TY - JOUR
T1 - Raman spectroscopic detection of changes in bioapatite in mouse femora as a function of age and in vitro fluoride treatment
AU - Freeman, J. J.
AU - Wopenka, B.
AU - Silva, M. J.
AU - Pasteris, J. D.
PY - 2001
Y1 - 2001
N2 - Laser Raman microprobe spectroscopy, which characterizes the molecular structure of a mineral, was used to analyze microscopically small regions of bioapatite in mouse femora in order to study the effect of mouse age and in vitro fluoride treatment on the bone mineral (i.e., mineral identity and degree of crystallinity). Both femora that had and those that had not undergone in vitro NaF treatment underwent point analysis of 1 μm spots in the center of the compact bone's cross-section. The Raman spectra of bones treated with fluoride showed a peak up-shift of the PO4 vibration mode from 961 to 964 Δcm-1 indicating a conversion from a carbonated hydroxylapatitic to a carbonated fluorapatitic mineral phase. The spectral band width of the 961 Δcm-1 PO4 vibration in femora of 4-, 10-, and 24-week-old mice showed that aging, as well as in vitro treatment with 1.5 M NaF for 12 hours, significantly increases the degree of crystallinity of the bioapatite. In vitro fluoridation of 10-week-old mouse femora increased the bioapatite's degree of crystallinity to about the same degree as did aging to 24 weeks. Four-point bending tests indicated that the age-related increase in crystallinity of untreated bones was associated with decreased deformation to failure, i.e., increased brittleness. In contrast, the increased crystallinity following fluoridation of 10-week-old bones was associated with increased deformation, i.e., increased ductility, perhaps due to the altered mineral composition. This study shows that the laser Raman microprobe readily detects the conversion of carbonated hydroxylapatite to carbonated fluorapatite, as well as changes in crystallinity of either mineral phase, in microscopically small regions of a bone sample.
AB - Laser Raman microprobe spectroscopy, which characterizes the molecular structure of a mineral, was used to analyze microscopically small regions of bioapatite in mouse femora in order to study the effect of mouse age and in vitro fluoride treatment on the bone mineral (i.e., mineral identity and degree of crystallinity). Both femora that had and those that had not undergone in vitro NaF treatment underwent point analysis of 1 μm spots in the center of the compact bone's cross-section. The Raman spectra of bones treated with fluoride showed a peak up-shift of the PO4 vibration mode from 961 to 964 Δcm-1 indicating a conversion from a carbonated hydroxylapatitic to a carbonated fluorapatitic mineral phase. The spectral band width of the 961 Δcm-1 PO4 vibration in femora of 4-, 10-, and 24-week-old mice showed that aging, as well as in vitro treatment with 1.5 M NaF for 12 hours, significantly increases the degree of crystallinity of the bioapatite. In vitro fluoridation of 10-week-old mouse femora increased the bioapatite's degree of crystallinity to about the same degree as did aging to 24 weeks. Four-point bending tests indicated that the age-related increase in crystallinity of untreated bones was associated with decreased deformation to failure, i.e., increased brittleness. In contrast, the increased crystallinity following fluoridation of 10-week-old bones was associated with increased deformation, i.e., increased ductility, perhaps due to the altered mineral composition. This study shows that the laser Raman microprobe readily detects the conversion of carbonated hydroxylapatite to carbonated fluorapatite, as well as changes in crystallinity of either mineral phase, in microscopically small regions of a bone sample.
KW - Apatite
KW - Bone
KW - Crystallinity
KW - Fluoridation
KW - Raman spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=0035028929&partnerID=8YFLogxK
U2 - 10.1007/s002230001206
DO - 10.1007/s002230001206
M3 - Article
C2 - 11351499
AN - SCOPUS:0035028929
SN - 0171-967X
VL - 68
SP - 156
EP - 162
JO - Calcified Tissue International
JF - Calcified Tissue International
IS - 3
ER -