Thioflavin T Lasing Probe for Mucin Detection in Simulated Tears as a Targeting Strategy for Brain Tumors.

A novel optical approach for a noninvasive detection of mucins in tear fluid is proposed, aiming at the early diagnosis of brain tumors such as glioblastoma. Utilizing Thioflavin T (ThT) as a fluorescent probe, our study demonstrates that ThT selectively binds to mucins (modeled by MUC3) in DEMI water, artificial tears, and simulated tears. Steady-state and time-resolved fluorescence spectroscopy reveal that mucin binding induces a significant enhancement in ThT fluorescence and prolonged emission lifetime, indicative of restricted intramolecular rotation. Importantly, the application of Fabry-Pérot cavity lasing spectroscopy enabled the resolution of distinct spectral signatures of the ThT-mucin complex, including the emergence of dual lasing peaks and an increased lasing threshold in mucin-rich samples compared to controls. These optical fingerprints provide compelling evidence of specific ThT-mucin interactions that are not discernible with conventional fluorescence techniques. Our findings highlight the potential of the ThT probe and lasing method as a sensitive, noninvasive platform for detecting mucins in tears, offering a promising strategy for the early detection of glioblastoma.