Impact of chlorogenic acid on surface and phase properties of cholesterol-enriched phosphatidylcholine membranes.

This study analyses the insertion of Chlorogenic acid (CGA) in phosphatidylcholine (PC) membranes enriched with cholesterol (Chol). While cholesterol decreases the area per lipid and increases the dipole potential, CGA increases and decreases these values, respectively. When CGA is inserted into cholesterol-containing DMPC membranes, these effects cancel out, resulting in values that overlap with those of DMPC monolayers without Chol and CGA. The presence of CGA also compensates the increase of dipole potential produced by Chol which can be explain as a consequence of the orientation of CGA molecule at the interphase opposing the cholesterol dipole moieties and water dipoles. This compensatory effect is less effective when lipids lack carbonyl groups (CO). When monolayers are composed by unsaturated PCs the Chol compensation is found at higher concentrations of CGA due to the direct interaction between CGA and Chol. These results suggest that cholesterol modulates the interaction and distribution of CGA in the lipid membrane, which may have implications for its biological activity.

Effect of Fluoxetine on the Surface Behavior of the Lipid Monolayers at Different Surface Pressures.

Fluoxetine (FLX), used in the clinic to treat depression, is a well-known cationic amphiphilic antidepressant. However, there is a lack of research on the effect of FLX on the surface behavior of lipid monolayers under different surface pressures. In this study, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/CHOL (DPPC/POPC/CHOL) monolayers were prepared via the Langmuir method, and FLX was added to these monolayers under various surface pressures. The effect of FLX on the surface behavior of DPPC/POPC/CHOL monolayers under various surface pressures was studied using a combination of surface pressure-area isotherms, compressibility modulus-surface pressure curves, and atomic force microscope (AFM). The results showed that the effect of FLX on the lipid monolayers was different under different surface pressures. The interaction between FLX and lipid molecules was weak under low surface pressures, and FLX could easily intercalate between the lipid molecules to inhibit monolayer phase transition. The interaction between FLX and lipid molecules was enhanced and FLX tended to self-aggregate to reduce the monolayer stability when the surface pressure was high. This study lays the foundation for further studies on the interaction between FLX and lipid monolayers.

Modulation of Membrane Trafficking of AQP5 in the Lens in Response to Changes in Zonular Tension Is Mediated by the Mechanosensitive Channel TRPV1.

In mice, the contraction of the ciliary muscle via the administration of pilocarpine reduces the zonular tension applied to the lens and activates the TRPV1-mediated arm of a dual feedback system that regulates the lens' hydrostatic pressure gradient. In the rat lens, this pilocarpine-induced reduction in zonular tension also causes the water channel AQP5 to be removed from the membranes of fiber cells located in the anterior influx and equatorial efflux zones. Here, we determined whether this pilocarpine-induced membrane trafficking of AQP5 is also regulated by the activation of TRPV1. Using microelectrode-based methods to measure surface pressure, we found that pilocarpine also increased pressure in the rat lenses via the activation of TRPV1, while pilocarpine-induced removal of AQP5 from the membrane observed using immunolabelling was abolished by pre-incubation of the lenses with a TRPV1 inhibitor. In contrast, mimicking the actions of pilocarpine by blocking TRPV4 and then activating TRPV1 resulted in sustained increase in pressure and the removal of AQP5 from the anterior influx and equatorial efflux zones. These results show that the removal of AQP5 in response to a decrease in zonular tension is mediated by TRPV1 and suggest that regional changes to PH2O contribute to lens hydrostatic pressure gradient regulation.

Preparation of Thin Films Containing Modified Hydroxyapatite Particles and Phospholipids (DPPC) for Improved Properties of Biomaterials.

