Insertion of semifluorinated diblocks on DMPC and DPPC liposomes. Influence on the gel and liquid states of the bilayer

Sabín, Juan; Prieto, Gerardo; Estelrich, Joan; Sarmiento, Félix; Costas, Miguel

doi:10.1016/j.jcis.2010.04.067

Cited by 8 publications

(9 citation statements)

References 19 publications

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“…Thus, this transition should not correspond with the expected T m for pure DMPC from a gel to the liquid disordered phase that has been reported at 23 1C. 25 The LAURDAN GP temperature profile was also observed (blue line) with no inflection at this temperature range. Although LAURDAN experiments could lead to an inflection below 15 1C, which denotes a phase transition, the DSC results did not show any change at this temperature range (À60 to 60 1C); thus, we assume that the main transition seems to be suppressed in the system studied.…”

Section: Resultsmentioning

confidence: 68%

“…For pure DPPC, a symmetric sharp peak is reported at a higher temperature, 41 1C, which corresponds to the main transition from the gel to the liquid disordered phase. 25 The high symmetry indicates a single phase; 26 in contrast, the peak is slightly asymmetrical for the DPPC/SCHOL system, which corresponds to more than one phase. 27 Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, the T m decreased from 41 1C for the pure DPPC 25 and DPPC/DHPC systems 35 to 34 1C for DPPC/ SCHOL (molar ratio 3.5 : 1). For DMPC/SCHOL (molar ratio 3.5 : 1), no temperature associated with the main lipid transition (from a gel to a liquid disordered phase) was detected; this temperature was determined to be 23 1C for pure DMPC.…”

Section: Discussionmentioning

confidence: 97%

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Bicellar systems to modify the phase behaviour of skin stratum corneum lipids

Rodríguez

Cócera

Rubió

et al. 2012

Phys. Chem. Chem. Phys.

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Bicellar systems are a fascinating category of versatile lipid assemblies that comprise bilayered disk-shaped nanoaggregates formed in water by long and short alkyl chain phospholipids. Bicelles bridge the gap between micelles and lipid vesicles by combining the attractive properties of both systems. These structures have recently been proposed in dermatological, cosmetic and pharmaceutical applications. Two new binary bicellar systems composed of cholesterol sulphate (SCHOL) and long-chain phospholipids (dimyristoyl-phosphatidylcholine, DMPC, or dipalmitoyl-phosphatidylcholine, DPPC) are characterised herein by differential scanning calorimetry, fluorescence spectroscopy, X-ray scattering and microscopy. Additionally, a comparative study on skin treated with the new SCHOL systems (DMPC/SCHOL and DPPC/SCHOL) and classic DHPC systems (DMPC/DHPC and DPPC/DHPC) was performed. These studies were conducted to determinate how deeply bicelles penetrate into the skin and the extension of their effect on the phase behaviour of stratum corneum (SC) lipids using attenuated total reflectance-Fourier transform infrared spectroscopy and two-photon excitation fluorescence microscopy. Our results show that SCHOL modified the typical discoidal morphology and the phase behaviour of the systems, inducing coexistence of two phases, liquid-ordered and ripple phases. The effect of the systems on SC lipids depends on their composition and is related to the fluidity of the SC lipid alkyl chains. Thus, systems with DMPC induced more disorder in SC lipids than systems with DPPC, and SCHOL did not modify the lipid arrangement. Perdeuterated systems in the infrared spectroscopy technique supported a different distribution in the tissue for every system. DMPC systems were primarily at the first layers of the SC, whereas DPPC systems were more widely distributed. Systems with SCHOL had enhanced distribution and penetration of bicellar systems throughout the SC.

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Section: Resultsmentioning

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 97%

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Bicellar systems to modify the phase behaviour of skin stratum corneum lipids

Rodríguez

Cócera

Rubió

et al. 2012

Phys. Chem. Chem. Phys.

