Infrared and Raman Spectroscopic Studies of Molecular Disorders in Skin Cancer

Abstract

Aim: To investigate the molecular structural disorders of cancerous skin.

Materials and methods: Human malignant melanoma and basal cell carcinoma biopsies were used for the investigation. Fourier transform infrared (FT-IR), Raman spectroscopy, and scanning electron microscopy were utilized. Spectral differences between healthy, basal cell carcinoma and melanoma tissues were recorded.

Results: The FT-IR bands of v_asCH₂, v_sCH₂ and Raman v_sCH₃ of cell membrane lipids were increased in intensity in melanoma due to an increased lipophilic environment. The FT-IR band at 1,744 cm^-1 assigned to malondialdehyde can be used as a band diagnostic of cancer progression. The amide I bands at 1,654 cm^-1 and 1,650 cm^-1 for Raman and FT-IR, respectively were broader in spectra from melanoma, reflecting changes of protein secondary structure from α-helix to β-sheet and random coil. The intensity of the FT-IR band at 1,046 cm^-1 was increased in melanoma, suggesting glycosylation of the skin upon cancer development. Another band that might be considered as diagnostic was found at about 815 cm^-1 in melanoma and was attributed to Z-DNA configuration. As far as we know, this is the first time that scanning electron microscopy revealed that metal components of titanium alloys from tooth implants were transferred to melanoma tissue taken from the back of one patient.

Conclusion: Vibrational spectroscopy highlighted increased glycosylation in melanoma.

Keywords: Raman spectroscopy; Skin cancer; bio-corrosion; infrared spectroscopy; metal implant.

Figure 1. Representative Fourier transform infrared spectra of skin tissues: (a-blue) normal, (b-red) basal cell carcinoma and (c-violet) melanoma in the region 4,000-500 cm–1.

Figure 2. Representative Raman spectra of skin tissues: (a-red) normal, (b-green) basal cell carcinoma and (c-blue) melanoma, in the region 3,200- 500 cm–1.

Figure 3. Scanning electron microscopy images showing the morphology of melanoma malignant from a patient who according to clinical history had titanium alloy tooth implants. A: Misfolded proteins (×160, scale 200 μm). B: Titanium-alloy deposit encapsulated by proteins (×4000, scale 10 μm). C: Mineral deposition aggregates on the surface of protein.