Molecular Characterization of Human Tissue Samples by Raman Spectroscopy with Different Laser Modes and Excitation Wavelengths

In recent years, Raman spectroscopy has emerged as a potentially useful tool for the detection and pathological diagnosis of cancerous tissues. This technique has the merit of being highly sensitive to the biochemical alterations in tissue compositions. Nevertheless, the use of Raman spectroscopy in cancer detection has been impeded by high background intensity which can mask the Raman signal of biological molecules. In this study, we aimed at investigating the origins of background and reducing it by studying the influence of both excitation wavelengths and optical modes. Different optical modes, single mode and multimode lasers, with the same excitation 785 nm and different excitation wavelengths, 785 nm and 830 nm lasers with the same multimode are compared here. According to this study, autofluorescence and multiple Mie scattering give rise to the high background intensities in the Raman spectra. The reduction in autofluorescence is demonstrated in the comparison between 785 nm multimode (785 MM) and 830 nm multimode (830 MM) lasers. 830 MM demonstrates better autofluorescence reduction ability than 785 MM. However, the Raman signal intensity is subsequently reduced by 830 MM. Therefore, the SNRs are not improved in spectra taken by 830 MM than by 785 MM. The reduction in multiple Mie scattering is demonstrated in the comparison between 785 MM and 785 nm single mode (785 SM). 785 SM demonstrates better Mie scattering reduction ability than 785 MM, with equal Raman signal intensities.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Li, Ran

Contributors dc:contributor

• Allen, Heather

• Chemistry

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365419543

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365419543