The main aims of thin biofilm synthesis are to either achieve a new form to promote the transport of drugs in oral delivery systems or as a coating to improve the biocompatibility of the implant's surface. In this study, the Langmuir monolayer technique was employed to obtain films containing Mg-doped hydroxyapatite with 0.5%, 1.0%, and 1.5% Mg(II). The obtained modified HA particles were analysed via the FT-IR, XRD, DLS, and SEM methods. It was shown that the modified hydroxyapatite particles were able to form thin films at the air/water interface. BAM microscopy was employed to characterized the morphology of these films. In the next step, the mixed films were prepared using phospholipid (DPPC) molecules and modified hydroxyapatite particles (HA-Mg(II)). We expected that the presence of phospholipids (DPPC) in thin films improved the biocompatibility of the preparing films, while adding HA-Mg(II) particles will promote antibacterial properties and enhance osteogenesis processes. The films were prepared in two ways: (1) by mixing DPPC and HA-Mg (II) and spreading this solution onto the subphase, or (2) by forming DPPC films, dropping the HA-Mg (II) dispersion onto the phospholipid monolayer. Based on the obtained π-A isotherms, the surface parameters of the achieved thin films were estimated. It was observed that the HA-Mg(II) films can be stabilized with phospholipid molecules, and a more stable structure was obtained from films synthesied via method (2).

Structural analysis of the peptides temporin-Ra and temporin-Rb and interactions with model membranes.

The skin of amphibians is widely exploited as rich sources of membrane active peptides that differ in chain size, polypeptide net charge, secondary structure, target selectivity and toxicity. In this study, two small antimicrobial peptides, temporin-Ra and temporin-Rb, originally isolated from the skin of the European marsh frog (Rana ridibunda), described as active against pathogen bacteria and presenting low toxicity to eukaryotic cells were synthesized and had their physicochemical properties and mechanism of action investigated. The temporin peptides were examined in aqueous solution and in the presence of membrane models (lipid monolayers, micelles, lipid bilayers and vesicles). A combined approach of bioinformatics analyses, biological activity assays, surface pressure measurements, synchrotron radiation circular dichroism spectroscopy, and oriented circular dichroism spectroscopy were employed. Both peptides were able to adsorb at a lipid-air interface with a negative surface charge density, and efficiently disturb the lipid surface packing. A disorder-to-helix transition was observed on the secondary structure of both peptides when either in a non-polar environment or interacting with model membranes containing a negative net charge density. The binding of both temporin-Ra and temporin-Rb to membrane models is modulated by the presence of negatively charged lipids in the membrane. The amphipathic helix induced in temporin-Ra is oriented parallel to the membrane surface in negatively charged or in zwitterionic lipid bilayers, with no tendency for realignment after binding. Temporin-Rb, instead, assumes a ß-sheet conformation when deposited into oriented stacked lipid bilayers. Due to their short size and simple composition, both peptides are quite attractive for the development of new classes of peptide-based anti-infective drugs.

Evaluating the Impact of Hydrophobic Silicon Dioxide in the Interfacial Properties of Lung Surfactant Films.

The interaction of hydrophobic silicon dioxide particles (fumed silicon dioxide), as model air pollutants, and Langmuir monolayers of a porcine lung surfactant extract has been studied in order to try to shed light on the physicochemical bases underlying the potential adverse effects associated with pollutant inhalation. The surface pressure-area isotherms of lung surfactant (LS) films including increasing amounts of particles revealed that particle incorporation into LS monolayers modifies the organization of the molecules at the water/vapor interface, which alters the mechanical resistance of the interfacial films, hindering the ability of LS layers for reducing the surface tension, and reestablishing the interface upon compression. This influences the normal physiological function of LS as is inferred from the analysis of the response of the Langmuir films upon the incorporation of particles against harmonic changes of the interfacial area (successive compression-expansion cycles). These experiments evidenced that particles alter the relaxation mechanisms of LS films, which may be correlated to a modification of the transport of material within the interface and between the interface and the adjacent fluid during the respiratory cycle.

Impact of Engineered Carbon Nanodiamonds on the Collapse Mechanism of Model Lung Surfactant Monolayers at the Air-Water Interface.

Understanding interactions between inhaled nanoparticles and lung surfactants (LS) present at the air-water interface in the lung, is critical to assessing the toxicity of these nanoparticles. Specifically, in this work, we assess the impact of engineered carbon nanoparticles (ECN) on the ability of healthy LS to undergo reversible collapse, which is essential for proper functioning of LS. Using a Langmuir trough, multiple compression-expansion cycles are performed to assess changes in the surface pressure vs. area isotherms with time and continuous cyclic compression-expansion. Further, theoretical analysis of the isotherms is used to calculate the ability of these lipid systems to retain material during monolayer collapse, due to interactions with ECNs. These results are complemented with fluorescence images of alterations in collapse mechanisms in these monolayer films. Four different model phospholipid systems, that mimic the major compositions of LS, are used in this study. Together, our results show that the ECN does not impact the mechanism of collapse. However, the ability to retain material at the interface during monolayer collapse, as well as re-incorporation of material after a compression-expansion cycle is altered to varying extent by ECNs and depends on the composition of the lipid mixtures.

