Thin liquid films as a model to study surfactant layers on the alveolar surface

Current Opinion in Colloid and Interface Science

Volumn 13, Issue 3, 2008, Pages 183-193

  Lalchev, Zdravko ^a   Todorov, Rumen ^b   Exerowa, Dotchi ^b  

^a UNIVERSITY OF SOFIA   (Bulgaria)

^b INSTITUTE OF PHYSICAL CHEMISTRY   (Bulgaria)

Author keywords

Bilayers and multilayers; Exogenous surfactant preparations; Foam films; ; Lung surfactant; Monolayers; Respiratory distress syndrome; Thin liquid films

Indexed keywords

MEDICINE; MOLECULAR INTERACTIONS; PROTEINS; SURFACE ACTIVE AGENTS;

ALVEOLAR SURFACE; LATERAL MOBILITY; THIN LIQUID FILMS;

LIQUID FILMS;

BERACTANT; DIPALMITOYLPHOSPHATIDYLCHOLINE; LUNG SURFACTANT; PORACTANT;

EXPERIMENTAL MODEL; FETUS LUNG MATURITY; FILM; HUMAN; LIPID MONOLAYER; LIQUID; LUNG ALVEOLUS SURFACE TENSION; MEDICINE; MOLECULAR INTERACTION; NONHUMAN; PROTEIN LIPID INTERACTION; RESPIRATORY DISTRESS SYNDROME; REVIEW; STRUCTURE ANALYSIS; SUBSTITUTION THERAPY;

EID: 43049120994     PISSN: 13590294     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.cocis.2007.11.005     Document Type: Review

References (88)

