Foam film study of albumin inhibited lung surfactant preparations: effect of added hydrophilic polymers

Georgiev, Georgi; Vassilieff, C.S.; Jordanova, A.; Tsanova, Asya; Lalchev, Zdravko

doi:10.1039/c2sm25937k

Cited by 10 publications

(7 citation statements)

References 54 publications

(88 reference statements)

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“…The importance of specic osmolyte effects has been implicated in several studies and has various applications including medical ones. [15][16][17] From the lamellar repeat distances of the two crystalline structures (with NaCl or the ionic liquid), we conclude that the lipids were more tilted in the presence of the ionic liquid than in the presence of NaCl. In the case of the ionic liquid, a further increase of its concentration melted the crystal phase of bilayers into a gel phase.…”

Section: Discussionmentioning

confidence: 86%

“…14 This osmotic pressure is expressed in the free energy by adding a constant pressure term. [15][16][17] The corresponding distance between layers at some pressure can be precisely measured using solution small-angle X-ray scattering (SAXS). Together, the information on the osmotic pressure with SAXS can be used to derive pressure-distance curves (or "equations of state") that can be modeled using expressions such as eqn (1).…”

Section: Introductionmentioning

confidence: 99%

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Charged membranes under confinement induced by polymer-, salt-, or ionic liquid solutions

et al. 2013

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Section: Discussionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Charged membranes under confinement induced by polymer-, salt-, or ionic liquid solutions

et al. 2013

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“…Surface pressure/area (p/A) isotherms were measured using a computer-controlled Langmuir surface balance (Kibron, Helsinki, Finland) equipped with a mTrough XL (area 225 cm 2 , volume 40 ml), using the Wilhelmy wire probe method (instrumental accuracy 0.01 mN m À1 ), as previously described. 22,23 Human meibum dissolved in chloroform was spread over the air-saline solution interface (PBS, pH 7.4) using a Hamilton microsyringe. Typically, 46 mg MGS were deposited on the surface.…”

Section: Langmuir Surface Balance Experimentsmentioning

confidence: 99%

Surface relaxations as a tool to distinguish the dynamic interfacial properties of films formed by normal and diseased meibomian lipids

et al. 2014

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The surface properties of human meibomian lipids (MGS), the major constituent of the tear film (TF) lipid layer, are of key importance for TF stability. The dynamic interfacial properties of films by MGS from normal eyes (nMGS) and eyes with meibomian gland dysfunction (dMGS) were studied using a Langmuir surface balance. The behavior of the samples during dynamic area changes was evaluated by surface pressure-area isotherms and isocycles. The surface dilatational rheology of the films was examined in the frequency range 10(-5) to 1 Hz by the stress-relaxation method. A significant difference was found, with dMGS showing slow viscosity-dominated relaxation at 10(-4) to 10(-3) Hz, whereas nMGS remained predominantly elastic over the whole range. A Cole-Cole plot revealed two characteristic processes contributing to the relaxation, fast (on the scale of characteristic time τ < 5 s) and slow (τ > 100 s), the latter prevailing in dMGS films. Brewster angle microscopy revealed better spreading of nMGS at the air-water interface, whereas dMGS layers were non-uniform and patchy. The distinctions in the interfacial properties of the films in vitro correlated with the accelerated degradation of meibum layer pattern at the air-tear interface and with the decreased stability of TF in vivo. These results, and also recent findings on the modest capability of meibum to suppress the evaporation of the aqueous subphase, suggest the need for a re-evaluation of the role of MGS. The probable key function of meibomian lipids might be to form viscoelastic films capable of opposing dilation of the air-tear interface. The impact of temperature on the meibum surface properties is discussed in terms of its possible effect on the normal structure of the film.

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“…via hydrogen bonding to the lipid headgroups. 7,8 Thus the rst aim of our work was to study the interaction of high molecular weight HA with lms of meibomian lipids at the air/water interface. Meibomian lipids are secreted by specialized meibomian glands located in the eyelid margin.…”

Section: Introductionmentioning

confidence: 99%

Surface chemistry study of the interactions of hyaluronic acid and benzalkonium chloride with meibomian and corneal cell lipids

et al. 2013

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Hyaluronic acid (HA) is a non-surface active water soluble anionic polyelectrolyte found in sub-nanomolar levels in human tears and implemented in substitutes of human tears' aqueous layer. In the current work we studied the interactions of high molecular weight (M w 1 Â 10 6 Da) HA with films of ocular surface lipids and investigated the potential of HA to modify the interactions of the lipid films with the low M w cationic surfactant dodecyldimethylbenzylammonium chloride (C12-BAC) known for its adverse effects on tear film compounds. The interactions of HA and/or C12-BAC with meibomian and corneal lipid films were examined using a Langmuir surface balance. The film morphology was monitored by Brewster Angle Microscopy. The HA/C12-BAC interactions at the air/water interface and in the solution bulk were also examined. HA interacted with meibomian lipids and enhanced the structure and the rheological properties of the meibum films. HA bound C12-BAC in bulky polymer/surfactant complexes and at $0.1% HA neutralized the capability of C12-BAC to penetrate the lipid layers and to disrupt their integrity and viscoelasticity. The results were correlated with the capability of HA to maintain the viability of C12-BAC treated corneal cells. Our study suggests a possible novel implementation of high M w anionic polyelectrolytes like HA: the polymers can be instilled on the ocular surface together with cationic surfactant containing drugs, and increase the biocompatibility of the ophthalmic formulations.A molecular scale mechanism is proposed for the interactions of HA with tear lipids and cationic surfactants.

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Foam film study of albumin inhibited lung surfactant preparations: effect of added hydrophilic polymers

Cited by 10 publications

References 54 publications

Charged membranes under confinement induced by polymer-, salt-, or ionic liquid solutions

Charged membranes under confinement induced by polymer-, salt-, or ionic liquid solutions

Surface relaxations as a tool to distinguish the dynamic interfacial properties of films formed by normal and diseased meibomian lipids

Surface chemistry study of the interactions of hyaluronic acid and benzalkonium chloride with meibomian and corneal cell lipids

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