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POPC transition temperature

In the case of pure POPC vesicles, with a main-transition temperature T m of (−2.9 ± 1.3)°C (Koynova and Caffrey, 1998), all the data shown correspond to the ld phase, and so it is clear that there is a significant variation in the values of 〈r〉 DPH even for the same phase (e.g., at 3°C, 〈r〉 ∼ 0.20, and at 60°C, 〈r〉 ∼ The mixture with Bio-Beads is incubated close to the transition temperature of the lipid (4 °C for POPC) for 4-12 h, and the Bio-Beads are then separated using a small gravity column or careful pipeting. Also, it was found that in those samples for which the glass transition temperature (Tg) was greater than the Tm of POPC, Tm was lowered by approx. 20 C degrees from the value for the fully hydrated lipid. X-ray diffraction data confirmed that acyl chain freezing was deferred to a lower temperature during cooling of vitrified samples All spectra were recorded for the orientation of planar membrane stacks relative to the incident beam at the temperatures of 248 K and 273 K, respectively, below and close to the gel-liquid phase transition temperature of POPC (= 271 K) The phase transition temperature is defined as the temperature required to induce a change in the lipid physical state from the ordered gel phase, where the hydrocarbon chains are fully extended and closely packed, to the disordered liquid crystalline phase, where the hydrocarbon chains are randomly oriented and fluid

Hello, I think DSC is a very good method studying the thermal behaviour of lipid mixtures. Please have a look at Patrick Garidel and Alfred Blume, Biochimica et Biophysica Acta 1371 ,1998, 83-95 We studied the effects of storage temperature on the stability of dehydrated POPC (1-palmitoyl-2-oleoyl-phosphatidylcholine) mixed with sucrose, trehalose, or a sucrose/raffinose mixture. We used DSC to measure the gel-to-fluid phase transition temperature (T m) of POPC after incubation either below or near the glass transition temperature (T g) of the sugars in the mixture. Glass formation by. POPC bilayers undergo a gel-to-liquid crystalline phase transition around − 2 °C. As such, all of the data shown in Fig. 5 are of liquid crystalline POPC bilayers. It is interesting to note the decreased number of lobes observed in the X-ray scattering form factors at 30 °C (see Fig. S14 of the Supplementary materials) From the dependence of the transition pressure we derived a value of 19 kJ/mol for the transition enthalpy ΔH m of POPC in excess water. With increasing cholesterol concentration, ΔH m drops to about 7 kJ/mol at 20 mol% cholesterol. Time-resolved pressure-scan (p-scan) and temperature-jump (T-jump) experiments reveal that at low cholesterol. We note similar phase behavior in a model membrane mixture without SM (DOPC / DPPC / Chol), but find no micron-scale liquid domains in membranes of POPC / PSM / Chol. We delineate the onset of solid phases below the miscibility transition temperature, and detail indirect evidence for a three-phase coexistence of one solid and two liquid phases

Sphingomyelin/Phosphatidylcholine/Cholesterol Phase

surface coverage of 89%. Several phase transitions are thenobserved as a function of increasing temperature. Duringheating of the DPPC bilayer, a broad main transition wasobserved at 42-52C (Fig. 1, bandc) leading to the for-mation of lower domains. The coexistence of two domain wide temperature range. It was shown that addition of the POPC to the DPPC/H. 2. O does not . change the temperature of the . DPPC . main phase transition T. m. The observed phase separation . occurs for the system DPPC/POPC/H. 2. O up to the pre - transition temperature T. r (gel . phase - ripple . phase) of the DPPC multilayers. 1.

