Langmuir Films Research Articles

Influence of Tacticity on the Structure Formation of Poly(methacrylic acid) in Langmuir/Langmuir–Blodgett and Thin Films

AbstractA perfect isotactic poly(methacrylic acid) (it‐PMAA) is synthesized and characterized by NMR spectroscopy. Surface pressure versus mean area per repeat unit (π−A) isotherms are recorded and compared with atactic poly(methacrylic acid) (at‐PMAA). it‐PMAA exhibits a π−A isotherm, indicating the formation of a stable Langmuir film. The isotherm has a characteristic pseudo‐plateau at π of ≈11–14 mN m−1 attributed to the creation of worm‐like entities confirmed by atomic force microscopy (AFM) in Langmuir–Blodgett (LB) films. These structures transform into spherical nanoparticles of ≈40 to 80 nm seen in LB films transferred at the end of the pseudo‐plateau of the isotherm. Grazing incidence wide‐angle X‐ray scattering (GI‐WAXS) shows a broad scattering signal (halo‐like) at a q position of ≈11.12 nm−1, revealing the amorphous nature of the nanoparticles. An ordered morphology, however, is observed in thin films prepared by precipitating it‐PMAA from dimethylformamide (DMF) solution under vigorous stirring and coating them on a solid support. Optical microscopy (OM), AFM, and GI‐WAXS reveal more details about the structure. Finally, various structural modifications of PMAAs are explained based on their tacticity and the subsequent hydrogen bonding effects between the carboxylic acid groups.

DEVELOPMENT OF X-RAY METHODS FOR STUDYING PROTEIN PLANAR SYSTEMS ON A LIQUID SURFACE USING SYNCHROTRON RADIATION

The structure of Langmuir lysozyme films on a liquid surface, formed from crystallization solutions with addition of metal chlorides as a precipitant, have been investigated. The thicknesses and densities of the films were determined using the X-ray reflectivity technique, and the concentration distribution profiles of the sulfur atoms present in protein molecules, as well as precipitant ions in the subphase surface region, have been obtained by the X-ray standing waves technique. Based on the experimental results, the dependence of the film structure on the precipitant used, as well as some specific features of application of X-ray reflectivity and X-ray standing waves techniques in the study of Langmuir films of globular proteins on a liquid surface, are analyzed.

Evaluation of triphenylene-based MOF ultrathin films for lithium batteries.

Metal-organic frameworks (MOFs) are attractive candidates to meet the requirement of next-generation batteries, as functional materials with a high surface area, well-defined metal centers, and organic linkers through coordination bonds. Due to their great tunability, MOFs have been investigated as electrodes or electrolytes in lithium batteries and more recently as protective layers in anode-less batteries. Here, we synthesize a Ni3(HHTP)2 MOF directly at the air-liquid interface of a Langmuir trough and grow the electrode on a conductive substrate by the transference process. The characterization during Langmuir film formation shows that the addition of crystallization time during the compression process enhances the formation of 2D crystalline domains, as observed by in situ grazing-incidence X-ray diffraction. Next, the transferred Ni3(HHTP)2 ultrathin films were studied as working electrodes in Li batteries in a half-cell configuration and compared with bare copper. The results show that the Ni3(HHTP)2 film protects the Cu collector from oxidation, and the negative charge accumulates in the organic ligand during the lithiation process while NiII oxidizes to NiIII, unlike other triphenylene-based MOFs with CuII or CoII metal nodes. The galvanostatic plating-stripping cycles of the batteries show that the inclusion of the crystallization time improves the coulombic efficiency, especially significantly in the first cycles when the SEI is formed. This work shows the Langmuir technique as a useful tool to test MOF based materials for batteries with the advantages of using a low amount of raw materials and without the need to introduce additives (binder and electron conductor) in the electrodes. The electrochemical study of this type of electrode allows a first screening to synthesize electrodes based on MOFs and can be a tool for the preparation of protective coatings under optimized conditions.

