scholarly journals Preparation of Non-Surface-Active Langmuir Trough Subphases from Milk

ACS Omega ◽  
2019 ◽  
Vol 4 (12) ◽  
pp. 14920-14927
Author(s):  
Luis Real Hernandez ◽  
Rafael Jimenez-Flores
Keyword(s):  
Langmuir Trough ◽  
Surface Active

scholarly journals INTERACTION OF NANOSTRUCTURED LIPID CARRIERS WITH HUMAN MEIBUM

2019 ◽  
pp. 35-42
Author(s):  
Pattravee Niamprem ◽  
Thomas J. Milla ◽  
Burkhardt S. Schuett ◽  
S. P. Srinivas ◽  
Waree Tiyaboonchai
Keyword(s):  
Particle Size ◽  
Surface Pressure ◽  
Tear Film ◽  
Nanostructured Lipid Carriers ◽  
Langmuir Trough ◽  
Surface Activities ◽  
Lipid Films ◽  
Pressure Area ◽  
Surface Active ◽  
High Pressure Homogenizer

Objective: This study aimed to determine the possibility of nanostructured lipid carriers (NLCs) as a bionic tear film by determining the surface activities of the developed NLCs and their interaction with human meibomian lipid films. Methods: NLCs with different types of solid lipids and surfactants were prepared by a high-pressure homogenizer. The particle size was determined by dynamic light scattering. The surface activities of the NLCs and NLCs mixed with meibomian lipids were measured using a Langmuir trough and the resulting surface pressure area (Π-A) profiles were compared. These lipid films were further analyzed using fluorescence microscopy and scanning electron microscopy (SEM). Results: The particle size of prepared NLCs varied from 38–280 nm based on types of solid lipid and surfactant. All NLCs were highly surface active as indicated by their maximum surface pressure (Πmax). The Π-A profiles of meibum seeded with NLCs showed higher surface pressure than meibum alone and the shape of profiles were dominated by the meibomian lipids. These findings were in agreement with fluorescence and SEM micrographs, which revealed that the NLCs could adsorb and integrate to the meibomian lipid films as well as diffuse from the subphase to the lipid films. Conclusion: NLCs are surface active and can integrate with meibomian lipid films formed stable films. The type of interaction can be tailored by altering the solid lipids used in the formulation of the NLCs which could provide the means to develop efficient formulations for targeting dry eye disease related to a non-functional tear film lipid layer.

Boundary lubrication imparted by pleural surfactants and their identification

1982 ◽  
Vol 53 (2) ◽  
pp. 463-469 ◽  
Author(s):  
B. A. Hills ◽  
B. D. Butler ◽  
R. E. Barrow
Keyword(s):  
Molecular Structure ◽  
Surface Tension ◽  
Classical Theory ◽  
Standard Method ◽  
Boundary Lubrication ◽  
Hydrodynamic Theory ◽  
Langmuir Trough ◽  
Adsorption Film ◽  
Surface Active ◽  
Synthetic Surfactants

Phospholipids have been identified in pleural washings from live dogs and were found to include phosphatidylethanolamines, sphingomyelin, and, predominantly, phosphatidylcholines. The extracts were highly surface active when studied on the Langmuir trough using a Wilhelmy balance and produced surface tension/area loops similar to those for synthetic phosphatidylcholines and phosphatidylethanolamines but differing from the pure dipalmitoyl derivative (DPL). The extracts, the synthetic surfactants and their mixtures, were all found to be good lubricants when tested by a standard method for evaluating textile “sizes.” The results are consistent with the classical theory of “boundary” lubrication for which surfactant molecules would have an almost ideal molecular structure for adsorption, film cohesion, and mutual interaction of the hydrophobic ends. This concept is suggested as a mechanism that can explain some of the anomalies in the hydrodynamic theory of sliding of the pleurae and may possibly apply to other surfaces.

Application of the Langmuir trough to the Study of Rubber Latex

1942 ◽  
Vol 15 (1) ◽  
pp. 107-114 ◽  
Author(s):  
W. G. Wren
Keyword(s):  
Active Material ◽  
Close Packing ◽  
Metal Salts ◽  
Dilute Solution ◽  
Langmuir Trough ◽  
Rubber Latex ◽  
Air Water Interface ◽  
Cent Sodium ◽  
Surface Active ◽  
Surface Active Material

Abstract When a drop of ammoniated latex is allowed to touch a cleaned water surface, it spreads rapidly and evenly at the air-water interface, none entering the bulk of the water. Microscopic examination of such a film shows that, given sufficient spreading area, the latex globules are clearly separate one from another, and form a layer one particle thick. On reducing the area occupied by the globules by compressing the film between waxed glass straight edges lying in the surface of the water, the particles are forced together until visible spaces or voids disappear. The film still appears to be one particle thick, and remains in the surface of the water. Further compression results in irregularities of the surface, which can be seen to consist of folds in the film and, on expansion, a proportion of the latex globules is found to have been forced from the surface into the bulk of the water. If a dilute solution of certain substances is used in place of water, the latex particles all remain on the surface, even under conditions of high compression. Dilute acids and solutions of divalent metal salts are found to be effective in keeping the particles in the surface but, on compression to the point where close packing of the particles occurs, the film sometimes forms a continuous coagulum and on release of the pressure, it does not expand. Solutions of a creaming agent, such as 0.1 per cent sodium alginate (Manucol V), are adequate, not only to prevent particles being forced out of the surface, but also to give films which expand readily on release of the pressure. The fact that the latex is instantly swept to one side by a trace of surface active material, such as oleic acid, confirms that the particles have not penetrated into the interior of the water.

Morphological behavior of compatibilized ternary blends prepared by mechanical mixing

1993 ◽  
Vol 51 ◽  
pp. 1200-1201
Author(s):  
S.D. Smith ◽  
R.J. Spontak ◽  
D.H. Melik ◽  
S.M. Buehler ◽  
K.M. Kerr ◽  
...  
Keyword(s):  
Interfacial Adhesion ◽  
Diblock Copolymers ◽  
Ternary Blends ◽  
Mechanical Mixing ◽  
Design Considerations ◽  
Covalently Bonded ◽  
Homopolymer Blends ◽  
Emulsifying Agent ◽  
Surface Active ◽  
Low Entropy

When blended together, homopolymers A and B will normally macrophase-separate into relatively large (≫1 μm) A-rich and B-rich phases, between which exists poor interfacial adhesion, due to a low entropy of mixing. The size scale of phase separation in such a blend can be reduced, and the extent of interfacial A-B contact and entanglement enhanced, via addition of an emulsifying agent such as an AB diblock copolymer. Diblock copolymers consist of a long sequence of A monomers covalently bonded to a long sequence of B monomers. These materials are surface-active and decrease interfacial tension between immiscible phases much in the same way as do small-molecule surfactants. Previous studies have clearly demonstrated the utility of block copolymers in compatibilizing homopolymer blends and enhancing blend properties such as fracture toughness. It is now recognized that optimization of emulsified ternary blends relies upon design considerations such as sufficient block penetration into a macrophase (to avoid block slip) and prevention of a copolymer multilayer at the A-B interface (to avoid intralayer failure).

The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

2018 ◽  
Author(s):  
Hossam H Tayeb ◽  
Marina Stienecker ◽  
Anton Middelberg ◽  
Frank Sainsbury
Keyword(s):  
Polyethylene Glycol ◽  
Colloidal Stability ◽  
Point Mutations ◽  
Pharmaceutical Formulations ◽  
Industrial Processes ◽  
Parent Molecule ◽  
Site Specific ◽  
Interfacial Activity ◽  
Surface Active ◽  
The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

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