**4. Conclusions**

From FT-IR spectra in the region 1700-1500 cm-1, which characterises the secondary structure of proteins, is found that demineralization changes the secondary structure of collagen from α-helix to β-pleated and random coil. Considerable intensity decrease was observed also in the region 1200-900 cm-1, where the absorptions bands of phosphates from hydroxyapatite appear, which are due to bone demineralization and bone damage. The presence of calcium antagonists inhibits partly the demineralization of bones, which is induced from EDTA. These results could lead to the conclusion that the bone diseases maybe change their secondary structure. These experimental data indicate that β-blockers may prevent bone loss in humans and new drugs to cure osteoporosis could be synthesized on this base.

#### **5. References**

268 Infrared Spectroscopy – Life and Biomedical Sciences

concentration of calcium increases up to 07.62. A similar result was obtained in the presence of atenolol, C14H22O2N2, but in both cases the calcium concentration was less than normal

In Fig. 7 are given the SEM images of cancellous bone sections with enlargement of X80. From the architecture and morphology of the images it is shown that after the reaction of bone with EDTA the sample does not show any bright regions, since the density of the bone

Fig. 7. SEM images of bone a) without any penetration, b) after demineralization with

Significant changes in the brightness of the image are observed, when the demineralization takes place in the presence of C13H24N4O3S. It is observed an increase in bone density and the deposition of calcium on bone tissue is obvious (Fig. 7c). The image in Figure 6d corresponds to the result, which was obtained after the reaction of bone with EDTA in the presence of C14H22O2N2. The picture shows that the bone gets a more amorphous structure. These results are in agreement with the FT-IR data, which led to the suggestion that the

From FT-IR spectra in the region 1700-1500 cm-1, which characterises the secondary structure of proteins, is found that demineralization changes the secondary structure of collagen from α-helix to β-pleated and random coil. Considerable intensity decrease was observed also in the region 1200-900 cm-1, where the absorptions bands of phosphates from hydroxyapatite appear, which are due to bone demineralization and bone damage. The presence of calcium antagonists inhibits partly the demineralization of bones, which is induced from EDTA. These results could lead to the conclusion that the bone diseases

EDTA, c) after demineralization in the presence of C13H24N4O3S and d) after

biological hydroxyapatite changed from low crystallinity to amorphous state.

demineralization in the presence of C14H22O2N2.

**4. Conclusions** 

is minimized (Fig. 7b) after the elimination of minerals of bone tissue.

concentration.


**16** 

*Greece* 

Vasiliki Dritsa

**FT-IR Spectroscopy in Medicine** 

Infrared spectroscopy has been widely applied for the characterisation of various substances. Due to its sensitivity to the chemical information and architecture of the molecule, infrared spectroscopy can play an important role in new applications such as in the life-science field and not only in the traditional fields of physics and chemistry. Spectroscopic techniques are simple, reproducible, non-destructive without particular sample preparation. As a result, they provide information for the functional groups, bonds

Herschel discovered the existence of infrared radiation when he tried to measure the heat produced by separate colors of a rainbow spectrum in 1800. He noted that the highest temperature fell beyond the red end of the spectrum, implying the existence of invisible light beyond the red. Herschel termed this light *calorifi*c *rays*. Infrared spectra originate on the vibrational motions of atoms in chemical bonds within molecules. When a beam of light containing the IR radiation band is passed through a sample, light energy from the photons is absorbed by the chemical bonds and excites the vibrational motions. As a molecule absorbs radiation at a specific frequency, it produces a band in the infrared spectrum at the corresponding wavenumber. The approximate position of an infrared absorption band is determined by the vibrating masses and the chemical bonds (single, double, triple). Τhe exact position of the band depends also on electron withdrawing or donating effects of the intra- and intermolecular environment and coupling with other vibrations. The strength of absorption increases with increasing polarity of the vibrating atoms. The modes of vibration in a molecule that can absorb infrared radiation are many and increase with increasing complexity of the molecule. The vibrations that contribute to the spectrum are bending and stretching vibrations between atoms and rocking, twisting and wagging of a functional

Fourier transform infrared spectroscopy is preferred over dispersive or filter methods of infrared spectroscopy due to the sensitivity and the rapid data collection. The FT-IR spectrometer uses an interferometer to modulate the wavelength from a broadband infrared source. Light emitted from the infrared source is split by a beam splitter. Half of the light is reflected towards a fixed mirror and from there reflected back towards the beamsplitter where about 50% passes to reach the detector. The other half of the initial light intensity passes the beam splitter on its first encounter, is reflected by the moving mirror back to the beamsplitter where 50% of it is reflected towards the detector (Figure 1).When the two

**1. Introduction** 

and molecular structure.

group (Theophanides, 1984; Goormaghtigh et al., 1999).

*National Technical University of Athens, NTUA* 