Iterative Blind Deconvolution Algorithm for Deblurring a Single PSP/TSP Image of Rotating Surfaces.

Imaging of pressure-sensitive paint (PSP) for pressure measurement on moving surfaces is problematic due to the movement of the object within the finite exposure time of the imager, resulting in the blurring of the blade edges. The blurring problem is particularly challenging when high-sensitivity PSP with a long lifetime is used, where the long luminescence time constant of exponential light decay following a burst of excitation light energy results in blurred images. One method to ameliorate this effect is image deconvolution using a point spread function (PSF) based on an estimation of the luminescent time constant. Prior implementations of image deconvolution for PSP deblurring have relied upon a spatially invariant time constant in order to reduce computational time. However, the use of an assumed value of time constant leads to errors in the point spread function, particularly when strong pressure gradients (which cause strong spatial gradients in the decay time constant) are involved. This work introduces an iterative method of image deconvolution, where a spatially variant PSF is used. The point-by-point PSF values are found in an iterative manner, since the time constant depends on the local pressure value, which can only be found from the reduced PSP data. The scheme estimates a super-resolved spatially varying blur kernel with sub-pixel resolution without filtering the blurred image, and then restores the image using classical iterative regularization tools. A kernel-free forward model has been used to generate test images with known pressure surface maps and a varying amount of noise to evaluate the applicability of this scheme in different experimental conditions. A spinning disk setup with a grazing nitrogen jet for producing strong pressure gradients has also been used to evaluate the scheme on a real-world problem. Results including the convergence history and the effect of a regularization-iteration count are shown, along with a comparison with the previous PSP deblurring method.

In Vivo Measurement of Surface Pressures and Retraction Distances Applied on Abdominal Organs During Surgery.

This study undertook the in vivo measurement of surface pressures applied by the fingers of the surgeon during typical representative retraction movements of key human abdominal organs during both open and hand-assisted laparoscopic surgery. Surface pressures were measured using a flexible thin-film pressure sensor for 35 typical liver retractions to access the gall bladder, 36 bowel retractions, 9 kidney retractions, 8 stomach retractions, and 5 spleen retractions across 12 patients undergoing open and laparoscopic abdominal surgery. The maximum and root mean square surface pressures were calculated for each organ retraction. The maximum surface pressures applied to these key abdominal organs are in the range 1 to 41 kPa, and the average maximum surface pressure for all organs and procedures was 14 ± 3 kPa. Surface pressure relaxation during the retraction hold period was observed. Generally, the surface pressures are higher, and the rate of surface pressure relaxation is lower, in the more confined hand-assisted laparoscopic procedures than in open surgery. Combined video footage and pressure sensor data for retraction of the liver in open surgery enabled correlation of organ retraction distance with surface pressure application. The data provide a platform to design strategies for the prevention of retraction injuries. They also form a basis for the design of next-generation organ retraction and space creation surgical devices with embedded sensors that can further quantify intraoperative retraction forces to reduce injury or trauma to organs and surrounding tissues.

Aromatic residues in the C terminus of apolipoprotein C-III mediate lipid binding and LPL inhibition.

Plasma apoC-III levels correlate with triglyceride (TG) levels and are a strong predictor of CVD outcomes. ApoC-III elevates TG in part by inhibiting LPL. ApoC-III likely inhibits LPL by competing for lipid binding. To probe this, we used oil-drop tensiometry to characterize binding of six apoC-III variants to lipid/water interfaces. This technique monitors the dependence of lipid binding on surface pressure, which increases during TG hydrolysis by LPL. ApoC-III adsorption increased surface pressure by upward of 18 mN/m at phospholipid/TG/water interfaces. ApoC-III was retained to high pressures at these interfaces, desorbing at 21-25 mN/m. Point mutants, which substituted alanine for aromatic residues, impaired the lipid binding of apoC-III. Adsorption and retention pressures decreased by 1-6 mN/m in point mutants, with the magnitude determined by the location of alanine substitutions. Trp42 was most critical to mediating lipid binding. These results strongly correlate with our previous results, linking apoC-III point mutants to increased LPL binding and activity at lipid surfaces. We propose that aromatic residues in the C-terminal half of apoC-III mediate binding to TG-rich lipoproteins. Increased apoC-III expression in the hypertriglyceridemic state allows apoC-III to accumulate on lipoproteins and inhibit LPL by preventing binding and/or access to substrate.

