Antimicrobial activity of photosensitizers: arrangement in bacterial membrane matters.

Porphyrins are well-known photosensitizers (PSs) for antibacterial photodynamic therapy (aPDT), which is still an underestimated antibiotic-free method to kill bacteria, viruses, and fungi. In the present work, we developed a comprehensive tool for predicting the structure and assessment of the photodynamic efficacy of PS molecules for their application in aPDT. We checked it on a series of water-soluble phosphorus(V) porphyrin molecules with OH or ethoxy axial ligands and phenyl/pyridyl peripheral substituents.

Water-Soluble Chlorin/Arylaminoquinazoline Conjugate for Photodynamic and Targeted Therapy.

A new water-soluble conjugate, consisting of a chlorin- photosensitizer part, a 4-arylaminoquinazoline moiety with affinity to epidermal growth factor receptors, and a hydrophilic β-d-maltose fragment, was synthesized starting from methylpheophorbide- in seven steps. The prepared conjugate exhibited low levels of dark cytotoxicity and pronounced photoinduced cytotoxicity at submicromolar concentrations in vitro, with an IC(dark)/IC(light) ratio of ∼368 and a singlet oxygen quantum yield of about 20%. In tumor-bearing Balb/c nude mice, conjugate preferentially accumulates in the tumor tissue.

Tuning photochemical properties of phosphorus(v) porphyrin photosensitizers.

Photosensitizing and emission properties of P(v) porphyrins were studied. The nature of the axial ligands, occupying the apical position on the P centre adopting an octahedral coordination geometry, strongly influences singlet oxygen generation and charge transfer and allows switching between the two processes.

Phosphorus(V) Porphyrin-Based Molecular Turnstiles.

A new cationic molecular turnstile based on a P(V) porphyrin backbone bearing two pyridyl interaction sites, one at the meso position of the porphyrin and the other on the handle connected to the porphyrin through P-O bonds, was designed and synthesized. The dynamic behavior of the turnstile 2, investigated by 1D and 2D H NMR techniques, showed that in the absence of an effector, the turnstile is in its open state and undergoes a free rotation of the rotor (the handle) around the stator (the porphyrin backbone). In the presence of an external effector such as Ag cation or H, the turnstile is switched to its closed states 2-Ag and 2-H, respectively.