Characterization of BxPC3-transplanted mice by hyperspectral autofluorescence imaging and Raman spectroscopy

Abstract

ABSTRACT Live subcutaneous tumor grown in nude mouse is studied in situ with hyperspectral autofluorescence imaging and Raman spectroscopy. The purpose of the study is to develop methods for characterization of biochemical changing and of histological type of tumor without labeling. The results show that there are site depending variation in the fluorescence and Raman spectra. At the spot in which calcification is in process, Raman spectra showed a strong and specific band at 957 cm -1 due to PO 4 species. The autofluosescence image can prove the histological changes based on the NADH and FAD which are major fluorophores in biological tissues. The hyperspectral image is analyzed with principal component analysis and the reconstructed images successfully depicts a different between necrotic and viable part within living subcutaneous tumor. Keywords: Raman spectroscopy, hyperspectral image, autofluorescence imaging 1. INTRODUCTION In the recent years, the developments in instruments to study live cells and tissues have been deepened. It was proved that some new technologies are particularly effective in diag nosis of cancer and/or understanding of biological character of cancer. However, cancer has more complex structures than other tissue so its form has not yet been fully clarified, especially in the live state. Tumor tissues are not homogenous in diversity and contain several types of cells: e.g. normal cell, fibrous tissue, lymph, blood vessel and extracellular matrix. On the other hand, it is not enough to clarify the activity of these tissues and cells when information comes only from dead and stained samples. It is necessary to extend the researches into the live cancer tissues. Pancreatic cancer is one of the most difficult kind of cancer to make a certain diagnosis.