Complexation of phospholipids and cholesterol by triterpenic saponins in bulk and in monolayers.

The interactions between three triterpene saponins: α-hederin, hederacoside C and ammonium glycyrrhizate with model lipids: cholesterol and dipalmitoylphosphatidylcholine (DPPC) are described. The oleanolic acid-type saponins (α-hederin and hederacoside C) were shown to form 1:1 complexes with lipids in bulk, characterized by stability constants in the range (4.0±0.2)·10(3)-(5.0±0.4)·10(4) M(-1). The complexes with cholesterol are generally stronger than those with DPPC. On the contrary, ammonium glycyrrhizate does not form complexes with any of the lipids in solution. The saponin-lipid interactions were also studied in a confined environment of Langmuir monolayers of DPPC and DPPC/cholesterol with the saponins present in the subphase. A combined monolayer relaxation, surface dilational rheology, fluorescence microscopy and neutron reflectivity (NR) study showed that all three saponins are able to penetrate pure DPPC and mixed DPPC/cholesterol monolayers. Overall, the effect of the saponins on the model lipid monolayers does not fully correlate with the lipid-saponin complex formation in the homogeneous solution. The best correlation was found for α-hederin, for which even the preference for cholesterol over DPPC observed in bulk is well reflected in the monolayer studies and the literature data on its membranolytic activity. Similarly, the lack of interaction of ammonium glycyrrhizate with both lipids is evident equally in bulk and monolayer experiments, as well as in its weak membranolytic activity. The combined bulk and monolayer results are discussed in view of the role of confinement in modulating the saponin-lipid interactions and possible mechanism of membranolytic activity of saponins.

Characterization of planar biomimetic lipid films composed of phosphatidylethanolamines and phosphatidylglycerols from Escherichia coli.

We have characterized planar lipid films composed of phosphatidylethanolamines (PE) and phosphatidylglycerols (PG) from E. coli bacteria. The nature of the interactions and miscibility of PE and PG components within mixed lipid films was evaluated based on surface pressure measurements and Brewster angle microscopy imaging at the air-water interface. We have found that PE and PG components show tendency to form separated domains at surface pressures relevant for biological membranes. Further, we have directly compared mechanisms of formation of supported lipid bilayers either on mica or Au(111) by spreading of small unilamellar vesicles. The bilayer formation was monitored by in situ atomic force microscopy imaging. The pathways of the vesicles spreading on each substrate are substantially different and the buildup of the bilayer on Au(111) occurs through complex multistep mechanism. The morphology and nanomechanical properties of the resulting PE/PG bilayers were thoroughly compared. We have found that the interactions between lipids and supporting substrate significantly affect molecular organization within the films since the bilayer on Au(111) is uniform in terms of the topography, while the same lipid composition on mica results in formation of distinct gel and liquid disordered domains. Different molecular organization affects also nanomechanical properties of lipid films. The latter were expressed in terms of Young's moduli and bending stiffness.

Modeling Lung Surfactant Interactions with Benzo[a]pyrene.

By reducing the surface tension of the air-water interface in alveoli, lung surfactant (LS) is crucial for proper functioning of the lungs. It also forms the first barrier against inhaled pathogens. In this study we inspect the interactions of LS models with a dangerous air pollutant, benzo[a]pyrene (BaP). Dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoylphosphatidylcholine, and their 1:1 mixture are used as LS models. Pressure-area isotherms are employed to study macroscopic properties of the monolayers. We find that addition of BaP has a condensing effect, manifested by lowering the values of surface pressure and shifting the isotherms to smaller areas. Atomistic details of this process are examined by means of molecular dynamics simulations. We show that initially BaP molecules are accumulated in the monolayers. Upon compression, they are forced to the headgroups region and eventually expelled to the subphase. BaP presence results in reduction of monolayer hydration in the hydrophilic region. In the hydrophobic region it induces increased chain ordering, reduction of monolayer fluidity, and advances transition to the liquid condensed phase in the DPPC system.

