Novel multimodal optical imaging and classification of the zebrafish cancer model

Abstract

Spectroscopic and microscopic imaging techniques, which are non-invasive and label free, are becoming increasingly popular in the medical field. The ongoing rapid development in this domain follows the trend of combining more of thesetechniques to make especially the diagnosis and support in clinical surgery of deadly diseases like cancer more efficient and accurate. In this work a label free novel multimodal imaging system applying optical coherence tomography (OCT), line scan Raman microscopy (LSRM) and multiphoton microscopy (MPM) on the zebrafish cancer model. Therefore, OCT was used to navigate on/inside the zebrafish tissue to find regions of interest (ROI) showing morphological abnormalities in the development of the zebrafish larvae. LSRM provides information on the chemical level for typical occurring biomarkers like proteins, lipids, carotenoids, collagen and DNA by scanning the zebrafish tissue on an electronically operated stage. MPM provides information of the metabolic status of cells by measuring the autofluorescence of the coenzymes NADH and FAD in separated photomultiplier channels according to the principle of two-photon excitation fluorescence (TPEF). Due to second harmonic generation (SHG), MPM also reveal disorders of myosin fibres in the skeletal muscles of danio rerio. Using all these collected results from different modalities, offers the possibility to discriminate between healthy (Ras-, HRAS gene not expressed), cancerous (Ras+, HRAS gene expressed) and transgenic Ras+ zebrafish larvae treated with Trametinib, a kinase inhibitor in the MAPK signal cascade. Furthermore, theunderstanding what the system is already capable of and what further optimizations can be implemented is important for upcoming developments.