Multilayer Langmuir Film of Monodisperse Au Nanoclusters: Unusual Growth via Bilayers

The assembly of nanomaterials into thin films is an important area in the nanofabrication of novel devices. The monodispersity of nanoparticles plays an essential role in the resulting quality of the assembled mono- and multilayers. Larger polydispersity leads to smaller lateral correlation lengths and smaller domains of aligned nanoparticles, thus resulting in more point and line defects. Perfectly monodisperse nanoparticles should therefore minimize the number of defects in the assembled films. Despite tremendous progress in reducing the polydispersity of nanoparticles, there has been limited research on the assembly of thin films out of perfectly monodisperse nanoclusters. Here, we show a formation of Langmuir films using perfectly monodisperse gold nanoclusters with composition Au32(nBu3P)12Cl8 exhibiting a diameter of 1.8 nm. Using both in situ and ex situ small-angle X-ray scattering, we show that the monolayer formed on a Langmuir-Blodgett trough exhibits long-range order. Moreover, after compressing the monolayer, we found that the stress accumulated prior to the monolayer collapse triggers a transition to a short-range order not previously reported. If such monolayer is compressed further, the second layer is not formed as in the case of standard nanoparticles. Instead, a growth of islands by an odd number of layers is observed, leading to a thin film with a structure consisting of two different orientations of the hexagonal lattice. Such anomalous behavior may have implications for the possibilities of thin-film formation.

Tracking Mechanical Stress and Cell Migration with Inexpensive Polymer Thin-Film Sensors.

Polydiacetylene (PDA) Langmuir films are well known for their blue to red chromatic transitions in response to a variety of stimuli, including UV light, heat, bio-molecule bindings and mechanical stress. In this work, we detail the ability to tune PDA Langmuir films to exhibit discrete chromatic transitions in response to applied mechanical stress. Normal and shear-induced transitions were quantified using the Surface Forces Apparatus and established to be binary and tunable as a function of film formation conditions. Both monomer alkyl tail length and metal cations were used to manipulate the chromatic transition force threshold to enable discrete force sensing from ~50 to ~500 nN μm-2 for normal loading and ~2 to ~40 nN μm-2 for shear-induced transitions, which are appropriate for biological cells. The utility of PDA thin-film sensors was demonstrated with the slime mold Physarum polycephalum. The fluorescence readout of the films enabled: the area explored by Physarum to be visualized, the forces involved in locomotion to be quantified, and revealed novel puncta formation potentially associated with Physarum sampling its environment.

Spatiotemporal analysis of structured Langmuir films formed from stabilised CdSe/CdS/ZnS quantum dots

Langmuir-Blodgett Films (LBFs) were studied using X-ray Diffraction (XRD), Raman Scattering (RS), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM), Electronic Data Processing (EDP), Atomic Force Microscopy (AFM), and ab-initio simulations. Unlike in the classical form of compression isotherms π(t), the transition to the time dependence Δπ(t) = π(t2) - π(t1) made it possible to reveal the “liquid–solid phase” transition starting from 500 s to 650 s, and nanofilm collapse after 1400 s as illustrated by Brewster images. According to AFM, HRTEM images, and XRD data, it is established that the formation of an LBF from CdSe/CdS/ZnS quantum dots is accompanied by a structural transition from sphalerite to dominant wurtzite close packing, which is in qualitative agreement with the results from combinatorial geometry and ab-initio calculations. The dominance of the wurtzite crystal structure was established by X-ray diffraction, HRTEM and RS methods.

Interfacial aggregation behavior of novel carbazole-based composite Langmuir-Blodgett films for photoelectric conversion and catalytic performance

The development of multifunctional film materials from novel organic small molecules has attracted the attention of researchers. In this study, novel carbazole organic molecules (CS-14, CS-38 and CS-39) were successfully composited with TsNiPc and TPPS subphases into multilayer films by LB technology. The nanostructure and morphology of the composite films were successfully assembled and analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, the stability of the composite film was proved by UV–vis spectroscopy and Fourier transform infrared spectroscopy. The results demonstrate that Langmuir films are transferred to the surface of substrates in different aggregated morphologies. In addition, the self-assembled LB film electrodes exhibit excellent photoelectrochemical performance. The photoelectric conversion of the multilayer films transferred to ITO (indium tin oxide) was tested, and CS-38/TsNiPc Langmuir film exhibits a stronger photoelectric conversion effect. The electrolysis reaction of LB films to water was also tested. Further analysis shows that the composite films with TsNiPc as the subphase all showed better catalytic performance than the composite films with TPPS as the subphase. Therefore, the prepared LB film has the potential to become an optoelectronic functional ultrathin film device.

