LIF spectroscopy of stained malignant breast tissues.

We employ laser induced fluorescence (LIF) spectroscopy to discriminate between normal and cancerous human breast (in-vitro) tissues. LIF signals are usually enhanced by the exogenous agents such as Rhodamine 6G (Rd6G) and Coumarin 7 (C7). Although we observe fluorescence emissions in both fluorophores, Rd6G-stained tissues give notable spectral red shift in practice. The latter is a function of dye concentration embedded in tissues. We find that such red shifts have a strong dependence on the dye concentration in bare, in stained healthy, and in malignant breast tissues, signifying variations in tubular abundances. In fact, the heterogeneity of cancerous tissues is more prominent mainly due to their notable tubular densities- which can provide numerous micro-cavities to house more dye molecules. We show that this can be used to discriminate between the healthy and unhealthy specimens in different biological scaffolds of ordered (healthy) and disordered (cancerous) tissues. It is demonstrated that the quenching process of fluorophore' molecules slows down in the neoplastic tumors according to the micro-partitioning, too.