1. Hawgood S., and Clements J. Pulmonary surfactant and its apoproteins. J Clin Invest 86 (1990) 1-6
2. Scarpelli E., and Mautone A. Surface biophysics of the surface monolayer theory is incompatible with regional lung function. Biophys J 67 (1994) 1080-1089
3. Schürch S., Goerke J., and Clements J.A. Direct determination of volume- and time-dependance of alveolar surface tension in excised lung. Proc Natl Acad Sci USA 75 (1978) 3417-3421
4. Zasadzinski J.A., Ding J., Warriner H.E., Bringezu F., and Waring A.J. The physics and physiology of lung surfactants. Curr Opin Colloid Interface Sci 6 (2001) 506-513. This review considers the relationships between lung surfactant composition, monolayer morphology, and monolayer physical parameters with special attention to the theories of monolayer collapse, phase behavior, LE-LC balance and the role of lipid saturation.
5. Piknova B., Schram V., and Hall S.B. Pulmonary surfactant: phase behavior and function. Curr Opin Struck Biol 12 (2002) 487-494. In this review is considered the phase behavior and transitions between bilayers and monolayers in relation to their physiological significance, e.g. in explaining the rapid adsorption of surfactant vesicles and the stability of the surfactant film. The correlation between phase behavior and monolayer metastability for the complete biological mixture, as well as the models regarding the collapse of the phospholipid films into the third dimension are discussed.
6. Morley C.J., Banhham A.D., Johnson P., Thorburn G.D., and Jenkin G. Physical and physiological properties of dry lung surfactant. Nature 271 (1978) 162-163
7. Hills B.A. An alternative view of the role(s) of surfactant and the alveolar model. J Appl Physiol 87 (1999) 1567-1583
8. Ueno M., Samura K., Fukuda K., Takeo N., Takej T., Takahashi A., et al. Surface rheological properties of the monolayer of synthetic lung surfactant. Colloids Surf B Biointerfaces 1 (1993) 221-232
9. Post A., Nahmen A.V., Schmitt M., Ruths J., Riegler H., Sieber M., et al. Pulmonary surfactant protein C containing lipid films at the air-water interface as a model for the surface of lung alveoli. Mol Membr Biol 12 (1995) 93-99
10. Schürch S., Bachofen H., Goerke J., and Green F. Surface properties of rat pulmonary surfactant studied with the captive bubble method: adsorption, hysteresis, stability. Biochim Biophys Acta 1103 (1992) 127-136
11. Schürch S., Schürch D., Curstedt T., and Robertson B. Surface activity of lipid extract surfactant in relation to film area compression and collapse. J Appl Physiol 77 (1994) 974-986
12. Putz G., Goerke J., and Clements J.A. Surface activity of rabbit pulmonary surfactant subfractions at different concentrations in a captive bubble. J Appl Physiol 77 (1994) 597-605
13. Schürch S., Green F.H., and Bachofen H. Formation and structure of surface films: captive bubble surfactometry. Biochim Biophys Acta. 1408 (1998) 180-202. In this review is emphasized that the surface film frequently appears multilaminated; also that disk-like structures or multilamellar vesicles appear partially integrated into the planar multilayered film. There is 'surplus' surfactant material in excess of a monolayer at the interface; film compressibility and mechanical stability are substantially better at the higher concentrations, which appears to be related to the multilaminated structure of the film.
14. Yamanaka T., Hayashi M., and Matuura R. Studies on the soap films stabilized by phospholipids. 1. Effects of metal ions on the free energy of black soap films. J Colloid Interface Sci 88 (1982) 458-466
15. Lalchev Z., Exerowa D., and Koumanov K. Thin liquid films as a model of alveolar lining layer. Ann Univ Sofia, Fac Chim 73 (1979) 163-170
16. Exerowa D, Lalchev Z, Marinov B, Ognyanov K. (1981) Method for Assessment of Fetal Lung Maturity, Patent No. 50291/03.01.1981, Institute Invention, Bulgaria.
17. Lalchev Z. Determination of the potential of electrical layer at air/alveolar surfactant solution interface. Ann Univ Sofia, Fac Biol 72/75 4 (1982) 38-46
18. Lalchev Z. Free liquid films from natural lipid-protein mixtures. PhD Thesis, Bulgarian Academy of Sciences, 1984.
