strain. The strain is affected by substitutions
in the structure and these results provide a starting point for comparison of the resulting mechanical
properties. There is a need for any biomaterial chosen for bone replacement to allow adequate
osteointegration. Thus the study this far shows that crocodile bone is a very promising source of
carbonated apatite for biomedical applications.
