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Polymorphism of Lipid-Water Systems: Epitaxial Relationships, Area-Per-Volume Ratios, Polar-Apolar Partition Vittorio Luzzati

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Polymorphism of Lipid-Water Systems: Epitaxial Relationships, Area-Per-Volume Ratios, Polar-Apolar Partition Vittorio Luzzati Polymorphism of Lipid-Water Systems: Epitaxial Relationships, Area-per-Volume Ratios, Polar-Apolar Partition Vittorio Luzzati To cite this version: Vittorio Luzzati. Polymorphism of Lipid-Water Systems: Epitaxial Relationships, Area-per-Volume Ratios, Polar-Apolar Partition. Journal de Physique II, EDP Sciences, 1995, 5 (11), pp.1649-1669. 10.1051/jp2:1995205. jpa-00248261 HAL Id: jpa-00248261 https://hal.archives-ouvertes.fr/jpa-00248261 Submitted on 1 Jan 1995 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. (1995) Phys II J France 1649-1669 5 1995, 1649 NOVEMBER PAGE Classification Physics Abstracts My Md Md 64 60 70 68 35 64 Polymorphism Lipid-Water Epitaxial Systems: of Relationships, Ratios, Area-per-Volume Polar-Apolar Partition Vittorio Luzzati Gdndtique Moldculaire, Centre de Scientifique, Centre National de la Recherche Gif-sur-Yvette, France 91198 (Received 1995) accepted 1995, March reiised June July 1995, 31 28 31 exp6rimentales nombreuses observations R4sum4. phases montr6 De deux les ont qui que lors dpitaxiales d'une des relations le respectent initial but de coexistent transition souvertt : d'exphquer phdrtomArte dtrartge Puisque travail dtait irttdractiorts irtterfaciales les cc ce sem- prddomirtant drtergdtique l'dquilibre blent darts lieu r61e de deux il les jouer y supposer un que a phases l'dquihbre superficielle le d'41dments I de dortt volume l'aire structure consistent sortt et paramktres Ces s'expnmer fortction des la irtvariants deux di- de peuvertt terteur et en en eau 416mentaires des phases deux valeurs mensions mailles des Atre leurs dortc ddtermindes peuvertt exp6rimentales partir donndes I de On le volume le des note, rapport outre, erttre que en lipidique de 414mertts de syst6me 4quivaut coefficient celui la du k composante et structure urt Lorsqu'on applique de donrtdes iddes littdrature observe coef- de le la partage. que ces aux on ficient remarquables fortement valeurs de varie corr41ations manifestent des partage et que ses parambtres chimiques physiques systbme d'autres suggkre sdparatiort Ceci la du des et avec que paraffiniques polaires lipides chairtes qu'ort des l'habitude des t6tes n'est de le aussi et nette pas a po1alrelapo1alre Cette d'un domaine; dans variable nouveaut4 portage notion est pertser une ce allleurs, jouer thermodynamique En le coefficient r61e intdressant de partage, pourrait par un publ14es qui 4pitaxiales analyse relations de les des donn4es telles montre que conceme une cc expliquer fr4querttes, beaucoup d'exceptiorts. Pour relations mais observations sont avec ces on l'hypothbse hypothbse 6pitaxiales cirt6tique. le 4met Cette des relations r61e surtout est que (dans large) dpitaxiales sdlectif Plusieurs conduit I relations avarttage sens associer aux un un exemples l'appui hypothAse citds I de cette sort empirical explanation original seek this of the Abstract. The of work to purpose was an epitaxial display rela- thermodynamic equilibrium pairs phases that often observation of in an polarlapolar predomi- play Considering interfacial tionship the interactions that to appear a ground proposition phases, the that there for all the that stabilize the role forces is nant among whose particular elements of phases phase the involved transition structure consist two any m expressed area/volume be of elements Volume and the invariant structure ratio as can area is phases. values their the cell of the functions of and the parameters coexisting two content water molecules) elemertts)/(lipid (structure experimentally determined The be volume thus ratio cart applied large avail- of data equivalent coefficient These ideas partition variety to to were a is a remarkably display found wide The coefficient partition literature able the variations, to was in that the physical the the chemical and system, the of correlated with suggesting parameters headgroups sharp is hydrocarbon polar segregation the of the chains from it not as away is as @ Physique Editions de Les 1995 PHYSIQUE JOURNAL DE II N°il 1650 polarlapolar commonly field, The novelty assumed variable the of partition notion is a m a thermodynamic coefficient this well interesting parameter partition into turn may moreover, an through significance relationships, epitaxial of the search As the the literature shows that to its a explain these observations has In order the exceptions conjecture put existence to many very is epitaxial phase effect kinetic forward that the coincidences have the In partic- transitions on a epitaxially display phases unlikely ular, suggested involving related that transition it to any is is (be advantage technological, possibility The also evoked metastable selective that states it a is experimental) relationships