Label-free optical bio-sensing of non-cancerous and cancerous tissues from mice: distinct spectroscopic features of thiazole orange

Abnormal cell growth leading to cancer is a major concern and warrants an easy and early diagnosis strategy. In this regard, spectroscopic distinction of non-cancerous and syngeneic cancerous tissues has been demonstrated by label-free fluorescence and circular dichroism (CD) spectral features of a probe dye, thiazole orange (TO), on binding to genomic DNAs isolated from the respective tissues. An enhanced fluorescence intensity and a distinct induced CD band of TO in the presence of DNAs from cancerous tissues (primary & metastatic sites) were recognized. The observations, validated in three syngeneic models, namely, Swiss albino fibrosarcoma, BALB/C WEHI-164 fibrosarcoma and C57BL/6J melanoma, conclusively documented the differences and offer a facile, effective, and label-free optical method for the diagnosis of cancer tissues. To the best of our knowledge, this is the first study wherein an optical probe was used to show differences in the CD signatures of genomic DNA isolated from normal and tumor tissues of a murine model and it is expected to have potential implications in the design and development of diagnostic markers. Demonstrated a reliable distinction in the emission and circular dichroism spectral features of TO dye, on binding to the DNAs from non-cancerous and cancerous tissues, which offers a label-free optical method for the diagnosis of cancer tissues.