One of the most important factors in choosing the temperature of a lipid bilayer is the phase transition temperature of the lipids. POPC should be fluid at either 300 K or 310 K, so that is not a concern. -Justin -- ===== Justin A. Lemkul, Ph.D. Research Scientist Department of Biochemistry Virginia Tech Blacksburg, VA jalemkul[at]vt.edu. The order-disorder transition temperature of dry POPC was reduced by 708C in the presence of fructan. Fructan increased the mobility of the acyl chains, but immobilized the lipid headgroup region. Most likely, fructans insert between the headgroups of lipids, thereby spacing the acyl chains. This results in a much lower phase transition. Transition temperature (in °C) as a function of tail length and saturation. All data are for lipids with PC headgroups and two identical tails. Tail Length Double Bonds Transition Temperature 12: 0-1 14: 0: 23 16: 0: 41 18: 0: 55 20: 0: 66 22: 0: 75 24: 0: 80 18: 1: 1 18: 2-53 18: 3-6 For POPC, changes in the structural properties such as the lipid tail order parameter, hydrocarbon trans-gauche isomerization, lipid tail tilt-angle, and level of interdigitation identified a phase transition at about 270 K Fully hydrated bilayers of monounsaturated palmitoyloleoylphosphatidylcholine (POPC) and diunsaturated dioleoylphosphatidylcholine (DOPC) lipids have low main phase transition temperatures (271 K for POPC and 253 K for DOPC)

The orientation of the lipids with respect to the surface normal shows basically no changes over the whole temperature range. The determined angles (average values over the whole temperature range) are β = 38.1 ° for POPC and β = 38.2 ° for POPC:POPG transition temperature (Tm) due to melting grain boundaries [1], resulting in a formulation that releases trapped markers and drug contents at the phase transition much more quickly (tens of seconds) than in the absence of lysolipid, and in the range clinically attainable by mild hyperthermia (39-40°C) [2] Molecular dynamics simulation of POPC at low hydration near the liquid crystal phase transition. Biochimie, 1998. Massimo Marchi. M. Ceccarelli. Massimo Marchi. M. Ceccarelli. Download PDF. Download Full PDF Package. This paper. A short summary of this paper. 37 Full PDFs related to this paper

Low proportions (5%) of CER caused the appearance of a shoulder on the high temperature side of the main POPC transition. The composite peak could be best fit by two components by deconvolution analysis, suggesting that part of the POPC molecules shift from a lower T m, POPC phase to a phase-separated, higher temperature melting,. POPC has a phase transition melting temperature of -2°C while the for DOPC is -20°C; thus they are in the liquid crystalline phase. Liposomes can be grafted with polymer coating onto metal-based stents to prolong the half-life of the drugs, by allowing their gradual release and restraining the occurrence of restenosis ture of the phase transition for each mixture. Similar experiments using binary mixtures of DMPC and 1- palmitoyl-2-oleoyl phosphatidylcholine (POPC) dem- onstrated that recombination occurs in a temperature range which is believed to approximate the lower bound of the phase transition for this mixture as well The phase behavior of the three binary systems PSM/POPC, PSM/cholesterol, and POPC/cholesterol is first experimentally determined. Phase coexistence boundaries are then determined for ternary mixtures at room temperature (23 degrees C) and the ternary phase diagram at that temperature is obtained

(PDF) Nanoscale Drug Delivery and Hyperthermia: The

POPC - an overview ScienceDirect Topic

  1. A transition temperature around 22 degrees Celsius is not a high one, but you should take precautions and preserve the lipids at low temperatures and to avoid oxidation
  2. Phase transition temperature of DMPC and POPC as a function of for Eq. (9). hydration pressure (open circles) and hydrostatic pressure (solid circles). For a further test of Eq. (9), FT-IR and DTA measure- decay constants teach us that there is a principal difference ments were performed
  3. The temperature of the hydrating medium should be above the gel-liquid crystal transition temperature (Tc or Tm) of the lipid with the highest Tc before adding to the dry lipid. After addition of the hydrating medium, the lipid suspension should be maintained above the Tc during the hydra tion period. For high transition lipids, this is easily.
  4. The lipid chain packing for the POPC bilayer is known to be more defective than that for the DPPC bilayer. For both the POPC and the DPPC bilayers, the 2 H ESEEM NMR-like spectra showed a sharp narrowing between 180 and 190 K. From the other side, in both bilayers at 188 K, an inflection was observed for the temperature dependence of molecular.
  5. Using wide-line deuterium NMR, the effects of pressure on saturated-chain orientational order and gel--to--liquid-crystal phase transition temperature were observed in bilayers of 16:0-18:1 PC-${d}_{31}$ (POPC-${d}_{31}$) and 16:0-18:2 PC-${d}_{31}$ (PLPC-${d}_{31}$). Spectra were recorded for a range of pressures at selected temperatures and for a range of temperatures at selected pressures.