Modulation of gastric lipase adsorption onto mixed galactolipid-phospholipid films by addition of phytosterols

The rapid and preferential adsorption of a gastric lipase recombinant dog gastric lipase (rDGL) in heterogeneous films of phospholipids and triacylglycerols has previously been unveiled using Langmuir films analyzed by tensiometry, ellipsometry and Langmuir-Blodgett transfer coupled to atomic force microscopy. Here we invest the adsorption behavior of rDGL in heterogeneous galactolipid and mixed galactolipid-phospholipid or galactolipid-phospholipid-phytosterol films representative of plant membrane. Again rDGL, preferentially got adsorbed at the expanded lipid phases of the films underlining the genericity of such adsorption behavior. The addition of phytosterols to these mixtures resulted in the creation of defects, favoring the adsorption of rDGL at the fluid phases, but also improving the adsorption capacities of the lipase at the phase boundaries and towards the defects in the condensed phase. rDGL, like all gastric lipases, does not show any activity on galactolipids and phospholipids but its adsorption impacts their lateral organization and may change the adsorption and activity of other lipolytic enzymes in the course of digestion.

Langmuir-Blodgett transfer from the oil-water interface

HypothesisAlmost all Langmuir-Blodgett (LB) films were prepared with the classical Langmuir film balance, developed more than a century ago. To date, the success of the classical Langmuir film balance and the LB transfer technique is primarily restricted to the study of self-assembled monolayers at the air-water surface. It is challenging to study self-assembled monolayers at the oil-water interface, since the Langmuir film balance requires stacked oil and water layers. We hypothesize that a newly developed experimental method, called constrained drop surfactometry (CDS), is capable of preparing and characterizing LB films from the oil-water interface. ExperimentsWe have developed a novel droplet-based LB transfer technique capable of preparing LB films from the oil-water interface. In conjunction with atomic force microscopy, we have demonstrated the capacity of the CDS in studying a natural pulmonary surfactant film self-assembled at the perfluorocarbon-water interface, and have compared to the LB films prepared from the air-water surface using the classical Langmuir film balance. FindingsOur findings have demonstrated a novel paradigm for studying self-assembled monolayers and for preparing LB films from the oil-water interface. The CDS holds great promise for expanding the applicability of the traditional LB transfer technique from the air-water surface to the oil-water interface.

The behavior of thiacarbocyanine dyes on the surface of few-layered hexagonal boron nitride

The adsorption and self-assembly of several thiacarbocyanine dyes on hexagonal boron nitride (hBN) was investigated by combining steady-state spectroscopy and atomic force microscopy. The adsorption isotherms indicate that at saturation the density of the cationic TDC (5,5-dichloro-3-3′-diethyl-9-ethyl-thiacarbocyanine) molecules on hBN is similar to that of TD2 (3-3′-diethyl-9-ethyl-thiacarbocyanine) molecules, while the densities of TD0 (3-3′-diethyl-thiacarbocyanine) molecules and the zwitterionic THIATS (5,5-dichloro-3-3′-disulfopropyl-9-ethyl-thiacarbocyanine) molecules are significantly higher. The intermolecular distances between neighboring adsorbed dyes, calculated from these saturation densities indicate a flat-on adsorption for TDC, TD2 and TD0 and a partial edge-on adsorption for THIATS. AFM micrographs of the adsorbed TDC, TD0 and THIATS molecules indicate that already at low dye concentrations in the solution, where only a small fraction of the hBN surface is covered, the dye molecules already form upon adsorption to hBN aggregates of at least 10 nm, separated by areas where no adsorbed dye molecules can be detected. The resolution of the micrographs was however insufficient to show details of the packing of the adsorbed molecules. For THIATS, the thickness of the adsorbed layer is compatible with an edge-on adsorption, while for TDC and TD0, the thickness of the adsorbed layer is twice the thickness expected for flat-on adsorption. The exciton interaction extracted from the steady-state spectroscopy of the adsorbed dyes is much smaller than observed for H- or J-aggregates of the same dyes in solution or adsorbed to other surfaces such as Langmuir films or silver halides. For TDC, TD2 and TD0, the values of the exciton interaction are compatible with a close packed flat-on adsorption. Hence, optimizing the interaction between the adsorbed dye and hBN rather than between the adsorbed dye molecules governs the packing of the adsorbed dye molecules. The observation of the spectral shifts attributed to the exciton interaction at low average coverage of the hBN surface indicates that the exciton interaction already occurs at low coverage of the hBN surface. This observation is in agreement with the AFM micrographs, which show clustering of the adsorbed dye molecules already at low coverages.

