Fig. 2.

Overlapping area between absorption-emission spectra for (b) DOX (d) Paclitaxel and (f) Bleomycin after XeCl laser shots at 308 nm. Spectral shift versus drug concentration for (a) DOX (c) Paclitaxel and (e) Bleomycin and corresponding FWHM of spectral overlap area as a function of concentration as an inset. The spectral shifts attest that the reabsorption events accompany the agglomeration of fluorophore molecules at higher concentration. Stern-Volmer equation is usually used to determine the thresholds of agglomeration from monomer to dimmer, while it fails to explain the quenching effects when both reabsorption and agglomeration are available. Please note that Cc indicates the concentration of chemo-drugs.