Structure and molecular dynamics of highly mobile polymer membranes

Fahmy, Tarek M.; Wesser, Joachim; Spiess, Hans Wolfgang

doi:10.1002/apmc.1989.051660103

Cited by 10 publications

(11 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…reported that UV polymerization of vesicles of dioctadecadienoylammonium bromide, a cross-linkable lipid, caused a 4-fold reduction in D which was attributed to a low number-average degree of polymerization ( X n ). Diacetylene lipids, both pure and mixed with nonpolymerizable, fluid-phase lipids, have been the subject of several studies. − Upon exposure to a high dose of UV irradiation, pure bis-diacetylene lipid bilayers are highly cross-linked which results in D ≈ 0 on the time scale of a FRAP measurement. , Lower UV doses, however, produce partially polymerized bilayers in which restricted lateral diffusion of coincorporated, nonpolymerizable lipids is observed. , Fahmy et al reported that thermal polymerization of bilayers composed of a zwitterionic lipid with a methacryloyl group in one tail caused a 500-fold increase in the time constant for fluorescence bleaching recovery. Kölchens et al examined diffusion in membranes composed of mono- and bis-acryloyl phosphatidylcholines that were polymerized using thermal initiation.…”

Section: Introductionmentioning

confidence: 99%

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity

et al. 2016

View full text Add to dashboard Cite

Polymerization of substrate-supported bilayers composed of dienoyl phosphatidylcholine (PC) lipids is known to greatly enhance their chemical and mechanical stability, however the effects of polymerization on membrane fluidity have not been investigated. Here planar supported lipid bilayers (PSLBs) composed of dienoyl PCs on glass substrates were examined to assess the degree to which UV-initiated polymerization affects lateral lipid mobility. Fluorescence recovery after photobleaching (FRAP) was used to measure the diffusion coefficients (D) and mobile fractions of rhodamine-DOPE in unpolymerized and polymerized PSLBs composed of bis-sorbyl phosphatidylcholine (bis-SorbPC), mono-sorbyl phosphatidylcholine (mono-SorbPC), bis-dienoyl phosphatidylcholine (bis-DenPC) and mono-dienoyl phosphatidylcholine (mono-DenPC). Polymerization was performed in both the Lα and Lβ phase for each lipid. In all cases, polymerization reduced membrane fluidity, however measurable lateral diffusion was retained which is attributed to a low degree of polymerization. The D values for sorbyl lipids were less than those of the denoyl lipids; this may be a consequence of the distal location of polymerizable group in the sorbyl lipids which may facilitate inter-leaflet bonding. The D values measured after polymerization were 0.1 to 0.8 of those measured before polymerization, a range that corresponds to fluidity intermediate between that of a Lα phase and a Lβ phase. This D range is comparable to ratios of D values reported for liquid-disordered (Ld) and liquid-ordered (Lo) lipid phases, and indicates that the effect of UV polymerization on lateral diffusion in a dienoyl PSLB is similar to the transition from a Ld phase to a Lo phase. The partial retention of fluidity in UV polymerized PSLBs, their enhanced stability, and the activity of incorporated transmembrane proteins and peptides is discussed.

show abstract

Section: Introductionmentioning

confidence: 99%

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity

et al. 2016

View full text Add to dashboard Cite

show abstract

“…According to the method described by Duda et al and from the photograph, an average monolayer is estimated to be 32 Å thick, because the thickness of the arbitrary 20 layers is 640 Å. These findings suggest that the structure of LB films of phospholipid-modified polypeptide 3 agrees with the model of polymeric lipids 3 Transmission electron micrograph of a cross-sectional view of the phospholipid-modified polypeptide 3 LB films (30 layers) stained on a PET film plate and imaged at an original 250 000× magnification. …”

Section: Resultsmentioning

confidence: 83%

Preparation and Properties of Phospholipid-Modified Polypeptide

Matsumoto

Wang

et al. 1996

Macromolecules

View full text Add to dashboard Cite

Poly(sodium glutamate) (DP = 160) was modified by sheep brain l-α-phosphatidylethanolamine with about 65% substitution in side chains via the active ester method. The structure of the modified polypeptide was characterized by its IR and 1H NMR spectral data and elemental analysis. The π−A isotherms of the modified polypeptide at different temperatures and pH were measured. Reproducible Y-type deposition, with a deposition ratio of 0.9 Y-type Langmuir−Blodgett films (30 layers) of the modified polypeptide were also prepared, and lamellar structure, together with an average 32 Å thick monolayer was observed by transmission electron microscopy. The formation of β-structure but no α-helix structure for cast film of the modified polypeptide was observed by circular dichroism spectroscopy. A wide-angle X-ray diffraction pattern investigation for the cast film showed a small peak at 2θ = 5.7° and a big peak at 2θ = 20.1°, corresponding to d spacing of 15.5 and 4.4 Å, respectively. In addition, investigation of Na+ ion and K+ ion transport behavior for cast film of the modified polypeptide showed that Na+ ion permeating through the cast film was easier than K+ ion, and both Na+ ion and K+ ion permeated through the film easier under acidic conditions (pH 4) than that under neutral conditions (pH 7).

show abstract

“…But the dynamic profile seen for standard micelles is superposed by the dynamic restrictions imposed by the polymer backbone as the backbone tends to immobilize the side chain fragments close by [276,386,387]. Whereas the general profile stays the same in polysoaps for "head" geometry as in standard surfactants, i.e., the head groups are the least mobile segments [388,389], polysoaps of "tail end" geometry show a dynamic profile of the surfactant fragments opposite to the one of the monomeric analogues.…”

Section: Dynamic Propertiesmentioning

confidence: 99%

Molecular concepts, self-organisation and properties of polysoaps

Laschewsky

Polysoaps/Stabilizers/Nitrogen-15 NMR

223

126

View full text Add to dashboard Cite

The article reviews water-soluble polymers characterized by surfactant side chains, and related amphiphilic polymers. Various synthetic approaches are presented, and rules for useful molecular architectures are given. Models for the self-organization of such polymers in water are presented comparing them with the micellization of low molecular weight surfactants. Highlighting key properties of aqueous polysoap solutions such as viscosity, surface tension and solubilization power, some structure-property relationships are established. Further, the formation of mesophases and of superstructures in bulk is addressed. Finally, the functionalization of polysoaps, and potential applications are discussed.

show abstract

Structure and molecular dynamics of highly mobile polymer membranes

Cited by 10 publications

References 20 publications

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity

Preparation and Properties of Phospholipid-Modified Polypeptide

Molecular concepts, self-organisation and properties of polysoaps

Contact Info

Product

Resources

About