Characteristics of Phospholipid-Immunosuppressant-Antioxidant Mixed Langmuir-Blodgett Films.

Hemocompatibility is one of the major criteria for the successful cardiovascular applicability of novel biomaterials. In this context, monolayers of certain biomolecules can be used to improve surface biocompatibility. To this end, biocoatings incorporating a phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC), an immunosuppressant (cyclosporine A, CsA), and an antioxidant material (lauryl gallate, LG) were fabricated by depositing Langmuir films onto gold or mica substrates using the Langmuir–Blodgett (LB) technique. These LB monolayers were thoroughly characterized by means of quartz crystal microbalance (QCM), atomic force microscopy (AFM), cyclic voltammetry (CV), and contact angle (CA) measurements. The obtained results indicate that the properties of these LB films are modulated by the monolayer composition. The presence of LG in the three-component systems (DOPC–CsA–LG) increases the molecular packing and the surface coverage of the substrate, which affects the wettability of the biocoating. From the different compositions studied here, we conclude that DOPC–CsA–LG monolayers with a DOPC/CsA ratio of 1:1 and LG molar fractions of 0.50 and 0.75 exhibit improved surface biocompatible characteristics. These results open up new perspectives on our knowledge and better understanding of phenomena at the biomaterial/host interface.

The role of monolayer viscosity in Langmuir film hole closure dynamics

We re-examine the model proposed by Alexanderet al.(Phys. Fluids, vol. 18, 2006, 062103) for the closing of a circular hole in a molecularly thin incompressible Langmuir film situated on a Stokesian subfluid. For simplicity their model assumes that the surface phase is inviscid which leads to the result that the cavity area decreases at a constant rate determined by the ratio of edge tension to subfluid viscosity. We reformulate the problem, allowing for a regularising monolayer viscosity. The viscosity-dependent corrections to the hole dynamics are analysed and found to be non-trivial, even when the monolayer viscosity is small; these corrections may explain the departure of experimental data from the theoretical prediction when the hole radius becomes comparable to the Saffman–Delbrück length. Through fitting, under these relaxed assumptions, we find the edge tension could be as much as six times larger ($\sim$4.0 pN) than reported previously.

Interaction mechanism of chitosan oligomers in pure water with cell membrane models studied by SFG vibrational spectroscopy

Chitosan is a versatile and biocompatible cationic antimicrobial polymer obtained from sustainable sources that is effective against a wide range of microorganisms. Although it is soluble only at low pH, chitosan oligomers (ChitO) are soluble in pure water and thus more appropriate for antibacterial applications. Although there is a vast literature on chitosan’s antimicrobial activity, the molecular details of its interaction with biomembranes remain unclear. Here we investigate these molecular interactions by resorting to phospholipid Langmuir films (zwitterionic DPPC and anionic DPPG) as simplified membrane models (for mammalian and bacterial membranes, respectively), and using SFG vibrational spectroscopy to probe lipid tail conformation, headgroup dynamics and interfacial water orientation. For comparison, we also investigate the interactions of another simple cationic antimicrobial polyelectrolyte, poly(allylamine) hydrochloride – PAH. By forming the lipid films over the polyelectrolyte solutions, we found that both have only a very small interaction with DPPC, but PAH adsorption is able to invert the interfacial water orientation (membrane potential). This might explain why ChitO is compatible with mammalian cells, while PAH is toxic. In contrast, their interaction with DPPG films is much stronger, even more so for ChitO, with both insertion within the lipid film and interaction with the oppositely charged headgroups. Again, PAH adsorption inverts the membrane potential, while ChitO does not. Finally, ChitO interaction with DPPG is weaker if the antimicrobial is injected underneath a pre-assembled Langmuir film, and its interaction mode depends on the time interval between end of film compression and ChitO injection. These differences between ChitO and PAH effects on the model membranes highlight the importance of molecular structure and intermolecular interactions for their bioactivity, and therefore this study may provide insights for the rational design of more effective antimicrobial molecules.

