Raman spectroscopic analysis of oral cells in the high wavenumber region

Author(s):Show less -

Carvalho, Luis Felipe C. S. ^{[1, 2]} ; Bonnier, Franck ^[3] ; Tellez, Claudio ^[4] ; dos Santos, Laurita ^[4] ; O'Callaghan, Kate ^[5] ; O'Sullivan, Jeff ^[5] ; Soares, Luis Eduardo S. ^[6] ; Flint, Stephen ^[5] ; Martin, Airton A. ^[4] ; Lyng, Fiona M. ^{[7, 8]} ; Byrne, Hugh J. ^[1]

Affiliation

^[1] Dublin Inst Technol, FOCAS Res Inst, Kevin St, Dublin 8 - Ireland

^[2] Univ Taubate UNITAU, Dept Odontol, Taubate - Brazil

^[3] Univ Francois Rabelais Tours, Fac Pharm, EA Nanomedicaments & Nanosondes 6295, 31 Ave Monge, F-37200 Tours - France

^[4] Univ Brasil UnBr, Biomed Vibrat Spect Grp, Biomed Engn Innovat Ctr, Rua Carolina Fonseca 235, BR-08230030 Sao Paulo, SP - Brazil

^[5] Dublin Dent Univ Hosp, Trinity Coll Dublin, Dublin 2 - Ireland

^[6] Univap Inst Pesquisa & Desenvolvimento, Lab Dent & Appl Mat, Ave Shishima Hifumi 2911, BR-12244000 Sao Jose Dos Campos, SP - Brazil

^[7] Dublin Inst Technol, FOCAS Res Inst, Radiat & Environm Sci Ctr, Kevin St, Dublin 8 - Ireland

^[8] Dublin Inst Technol, Sch Phys, Kevin St, Dublin 8 - Ireland

• Document type: Journal article
• Source: Experimental and Molecular Pathology; v. 103, n. 3, p. 255-262, DEC 2017.
• Web of Science Citations: 2

Abstract

Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with submicrometer spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1800 cm(-1)) has been shown to be very promising for optical biopsy purposes. However, limitations for discrimination of dysplastic and inflammatory processes based on the fingerprint region have been demonstrated. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2800-3600 cm(-1)) provides more specific information based on N-H, O-H and CH vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the high-wavenumber spectral region in this context by collecting Raman spectra of nucleolus, nucleus and cytoplasm from oral epithelial cancer (SCC-4) and dysplastic (DOK) cell lines and from normal oral epithelial primary cells, in vitro, in water immersion, which were then analyzed by principal components analysis as a method to discriminate the spectra. Analysis was performed before and after digital subtraction of the bulk water signal. In the normal cell line, the three subcellular regions are well differentiated before water subtraction, although the discrimination of the two nuclear regions is less well defined after water subtraction. Comparing the respective subcellular regions of the three cell lines, before water subtraction, the cell lines can be discriminated using sequential PCA and Feature Discriminant Analysis with up to similar to 100% sensitivity and 97% specificity for the cytoplasm, which is improved to 100% sensitivity and 99% specificity for the nucleus. The results are discussed in terms of discrimination comparing the CH vibrational modes of nucleic acids, proteins and lipids. The potential role of the OH vibrations, considering free water and confined water, in the discrimination of cell cultures and pathological processes are also discussed. (AU)

• FAPESP's process: 14/05978-1 - In vivo Raman spectroscopy for pathological processes of oral mucosa diagnosis
• Grantee: Luis Felipe das Chagas e Silva de Carvalho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral