Interfacial properties of pulmonary surfactant layers

Wüstneck, R.; Pérez‐Gil, Jesús; Wüstneck, N.; Cruz, Antonio; Fainerman, V. B.; Pison, U.

doi:10.1016/j.cis.2005.05.001

Cited by 188 publications

(173 citation statements)

References 180 publications

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“…Phospholipids constitute around 80% per mass of surfactant and are the main surface active molecules, able to form interfacial films capable of reducing the surface tension at the alveolar air-liquid interface until values close to 0 mN/m, which are reached at the end of expiration, a strict requirement to prevent atelectasis and alveolar collapse [3]. Surfactant phospholipids assemble in the type II pneumocytes of the lung epithelium in the form of bilayered membranes.…”

Section: Pulmonary Surfactant Function and Dysfunctionmentioning

confidence: 99%

“…Pulmonary surfactant, a lipid-protein complex produced by the alveolar epithelium of lungs, has been optimised to coordinate two main activities through natural evolution. On the one hand, it stabilises the respiratory surface against physical forces, therefore minimising the work required to maintain the large respiratory surface open to air [2][3][4]. On the other hand, pulmonary surfactant contains elements responsible for establishing a primary innate antipathogenic barrier, essential to ensure an intrinsically low pathogen load in the absence of induced defence mechanisms [5].…”

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confidence: 99%

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Synthetic Pulmonary Surfactant Preparations: New Developments and Future Trends

Mingarro¹,

Lukovic²,

Vilar³

et al. 2008

CMC

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Pulmonary surfactant is a lipid-protein complex that coats the interior of the alveoli and enables the lungs to function properly. Upon its synthesis, lung surfactant adsorbs at the interface between the air and the hypophase, a capillary aqueous layer covering the alveoli. By lowering and modulating surface tension during breathing, lung surfactant reduces respiratory work of expansion, and stabilises alveoli against collapse during expiration.Pulmonary surfactant deficiency, or dysfunction, contributes to several respiratory pathologies, such as infant respiratory distress syndrome (IRDS) in premature neonates, and acute respiratory distress syndrome (ARDS) in children and adults. The main clinical exogenous surfactants currently in use to treat some of these pathologies are essentially organic extracts obtained from animal lungs. Although very efficient, natural surfactants bear serious defects: i) they could vary in composition from batch to batch; ii) their production involves relatively high costs, and sources are limited; and iii) they carry a potential risk of transmission of animal infectious agents and the possibility of immunological reaction. All these caveats justify the necessity for a highly controlled synthetic material.In the present review the efforts aimed at new surfactant development, including the modification of existing exogenous surfactants by adding molecules that can enhance their activity, and the progress achieved in the production of completely new preparations, are discussed. Pulmonary surfactant function and dysfunctionThe respiratory surface of lungs constitutes the largest area of the human body exposed to the environment. Efficient gas exchange requires a large enough surface to be continuously exposed to air while minimising the barriers for oxygen and carbon dioxide to diffuse between air and the blood compartment [1]. At the same time, a selection of combined defence mechanisms is required to help keep such an essentially exposed area sterile of potential pathogenic microorganisms. Pulmonary surfactant, a lipid-protein complex produced by the alveolar epithelium of lungs, has been optimised to coordinate two main activities through natural evolution. On the one hand, it stabilises the respiratory surface against physical forces, therefore minimising the work required to maintain the large respiratory surface open to air [2][3][4]. On the other hand, pulmonary surfactant contains elements responsible for establishing a primary innate antipathogenic barrier, essential to ensure an intrinsically low pathogen load in the absence of induced defence mechanisms [5]. Extensive research in the last few decades has revealed some of the molecular mechanisms involved in pulmonary surfactant action. However, the manner in which both the biophysical and defence activities are intermingled and coordinately modulated in the alveolar spaces is now only beginning to be envisioned.Pulmonary surfactant is composed of approximately 90% lipids and 8-10% proteins, although only around 5% ...