19. Exerowa D., and Kruglyakov P.M. Foam and foam films (1998), Elsevier, Amsterdam
20. Lalchev Z. Surface properties of lipids and proteins at bio-interfaces. In: Birdi K.S. (Ed). Handbook of surface and colloid chemistry (1997), CRC Press, New York
21. Lalchev Z. Phospholipid foam films - types, properties and applications. In: Tadros T. (Ed). Colloid Stability - The Role of Surface Forces vol. 1 (2006), Wiley-VCH Verlag GmbH, Weinheim
22. Cohen R., Todorov R., Alexandrov S.v., Christova Y., Lalchev Z., and Exerowa D. Direct measurement of molecular interaction forces in foam films from lung surfactant fraction. Colloid Polym Sci 284 (2005) 546-550
23. Lalchev Z. Properties and behavior of lipids and proteins in model membrane systems. DSc Thesis, University of Sofia, 2004.
24. Benattar J.J., Shen Q., Bratskaya S., Petkova V., Krafft M.P., and Pucci B. Modification of black film hydration by infrared irradiation. Langmuir 20 (2004) 1047-1050
25. Cuvillier N., Millet F., Petkova V., Nedyalkov M., and Benattar J.J. Structure of freestanding phospholipidic bilayer films. Langmuir 16 (2000) 5029-5035
26. Petkova V., Platikanov D., and Nedyalkov M. Phospholipid black foam films: dynamic contact angles and gas permeability of DMPC+DMPG black films. Adv Colloid Interface Sci 104 (2003) 37-51
27. Nedyalkov M., Petkova V., and Platikanov D. Phospholipid black foam films: dynamic film tension of DMPC bilayer films. Colloids Surf A Physicochem Eng Asp 220 (2003) 35-43
28. Brezesinski G., Muller H.J., Toca-Herrera J.L., and Krustev R. X-ray diffraction and foam film investigations of PC head group interaction in water/ethanol mixtures. Chem Phys Lipids 110 (2001) 183-194
29. Toca-Herrera J.L., Krustev R., Muller H.J., and Mohwald H. Phospholipid foam films studied by contact angle measurements and fluorescence microscopy. Colloid Polym Sci 278 (2000) 771-776
30. Tranchant J.F., Bonté F., Leroy S., Nedyalkov M., Platikanov D., Javierre I., et al. Black foam films from aqueous solutions of a mixture of phospholipids and a permeation enhancer. J Colloid Interface Sci 249 (2002) 398-404
31. Possmayer F. Pulmonary perspective: a proposed nomenclature for pulmonary surfactant associated proteins. Am Rev Respir Dis 138 (1988) 990-998
32. Veldhuizen E.J., and Haagsman H.P. Role of pulmonary surfactant components in surface film formation and dynamics. Biochim Biophys Acta 1467 (2000) 255-270. SP-B plays the major role in adsorption of new material into the interface during inspiration, while SP-C's main functions are to exclude non-DPPC lipids from the interface during expiration and to attach the bilayer structures to the lipid monolayer.
33. Piknova B., Schief W.R., Vogel V., Discher B.M., and Hall S.B. Discrepancy between phase behavior of lung surfactant phospholipids and the classical model of surfactant function. Biophys J 81 (2001) 2172-2180. Using fluorescence microscopy and BAM the classical model of how pulmonary surfactant forms metastable film at high surface pressures is tested. It is concluded that the LE films of mixed components, over half of which exceed their gel-to-liquid crystal transition temperatures, can also achieve and maintain high surface pressure.
34. Perez-Gil J. Lipid-protein interactions of hydrophobic proteins SP-B and SP-C in lung surfactant assembly and dynamics. Pediatr Pathol Mol Med 20 (2001) 445-469. This review summarizes some results on the parameters governing lipid-protein interactions of the SP-B and SP-C with the main surfactant phospholipids.
35. Serrano A.G., and Perez-Gil J. Protein-lipid interactions and surface activity in the pulmonary surfactant system. Chem Phys Lipids 141 (2006) 105-118. This review considers the structure, disposition and lipid-protein interactions of the SP-B and SP-C in the light of evaluation of their surface activity in surfactant preparations, mechanisms of action and development of new clinical preparations.
