Fourier Transform Infrared Spectroscopy (FTIR) can provide information on the macromolecular make-up of biological samples, based on the absorption of infrared light at specific wavelengths depending on the chemical bonds that are present in a bio-molecule. The specific absorptions constitute spectra that can be considered as molecule-specific as fingerprints. These can be used to identify one cell/tissue type from another, for examples cancer and non-cancer cells. By sub-dividing an area of a biological sample into smaller sub-sections, and collecting infrared spectra from each sub-section, an image based on the bio-molecular information of the cells can be constituted. Using an FTIR instrument coupled to a microscope, we successfully collected infrared spectra from a human hair bulb from a human scalp skin cryosection. After applying chemometric analyses using Cytospec software, based solely on the spectroscopic hence bio-molecular variations between sub-sections, we were able to discern the tissue layers in the hair bulb. Each spectral cluster can be identified as a different tissue layer, and an average spectrum from each cluster was calculated. Each average spectrum provides information on the levels of protein, lipid, fatty acid, carbohydrate and nucleic acid contents, as well as secondary structure of proteins, so that the level of presence of keratin, collagen, proteoglycan etc. can be extracted and compared. FTIR microspectroscopy imaging is to our knowledge applied to discerning hair follicle layers for the first time, and based on this success, we aim to apply this label-free and non-destructive technique to other aspects of hair follicle and skin research, so that single cell variations within a tissue layer can be investigated, and effects of gene knock-out’s and application of diffusible factors/drugs uncovered.
|Number of pages
|Published - 2010