Abstract
In this study we explore the hypothesis that there is a correlation between the ratio of the intensities of specific peaks of the Raman spectrum of bone tissue and the material properties of that particular type of bone. Raman spectroscopy is a powerful analytical technique capable of providing rich chemical information on the composition of skeletal tissue matrices and it has been used extensively to interrogate bone in the past. Spectra are presented of a selection of animal bones, each having greatly differing material properties, the differences having been produced by evolution in response to their greatly differing functions. The main examples described are deer antler (a bone naturally selected for toughness), tympanic bulla from a fin whale (naturally selected for stiffness) and the intermediate ‘standard’ bone from adult mammalian limbs which must be both tough enough to resist fracture and stiff enough to resist deformation during physiological loading (from an ovine femur in our case). In order to illustrate the specific relationship between material properties and Raman spectra additional mineralized tissues also with differing functions and of known Young's moduli are also introduced. The results show that a strong correlation exists between the mineral to collagen ratio of these different bone tissues as measured with Raman spectroscopy and their (previously published) Young's moduli. Raman spectra have been retrieved through skin and tissue in other studies in the past, an amalgamation of refined versions of those in vivo techniques with the work introduced here paves the way for the emergence of novel systems for assessing the material properties of bone tissue at specific anatomical sites in vivo in the future.