36. Ryan M.A., Qi X., Serrano A.G., Ikegami M., Perez-Gil J., Johansson J., et al. Mapping and analysis of the lytic and fusogenic domains of surfactant protein B. Biochemistry 44 (2005) 861-872. This work indicates that SP-B fusion, lytic and surface activities map predominantly to the N-terminal half (residues 1-37) of SP-B.
37. Cruz A., Vazquez L., Velez M., and Perez-Gil J. Effect of pulmonary surfactant protein SP-B on the micro- and nanostructure of phospholipid films. Biophys J 86 (2004) 308-320. This paper reveals that both LE and LC regions of DPPC films are heterogeneous - LC microdomains contained expanded-like islands whereas LE regions are covered by a condensed-like framework of interconnected nanodomains. SP-B causes alterations of the nanoscopic structures of the films and provides structural stability and dynamical flexibility in surfactant films at the extreme conditions.
38. Diemel R.V., Snel M.M., Waring A.J., Walther F.J., van Golde L.M., Putz G., et al. Multilayer formation upon compression of surfactant monolayers depends on protein concentration as well as lipid composition. An atomic force microscopy study. J Biol Chem 277 (2002) 21179-21188. Formation of hexagonal network structures depends on the SP-B concentration and the height of protrusions depends on unsaturated fatty acyl chain content and presence of PC or PG.
39. Alonso C., Alig T., Yoon J., Bringezu F., Warriner H., and Zasadzinski J.A. More than a monolayer: relating lung surfactant structure and mechanics to composition. Biophys J 87 (2004) 4188-4202. In this work by AFM study after Langmuir-Blodgett deposition of Survanta is shown a coexistence of discrete monolayer islands of solid phase coexisting with continuous multilayer "reservoirs" of fluid phase adjacent to the air-water interface.
40. Ding J.Q., Warriner H.E., and Zasadzinski J.A. Viscosity of two-dimensional suspensions. Phys Rev Lett 88 (2002) 168102
41. Wang L., Cai P., Galla H.J., He H., Flach C.R., and Mendelsohn R. Monolayer-multilayer transitions in a lung surfactant model: IR reflection-absorption spectroscopy and atomic force microscopy. Eur Biophys J 34 (2005) 243-254. The current work uses AFM on Langmuir-Blodgett films to verify the formation of multilayers in a DPPC-DPPG-cholesterol - SP-C model system and IR reflection-absorption spectroscopy indicating that the helical structure of SP-C changes its orientation in monolayers versus multilayers.
42. Ross M., Krol S., Janshoff A., and Galla H.J. Kinetics of phospholipid insertion into monolayers containing the lung surfactant proteins SP-B or SP-C. Eur Biophys J 31 (2002) 52-61. This work shows the role of SP-B and SP-C for the kinetics of lipid insertion at the interface; long-range electrostatic interactions in attracting vesicles to the surface and the role of SP-B-DPPG interactions for rupture of attached to the monolayer liposomes, observed by in situ SFM.
43. Alonso C., Waring A., and Zasadzinski J.A. Keeping lung surfactant where it belongs: protein regulation of two-dimensional viscosity. Biophys J 89 (2005) 266-273. This paper presents that monolayer transformation from fluid-like to solid-like state causes three orders of magnitude increase in surface viscosity that helps the alveoli against collapse.
44. Glasser S.W., Burhans M.S., Korfhagen T.R., Na C.L., Sly P.D., Ross G.F., et al. Altered stability of pulmonary surfactant in SP-C-deficient mice. Proc Natl Acad Sci USA 98 (2001) 6366-6371
45. Ding J., Doudevski I., Warriner H.E., Alig T., Zasadzinski J.A., Waring A.J., et al. Nanostructure changes in lung surfactant monolayers induced by interactions between palmitoyloleoylphosphatidylglycerol and surfactant protein B. Langmuir 19 (2003) 1539-1550
46. Schram V., and Hall S.B. SP-B and SP-C alter diffusion in bilayers of pulmonary surfactant. Biophys J 86 (2004) 3734-3743. By FRAP is compared the lateral diffusion in multilayers containing the lipids and proteins in calf lung surfactant extract and that without the proteins - it is suggested that above 35 °C the proteins rigidify the lipid bilayer.