Interactions between soluble sugars and POPC (1-palmitoyl

  1. ation of the main phase transition temper-ature was also done by using a high-pressure differential thermal analysis (DTA)-calorimeter. In general, the heating rate was 1 K/
  2. ing transition temperature for POPC (80±C) compared to DMPC (95±C), even though k of POPC bilayers is larger by almost a factor of 2 [14], seemed to support this con-clusion. However, as will be discussed below, one has to be careful in attributing the sudden disappearance of the Bragg peak to the unbinding transition. d o
  3. lyophilized POPC membrane (TRE-POPC) at various tem-peratures. Fig. 1 shows the 31P spectra of hydrated POPC bilayers with 35 wt% water (a) and lyophilized POPC membrane containing 20 wt% trehalose (b). The transition temperature for the headgroup region of the TRE-POPC membrane is 323 K, which is 50 K higher than that of the hydrated POPC.
  4. The DPPC interval contains the experimental values of the actual phase transition temperature as obtained in experiments (315 K, see ), whereas the experimental transition temperatures for DOPC and POPC are slightly below our bracketed intervals (about 253 K for DOPC, see ; and about 270 K for POPC, see ). Concerning the effect of an.
  5. temperature-dependence of M1 for dispersions of POPC-d31/Cer. As seen in Fig. 3, pure POPC-d31 undergoes a sharp transition from the gel to the lc phase, as indicated by the drastic drop in M1 at T 10°C. In contrast, in the presence of 10-25 mol % Cer, POPC-d31 displays a much broader transition, with a gradual decrease in M1. Th

whose main phase transition temperature Tm = 53 C) were far more robust lubricants than liquid state lipids (e.g., palmitoyl-oleoyl PC (POPC), Tm = 20 C) in lipid-free aqueous media due to the lower structural integrity of POPC lipid layers. In contrast, POPC lipid layers provide excellent lubricatio including POPC structures. We have shown that Quantum effect has appeared in a small free space such as physiological temperature will influence its capacitance. We exhibit the cellular electrical properties and electromagnetic fields effects on cells cases and a transition voltage is able to change the dimensions of a membrane and the. 31 P spectra indicate that the lipid headgroup of trehalose-protected dry POPC membrane (TRE-POPC) have an effective phase transition temperature that is ̃50 K higher than that of the hydrated POPC membrane. In contrast, the acyl chains have similar transition temperatures in the two membranes Different types of nonionic vesicles were prepared from commercial Span 80 (also called sorbitan monooleate), as an inexpensive, biocompatible alternative to conventional phospholipid-based vesicles (liposomes). The vesicles were characterized by different techniques and comparison was made with vesicles formed from POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) or DOPC (1,2-dioleoyl. POPC and DMPC were investigated in the dry state by H-2, P-31 NMR, and Fourier transform infrared spectroscopy using two types of fructan and dextran. The order-disorder transition temperature of dry POPC was reduced by 70degreesC in the presence of fructan

