Raman spectroscopic characterization of blood plasma of oral cancer

Abstract

Raman Spectroscopy is a versatile technique to probe in to the vibrational or rotational transitions of a molecule and extract complete information about the biochemical composition of the sample under investigation. The metabolic end products of the cell that were released in to the circulating blood would change the biological molecules and thus alter their spectral signatures. Based on this, a pilot study was carried out to discriminate oral cancer patients (n=14) from that of healthy subjects (n=14), using the Raman spectroscopy of blood plasma using Lab RAM HR 800 (HORIBA Jobin Yvon, France) instrument for the spectral range 800- 1800 cm-1. From the spectral profiles of the bio constituents such as protein, amino acids, glucose and lipid, markable difference was observed between the cancer patients and the healthy subjects. Raman peaks corresponding to bio components such as phenylalanine in albumin (939, 1002 cm-1), glucose (1124 cm-1), tryptophan (1205 & 1342 cm-1), amide III (1247 cm-1) and phospholipids (1450 & 1656 cm-1) were different for oral cancer patients from that of healthy subjects. The averaged spectra of cancer patients showed a noticeable blue shift for the peaks corresponding to protein at 1002 cm-1, lipid at 1450 and 1656 cm-1 and a overall decrease in intensity was observed for cancer spectrum. Further, the Raman spectra were analyzed employing the multivariant statistical methods such as principal component analysis (PCA) and linear discriminant analysis (LDA), for the range 800- 1800 cm-1. The results were promising in discriminating blood plasma of oral cancer patients from that of healthy ones.