Biological Applications of Near-infrared Excited Raman Spectroscopy.

Abstract

Recent introduction of near-infrared (NIR) Raman spectroscopy (NIR Fourier transform (FT) Raman and NIR multichannel Raman spectroscopy) to the studies of biological systems has opened new era in the bio-Raman field. NIR Raman spectroscopy has following advantages for the biological studies. First, Raman measurements of fluorescent materials and photolabile com-pounds become feasible. Second, the light in the NIR region can penetrate biological tissues suffi-ciently, and thus the use of NIR excitation enables one to directly extract useful information ab-out biological molecules included inside the tissues from their Raman spectra. FT-Raman spec-troscopy has three additional advantages. One is easiness of sample setting and optical adjust-ment. Another is that the simultaneous measurement of almost the entire Raman spectral region (4000-50 cm-1) is possible. Yet another is that reliable difference spectra can be calculated. The purpose of the present review is to show the potential of NIR Raman spectroscopy by tak-ing up examples in biochemistry, biophysics, medicine, and food sciences.