47. Lalchev Z.I., Todorov R.K., Christova Y.T., Wilde P.J., Mackie A.R., and Clark D.C. Molecular mobility in the monolayers of foam films stabilized by porcine lung surfactant. Biophys J 71 (1996) 2591-2601. In this paper is compared the lateral diffusion in the plane of foam films composed of lung surfactant, its fractions, pure DPPC; also the influence of SP-A as "inhibitor" of the diffusion is estimated.
48. Grunder R., Gehr P., Bachofen H., Schurch S., and Siegenthaler H. Structures of surfactant films: a scanning force microscopy study. Eur Respir J 14 (1999) 1290-1296. The paper reveals, using SFM, that addition of SP-B and SP-C to surfactant phosholipids contributes to the complexity of surface films and the protrusions formed are well distinguishable from the large polygonal liquid condensed-domains characteristic of pure phospholipid films.
49. Malcharek S., Hinz A., Hilterhaus L., and Galla H.J. Multilayer structures in lipid monolayer films containing surfactant protein C: effects of cholesterol and POPE. Biophys J 88 (2005) 2638-2649. This paper demonstrates the stabilizing effect of cholesterol on bilayers formed underneath the monolayer, that 30 mol% of cholesterol causes an increased monolayer rigidity, thus preventing reversible multilayer formation and that unsaturated POPE stabilizes the edges of protrusions leading to more narrow protrusions.
50. Larsson M., Larsson K., Nylander T., and Wollmer P. The bilayer melting transition in lung surfactant bilayers: the role of cholesterol. Eur Biophys J 31 (2003) 633-636. In this paper the role of cholesterol in aqueous dispersions of a porcine lung surfactant extract is examined and analyzed by X-ray scattering study showing consistencies with phase segregation within the bilayer of pure PC-cholesterol systems.
51. Follows D., Tiberg F., Thomas R.K., and Larsson M. Multilayers at the surface of solutions of exogenous lung surfactant: direct observation by neutron reflection. Biochim Biophys Acta 1768 (2007) 228-235. By neutron reflection is studied exogenous preparations and the organization of the surface phase, consisting of a multilayer structure of lipid/protein bilayers alternating with aqueous layers, is analyzed. Multilayer structure can be formed even at very low concentrations in exogenous surfactant and the protein is present in the immediate vicinity of the surface at a much higher concentration than in the bulk - making the surface region viscous, which would reduce the process of gas transport.
52. Winsel K., Honig D., Lunkenheimer K., Geggel K., and Witt C. Quantitative Brewster angle microscopy of the surface film of human broncho-alveolar lavage fluid. Eur Biophys J 32 (2003) 544-552. This paper presents results on the morphology, thickness and surface pressure of the surfactant film of broncho-alveoalar lavage (BAL) from patients with sarcoidosis showing the inhomogeneous film formation even at low surface pressures, and suggesting adsorption mechanism involving the spreading of vesicles at the interface and formation of multilamellar structure.
53. Brown D.A., and London E. Structure and function of sphingolipid- and cholesterol-rich membrane rafts. J Biol Chem 275 (2000) 17221-17224
54. Dietrich C., Bagatolli L.A., Volovyk Z.N., Thompson N.L., Levi M., Jacobson K., et al. Lipid rafts reconstituted in model membranes. Biophys J 80 (2001) 1417-1428
55. Taeusch H.W., de la Serna J.B., Perez-Gil J., Alonso C., and Zasadzinski J.A. Inactivation of pulmonary surfactant due to serum-inhibited adsorption and reversal by hydrophilic polymers: experimental. Biophys J 89 3 (2005 Sep) 1769-1779. This paper shows that native porcine surfactant, its organic extracts and the exogenous surfactant preparations spread on subphases containing serum slower comparable to serum-free subphases, and that some hydrophilic polymers help surfactant to overcome the serum-induced barrier to adsorption.
56. Georgiev G.D., Georgiev G.A., and Lalchev Z. Formation and interaction of liquid DMPC mono- and bilayer nano-sized films with poly ethylene glycols. In: Balabanova E., and Dragieva I. (Eds). Nanoscience and Nanotechnology vol. 5 (2006), Heron Press, Sofia 215-219
57. Georgiev G.A., Georgiev G.D., and Lalchev Z. Thin liquid films and monolayers of DMPC mixed with PEG and phospholipid linked PEG. Eur Biophys J 35 (2006) 352-362
