“…Porphyrin photosensitizers contain a heterocyclic ring, where various substituents, which define their properties, can be attached to it. Protoporphyrin and hematoporphyrin are very abundant thanks to the easiness of structure modification like the photosensitizers used in the work (Gomer, 1990;Pass, 1993;Graczyk & Konarski, 1995;Noodt et al, 1996;Ochsner, 1997;Żołądek et al, 1997;Sternberg & Dolphin, 1998;Graczyk, 1999;Li et al, 1999;Kessel & Luo, 1999;Graczyk & Kwaśny, 2002;Castano et al, 2005a;2005b;Kwitniewski et al, 2005;You et al, 2006;Misiewicz-Krzemińska et al, 2009). Usually, due to photosensitizers toxicity, their cytotoxicity in darkness must be examined.…”