Polymer Irradiation: Glass Transition Temperature | E-BEAM

In contrast, the synthetic phospholipids shown in Table I are highly pure (≥99 %) and have well-defined main phase transition temperatures (T m) as lipid assemblies. DOPC and POPC, which both contain monounsaturated acyl chains, have low phase transition temperatures (<0°C) due to the packing disorder imposed by the unsaturated chains At temperatures roughly 5 °C, 10 °C, 20 °C and 30 °C above its gel-to-liquid crystal phase transition temperature (−1.8 °C (ref. 38)), POPC-nAChR does not bind ethidium, showing that in all. The longer tails would raise the melting temperature, while the double bond lowers it, and it turns out that in this case, both effects compensate: both DLPC and POPC undergo their main phase transition at approximately the same temperature, −1 °C for DLPC 53 53. P. R For POPE, three temperature ranges were identified, in which the lower one (270−280 K) was associated with a pre-transition state and the higher (290−300 K) with the post-transition state. In the pre-transition state, there was a significant increase in the number of gauche arrangements formed along the lipid tails (46.0), POPC(7.6), R S/L =17, the thermal sequence showed the following phases and respective phase transition temperatures both on heating and cooling scans. L α 29°C L α + Ia3d(V 2) 32°C Ia3d 38°C Ia3d + Pn3m 39°C Pn3m Starting from a lamellar L α phase at 20°C and raising the temperature two subsequent forming bicontinuous cubic.

Molecular Dynamics of POPC Phospholipid Bilayers through

The response optimization of experiments was the liposome formulation with DOPC: 46%, POPC: 12% and DPPC: 42%. The optimal liposome formulation had an average diameter of 127.5 nm, a phase-transition temperature of 11.43 °C, a ζ-potential of −7.24 mV, fluidity (1/P) TMA-DPH (¬) value of 2.87 and an encapsulation efficiency of 20.24%. The. 50:50 POPC/DPPC was in gelþfluid phase coexistence at 17 C. As the temperature increased, the proportion of the fluid-phase domains increased. At 33 C, the membranes had fully transformed into the fluid phase. Figure 2. Fluorescence images as a function of temperature for GUVs of (A) 30:70 POPC/DPPC; (B) 50:50 POPC/DPPC; (C) 70:30 POPC/DPPC This observations is consistent with the effects of the nAChR on the gel-to-liquid crystal phase transition temperature of the POPC/POPA membranes (Fig. 5, right panel, spectrum A). In contrast, reconstitution of the nAChR into POPC has a minimal effect on the relative proportion of the two lipid ester carbonyl vibrations, suggesting minimal. POPC, used in the formulation of ETC-216 rHDL, 12 is a phosphatidylcholine with unsaturated acyl fatty acid and a transition temperature (T m) of −2°C. 17 eSM, used to prepare CER-001 rHDL 12 and ETC-642 sHDL, 14 is a naturally occurring lipid with mostly saturated fatty acids and an effective T m near 40°C. 18 We chose to test these.

What Is The Transition Temperature Of The Lipid? Avanti

temperature. Therefore, Gb 3 lipids at only a level of 1% impacts lipid order in bilayers in a manner that leads to the observed change of phase transition temperature. When Shiga toxin was introduced at the temperature above the chain melting point, the resulting shape and size of the gel domains were affected, compare the uorescent images wit The natural lipids with highest main transition temperature (T m) in membranes are (glyco)sphingolipids, some of them having T m much higher than 37°C (e.g., cerebrosides (Marsh, 1990. In the case of pure POPC vesicles, with a main-transition temperature T m of (−2.9 ± 1.3)°C (Koynova and Caffrey, 1998. Koynova R POPC and EYSM phospholipids. The respective single-component data sets obtained at 48 °C are shown in Fig. 2b and c where both phospholipids are inthel d phase.Thistemperatureis≈10 °Cabove the solid-ordered (s o)tol d phase transition temperature T M of EYSM bilayers. The DROSS experiment is restricted to experiments conducted above the T M o

Analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K, i.e. above the melting transition temperature of the two lipids the molecular properties of raft phases. It shows a narrow phase transition at a temperature of 311 K and is commercially available with a perdeuterated sn-2 chain. Fluorescence microscopy shows that large inhomogeneities in the mixed membranes are observed in the coexistence region of liquid-ordered and liquid-disordered lipid phases. Above.