Synthesis of polymer suspensions in the presence of organosilicon surfactants of various nature

The colloid-chemical properties of organosilicon surfactants with different solubility in water were studied. The behavior of organosilicon surfactants of various structures in model systems - Langmuir films at the water-air interface has been studied. The results obtained showed that high stability of polymer suspensions is observed only in the presence of insoluble in water organosilicon surfactants.

Bisphenol A exposure induces multiple effects in DOPC membrane models

• BPA affects the DOPC π-A isotherms without altering the lipid fluidity. • BPA surface activity has an important role in the morphology of lipid monolayers. • The interaction with lipid occurs by phosphate groups and promotes a disorder in the lipid tail. • BPA induces multiple morphology changes on giant unilamellar vesicles. • The effect of BPA on vesicles showed a size dependence. Due to its now well-known endocrine-disrupting behavior, Bisphenol A (BPA) has focused on many interactions, detection, and removal studies in the last few years. The application of simple membrane models to identify specific interactions in some regions of the cells, such as the membrane, is essential to help understand the aspects of the mechanisms of action. This work evaluated the effects of the BPA exposure over membrane models of a fluid phospholipid, the 1,2-dioleoyl- sn -glycero-3-phosphocholine (DOPC). The BPA interaction with the DOPC monolayers was performed using Langmuir films, evaluating changes in π-A isotherms, lipid fluidity, and interaction at the molecular level by PM-IRRAS spectroscopy. Giant unilamellar vesicles (GUVs) were used to reveal alteration in the shape and morphology of the lipid bilayers promoted by BPA. Multiple effects were observed in the GUVs, including surface fluctuations, an endocytosis-like effect, the formations of budding, and scissions. These alterations could be related to changes observed in the phosphate groups of DOPC in the PM-IRRAS analysis and the lipophilic properties of BPA. Furthermore, the changes observed indicate that BPA has an affinity to the membrane, which could lead to different implications or effects in cells not yet understood, which requires further investigations.

The Role of Cholesterol in the Interaction of the Lipid Monolayer with the Endocrine Disruptor Bisphenol-A.

Among pollutants of emerging concern, endocrine disruptors (ED) have been shown to cause side effects in humans and animals. Bisphenol-A (BPA) is an ED by-product of the plastic industry and one of the chemicals with the highest volume produced yearly. Here, we studied the role of cholesterol in the BPA exposure effects over membrane models. We used Langmuir films of both neat lipid DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and cholesterol (Chol) and a binary mixture containing DPPC/Chol, exposing it to BPA. We evaluate changes in the π-A isotherms and the PM–IRRAS (polarization modulation–infrared reflection adsorption spectroscopy) spectra. BPA exposure induced changes in the DPPC and Chol neat monolayers, causing mean molecular area expansion and altering profiles. However, at high surface pressure, the BPA was expelled from the air–water interface. For the DPPC/Chol mixture, BPA caused expansion throughout the whole compression, indicating that BPA is present at the monolayer interface. The PM–IRRAS analysis showed that BPA interacted with the phosphate group of DPPC through hydrogen bonding, which caused the area’s expansion. Such evidence might be biologically relevant to better understand the mechanism of action of BPA in cell membranes once phosphatidylcholines and Chol are found in mammalian membranes.

Interaction of Human Resistin with Human Islet Amyloid Polypeptide at Charged Phospholipid Membranes.

An X-ray reflectivity study on the interaction of recombinant human resistin (hRes) with fibrillation-prone human islet amyloid polypeptide (hIAPP) at anionic phospholipid Langmuir films as model membranes is presented. Aggregation and amyloid formation of hIAPP is considered the main mechanism of pancreatic β-cell loss in patients with type 2 diabetes mellitus. Resistin shows a chaperone-like ability, but also tends to form aggregates by itself. Resistin and hIAPP cross multiply metabolism pathways. In this study, we researched the potential protective effects of resistin against hIAPP-induced lipid membrane rupture. The results demonstrate that resistin can inhibit or prevent hIAPP adsorption even in the presence of aggregation-promoting negatively charged lipid interfaces. Moreover, we found strong hydrophobic interactions of resistin at the bare buffer–air interface.

