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A new methodology for fibre-optic Raman mapping and FTIR imaging of secondary cancer cells, metastases, and detecting tumour cells has been developed by researchers in Germany. The technique facilitates imaging of samples thicker than 50 micrometres and could be used in detecting cancer cells, as a tool for molecular histopathology, in metabolic fingerprinting, general disease diagnostics. Christoph Krafft now in the Department of Materials and Natural Resources, at the University of Trieste, Italy, and colleagues at Dresden University of Technology, set out to optimize the preparation of pristine brain tissue for reference information to allow them to analyse previous results obtained from human brain tumours, metastases of malignant melanoma, skin cancer, to an animal model, which will ultimately improve our understanding of metastasis from this disease and potentially lead to improve treatments or preventative measures. Fundamentally, however, their new approach opens up the possibilities for the technique to a wide range of diagnostics. "This fibre-optic Raman method will allow detecting tumour cells and tumour tissue in vivo and enable studies of tumor development," Krafft told SpectroscopyNOW.com To demonstrate proof of principle, the team prepared three series of sections consecutively from whole mouse brains: dried, thin sections for FTIR imaging, hematoxylin and eosin-stained thin sections for histopathological assessment, and pristine, 2 mm thick sections for Raman mapping. They then recorded FTIR images with a multi-channel spectrometer and obtained Raman maps serially using a spectrometer coupled to a fibre-optic probe. The team carried out cluster analyses of the FTIR and Raman maps. They were able to see more detail in less time with FTIR, although it did not reveal the metastatic cells. In contrast, the spectral contributions of melanin in tumour cells were resonance enhanced in the Raman spectra (excitation at 785 nm), which meant the Raman results revealed sensitive detection of the metastatic cells. "If evaluation of the techniques in small animal models proves successful, transfer to larger human brain tumors can also be expected to be feasible. This proof-of-concept study is, therefore, an important step in the development of new diagnostic tools based on vibrational spectroscopy," the researchers say. Krafft will return to Dresden in September 2007 and continue the Raman and FTIR work on this mouse model, under a new grant. Related links:
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Krafft, mapping tumour cells
Raman brain map |