It was shown that addition of the POPC to the DPPC/H 2 O does not change the temperature of the DPPC main phase transition T m . The observed phase separation occurs for the system DPPC/POPC/H 2 O up to the pre-transition temperature T r (gel phase - ripple phase) of the DPPC multilayers As shown in Fig. 2 Aa and B, the excess heat capacity vs. temperature plot of pure POPC liposomes exhibits the presence of an endothermic transition, centered at -3.4°C, corresponding to the T m of the lipid, with an associated enthalpy (ΔH) of 3.22 kcal/mol. Insertion of b 5 wt (Fig. 2 Ab)orb 5 ext (Fig. 2 Ac) in the liposome bilayer caused.

Transition temperature of lipid mixture

transition as temperature is raised up through Tm. Gel Phase Liquid Crystalline Phase (L ) A.K.A.: Fluid Phase Disordered Phase Bilayers can undergo phase transitions at a critical temperature, Tm. Native bilayers are usually in the fluid (liquid crystalline) phase. The Tmfor DMPC is 24.5ºC. The Tmfor POPC and DOPC are both < 0ºC gel transition temperature (Needham and Evans, 1988). Similarly, for mixtures we found that temperatures above the single highest transition temperature (in this case, DPPCs, with T g; 418C (Silvius, 1982)) were needed to create vesicles with the desired composition. Therefore, the interior solution was preheated and electroformation process. Molecular Dynamics of POPC Phospholipid Bilayers through the Gel to Fluid Phase Transition: An Incoherent Quasi-Elastic Neutron Scattering Study U.Wanderlingh,1 C.Branca,1 C.Crupi,1 V.ContiNibali,2 G.LaRosa,3 S.Rifici,1 J.Ollivier,4 andG.D'Angelo1 Temperature (K) EISF fast (a.u.

The available membranes are DPPC, POPC, POPE, and DMPC. The temperature at which the membrane patch was preequilibrated is given in parentheses after the membrane name. Because DPPC has a gel transition temperature around 313 K, the recommended minimum is also 325 K. Transmembrane atoms ASL text box and buttons POPC is 24˚C (Marsh, 2013). The big difference of the transition temperatures induces phase separation and clustering of SM. In contrast, the transition temperatures of POPE and POPS are 26˚C and 14˚C, respectively (Marsh, 2013). An egg SM transition temperature that is closer to that of POPE than of POPC increase

(PDF) Joint small-angle X-ray and neutron scattering data

The effect of storage temperature on interactions between

thickness of the polymers and the melting transition temperature of the lipids have been demonstrated to significantly affect the formation, morphology and/or stability of hybrid GUVs, as well [14]. It was observed that at high lipid composition, mixing POPC (melting transition temperature = −2 °C) wit The interactions of oleic acid with POPC membranes have been previously explored, primarily in the context of vesicle growth and stability,[7-9] but little is known of the permeability properties of such membranes, or their stability in the presence of divalent cations. The transition of primitive cells to moder Therefore, there is no significant difference in the average angle between a membrane of pure POPC and a 1:1 mixture of POPC and POPG. Both lipids are expected to be well above their phase transition temperature and in their liquid phase. The phase transition occurs at −2°C for POPC and close to or below 0°C for POPG . Furthermore, we could.

Why some polymers did not exhibit glass transition

Fluid phase lipid areas and bilayer thicknesses of

Lipids were dissolved in chloroform, dried under a stream of N2 , hydrated (50 mM Tris⋅HCl, pH 7.5, experimental buffer), and sonicated (Bransonics 1510 bath sonicator, Branson, Danbury, CT) at a temperature above Tc (the gel-liquid crystal transition temperature) for 30 min (this ranged from room temperature to ≈40°C, depending on. Titration of a C 12 E 8 /POPC mixture (1:2 mol/mol) at 30°C into a 10 mM solution of C 12 E 8 yielded a negligible enthalpy, indicating that the POPC dilution does not involve a chain-melting transition (Fig. 4A). Likewise, no thermal transitions were found by DSC performed in the temperature range from 20°C to 45°C It was found that lipids in their gel phase (such as hydrogenated soy PC (HSPC), whose main phase transition temperature T m = 53 °C) were far more robust lubricants than liquid state lipids (e.g., palmitoyl-oleoyl PC (POPC), T m = −20 °C) in lipid-free aqueous media due to the lower structural integrity of POPC lipid layers Temperature dependence of the symmetric CH 2 stretching vibration of the fatty acyl chains of liposomes in the dry state. Melting curves in (A) and (C) are from liposomes prepared in distilled water from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and different weight fractions of digalactosyldiacylglycerol (DGDG) or 1,2-dilinolenoyl-sn-glycero-3-phosphatidylcholine (DLPC.

