Raman spectroscopy: elucidation of biochemical changes in carcinogenesis of oesophagus

Abstract

Several techniques are under development to diagnose oesophageal adenocarcinoma at an earlier stage. We have demonstrated the potential of Raman spectroscopy, an optical diagnostic technique, for the identification and classification of malignant changes. However, there is no clear recognition of the biochemical changes that distinguish between the different stages of disease. Our aim is to understand these changes through Raman mapping studies. Raman spectral mapping was used to analyse 20-mm sections of tissue from 29 snap-frozen oesophageal biopsies. Contiguous haematoxylin and eosin sections were reviewed by a consultant pathologist. Principal component analysis was used to identify the major differences between the spectra across each map. Pseudocolour score maps were generated and the peaks of corresponding loads identified enabling visualisation of the biochemical changes associated with malignancy. Changes were noted in the distribution of DNA, glycogen, lipids and proteins. The mean spectra obtained from selected regions demonstrate increased levels of glycogen in the squamous area compared with increased DNA levels in the abnormal region. Raman spectroscopy is a highly sensitive and specific technique for demonstration of biochemical changes in the carcinogenesis of Barrett's oesophagus. There is potential for in vivo application for real-time endoscopic optical diagnosis.

Detection of endogenous biomolecules in Barrett's esophagus by Fourier transform infrared spectroscopy

“…Consequently, Raman requires expensive detectors and sophisticated spectral processing, conditions that can be difficult to translate to the clinic for screening purposes (32,33). On the other hand, FTIR is an infrared absorption process that produces large signals that are insensitive to tissue autofluorescence.…”

Spectroscopic and chemometric approaches to radiobiological analyses

“…The higher signal levels achievable with FTIRM result in increased speed of measurement and consequently higher sample throughput over CRM [21]. The strengths of both are now well established in hyperspectral imaging for non-invasive and label-free histopathology [22][23][24][25][26][27][28][29][30], while the capabilities of CRM to detect tissue abnormalities in-vivo without the complication of contamination of spectral measurements by water and atmospheric features has resulted in a move to the development of clinical devices [31].…”

Extraction and Characterization of Pectin From Fresh Globe Artichoke and Canned Artichoke Waste

“…The increase in the intensity of these bands indicated the increase in the methoxyl bands as seen in Figure 4b. Similarly, the band at 971 cm -1 was assigned to O-CH 3 groups of pectin and had higher intensity values for the industrial waste samples as shown in Figure 4d (24). The amount of methoxyl groups for the waste samples was found to be lower in the chemical analyses.…”