Long Range Interactions beyond first neighbour Intermolecular forces organizing complex fluids …Laboratory experiments for challenging predictive theories. 4-The equation of state of lipids in the multi-lamellar vesicle state in the presence of additives ..charged lipids.. ,plus salts and non-electrolytes thomas.zemb@icsm.fr

With free counter-ion :Charged lipids Measuring EOS is a way to test the validity of colloidal electrostatics 1,2-Dioleoyl-sn-Glycero-3-Phospho-L-serine-N-sodium salt Formula: Molar Mass = 810 Structural charge = 1e/molecule B. Demé (2002) : Giant Collective Fluctuations of Charged Membranes at the Lamellar-to-Vesicle Unbinding Transition

With free counter-ion :Charged lipids Measuring EOS is a way to test the validity of colloidal electrostatics 1,2-Dioleoyl-sn-Glycero-3-Phospho-L-serine-N-sodium salt Formula: Molar Mass = 810 Structural charge = 1e/molecule B. Demé (2002) : Giant Collective Fluctuations of Charged Membranes at the Lamellar-to-Vesicle Unbinding Transition

With added salt (« buffer » ) : e-kdw What theory says : counter-ion entropy inducethe osmotic pressure D*= dw+2t dw 2t Without added salt With added salt (« buffer » ) : e-kdw

Mg Cl2 P/P0=33% Mg NO3 P/P0=53% Na Cl P/P0=75% K Cl P/P0=80% K2SO4 10 K Cl P/P0=80% Ba Cl P/P0=85% K2SO4 P/P0=95% B. Demé, Langmuir, Part II, 18, 2002, 1005-1013

Evolution of SAXS pattern versus dilution B. Demé, Langmuir Part I:, 18, 2002, 997-1004

Form factor of a single DOPS bilayer (SAXS) B. Demé, M. Dubois, Th. Gulik-Krzywicki and Th. Zemb, Langmuir Part I:, 18, 2002, 997-1004

Extract teh structure factor (powder average) 5 Extract teh structure factor (powder average) X-rays Neutron B. DeméLangmuir Part I:, 18, 2002, 997-1004

6 DOPS 30% DOPS 14% DOPS 5 %

« Diluted state »: spontaneous vesicles (inside/outside counter- ion distribution difference)* *= M. Dubois et al. Langmuir (1991)

« OYSTER » STATE CHARACTERISTICS: kc≈ 0.06 dw/Lb => x= t.ekc=200nm d=30 nm; s=80nm;2t=4nm ld > 100nm; lG-C = 1nm; Lb = 0.7nm B. Demé, M. Dubois, Th. Gulik-Krzywicki and Th. Zemb, Langmuir Part I:, 18, 2002, 997-1004

« MICROSTARUCTURES » WHILE DECREASING OSMOTIC PRESSURE 9 « MICROSTARUCTURES » WHILE DECREASING OSMOTIC PRESSURE B. Demé, , Langmuir Part I:, 18, 2002, 997-1004

B. Demé, Langmuir, Part II, 18, 2002, 997-1004

Vapor pressure Data for DPPG from Cowley et al, 1978 Osmotic stress using PEG 110 B. Demé, M. Dubois, Th. Gulik-Krzywicki and Th. Zemb Langmuir, Part II, 18, 2002, 1005-1013

In cationic lipids, thory overestimates the osmotic pressure, ??? 14 In cationic lipids, thory overestimates the osmotic pressure, ??? DDAB DOPS

DDAB avec deux plateaux 15 DDAB avec deux plateaux

M. Dubois, Th. Zemb , Current Opinion in Coll. and Interf. Sci

Charged layers in the presence of added salts The two first are obesrved experimentally D. Andelmann (1995) «Electrostatic properties of membranes » 

What theory says at saturation plus added salt : M. Dubois. « Osmotic pressures in lamellar phases in the presence of added salt » (1992)

Addition of small solutes: DMPC + SUGAR ? 2 cases: Lipids with sugar in the « interlayer » water Addition of small solutes: DMPC + SUGAR ? 2 cases: -excess water: zero pressure - in the linear swelling regime

« Where » is the sugar gone ? B. Demé, J. Applied Cryst. (2000 ) 33, 569-573

Sugar adsortion equilibria : partial release of bound water Demé, B: Hydration forces between bilayers in the presence of dissolved or surface-linked sugars (2011)

20% DMPC with added glucose and fructose

20% DMPC with added glucose and fructose

Demé, B (2002) : Swelling of lecithin lamellar phases Swelling AND peak broadening the stack is observed at eqiilibrium Demé, B (2002) : Swelling of lecithin lamellar phases in the presence of small carbohydrates

Force balance in the presence of solute at 20% lecithin Demé, B (2002) : Swelling of lecithin lamellar phases in the presence of small carbohydrates

Equation of state when the solvent is a glucose solution Hydration force and undulation increase ? DMPC/glucose/dextran/H2O quaternary samples in excess sugar solution

What we have learnt for non-electrolytes : Measuring EOS is a way to test force balance for bilayers van der Waals, hydration, electrostatic, depletion + steric entropic… (.. But lateral equation of state is needed in anisotropic systems…) Water soluble additives: -are either dissolved or adsorbed (steric) -always change the van der Waals forces -may induce softening and undulations - change the hydration force ? B. Demé (2011) Hydration forces bewteen bilayers in the presence of dissolved or surface-linked sugars