The effects of dendrimer size and central metal ions on photosensitizing properties of dendrimer porphyrins.

A series of dendrimer porphyrins (G nDPM; n = generation of dendrimer, n = 1-3; M = coordination metal, M = freebase, Zn, Pt) were prepared and their photosensitizing properties were compared. All G nDPM exhibited sharp absorption in organic solvents. However, the Soret absorptions of G nDPM(CO2H) in 10 mM phosphate buffer solution (pH = 7.4) are broader than those of G nDPM in organic solvents, indicating inhomogeneous microenvironments of the focal porphyrin derivatives. All G3DPM(CO2H) successfully formed globular polyion complex micelles that were uniform in size. Under dark conditions, all G nDPM(CO2H) showed negligible cytotoxicity. However, all samples exhibited concentration-dependent photocytotoxicity under light irradiation. In vitro photocytotoxicity as well as singlet oxygen generation revealed that G3DPZn(CO2H) is the best dendritic PS of the three different dendrimer porphyrin species. [ABSTRACT FROM AUTHOR]