Structural, dynamic and mechanical properties of POPC at

Phys. Rev. Lett. 94, 148101 (2005) - Miscibility Phase ..

The phase transition temperature of membranes depends on the length of the lipids' acyl chain and their number of double bonds. Shorter and unsaturated acyl chains have reduced possibilities to interact with each other and, as a result, lower the phase transition temperature crystal transition temperatures, which range from -5°C for POPC to 63°C DPPE (DPPC 41C, DPPS 5 1°C). At 0 = 0 each bilayer is at its respec- tive phase transition temperature. It is assumed that membranes which are measured at the same 0 value are approximately in the same physical state The temperature effects and the conformational changes of unsaturated and saturated PCs were confirmed by the computer simulation study of the cis-trans transition with POPC and DPPC(C16). The cis­ trans conformational energy difference of POPC is 62.06 kcal/mol and that of DPPC(C16) is 6.75 kcal/mol

mixtures of the lipids 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG), small phase transition temperature of the lipid. We established that without the induction of interdigitation by ethanol, or by hydrostatic pressure [15], those gels would not form. Whil h. The temperature used for GUV formation was well above the fluid/gel phase transition temperature (;80 C for all samples). One of the advantages of these chambers (see Fig. 1, A and B) is the fact that vesicle formation can be directly observed in the microscope. In this last case, the vesicles remai DIBMA/POPC molar ratio, RDIBMA/POPC, in the presence of temperature, T, for 5 mM DMPC and 0.5mM DIBMA without divalent cations or with either 10mM Mg2+ or 7.5mM Ca2+. • The presence of 10mM Mg2+ or 7.5mM Ca2+ reduced the main transition temperature, Tm, from ∼24 °C to ∼22 °C.. phase transition temperature of the lipids was measured with a MicroCal VP-DSC differential scanning calorimeter (Northampton, MA). A minimum of three scans was performed from 10 to 60 C with a temperature increase of 1 C/min and a 15min equilibration period before each scan. In all cases, the thermogram of buffe ref_t, gen_temp = 323: We must use a temperature that is above the phase transition temperature of the lipid. For DPPC, 323 K is commonly used. tc-grps = Protein_DPPC Water_and_ions: The two groups are coupled separately for due to the different rates of diffusion of the two phases

Metabolic Dysfunction and Unabated Respiration Precede theHydration and Lateral Organization in Phospholipid

Isoenthalpic temperature T m Phase transition temperature TMA-DPH 1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene Tris buffer (tris(hydroxymethylo)-aminomethane) Triton X-100 ( TX-100) polyethylene glycol p-(1,1,3,3-tetramethylbutyl)-phenyl ether UM n-Undecyl-β-D-Maltopyranoside Val Valin melting transition temperature of the two lipids. 3. Materials and methods 3.1. Sample preparation All lipids, including their isotopes (POPC-d13, POPC-d31, POPC-d44, DPPC-d13, DPPC-62) were purchased from Avanti Polar Lipids (Alabaster, AL, USA) and used without further purification (see Fig. S6 of the supporting informatio The temperature was kept at 310K, approximately 40 degree higher than the transition temperature of POPC. According to the description in paper, the POPC bilayer should form a vesicle in 100 ns under same temperature. I am using Lammps rather than Gromacs. And everything else is kept same as in the paper V.1.1. Studies at a controlled temperature of 24 ºC To simplify the system monolayers were studied as model membranes at a room temperature of 24 ºC. All isotherms were obtained as described in the Experimental Methods chapter. V.1.1.1. POPE and POPC mixtures Figure 47 shows the variation of the surface pressure as a function of the molecula The POPC has a greater effect than POPS, probably because the former lipid is more miscible with POPE. Addition of 10 mM CaCl2 has little effect on the phase-transitions of POPE/POPC mixtures, but it greatly decreases the effectiveness of POPS in raising the bilayer-to-hexagonal phase-transition temperature of POPE

