The design and synthesis of glycol-functionalized porphyrins that contain one to four low molecular weight glycol chains that are linked via ether bonds to the meta-phenyl positions of meso-tetraphenylporphyrin and the comparison of fluorinated and nonfluorinated para derivatives are reported. The cellular uptake and photodynamic activity significantly depend on terminal groups of the glycol substituent. Hydroxy glycol porphyrins, in contrast with methoxy glycol porphyrins, show efficient intracellular transport and a high induction of apoptosis in tumor cell lines in vitro . Furthermore, the ethylene glycol chain at the meta position exhibits a superior efficacy that leads to the permanent ablation of human breast carcinoma (MDA-MB-231) in nude mice. In addition, fluorination enhanced the photosensitizing potential of para-phenyl derivatives. The analysis of the cell-death mechanism revealed that glycol-functionalized porphyrins represent novel nonmitochondrially localized photosensitizers that have a profound ability to induce apoptosis in tumor cells that act upstream of caspase activation. The strong interaction with a tumor marker (sialic acid) indicates the preferential association of these compounds with tumor cells.

Different bridging geometries can explain the observation that porphyrin molecules with added thiol end groups and pyridine axial groups form more‐stable single‐molecule junctions with an increased spread in low‐bias conductance. The stability of these geometries is demonstrated by time‐dependent conductance measurements. In contrast, rodlike molecules show one preferential binding geometry.

The porphyrin-cyclodextrin conjugates were prepared and tested for selective and effective multifunctional drug delivery and therapy. The porphyrin receptor system combines efficient binding of the selected drug to the cyclodextrin cavity and photosensitizing properties of the porphyrin moiety with high accumulation of the whole complex in cancer tissue. The combined effect of chemotherapy and photodynamic therapy is demonstrated by in vitro and in vivo studies.