Fig 1.
FTIR spectra of PP film and glue.
(a) FTIR spectrum of the PP film. (b) FTIR spectrum of the glue. The spectra were extracted from the FTIR maps and normalized against 1 absorbance with respect to the highest band.
Fig 2.
Schematic overview of femur section mounting.
The frozen section on the glue-coated side of the PP film was placed face down on the regular BaF2 substrate in order to fix the sample position, while leaving a space in which the BaF2 substrate not covered with the PP film + glue.
Table 1.
Bone chemical composition parameters and wavenumbers of FTIR bands.
Fig 3.
FTIR spectra of PP film + glue and PMMA.
These spectra were extracted from the FTIR maps and normalized against 1 absorbance with respect to the highest band.
Fig 4.
A series of FTIR polarization spectra and their angle-dependent absorbance.
(A) The FTIR polarization spectra were collected in the range from 0 to 180° in increments of 10°. (B) The angle-dependent absorbance was obtained at 1167 cm-1, 997 cm-1, 972 cm-1, and 840 cm-1. (a) Absorption at 1167 cm-1 is a combination of the C-C stretching [ν(C-C)] and CH3 rocking vibration [ρ(CH3)]. (b) Absorption at 997 cm-1 is a combination of the C-CH3 rocking vibration [ρ(C-CH3)], C-CH3 stretching [ν(C-CH3)] and CH deformation band [δ(CH)]. Absorption at both 972 cm-1 and 840 cm-1 are combinations of the CH3 rocking vibration [ρ(CH3)] and C-C stretching [ν(C-C)].
Fig 5.
Visible and FTIR images of mouse femurs.
(a) Visible image of RESIN-S. (b) Visible image of FROZEN-S. (c) FTIR image of the distribution of the PO43- band in RESIN-S. (d) FTIR image of the distribution of the PO43- band in FROZEN-S.
Fig 6.
Bone quality of femur sections prepared by different sectioning procedures.
(a) Mineral-to-matrix ratio in RESIN-S and FROZEN-S. (b) Carbonate-to-phosphate ratio in RESIN-S and FROZEN-S. (c) Crystallinity in RESIN-S and FROZEN-S. Small closed circles and triangles represent the average bone quality values for 30 FTIR spectra extracted from each femur for the cortical and trabecular bone, respectively. Blue open circles and triangles represent the average of 3 plots for cortical bone. Red open circles and triangles represent the average of 3 plots for trabecular bone. Statistical analysis was performed by unpaired t-test (n = 3) to compare RESIN-S and FROZEN-S, and the p values are shown above the plots.
Fig 7.
FTIR spectra of RESIN-S and FROZEN-S sections.
The red line shows the FTIR spectrum of RESIN-S, and the blue line shows that of FROZEN-S. The spectra were normalized against the amide l band. A subtraction (black line) was obtained by subtracting the FTIR spectrum of the FROZEN-S section from that of the RESIN-S section.