biological epitaxial be associated with the of This existence may or by examples illustrated drawn from literature several the conjecture is Introduction 1. Many X-ray lipid-water reported of the authors ,vho have scattering systems experiments on especially phases noted, spacing first reflection of of if the of the have I. that the in type [21ii hexagonal phase phases of reflection lamellar of spacing of cubic and the and the the the plotted function follow of the often and then Q~~° concentration, smooth points Q~~~ as are a a (see, study phase example, Besides, boundaries when crossed for the 2])(~ ). curve, even 11, are quasi-monocrystalline samples of correspond has shown the coincidences often that spacing relationships genuine epitaxial elegant analyses of This has 3-D observation led to [3, to 4] [3,4]. relationships the geometric phases the Similar between observations have been two (see 2) Apparently, recently phases extended of all Sect. authors II and 3 the type to [5] puzzling phenomenon fact, ,vondering why phases of ,vithout of take this in matter pairs as a thermodynamic (the explanation equilibrium epitaxially related should be each othf<r put to utterly unsatisfactory, by find Manani, Amaral coworkers I discussed forward and that is 11,6], Appendix) developed prompted by question- the The work this later into present in it was a touching lipid polymorphism elaborate of endeavour other facets upon more Regarding relationships epitaxial confirmed the of literature the of the that question review a phases thermodynamic equilibrium epitaxially often other, i-elated but also in each it to are puzzling showed that the exceptions. phe- rule has In rationalize this attempt to many an whereby explanation, forward I epitaxial relationships the kinetic oi put nomenon presence a lowering effect of the the barrier of has kinetic also held that the I conjecture transition. the out epitaxial the relationships of advantage lipid-water existence impart selective very may a on systems Confronted phase collection of with led such I 1n.hether wonder transitions to any par- was a ticular likely structural directly potential be related chemical be parameter to to to is so as phases thermodynamic equilibrium sight the best candidate At first invariant at in appears be predominant mterfaoal forces the lipid-water indeed the ,vork systems to at as area, in polarlapolar originate from interfacial Naturally, possibility the of the interactions. to seem testing hypothesis hinges along lipid this interface position the of the the molecules This upon iii problem example, often has early discussed been For been shown and in the has past. it polarlapolar amply confirmed since, the if that interface the between the is set at separation hydrocarbon headgroups, polar area-per-chain chains and the then the found is increase to or phase decrease but of the remain when constant, to amount to water increases, never as even polymorphism early lipid produced days the this of observation argument In sometimes was as an (~ (now Hi) hexagonal phase phase" and of what the "iuiddle the then called against structure m ~vas phasis (personal prevalent lipid lamellar that the all the of that proposition. support at time~ are recollection) RELATIONS, PHASES, EPITAXIAL LIPID N°11 SPECIFIC AREAS 1651 boundaries stressed, crossed. be In this area-per-chain interface the the it must at case, are phase different within with take the and values of in content water vary may may one pairs phases. recently coexisting focused More several authors have the virtual the attention on (called "pivotal", surfaces phase, "neutral" supposed whose within be is [8, to 9] area, or one with the of also the In invariant area-per-chain the this respect system. water to content case phases. different take values of coexisting may pairs in analysis presented from The this lipid-water proposition wherever work the that in stems a m thermodynamic phases equilibrium, phases these be visualized in system coexist two to can having of elements the chemical and the composition consist structure area-per- same same shape objects, volume elements whose The ideal be assumed ratio. structure consistent to are is (planar cylindrical phase phase phase prismatic for for L, the of the slabs rods with symmetry or (sometimes hydrocarbon by accompanied fraction HI- the of that either chains contain ), etc a moiety) polar only hydrocarbons arbitrarily fraction short, of the In somewhat and the or a "apolar" respectively "polar" the of shall call and elements the I moieties contents structure and of the interstices. surface/volume phase of of known the be For the ratio elements structure structure a can phases expressed pair function of their fraction of dimensions the of volume and cell For as a a of equilibrium simple fraction that the volume the elements sho~v arguments structure can in of lipid the and cell determined if the,,olume the the be component, concentration structure phases and made that the of the known.
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