Nasal septum configuration as a basis for novel septal splints.

The objective is to use anatomical determinations of nasal septum shape and surface area in adults as a design basis for silastic septal splints of universal size and fit and offering maximum possible surface coverage. The objective is also to devise a method of securing the septal splints, so that surface pressure on septal mucosa is distributed as evenly as possible while not interfering with capillary perfusion. Nasal septum area was determined in 21 Caucasian body donors, and nasal septum thickness was measured in 20 CT scans. Septal splints of universal size and shape were prepared from silastic sheeting. The holding force of various neodymium-iron-boron (NdFeB) magnets, and the surface pressure exerted by magnet-containing septal splints was calculated. These septal splints of novel design offer a satisfactory fit in routine clinical practice. The splints can be securely attached with built-in NdFeB magnets, and surface pressure can be distributed evenly across the nasal septum while not interfering with mucosal tissue perfusion. With their simple intranasal insertion, these magnet-containing septal splints of universal size and optimised shape offer maximum possible septum coverage following septoplasty/septorhinoplasty. The absence of interference with septal tissue perfusion means that they are likely to be associated with fewer postoperative complications and better outcomes.

A constant area monolayer method to assess optimal lipid packing for lipolysis tested with several secreted phospholipase A2.

We present an analysis of lipid monolayer hydrolysis at a constant area to assess the optimal lateral surface pressure value (Πopt) and thus, the surface packing density of the lipid, at which the activity of a given lipolytic enzyme is maximal. This isochoric method consists of a measurement of the decrease down to zero of the Πopt of phospholipid substrate monolayer due to continuous hydrolysis using only one reaction compartment. We performed the comparison of both approaches using several commercially available and literature-evaluated sPLA2s. Also, we characterized for the first time the profile of hydrolysis of DLPC monolayers catalyzed by a sPLA2 from Streptomyces violaceoruber and isoenzymes purified from Bothrops diporus venom. One of these viper venom enzymes is a new isoenzyme, partially sequenced by a mass spectrometry approach. We also included the basic myotoxin sPLA2-III from Bothrops asper. Results obtained with the isochoric method and the standard isobaric one produced quite similar values of Πopt, validating the proposal. In addition, we propose a new classification parameter, a lipolytic ratio of hydrolysis at two lateral pressures, 20 mN·m(-1) and 10 mN·m(-1), termed here as LR20/10 index. This index differentiates quite well "high surface pressure" from "low surface pressure" sPLA2s and, by extension; it can be used as a functional criterion for the quality of a certain enzyme. Also, this index could be added to the grouping systematic criteria for the superfamily proposed for phospholipase A2.

Soft electrostatic repulsion in particle monolayers at liquid interfaces: surface pressure and effect of aggregation.

Non-densely packed interfacial monolayers from charged micrometre-sized colloid particles find applications for producing micropatterned surfaces. The soft electrostatic repulsion between the particles in a monolayer on an air/water (or oil/water) interface is mediated by the non-polar fluid, where Debye screening is absent and the distances between the particles are considerably greater than their diameters. Surface pressure versus area isotherms were measured at the air/water interface. The experiments show that asymptotically the surface pressure is inversely proportional to the third power of the interparticle distance. A theoretical model is developed that predicts not only the aforementioned asymptotic law but also the whole surface pressure versus area dependence. An increase in the surface pressure upon aggregation of charged particles in the interfacial monolayers is experimentally established. This effect is explained by the developed theoretical model, which predicts that the surface pressure should linearly increase with the square root of the particle mean aggregation number. The effect of added electrolyte on the aggregation is also investigated. The data lead to the conclusion that 'limited aggregation' exists in the monolayers of charged particles. In brief, the stronger electrostatic repulsion between the bigger aggregates leads to a higher barrier to their coalescence that, in turn, prevents any further aggregation, i.e. negative feedback is present.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

Hydration in Lipid Monolayers: Correlation of Water Activity and Surface Pressure.