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Section: Pulmonary Surfactant Function and Dysfunctionmentioning

confidence: 99%

mentioning

confidence: 99%

Synthetic Pulmonary Surfactant Preparations: New Developments and Future Trends

Mingarro¹,

Lukovic²,

Vilar³

et al. 2008

CMC

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“…A wide variety of low-and high-molecular-weight surfactants are frequently used in pharmaceuticals, cosmetics and food products among their other applications. Complex interfacial structures are present not only in these products but also in biological systems such as cell membranes (7,8) and the surfactant film on lung alveoli (9,10). Furthermore, the majority of natural biochemical reactions occur at interfaces, and only by understanding interfacial characteristics, we are able to explain these processes and successfully mimic biological systems.…”

mentioning

confidence: 99%

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Pelipenko¹,

Kristl²,

Rošic³

et al. 2012

Acta Pharmaceutica

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Colloidal disperse systems represent the increasing number of modern delivery systems whose primary characteristic, a large interfacial area, causes thermodynamic instability. Therefore, the foremost challenge in dispersion design is the reduction of interface instability and an understanding of the behaviour of interfaces. Interfacial rheology is one of the most powerful tools for observing occurrences at the interphase. As previously mentioned, the stability of such systems is provided by the formation of a stable interfacial layer of surfactants around each dispersible particle. The stability of these systems can be improved by using more than one surfactant, but it must be kept in mind that different surfactants can have varying mechanisms of stabilisation, some of which can be mutually incompatible. Surfactant selection is therefore crucial and must be based on physicochemical properties, stability of the interfacial film, mobility of the molecules in the interfacial film, HLB, film formation kinetics, compatibility and interactions between molecules on the surface, CMC, etc. Interfacial rheological properties have yet to be thoroughly explored. Only recently, methods have been introduced that provide sufficient sensitivity to reliably determine viscoelastic interfacial properties. In general, interfacial rheology describes the relationship between the deformation of an interface and the stresses exerted on it.Due to the variety in deformations of the interfacial layer (shear and expansions or compressions), the field of interfacial rheology is divided into the subcategories of shear and dilatational rheology. While shear rheology is primarily linked to the long-term stability of dispersions, dilatational rheology provides information regarding short-term stability. Interfacial rheological characteristics become relevant in systems with large interfacial areas, such as emulsions and foams, and in processes that lead to a large increase in the interfacial area, such as electrospinning of nanofibers.

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“…Moreover, under non-equilibrium conditions, the surface tension becomes a tensor, and depends on the rate of strain even in the simple case of pure two-dimensional deformations [32]. It is now well accepted that this dynamic character of fluid interfaces plays a key role in understanding the stability of thin films, foams, suspensions and emulsions [16,33], as well as the mobility of bubbles and drops in viscous fluids [34], the correlation between the structure of the monolayers and the corresponding one of its LangmuirBlodgett films [35], and in the stability of the biological membranes [36], and lung surfactants [37].…”

Section: Introductionmentioning

confidence: 99%

Dynamics in Ultrathin Films: Particle Tracking Microrheology of Langmuir Monolayers

Bonales¹,

Ritacco²,

Rubio³

et al. 2007

TOPCJ

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Particle tracking has been shown to be a powerful technique for measuring bulk and interfacial rheology of fluids. The Brownian motion of microparticles trapped at interfaces is very sensitive to the viscosity of the subphase, and to the contact angle of the particles. The Stokes-Einstein relation is fulfilled if the friction factor is properly taken into account. The diffusion coefficient of the latex microparticles spread on surfactant monolayers allows one to calculate the shear viscosity of the monolayer using Danov's theory. Good agreement was found with previous results for monolayers of pentadecanoic acid. The method has also been used to study monolayers of n-dodecanol. Moreover, the shear viscosity of a polymer monolayer has been calculated by particle tracking, and the results show good agreement with data obtained by canal viscosimetry. The temperature dependence of the shear viscosity shows the existence of a glass transition for monolayers of poly(4-hydroxystyrene).

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Interfacial properties of pulmonary surfactant layers

Cited by 188 publications

References 180 publications

Synthetic Pulmonary Surfactant Preparations: New Developments and Future Trends

Synthetic Pulmonary Surfactant Preparations: New Developments and Future Trends

Interfacial rheology: An overview of measuring techniques and its role in dispersions and electrospinning

Dynamics in Ultrathin Films: Particle Tracking Microrheology of Langmuir Monolayers

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