Thermal behavior of novel non-sonicated arsonolipid-containing liposomes

The thermal properties of novel arsonolipid-containing liposomes in PBS pH 7.4 and in water in absence and presence of Ca2+ ions are reported. Liposomes composed of arsonolipids with different acyl chains (C12, C16 and C18) were prepared by the one step method. Microcalorimetry results showed that (i) the thermotropic transitions of arsonoliposomes (in PBS, pH 7.4, and in water) increase as a function of arsonolipid fatty acyl chain length, (ii) arsonoliposomes of long fatty acyl chain arsonolipids (C16 and C18) showed higher enthalpy and transition temperature in the buffer compared to those observed in water (for arsonoliposomes of C12-fatty acyl chain arsonolipid, the order was reversed which might be attributed to their different structure), and (iii) the presence of 2 mM CaCl2 has more pronounced effects on the thermal properties of arsonoliposomes in distilled water than in buffer, which suggests that the ionic strength of the dispersion medium plays an important role in determining the thermal properties of arsonoliposomes.