Biochemical Profiles of In Vivo Oral Mucosa by Using a Portable Raman Spectroscopy System

Marcelo Saito Nogueira,Luis Felipe Das Chagas E Silva De Carvalho Carvalho,Felipe Peralta,Victoria Ribeiro,Marianna Pires

doi:10.3390/opt2030013

Marcelo Saito Nogueira, Luis Felipe Das Chagas E Silva De Carvalho Carvalho + Show 3 more

Open Access

https://doi.org/10.3390/opt2030013

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Abstract

Most oral injuries are diagnosed by histopathological analysis of invasive and time-consuming biopsies. This analysis and conventional clinical observation cannot identify biochemically altered tissues predisposed to malignancy if no microstructural changes are detectable. With this in mind, detailed biochemical characterization of normal tissues and their differentiation features on healthy individuals is important in order to recognize biomolecular changes associated with early tissue predisposition to malignant transformation. Raman spectroscopy is a label-free method for characterization of tissue structure and specific composition. In this study, we used Raman spectroscopy to characterize the biochemistry of in vivo oral tissues of healthy individuals. We investigated this biochemistry based on the vibrational modes related to Raman spectra of four oral subsites (buccal, gingiva, lip and tongue) of ten volunteers as well as with principal component (PC) loadings for the difference between the four types of oral subsites. Therefore, we determined the biochemical characteristics of each type of healthy oral subsite and those corresponding to differentiation of the four types of subsites. In addition, we developed a spectral reference of oral healthy tissues of individuals in the Brazilian population for future diagnosis of early pathological conditions using real-time, noninvasive and label-free techniques such as Raman spectroscopy.

Highlights

There is an increasing need for techniques capable of providing biochemical characterization of tissues in real time
Prominent characteristics include the peaks at 938 cm−1 and 1130 cm−1 most prominent in tongue tissues, the phosphate peak at 960 cm−1 in gingiva and the peaks at 1271 cm−1, 1303 cm−1, 1447 cm−1 and 1657 cm−1 in buccal mucosa and lip
According to Lascala et al [64], in the histological point of view, the periodontium consists of connective tissue, covered by stratified parakeratinized squamous epithelium, which can vary with the degrees of keratinization (Figure 9)

Summary

Introduction

There is an increasing need for techniques capable of providing biochemical characterization of tissues in real time. A range of applications requires development of those techniques in order to improve the accuracy of tissue identification, disease detection and surgical guidance. One of these applications is oral cancer diagnosis. Histopathological examination is currently the most accurate and reliable method of diagnosis, this examination has several limitations. Surgical biopsies are invasive, require sample preparation and take a long time to analyze, which can cause anxiety and discomfort to patients, resulting in treatment delays. For all the aforementioned reasons, a non-invasive, real-time point-of-care method to detect and accurately

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Conclusion