Raman Microspectroscopy of Hair Cuticle With Polarized Excitation: Problem of Protein Secondary and Tertiary Structure

The study investigates the Raman spectra of human hair cuticle using polarized excitation to understand the protein secondary and tertiary structures. The research identifies specific bands (~150, 220–230, 900, 935, 1321, 1338, and 1652 cm−1) that are sensitive to polarization and linked to the skeletal vibrations of α-helices in hair keratins. It highlights that different Raman spectra can be obtained based on the direction of signal collection, even under identical polarization conditions. Additionally, certain markers of keratin's secondary structure (~150, 935, and 1338 cm−1) may also indicate changes in the tertiary structure. The authors report no conflicts of interest and received no specific funding for this work.