Effects of Fipronil and surface behavior of neuronal insect and mammalian membranes

The effects of Fipronil as well as the comparison between synaptosomal natural membranes (NMs) of mammal (NMBt) and insect (NMTi), that contain the ionotropic receptor GABA, was studied.This is the first report of biophysical studies of insect NMs and one of the first on the effects of Fipronil over membranes.Our result showed that NMTi appears to be more disordered than NMBt, generates more compressible films at the air-water interphase and they both showed a 2D transition in its compression isotherm. Each NM showed different lateral distribution and characteristic domain shapes when observed by DiI-C18 epifluorescence microscopy. Laurdan GP images suggested that in NMTi films, Ld and Ld-Lo phases are evenly abundant whereas in NMBt the Ld-Lo phase predominates. The differences observed might be attributed to differences in NMs lipid composition.The lipophilic insecticide Fipronil penetrated both NMs packed up to bilayer-compatible lateral pressures. The interface rearrangement after πt affected the interaction of Fipronil mainly in NMTi. The capability of the compound to be incorporated in expanded Langmuir films and remain when they are compressed was also observed. Fluorescence microscopy images suggest a disordering effect in NMTi while it ordered NMBt, showing that Fipronil affected the lateral distribution of lipids in NMs.We suggest that changes in order and lipid lateral organization caused by Fipronil might contribute to its mechanism of action.Our experiments evidenced that differences in the physical state of insect and mammal membranes become relevant for the design of new compounds with potential biological activity.

Gas-Responsive and Self-Powered Visual Composite Langmuir–Blodgett Films for Ultrathin Gas Sensors

The complex and variable environments are challenging the development of related detection and analysis. Ammonia (NH3) and hydrogen chloride (HCl) gases are both commonly used in industry, but they are considered to be toxic and corrosive substances that can threaten human health and the environment. Therefore, it is necessary here to develop a convenient, sensitive, and reliable sensor device for acid-alkali gas detection. Herein, we propose the synthesis strategy of an ultrathin film gas sensor based on the pH-responsive, self-powered, and visible composite Langmuir-Blodgett (LB) films. In our work, the LB films with nanometric thicknesses are obtained based on the sensitive materials of two novel carbazole structural sensitizers (abbreviated as CS-35 and CS-37) and several dye molecules. The composite LB films are formed with Carbazole samples and dye molecules through hydrogen bonding, π-π stacking, synergistic electrostatic interactions, and hydrophobic interactions, existing as J-aggregate or H-aggregate. The formation of high-quality and uniform Langmuir films is confirmed with transmission electron microscope (TEM), UV-vis spectrum, atomic force microscopy (AFM), and other measurements. In addition, based on the simple protonation and deprotonation, the prepared LB films can be assembled into a visual sensor for the response of pH gases. The response is confirmed by the study of ultraviolet spectroscopy and electrical output in vertical contact separation mode, which potentially unlocks a sustainable future for the application of ultrathin self-powered gas sensors.

Nondestructive Compression and Fluidization of Phospholipid Monolayers by Gaseous and Aerolized Perfluorocarbons: Promising Substances for Lung Surfactant Treatment.

We present a surface-sensitive X-ray scattering study on the influence of gaseous and aerolized perfluorocarbons (FCs) on zwitterionic and anionic phospholipid Langmuir films, which serve as a simplified model system of lung surfactants. It was found that small gaseous FC molecules like F-propane and F-butane penetrate phospholipid monolayers and accumulate between the alkyl chains and form islands. This clustering process can trigger the formation of lipid crystallites at low initial surface pressures. In contrast, the large linear FC F-octyl bromide fluidizes membranes, causing a dissolution of crystalline domains. The bicyclic FC F-decalin accumulates between the alkyl chains of 1,2-dipalmitoyl phosphatidylcholine but cannot penetrate the more densely packed 1,2-dipalmitoyl phosphatidic acid films because of its size. The effects of FCs on lung surfactants are discussed in the framework of currently proposed therapeutic methods for acute respiratory distress syndrome using FC gases, vapor, or aerosol ventilation causing monolayer fluidization effects. This study implies that the highly biocompatible and nontoxic FCs could be beneficial in the treatment of lung diseases with injured nonfunctional lung surfactants in a novel approach for ventilation.