The Permeability Coefficient of Bilayer Lipid Membrane for Cationic Porphyrins

Abstract

The interaction of porphyrins with membranes is an important part in understanding the mechanism of action of porphyrins on the biological object. Porphyrins exhibit biological effect as a result of direct interaction with biological membranes, or interaction with intracellular structures, as a result of its passing through the membrane. That's why it is very important to study the interaction of different porphyrins with membranes and to check if this interaction had any effect on the physicochemical properties of membranes. Because of the complicated organization and functioning of cellular membranes, it is appropriate to conduct experiments on model object, such is bilayer lipid membrane (BLM).The effect of meso-tetra-[4-N-(2′-oxyethyl) pyridyl] and Zn-meso-tetra-[4-N-(2′- oxyethyl) pyridyl] porphyrins on the permeability of BLM is studied using optical (UV/Vis absorption) method. The special cell adapted to UV/VIS spectrophotometer is made for the investigation of porphyrin penetration through BLM. The passage of porphyrins through the membrane is investigated by absorption in the Soret band as a function of time. As a result the permeability coefficient of BLM is calculated for these porphyrins by the method of least-squares [1].Obtained results allow to understand the mechanisms of porphyrins passage through the cell membranes. This approach is aimed at understanding and optimizing the chemical structure and pharmacological properties of porphyrins usable in medicine. These investigations are also important in terms of interaction of porphyrins with liposomes [2], as liposomes, the structural basis of which are bilayer membranes, are widely used as transportation to deliver drugs (for example, based on porphyrins) to the target-cell.[1] A. Torosyan, V. Arakelyan, R. Ghazaryan. The 5th EMBO meeting, Amsterdam, Abstract book, p. 230 (2013).[2] F. Postigo, M. Mora, M. De Madariaga et al. International Journal of Pharmaceutics, 278(2): 239-54 (2004).