Laser induced fluorescence spectroscopy of chemo-drugs as biocompatible fluorophores: irinotecan, gemcitabine and navelbine

The fluorescence nature of chemo-drugs is useful for simultaneous cancer diagnosis and therapy. Here, the laser induced fluorescence (LIF) properties of irinotecan, gemcitabine and navelbine are extensively investigated. The UV photons provoke the desired transitions of the several chemo-drugs by virtue of the XeCl laser at 308 nm. It is shown that LIF spectra are strongly dependent on the fluorophore concentration, while no spectral shift is measured for irinotecan, gemcitabine and navelbine because of a large Stokes shift. On the other hand, doxorubicin is characterized by a large overlapping between absorption and emission spectra giving rise to a sensible red shift. The fluorescence extinction α and self-quenching k coefficients as well as the quantum yield η f of those chemo-drugs are determined accordingly. In fact, irinotecan shows the highest quantum efficiency among the chemo-drugs of interest.