58. Exerowa D., and Lalchev Z. Bilayer and multilayer foam films: model for study of the alveolar surface and stability. Langmuir 2 (1986) 668-671. This paper proves for the first time the possibility for formation of stable bilayer and multilayer foam films from native lung surfactant and its fractions, leading to the suggestion for their existence in vivo.
59. Exerowa D., Lalchev Z., Marinov B., and Ognyanov K. Method for assessment of fetal lung maturity. Langmuir 2 (1986) 664-668. Using amniotic fluid (AF) samples from pregnant women it is demonstrated that the formation of stable bilayer foam film from AF correlates with no risk for RDS development in newborns and that rupture of AF foam film indicates 95% risk for RDS development.
60. Exerowa D., Lalchev Z., and Kashchiev D. Stability of foam lipid bilayers of amniotic fluid. Colloids Surf 10 (1984) 113-121. In this paper is proved experimentally that the black films from amniotic fluids are bilayer ones and that the probability for their formation depends on nature of the phospholipids.
61. Cordova M., Mautone A.J., and Scarpelli E.M. Rapid in vitro tests of surfactant film formation: advantages of the Exerowa black film method. Pediatr Pulmonol 21 (1996) 373-382. Comparison between the black foam film method and four other methods for study of lung surfactant is made and the new parameters available by the former method are evaluated.
62. Lalchev Z., Georgiev G., Jordanova A., Todorov R., Christova E., and Vassilieff C. A comparative study of exogenous surfactant preparations and tracheal aspirate: interfacial tensiometry and properties of foam films. Colloids Surf B Biointerfaces 33 (2004) 227-234. New observations on the properties of foam films from Exosurf, Survanta, Curosurf, Alveofact and clinical samples of newborns with RDS treated with Curosurf are reported.
63. Scarpelli E., Mautone A., Lalchev Z., and Exerowa E. Surfactant liquid and black foam film formation and stability in vitro and correlative conditions in vivo. Colloids Surf B Biointerfaces 8 (1997) 133-145. This paper demonstrates that the foam films composed of different exogenous surfactant preparations show different hydrodynamic and thermodynamic film properties and that this model can evaluate the preparations.
64. Todorov R. Alveolar surfactant - composition and properties studied by monolayers and thin liquid (foam) films. PhD Thesis, University of Sofia, 1999.
65. Todorov R., Lalchev Z., Vasilev D., Gerginova V., Gekova N., Dyankova D., et al. Biochemical and biophysical parameters of pulmonic maturity during Exosurf therapy. Acta Med Bulg 1 (1995) 10-19
66. Antonova N., Todorov R., and Exerowa D. Rheological behavior and parameters of the in vitro model of lung surfactant systems: the role of the main phospholipid component. Biorheology 405 (2003) 531-543
67. Exerowa D. Thin liquid films from phospholipids: formation, stability and transitions. Progr Colloid Polym Sci 128 (2004) 135-138
68. Naydenova S., Lalchev Z., Petrov A., and Exerowa D. Pure and mixed lipid black foam films as models of membrane fusion. Eur Biophys J 17 (1990) 343-347. This paper shows that fusogenic agents for membrane-membrane fusion provoke rupture of the foam films and vice versa - agents that stabilize the film are "inhibitors" of fusion.
69. Oosterlaken-Dijksterhuis M.A., Haagsman H.P., van Golde L.M., and Demel R.A. Interaction of lipid vesicles with monomolecular layers containing lung surfactant proteins SP-B or SP-C. Biochemistry 30 (1991) 8276-8281
70. Lalchev Z., Ishida H., and Nakazawa H. Fluorescence photobleaching recovery measurements on lecithin foam films. In: Jennings B., and Stoylov S. (Eds). Colloid and molecular electro-optics (1991), Institute of Physics Publishing, Bristol & Philadelphia. First measurement of lateral diffusion coefficients in phospholipid foam films by FRAP.
71. Lalchev Z., Todorov R., Ishida H., and Nakazawa H. Lateral mobility of phospholipid molecules in thin liquid films. Eur Biophys J 23 (1995) 433-438. This paper shows the dependence of the lateral diffusion on the type of the phospholipid foam film.
