UV Luminescence and Light Scattering in Photoditazine Systems with Sodium Alginate, Poly-N-Vinylpyrrolidone, and Tryptophan

Fluorescence and Rayleigh light scattering in polymer systems based on the chlorine photosensitizer photoditazine (PD) for photodynamic therapy are studied upon excitation at wavelengths λex = 260, 280, 400, and 450 nm. Nontoxic water-soluble poly-N-vinylpyrrolidone (PVP) and a plant polysaccharide (sodium alginate (SA)) were used as polymers. The PD–SA double system is characterized by dependence of its characteristics on the synthesis conditions, while the PD–SA–PVP triple complex exhibits a positive combined effect of SA and PVP polymers on the PD molecule due to the formation of a local microenvironment of the active PD center with a higher polarity. It is shown that the introduction of tryptophan, which is used as a substrate in model photooxidation processes for testing the efficiency of photosensitizers in singlet-oxygen generation, does not considerably change the fluorescence parameters of the PD–SA–PVP complex.