Thermograms correspond to the second heating scan after cooling the samples from 100 to −60°C and subsequent equilibration at this temperature for 5 min. D R Silvius. Due to this limited mobility, gel bilayers lack an important property of liquid bilayers: the ability to reseal small holes. The phase behavior of lipid bilayers is largely determined by the strength of the attractive Van der Waals interactions between adjacent lipid molecules. If you are viewing this page on a mobile device or would like to print this information for offline use, we have formatted the data into an easy to read PDF. Biochim Biophys Acta. Alabaster, Alabama 35007-9105, Phase Transition Temperatures for Glycerophospholipids, Preparation of Multilamellar Liposomes (LMV), Preparing Large, Unilamellar Vesicles by Extrusion (LUVET), Current Applications of Liposome Formulations, Preparation of Cationic Liposomes & Transfection of Cells, Procedure for Preparation of Cationic Lipid/Oligomer Complex, Thin Layer Chromatography (TLC) Analysis of Phospholipids, Detection Methods for Thin Layer Chromatography, Fatty Acid Analysis of Phospholipids by GC/FID, Determination of Phospholipid Oxidation by UV/VIS Spectroscopy, Miscibility of Phospholipid Binary Mixtures. Alabaster, Alabama 35007-9105 Aside from chain length, transition temperature can also be affected by the degree of unsaturation of the lipid tails. Crowe JH, Oliver AE, Hoekstra FA, Crowe LM. Such mixtures often exhibit properties intermediate to their components, but are also capable of a phenomenon not seen in single component systems: phase separation. Motion constraints on lipids in lipid bilayers are also imposed by presence of proteins in biological membranes, especially so in the annular lipid shell 'attached' to surface of integral membrane proteins. Comp Biochem Physiol A Mol Integr Physiol. USA.gov. | [6][7] The mode of this interaction has more recently been shown to be due to cholesterol intercalating between lipid molecules, filling in free space and decreasing the flexibility of surrounding lipid chains. The biology of tardigrade disordered proteins in extreme stress tolerance. Int J Nanomedicine. Here, we show that this is not the case. eCollection 2018. In fact, T(m) is significantly reduced at mass ratios where no bulk sugar glass phase is detectable by Fourier transform infrared spectroscopy or differential scanning calorimetry. See Fig. Broadly, at a given temperature a lipid bilayer can exist in either a liquid or a solid phase. (2000) 328-39. (1988) 155 -166. In fact, most organisms that are able to survive desiccation accumulate high concentrations of sugars in their cells. [8] This interaction also increases the mechanical rigidity of fluid membrane lipid bilayers[9] and decreases their lateral diffusion coefficient. Since fusion is prevented at lower sugar/lipid mass ratios than leakage, it has been assumed that more sugar is needed to depress T(m) than to prevent fusion. Get the latest research from NIH: https://www.nih.gov/coronavirus. 2002 Mar;131(3):515-25. doi: 10.1016/s1095-6433(01)00514-1. The bilayer transition temperatures of saturated asymmetrical phosphatidylcholines are interpreted by assuming that the transition enthalpy and transition entropy are linearly related to the absolute value of the difference in chain length between the sn-1 and sn-2 chains, with constant end contributions. Cacela C(1), Hincha DK. 79. 1993, Princeton, NJ: Princeton University Press. Thus, at a given temperature, a short-tailed lipid will be more fluid than an otherwise identical long-tailed lipid. Liquid phase bilayers can spontaneously heal small voids, much the same way a film of oil on water could flow in to fill a gap. It has been proposed that the lyoprotection of liposomes depends on the depression of the gel to liquid-crystalline phase transition temperature (T(m)) of the dry membranes below ambient and on the prevention of membrane fusion by sugar glass formation, because both lead to leakage of soluble content from the liposomes. All lipids have a characteristic temperature at which they undergo a transition (melt) from the gel to liquid phase. 2010 Aug;61(1):108-14. doi: 10.1016/j.cryobiol.2010.06.001. The solid phase is commonly referred to as a “gel” phase. Phosphatidylcholine Phosphatidylglycerol (Sodium Salt) Product Tm (°C) Product Tm (°C) 12:0 PC (DLPC)-2: 12:0 PG (DLPG)-3: 13:0 PC: 14: 14:0 PG (DMPG) 23: 14:0 PC (DMPC) 24: 16:0 PG (DPPG) 41: 15:0 PC: 35: 18:0 PG (DSPG) 55: 16:0 PC (DPPC) 41: 18:1 PG (DOPG)-18: 17:0 PC: 50: 16:0-18:1 PG (POPG)-2: 18:0 PC (DSPC) 55: Phosphatidylserine (Sodium Salt) 19:0 PC: 62: 14:0 PS (DMPS) 35: 20:0 … The mechanisms involved in the stabilization of cellular membranes in the dry state have been investigated using model membranes, such as phosphatidylcholine liposomes. | Website by Infomedia, Avanti Polar Lipids |
