Branching pattern effect and co-assembly with lipids of amphiphilic Janus dendrimersomes

Abstract

The influence of the branching patterns on the membrane properties of Janus dendrimers in water has been investigated by dissipative particle dynamics simulations. The hydrophobic fluorinated dendron (R_F) contains three types of branching patterns, including 3,4-, 3,5-, and 3,4,5-R_F. Consistent with experimental results, the hydrophobic layer thickness (H_B) follows the order: 3,5-R_F < 3,4-R_F < 3,4,5-R_F, which can be explained by the extent of interdigitation (Δh): 3,5-R_F > 3,4-R_F > 3,4,5-R_F. Moreover, the 3,4,5-R_F membrane shows the highest stretching modulus (K_A) and the lowest lateral diffusivity (D). The 3,5-R_F membrane is similar to the 3,4-R_F membrane but exhibits a higher K_A and smaller D. For the nano-sized dendrimersome, its bilayer thickness is less than that of the planar membrane due to its larger extent of interdigitation. The co-assembly of dendrimersomes with lipids has been studied as well. The thickness and the extent of interdigitation of the lipid-rich domain for the hybrid membrane are significantly affected by the lipid concentration (ϕ_l) and the branching patterns. As ϕ_l increases, the thickness of the lipid-rich domain grows corresponding to the decrease of interdigitation of the lipid-rich domain.