72. Lalchev Z., Wilde P., and Clark D. Surface diffusion in phospholipid foam films 1. Dependence of the diffusion coefficient on the lipid phase state, molecular length, and charge. J Colloid Interface Sci 167 (1994) 80-86. The paper presents how phospholipid diffusion in the plane of foam films depends on the nature and phase state of the lipid.
73. Lalchev Z., Wilde P., Mackie A., and Clark D. Surface diffusion in phospholipid foam films 2. The effect of film type and temperature cycling on surface diffusion. J Colloid Interface Sci 174 (1995) 283-288. Hysteresis behavior of the lateral diffusion in foam films during heating-cooling cycle is observed for the first time.
74. Lalchev Z., and Mackie A. Molecular lateral diffusion in model membrane systems. Colloids Surf B Biointerfaces 15 (1999) 147-160. This paper shows how the lipid lateral diffusion in membrane systems depends, in equal other conditions and composition, on the structure organization of the membrane, using lipid monolayers, BLMs and foam films of different types.
75. Nikolova A., Exerowa D., Lalchev Z., and Tsonev L. Thermal transitions in dimyristoylphosphatidylcholine foam bilayers. Eur Biophys J 23 (1994) 145-152. Surface phase transition in phospholipid foam films is detected for the first time and the molecular binding energy in the different states observed is calculated.
76. Nikolova A., and Exerowa D. Foam bilayer from amniotic fluid: formation and phase state. Langmuir 12 (1996) 1846-1850
77. Jordanova A., Lalchev Z., and Tenchov B. Formation of monolayers and bilayer foam films from lamellar, inverted hexagonal and cubic lipid phases. Eur Biophys J 31 (2003) 626-632. This work shows that the probability for formation and stability of phospholipid foam films depend on the lipid phase state.
78. Tenchov B. On the reversibility of the phase transitions in lipid-water systems. Chem Phys Lipids 57 (1991) 165-177
79. Kashchiev D., and Exerowa D. Nucleation mechanism of rupture of Newtonian black films. I. Theory. J Colloid Interface Sci 77 (1980) 501-511
80. Georgiev GA, Dipak SK, Othman Al-Hanbali, Georgiev GD, Lalchev Z. Effects of poly (ethylene glycol) chains conformational transition on the properties of mixed DMPC/DMPE-PEG thin liquid films and monolayers. Colloids Surf B Biointerfaces 2007;59:184-193. This paper shows how PEG chain size and mushroom-to-brush conformational transition influence the properties of phospholipid foam films.
81. 2+ ions.
82. Georgiev G.D., Georgiev G.A., and Lalchev Z. Influence of steroid hormone progesterone on the properties of phosphatidyl serine monolayers and thin liquid films. Biophys Chem 130 (2007) 48-54
83. Georgiev G.A., Georgiev G.D., and Lalchev Z. Interaction of DMPE-linked PEGs with phosphatidylcholine and sugar ester surfactants in mono- and bilayer films at the air/water interface. Proc. Balkan Scientific Conference of Biology (2005) 109-126 Plovdiv
84. Lalchev Z., Exerowa D., Koumanov K., and Neicheva T. Foam films of rat lung surfactant obtained under different preparative conditions. Annu Univ Sofia Fac Biol 77 (1983) 35
85. Lalchev Z., Dimitrova L., and Exerowa D. Phospholipid black foam bilayers and structure of the alveolar surface. Proc. Int. Congress on Membranes and Membrane Processes (1987), ICOM, Tokyo 727
86. Kashchiev D., and Exerowa D. Structure and surface energy of the surfactant layer on the alveolar surface. Eur Biophys J 30 (2001) 34-41. Monolayer-bilayer (MB) model is proposed, which unites the known monolayer and bilayer models of alveolar surface layer, providing a more realistic description of this layer.
87. Scarpelli E.M. Structure and surface energy of the surfactant layer on the alveolar surface: inaccuracies and their correction. Eur Biophys J 31 (2002) 485-486
88. Engelskirchen S. The pseudo-binary pulmonary surfactant system. Curr Opin Colloid Interface Sci 12 (2007) 68-74. This paper is reviewing the recent results on adsorption kinetics and phase behavior of pulmonary surfactant, providing a thermodynamic model.