Chemical structures of PSs described in this review. (A) Cationic phthalocyanine, Zn-PC-Me; (B) Hydroxygallium(III) 2,3,9,10,16,17,23,24-octakis-[3-(N-methyl) -pyridyloxy]-phthalocyanine octaiodide; (C) Toluidine blue O; (D) 3,7-Bis(N,N-dibutylamino) phenothiazinium bromide, PPA904; (E) 5-Phenyl-10,15,20-tris(N-methyl-4-pyridyl)-porphine trichloride, Sylsens B; (F) Rose Bengal; (G) Riboflavin; (H) Curcumin; (I) Polyethylenimine chlorin(e6), PEI-ce6; (J) Merocyanine 540; (K) Poly-S-lysine porphyrin conjugate, pL-TMPP; (L) Functionalized fullerene, C60(>ME1N6+C3); (M) Tri-meso (N-methyl-pyridyl), meso (N-tetradecyl-pyridyl) porphine, C14.