Re: [gmx-users] Temperature in simulatio

temperature of the long-chain saturated component in ternary mixtures. We also see that there is a correlation between higher miscibility transition temperatures and higher melting temperature lipids (Samsonov et al., 2001; Veatch and Keller, 2002). The relationship between the main chain transition temperature and liquid immiscibil Five types of gas-encapsulated liposomes (bubble liposomes) were produced and their stability was studied under static pressure and dynamic pressure conditions. Five types of phosphatidylcholine, DOPC, POPC, DMPC DPPC and DSPC, with different transition temperatures between liquid-crystalline and gel phases in the range from -22??C to +55??C were used as a main component of the liposomes pressure transition temperature for that lipid @2#. A self-consistent field theory calculation showed a similar depen-dence, on temperature, of the slope of orientational order versus pressure for dipalmitoyl phosphatidylethanolamine ~DPPE!@8#. Hydrostatic pressure is transmitted uniformly throughou POPC or DOPC, or highly-branched DPhPC), and cholesterol (Chol). These mixtures separate into liquid-ordered (Lo) and liquid-disordered (Ld) phases below a miscibility transition temperature, T misc, as observed previously. 31,43−45 Finally, we characterized the temperature-dependent capacitance of DIBs assembled from bTLE, a natural lipid.

The pure lipid bilayer was made of 40 POPC molecules, while the heterogeneous lipid bilayer was made of 36 POPC and 4 cholesterol molecules [POPC:CHOL (0.9:0.1)]. The bilayer was placed in the x-y plane and solvated by 2200 water molecules amounts of DOPC and POPC can be controlled precisely in order to study the macro-to-nano transition [8]. The relative amount of DOPC and POPC can be described by ρ, given as, ρ ≡ χ DOPC χ DOPC +χ POPC, (1) where χ DOPC and χ POPC are the mole fractions of DOPC and POPC, respectively. In this way, ρ = 1.00 corresponds to

Here, analysis of asymmetric dipalmitoyl phosphatidylcholine/POPC vesicles did not reveal evidence of transbilayer coupling between the inner and outer leaflets at 323 K,i.e.above the melting transition temperature of the two lipids It shows a narrow phase transition at a temperature of 311K and is commercially available with a perdeuterated sn-2 chain. Fluorescence microscopy shows that large inhomogeneities in the mixed membranes are observed in the coexistence region of liquid-ordered and liquid-disordered lipid phases Abstract Inorganic mercury (Hg. 2+) and cadmium (Cd 2+) are toxic heavy metals linked to the etiology of cancer and diabetes. The binding affinity of these metals to biomimetic erythrocyte (RBC) membranes and their influence on membrane phase transition (Tm) were investigated using isothermal titration calorimetry (ITC) and dynamic ligh PRESERVATION OF POPC MODEL MEMBRANE INTEGMTY BY TREHALOSE. A *H AND 31P NMR STUDY. '4 Thesis Presented to The Faculty of Graduate Studies of The University of Guelph. The effect of cholesterol on the acyl chain order of three glycerophosphocholines with 14, 16, and 18 carbons per acyl chain, namely, di(14:0)PC, di(16:0)PC, and di(18:0)PC, above the gel to liquid-crystalline phase transition temperature was investigated by using {sup 2}H nuclear magnetic resonance spectroscopy POPC/POPE and POPC/POPG were mixed 40:60 mol. Nonspecific adhesion on plastic was subtracted. 0, n = 135; POPC, n = 25; POPC/POPE because as long as we worked at a temperature above their phase transition temperature (T m), no changes were introduced to the ordered gel phase. DOPC trans was also tested at 4°C, as it has a phase T m of 12°C