In order to give a physical meaning to each region of the membrane we define the interphase as the region in a lipid membrane corresponding to the polar head groups imbibed in water with net different properties than the hydrocarbon region and the water phase. The interphase region is analyzed under the scope of thermodynamics of surface and solutions based on the definition of Defay-Prigogine of an interphase and the derivation that it has in the understanding of membrane processeses in the context of biological response. In the view of this approach, the complete monolayer is considered as the lipid layer one molecule thick plus the bidimensional solution of the polar head groups inherent to it (the interphase region). Surface water activity appears as a common factor for the interaction of several aqueous soluble and surface active proteins with lipid membranes of different composition. Protein perturbation can be measured by changes in the surface pressure of lipid monolayers at different initial water surface activities. As predicted by solution chemistry, the increase of surface pressure is independent of the particle nature that dissolves. Therefore, membranes give a similar response in terms of the determined surface states given by water activity independent of the protein or peptide.

Antiradical activity of gallic acid included in lipid interphases.

Polyphenols are well known as antioxidant agents and by their effects on the hydration layers of lipid interphases. Among them, gallic acid and its derivatives are able to decrease the dipole potential and to act in water as a strong antioxidant. In this work we have studied both effects on lipid interphases in monolayers and bilayers of dimyristoylphosphatidylcholine. The results show that gallic acid (GA) increases the negative surface charges of large unilamellar vesicles (LUVs) and decreases the dipole potential of the lipid interphase. As a result, positively charged radical species such as ABTS(+) are able to penetrate the membrane forming an association with GA. These results allow discussing the antiradical activity (ARA) of GA at the membrane phase which may be taking place in water spaces between the lipids.

Atypical surface behavior of ceramides with nonhydroxy and 2-hydroxy very long-chain (C28-C32) PUFAs.

Unique species of ceramide (Cer) with very-long-chain polyunsaturated fatty acid (VLCPUFA), mainly 28-32 carbon atoms, 4-5 double bonds, in nonhydroxy and 2-hydroxy forms (n-V Cer and h-V Cer, respectively), are generated in rat spermatozoa from the corresponding sphingomyelins during the acrosomal reaction. The aim of this study was to determine the properties of these sperm-distinctive ceramides in Langmuir monolayers. Individual Cer species were isolated by HPLC and subjected to analysis of surface pressure, surface potential, and Brewster angle microscopy (BAM) as a function of molecular packing. In comparison with known species of Cer, n-V Cer and h-V Cer species showed much larger mean molecular areas and increased molecular dipole moments in liquid expanded phases, which suggest bending and partial hydration of the double bonded portion of the VLCPUFA. The presence of the 2-hydoxyl group induced a closer molecular packing in h-V Cer than in their chain-matched n-V Cer. In addition, all these Cer species showed liquid-expanded to liquid-condensed transitions at room temperature. Existence of domain segregation was confirmed by BAM. Additionally, thermodynamic analysis suggests a phase transition close to the physiological temperature for VLCPUFA-Cers if organized as bulk dispersions.

Predicting the Agitation-Induced Aggregation of Monoclonal Antibodies Using Surface Tensiometry.

Adsorption of antibody therapeutics to air-liquid interfaces can enhance aggregation, particularly when the solution does not contain protective surfactant or when the surfactant is diluted as occurs during preparation of intravenous infusion bags. The ability to predict an antibody's propensity for interfacially mediated aggregation is particularly useful during product development to ensure the quality, potency, and safety of the therapeutic. To develop a predictive tool, we investigated the surface pressure and surface excess of a panel of 16 antibodies as well as determined their aggregation propensity at the air-liquid interface in an agitation stress model. Our data demonstrated that the initial rate of surface pressure increase upon antibody adsorption to the air-liquid interface strongly predicted the extent of agitation-induced aggregation. Other factors, including the hydrophobicity, equilibrium surface pressure, and interfacial concentration of an antibody, were not adequate predictors of its susceptibility to aggregation. In addition to developing a predictive tool, we extended the interfacial characterization to better understand the mechanisms of antibody aggregation at an air-liquid interface during agitation stress. We believe that the kinetics of antibody rearrangement and conformational change after adsorbing to the interface, leading to the development of attractive antibody-antibody interactions, dictated the extent of aggregation. Overall, our results demonstrate how surface pressure measurements can be implemented as a rapid screening tool for the identification of antibodies with a high propensity to aggregate upon adsorption to an air-liquid interface while also furthering our understanding of interfacially mediated protein aggregation.