In contrast to this large in-plane mobility, it is very difficult for lipid molecules to flip-flop from one side of the lipid bilayer to the other. | Report Website Error 1973 Dec; 70 (12):3443–3444. Although it is a lipid, cholesterol bears little resemblance to a phospholipid. Fatty Acid Synthase (FASN) siRNA-Encapsulated-Her-2 Targeted Fab'-Immunoliposomes for Gene Silencing in Breast Cancer Cells. This phenomenon is analogous to the fact that paraffin wax, which is composed of long alkanes, is solid at room temperature, while octane (gasoline), a short alkane, is liquid. The phase behavior of lipid bilayers is largely determined by the strength of the attractive Van der Waals interactions between adjacent lipid molecules. National Center for Biotechnology Information, Unable to load your collection due to an error, Unable to load your delegates due to an error, Lipid melting curves of dry EPC liposomes as determined by FTIR spectroscopy. A detailed analysis of the interactions of sucrose with the P=O, C=O, and choline groups of the lipid and a comparison to published data on water binding to phospholipids suggests that T(m) is reduced by sucrose through a "water replacement" mechanism. Privacy Policy | Reset Location Preferences Protection of large unilamellar EPC liposomes from damage during drying by different Suc/EPC mass ratios. One property of a lipid bilayer is the relative mobility (fluidity) of the individual lipid molecules and how this mobility changes with temperature. Thermotropic Phase Transitions of Pure Lipids in Model Membranes and Their Modifications by Membrane Proteins. This response is known as the phase behavior of the bilayer. Thus, at a given temperature, a short-tailed lipid will be more fluid than an otherwise identical long-taile… 1998;60:73-103. doi: 10.1146/annurev.physiol.60.1.73. Enriquez T, Renault D, Charrier M, Colinet H. Front Physiol. In air-dried egg phosphatidylcholine liposomes, T(m) is depressed by >60 degrees C at sucrose/lipid mass ratios 10-fold lower than those needed to depress fusion to below 20%. Author information: (1)Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14424 Potsdam, Germany. DSC heating thermograms of dry EPC liposomes in the presence of different amounts of Suc. W. Rawicz, K. C. Olbrich, T. McIntosh, D. Needham and E. 2002, Cambridge, UK: Cambridge University Press, "Partitioning of Thy-1, GM1, and cross-linked phospholipid analogs into lipid rafts reconstituted in supported model membrane monolayers", "Elastic deformation and failure of lipid bilayer membranes containing cholesterol", "Lateral diffusion in binary mixtures of cholesterol and phosphatidylcholines", "Phase diagram of a 4-component lipid mixture: DSPC/DOPC/POPC/chol", "Lipid rafts reconstituted in model membranes", "Destabilisation of lamellar dispersions of thylakoid membrane lipids by sucrose", "Determination of membrane lipid phase transition temperature from 13C NMR intensities", https://en.wikipedia.org/w/index.php?title=Lipid_bilayer_phase_behavior&oldid=988284382, Creative Commons Attribution-ShareAlike License, This page was last edited on 12 November 2020, at 06:36. 700 Industrial Park Drive
R. Homan and H. J. Vásquez-Rivera A, Oldenhof H, Dipresa D, Goecke T, Kouvaka A, Will F, Haverich A, Korossis S, Hilfiker A, Wolkers WF. Unlike liquid phase bilayers, the lipids in a gel phase bilayer are locked in place and exhibit neither flip-flop nor lateral mobility. The resulting Suc/EPC mass ratios are indicated to the right of each trace. Saturated phosphatidylcholine lipids with tails longer than 14 carbons are solid at room temperature, while those with fewer than 14 are liquid.