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“…With the DMPC–PFO systems, as previously discussed , the peaks of the thermograms are broader and shifted to higher temperatures (Table ) compared with pure phospholipid upon addition of PFO. This is also observed for DPPC–PFO and it is indicative of the inclusion of the polymer into the lipid bilayer (a schematic representation is shown in scheme S1), probably with the octyl chain of the PFO interdigitated with the phospholipid chains, as suggested by the changes in the thermograms, which are similar to those observed in other phospholipid systems in which interdigitation is described upon addition of a polymer . With the other phospholipid systems, any changes in the thermograms on addition of PFO are within the experimental uncertainties, and no definite conclusions can be made.…”

Section: Resultsmentioning

confidence: 75%

Effect of the Phospholipid Chain Length and Head Group on Beta‐Phase Formation of Poly(9,9‐dioctylfluorene) Enclosed in Liposomes

Tapia

Monteserín

Melo

et al. 2013

Photochem & Photobiology

Self Cite

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We have studied the effect of head group and alkyl chain length on β-phase formation in poly(9,9-dioctylfluorene) (PFO) solubilized in phospholipid liposomes. Systems studied have three different alkyl chain lengths (1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine [DMPC], 1,2-didodecanoyl-sn-glycero-3-phosphatidylcholine [DLPC], 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine [DPPC]) and head groups (1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt [DMPA], 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine [DMPE] and 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine sodium salt [DMPS]). Changes in liposome size upon addition of PFO are followed by dynamic light scattering. All the phospholipids induce the formation of PFO β-phase, which is followed by the emission intensity and deconvolution of the absorption spectra. Both the head group and alkyl chain length affect the yield of β-phase. The photophysics of PFO incorporated in liposomes is characterized by stationary and time-resolved fluorescence, whereas the polymer-phospholipid interactions have been studied by the effect of the PFO concentration on the phospholipid phase transitions (differential scanning calorimetry [DSC]).

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“…1 In the process of liposome formation, they can entrap both water and lipid soluble compounds, while polyelectrolytes can be adsorbed on their surface through electrostatic interactions. 1 In addition, liposomes, which typically have sizes on the hundred nanometer scale, can be considered as good carriers for various molecules, and can solubilize neutral compounds, 2 including polymers, [3][4][5] to form aqueous dispersions. 5,6 The variety of interactions makes liposomes interesting carriers of drugs for therapeutic applications, 1,7-9 including photodynamic therapy.…”

Section: Introductionmentioning

confidence: 99%

From molecular modelling to photophysics of neutral oligo- and polyfluorenes incorporated into phospholipid bilayers

et al. 2015

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The combination of various experimental techniques with theoretical simulations has allowed elucidation of the mode of incorporation of fluorene based derivatives into phospholipid bilayers. Molecular dynamics (MD) simulations on a fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine (DMPC) bilayer, with benzene (B), biphenyl (BP), fluorene (F) and tri-(9,9-di-n-octylfluorenyl-2,7-diyl), TF, have provided insights into the topography of these molecules when they are present in the phospholipid bilayer, and suggest marked differences between the behavior of the small molecules and the oligomer. Further information on the interaction of neutral fluorenes within the phospholipid bilayer was obtained by an infrared (IR) spectroscopic study of films of DMPC and of the phospholipid with PFO deuterated specifically on its alkyl chains (DMPC-PFO-d34). This was complemented by measurements of the effect of F, TF and two neutral polymers: polyfluorene poly(9,9-di-n-octylfluorenyl-2,7-diyl), PFO, and poly(9,9-di-n-dodecylfluorenyl-2,7-diyl), PFD, on the phospholipid phase transition temperature using differential scanning calorimetry (DSC). Changes in liposome size upon addition of F and PFO were followed by dynamic light scattering. In addition, the spectroscopic properties of F, TF, PFO and PFD solubilised in DMPC liposomes (absorption, steady-state and time-resolved fluorescence) were compared with those of the same probes in typical organic solvents (chloroform, cyclohexane and ethanol). Combining the insight from MD simulations with the results at the molecular level from the various experimental techniques suggests that while the small molecules have a tendency to be located in the phospholipid head group region, the polymers are incorporated within the lipid bilayers, with the backbone predominantly orthogonal to the phospholipid alkyl chains and with interdigitation of them and the PFO alkyl chains.

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Insertion of semifluorinated diblocks on DMPC and DPPC liposomes. Influence on the gel and liquid states of the bilayer

Cited by 8 publications

References 19 publications

Bicellar systems to modify the phase behaviour of skin stratum corneum lipids

Bicellar systems to modify the phase behaviour of skin stratum corneum lipids

Effect of the Phospholipid Chain Length and Head Group on Beta‐Phase Formation of Poly(9,9‐dioctylfluorene) Enclosed in Liposomes

From molecular modelling to photophysics of neutral oligo- and polyfluorenes incorporated into phospholipid bilayers

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