Liposomes or biological vesicles can be created from cholesterol, phospholipid, and water. Their stability is affected by their phospholipid composition which can influence disease treatment and drug delivery efficacy. In this study, the effect of phospholipid type on the formation and stability of liposomes using coarse-grained molecular dynamics simulations is investigated. For this purpose, the simulation study of the DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) and DPSM (Egg sphingomyelin) lipids were considered. All simulations were carried out using the Gromacs software and Martini force field 2.2. Energy minimization (3000 steps) model, equilibrium at constant volume to adjust the temperature at 400 Kelvin and equilibrium at constant pressure to adjust the pressure, at atmospheric pressure (1 bar) have been validated. Microsecond simulations, as well as formation analysis including density, radial distribution function, and solvent accessible surface area, demonstrated spherical nanodisc structures for the DPSM and DSPC liposomes. The results revealed that due to the cylindrical geometric structure and small-size head group, the DSPC lipid maintained its perfectly spherical structure. However, the DPSM lipid showed a conical geometric structure with larger head group than other lipids, which allows the liposome to form a micelle structure. Although the DSPC and DPSM lipids used in the laboratory tests exhibit liposome and micelle behaviors, the simulation results revealed their nanodisc structures. Energy analysis including overall energy, Van der Waals interaction energy, and electrostatic interaction energy showed that DPSM liposome is more stable than DSPC liposome.

Curcumin is well known in biomedical investigations with an extensive antimicrobial properties and wound repair effect. However, clinical criteria recommend curcumin should be formulated for topical medication. In this study, we prepared Ethosomal curcumin (Etho-cur) formulation for wound healing and bacterial flora assessments in treated rats which were subjected to second degree burn under a standard procedure. Applying once daily of Etho-cur (0.2%) topically on rat's dorsal for 14 days significantly recovered main aspects of wound repair including re-epithelization (P<0.01), neovascularization (P<0.01), collagen synthesis (P<0.001), granulation tissue formation (P<0.001) compared with control. Considerable wound contraction was occurred by Etho-cur treatment sooner than other groups and after 16 days it was completed with a significant (P<0.001) value. Furthermore, ethosomal formulation of curcumin similar to silver sulfadiazine (SSD) cream 1% potentially inhibited (P<0.001) growth of the burn bacterial flora including as predominant bacteria among experimental isolations during 14 days treatment. Also, antibacterial activity of Etho-cur was estimated approximately 11% more potent than free curcumin in reduction of the burn bacterial flora. Regarding the results, ethosomal curcumin efficiently fights against wound infection and promotes wound repair in burn injuries in rats.

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