Raman spectroscopy biological applications

For a quantitative analysis or classification of biological or medical problems by means of Raman spectroscopy the application of multivariate spectral analysis methods is required. These multivariate methods allow one to extract diagnostic, chemical, and morphological relevant information out of the complex Raman spectrum and must be applied due to the high amount of similar spectral features. 

Myers A B and Mathies R A 1987 Resonance Raman intensities A probe of excited-state structure and dynamics Biological Applications of Raman Spectroscopy yo 2, ed T G Spiro (New York Wiley-Interscience) pp 1-58... 

Figure Bl.2.11. Biologically active centre in myoglobin or one of the subunits of haemoglobin. The bound CO molecule as well as the proximal and distal histidines are shown m addition to the protohaeme unit. From Rousseau D L and Friedman J M 1988 Biological Applications of Raman Spectroscopy vol 3, ed T G Spiro (New York Wiley). Reprinted by pennission of John Wiley and Sons Inc.

Spiro, T. G. Biological Applications of Raman Spectroscopy Wiley New York, 1987 Vol. 3. 

T. G. Spiro Biological Applications of Raman Spectroscopy Resonance Raman Spectra of Heme and Metalloproteins, (1988) Wiley, New York. 

Resonance Raman Spectroscopy. If the excitation wavelength is chosen to correspond to an absorption maximum of the species being studied, a 102—104 enhancement of the Raman scatter of the chromophore is observed. This effect is called resonance enhancement or resonance Raman (RR) spectroscopy. There are several mechanisms to explain this phenomenon, the most common of which is Franck-Condon enhancement. In this case, a band intensity is enhanced if some component of the vibrational motion is along one of the directions in which the molecule expands in the electronic excited state. The intensity is roughly proportional to the distortion of the molecule along this axis. RR spectroscopy has been an important biochemical tool, and it may have industrial uses in some areas of pigment chemistry. Two biological applications include the determination of helix transitions of deoxyribonucleic acid (DNA) (18), and the elucidation of several peptide structures (19). A review of topics in this area has been published (20). 

Biological Systems. Whereas Raman spectroscopy is an important tool of physical biochemistry, much of this elegant work is of scant interest to the industrial chemist. However, Raman spectroscopy has been used to locate cancerous cells in breast tissue (53) and find cataractous tissue in eye lenses (54), suggesting a role in industrial hygiene (qv). Similarly, the Raman spectra of bacteria are surprisingly characteristic (55) and practical applications are beginning to emerge. 

A series of advances over the past decade have made CRS microscopy a highly sensitive tool for label-free imaging and vibrational microspectroscopy that is capable of real-time, non-perturbative studies of complex biological samples based on molecular Raman spectroscopy. In particular, biomedical applications where fluorescent labeling of small molecules represents a severe pertur-... 

Abstract This chapter will reviews the Raman spectroscopy of the subject tissues. After a brief introduction to the structure, biology, and function of these tissues, we will describe the spectra and band assignments of the tissues and then summarize applications to studies of tissue development, mechanical function and competence, and pathology. Both metabolic diseases and genetic disorders will be covered. 

In the past decade Raman spectroscopy has assumed an important role in musculoskeletal tissue studies, especially in bone tissue studies. Applications to a wide range of problems in basic biology, biomechanics, and medicine have appeared in the journal literature. Most workers have used cell cultures or excised bone tissue, including human biopsy and cadaveric tissue. We expect that Raman spectroscopy will become increasingly important in such studies, as more life scientists and engineers learn how to employ it. Just as importantly, recent reports of non-invasive spectroscopy suggest that Raman spectroscopy may have a role in human subjects studies of bone development, function, and disease. 

H.G.M. Edwards, E.A. Carter, Biological Applications of Raman Spectroscopy, vol. 24 (Marcel Dekker, New York, 2001)... 

A limiting factor in noninvasive optical technology is variations in the optical properties of samples under investigation that result in spectral distortions44 8 and sampling volume (effective optical path length) variability 49-54 These variations will impact a noninvasive optical technique not only in interpretation of spectral features, but also in the construction and application of a multivariate calibration model if such variations are not accounted for. As a result, correction methods need to be developed and applied before further quantitative analysis. For Raman spectroscopy, relatively few correction methods appear in the literature, and most of them are not readily applicable to biological tissue.55-59... 

NONCOVALENT FUNCTIONALIZATION OF SINGLE-WALLED CARBON NANOTUBES FOR BIOLOGICAL APPLICATION RAMAN AND NIR ABSORPTION SPECTROSCOPY... 

By tuning the laser source to the absorption maximum of the chromophore, the Raman spectrum obtained is the enhanced spectrum of that chromophore with little interference from the dense vibration modes of the protein or the water itself. For a quantitative discussion of resonance Raman spectroscopy (14) and its application to biological systems (15), the reader is referred to other papers. 

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