Dipalmitoyl-phosphatidylethanolamine DPPE

The next development on water-oil isotherms was presented by Mohwald s group at the Max-Planck Institute in Berlin [21,22]. They investigated monolayers of dipalmitoyl phosphatidylethanolamine (DPPE) at interfaces of water and hydrocarbons -dodecane (C]2, -hexadecane (Cig), and bicyclohexyl (BCH). The transition pressure was increased and the molecular area at transition decreased in the order Cig—C12 BCH. Also the heat of transition was decreased in the same order, and was more strongly decreasing with... 

Water-soluble fusogens. Large decreases of the surface potential were observed when dipalmitoylphosphatidylcholine (dpPC) was spread on subphases containing glycerol, dimethyl sulphoxide, sucrose, sorbitol or poly(ethyleneglycol) of M.W. 1500 6000 3 x 10 or 5 X 10 (Fig, 1). Similar results were obtained for dipalmitoyl-phosphatidylethanolamine (dpPE). 

In the above subsection it was demonstrated that the inclusion of electrostatic interactions into the pressure-area-temperature equation of state provides a better fit to the observed equilibrium behavior than the model with two-dimensional neutral gas. Considering this fact, we would like to devote our attention now to the character of the lipid film under the dynamical, nonequilibrium conditions. In the following we shall describe the dynamical behavior of the phospholipid(l,2-dipalmitoyl-3-sn-phosphatidylethanolamines DPPE) thin films in the course of the compression and expansion cycles at air/water interface. 

Figure 2 Structure of functionalized anchors and heterobifunctional reagents. DPPE is given as an example. Abbreviations DPPE, l,2-dipalmitoyl-sn-glycero-3-phos-phoethanolamine DPPE-AcBr, bromoacetyl dipalmitoyl phosphatidylethanolamine.

Figure Bl.20.11. Force curves of DMPC/DPPE (dimyristoyl phosphatidylcholine and dipalmitoyl phosphatidylethanolamine) bilayers across a solution of PEG at different concentrations. Clearly visible is a concentration-dependent depletion attraction, with permission from [17]. 

Lipids with L-a-phosphatidylethanolamine derivatives with spermidines 1,2-dipalmitoyl-pho sphatidy lethanolamido spermine(DPPES) (116) or L-a-phosphatidylcholine with phos-phonate diester (127,128). 

---