Spectroscopic and photodynamic properties of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin and its tetracationic derivative in different media

• Photodynamic activity of cationic and non-charged porphyrins was compared in different media.
• Porphyrin interactions were determined in β-cyclodextrin and AOT reverse micelles.
• Anthracene derivatives were used as molecule trap of singlet molecular oxygen.
• Efficient photosensitized oxidation of tryptophan was found using non-charged porphyrin.
• Porphyrin substituted by aliphatic amine groups represents an interesting agent to photoinactivate microbes.

The spectroscopic properties and the photodynamic activity of 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (TAPP) and its tetracationic derivative (TAPP4+) were studied in homogeneous media and in microheterogeneous systems. The results were compared with those of 5,10,15,20-tetra(4-N,N,N-trimethylammoniumphenyl)porphyrin (TMAP4+), which represents an active tetracationic photosensitizer. Absorption and fluorescence studies indicated that the tetrapyrrolic macrocycle retains its individual spectroscopic properties. Interaction with β-cyclodextrin (β-CD) was found for TAPP4+ by fluorescence emission. Also, these porphyrins interact with n-heptane/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/water reverse micelles. Photosensitization ability was evaluated using 9,10-dimethylanthracene in N,N-dimethylformamide and AOT micelles, while tetrasodium 2,2′-(anthracene-9,10-diyl)bis(methylmalonate) was used in aqueous solutions. Also, photosensitized decomposition of l-tryptophan was investigated in these media. In particular, Trp was fast photooxidized by TAPP in a biomimetic media formed by AOT reverse micelles. Therefore, this intrinsically non-charged porphyrin represents an interesting photosensitizer for the photodynamic inactivation of microorganisms.

The spectroscopic properties and the photodynamic activity of porphyrins substituted by aminopropoxy groups were investigated in homogeneous media and in microheterogeneous systems.Figure optionsDownload as PowerPoint slide