Dynamic and mechanical properties of supported lipid bilayers

Supported lipid bilayers (SLBs) offer an excellent model system for investigating the physico-chemical properties of the cell membrane. In this work, dynamic and mechanical properties of SLBs are explored by dissipative particle dynamics simulations for lipids with different architectures (chain length, kink, and asymmetry associated with lipid tails). It is found that the lateral diffusivity (D_x) and flip-flop rate (FF) grow with increasing temperature in both gel and liquid phases and can be described by an Arrhenius-like expression. Three regimes can be clearly identified for symmetric and asymmetric saturated lipids but only two regimes are observed for kinked lipids. Both D_x and FF grow with decreasing tail length and increasing number of kinks. The stretching (K_A) and apparent bending (K_B) moduli exhibit concave upward curves with temperature and the minima are attained at T_m. In general, the minima of K_A and K_B decrease with the chain length and increase with number of kinks. The typical relation among the bending modulus, area stretching modulus, and bilayer thickness is still followed, K_B = βK_Ah² and β is much smaller in the gel phase. The dynamic and mechanical properties of lipids with asymmetric tails are found to situate between their symmetric counterparts.