Infrared (IR) microspectroscopy has been used increasingly in recent years as a technique for analysing cell samples for diagnostic purposes, even in the very early stages of a disease. This analysis, based on the study of biochemical changes in cells, is far more accurate and sensitive than a classic cytological analysis, where much depends on how the operator assesses the appearance of the cells. When a spectral analysis is performed on single cells, however, the wavelengths of the incident IR radiation are comparable to the size of the object being observed. As a result, the cells scatter the radiation, and the measurements are significantly altered.
To avoid this problem, English, Norwegian and Irish teams have developed a corrective algorithm to be applied to IR spectroscopy measurements. The spectra obtained from human (prostate) cancer cells were recorded on the SMIS beamline. The effectiveness of this method was further improved by the application of an iterative approach whereby the reference spectrum for the correction is improved at each iteration. This allowed the artefact caused by scattering to be eliminated.
References:
Bassan, P., Kohler, A., Martens, H., Lee, J., Byrne, H. J., Dumas, P., Gazi, E., Brown, M. D., Clarke, N. W., & Gardner, P.
Resonant Mie Scattering (RMieS) correction of infrared spectra from highly scattering biological samples.
Analyst, 2010, 135(2): 268-277
Bassan, P., Kohler, A., Martens, H., Lee, J., Jackson, E., Lockyer, N., Dumas, P., Brown, M., Clarke, N. W., & Gardner, P.
RMieS-EMSC correction for infrared spectra of biological cells: Extension using full Mie theory and GPU computing.
Journal of Biophotonics, 2010, on-line first.
