<i>Interfacial Phenomena</i>

Davies, J. T.; Rideal, E. K.; Rice, Stuart A.

doi:10.1063/1.3058154

Cited by 104 publications

(156 citation statements)

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“…The maximum elasticity is higher than one found for pure protein monolayers ( 10 mN/m at A : 1 m 2 /mg) (Davies and Rideal, Appendix-25 1963), and it agrees well with those found for cell membrane protein monolayers (Blank et al, 1979). When compared with pure protein films, the higher values of elasticity of lipid-protein monolayers indicate a better stability (Davies and Rideal, 1963). Fig.…”

Section: Monolayers Containing Salmonella Antibodysupporting

confidence: 84%

Rapid and sensitive biosensor for Salmonella

Pathirana

Barbaree

Chin

et al. 2000

Biosensors and Bioelectronics

147

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The rapid and sensitive detection of Salmonella typhymurium based on the use of a polyclonal antibody immobilized by the Langmuir-Blodgett method on the surface of a quartz crystal acoustic wave device was demonstrated. The binding of bacteria to the surface changed the crystal resonance parameters; these were quantified by the output voltage of the sensor instrumentation. The sensor had a lower detection limit of a few hundred cells/ml, and a response time of B 100 s over the range of 10 2 -10 10 cells/ml. The sensor response was linear between bacterial concentrations of 10 2 -10 7 cells/ml, with a sensitivity of 18 mV/decade. The binding of bacteria was specific with two binding sites needed to bind a single cell. The sensors preserve 75% of their sensitivity over a period of 32 days.

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Section: Monolayers Containing Salmonella Antibodysupporting

confidence: 84%

Rapid and sensitive biosensor for Salmonella

Pathirana

Barbaree

Chin

et al. 2000

Biosensors and Bioelectronics

147

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“…In the present approach, calculation of the surface potentials was carried out by means of a rather simple form of the GouyChapman theory and by considering possible adsorption of cations at the interface, i. e. the existence of a Stern layer. Such a theory is known to suffer criticisms [43,44]. Nevertheless, it has been successfully used for describing the binding of ligands [25, 631 or cations [35 -37, 55 -621 at membrane lipid surfaces.…”

Section: Discussionmentioning

confidence: 99%

“…More precisely, the Gouy-Chapman equation [36,43, 441 enables us to calculate the electrical potential i ,ho which exists at the interface for a given surface charge density 0 :…”

Section: Theorymentioning

confidence: 99%

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Effect of pH and Monovalent Cations on the Ionization State of Phosphatidylglycerol in Monolayers

Lakhdar-Ghazal

Tichadou

Tocanne

1983

European Journal of Biochemistry

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Ionization of the acidic phospholipid phosphatidylglycerol has been studied by measuring the surface potential of monomolecular films of the lipid as a function of the aqueous subphase pH and the concentration of monovalent cations (Li, Na, Cs). It is shown that theexperimental data can be interpreted by means of the Gouy-Chapman theory in its simplest formulation, provided an adsorption of cations at the membrane surface is accounted for. This allows us to predict the ionization state of the lipid for given ionic conditions in the subphase. Above pH 4, for subphase ion concentration higher than 10 mM, or for ion concentrations above 0.1 mM at pH 5.6, phosphatidylglycerol is fully deprotonated. Within the limits of our theoretical approach, association constants of the cations to the lipid lie around 0.1-0.6 M-I.With the exception of phosphatidylcholine and phosphatidylethanolamine which are zwitterions over a large pH range (3 -8) [l], phospholipids in biomembranes are acidic substances bearing a net negative charge when they are ionized. Ionization or protonation of these acidic lipids as well as their interactions with cations can have considerable consequences on both membrane structure and functions.From a structural point of view, changes in the pH or the ionic strength of the aqueous phase have been shown to trigger phase transition of acidic phospholipids [2-111. The bivalent cations Mg2+ and Ca2+ can bring about phase separation within mixtures of zwitterionic and acidic phospholipids [12-191. Cations can also modify the dynamic properties of lipids, i.e. their lateral diffusion rate [20], as well as being able to promote morphological changes [21]. As an example, cardiolipin, which normally exists in a lamellar phase in the presence of sodium, adopts the hexagonal H,, phase in the presence of calcium [22, 231. Dipalmitoylglycerophosphoglycerol, which normally stays in a lamellar phase in the presence of sodium, has been shown to exist in an interdigitated phase in the presence of the organic cations choline and acetylcholine [24].From a functional point of view, phospholipids can modulate the activity of membrane enzymes by monitoring, at the membrane surface, a concentration of protons, cations and of any charged metabolites which is quite different from that existing in the bulk [25]. Charges at the membrane surface also contribute to the establishment of transmembrane potentials which are involved in energy-linked transmembrane transport processes [26] and which are postulated to monitor the orientation [27 -291 and the activity of certain membrane proteins [28 -341.For all these reasons, it is of great importance to have a full understanding of the ionization process of acidic phospholipids in membrane systems. This would allow a correct prediction of their ionization state and of the surface potential they generate, for given ionic conditions in the aqueous phase. As a first approach, ionization of phosphatidylglycerol was studied in monolayers by measuring changes in film surface pressure again...

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“…[3][4][5][6][7][8][9][10] Because the surface tension of a liquid-vapor interface is a function of temperature, 11 the presence of a temperature gradient at the free-surface results in a surface tension gradient or Marangoni stress. The thermocapillary flows induced by such stresses can cause interfacial instabilities, 12,13 which have been studied extensively for uniformly heated surfaces.…”

Section: Introductionmentioning

confidence: 99%

Stabilization of thin liquid films flowing over locally heated surfaces via substrate topography

Tiwari¹,

Davis²

2010

Physics of Fluids

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A long-wave lubrication analysis is used to study the influence of topographical features on the linear stability of noninertial coating flows over a locally heated surface. Thin liquid films flowing over surfaces with localized heating develop a pronounced ridge at the upstream edge of the heater. This ridge becomes unstable to transverse perturbations above a critical Marangoni number and evolves into an array of rivulets even in the limit of noninertial flow. Similar fluid ridges form near topographical variations on isothermal surfaces, but these ridges are stable to perturbations. The influence of basic topographical features on the stability of the locally heated film is analyzed. In contrast to its destabilizing influence on liquid films resting on heated, horizontal walls, even such nonoptimized topography is found to be effective at stabilizing the flowing film with respect to rivulet formation and subsequent rupture. Optimal topographical features that suppress variations in the free-surface shape are also determined. The critical Marangoni number at the instability threshold increases substantially with appropriate topography even for nonzero Biot numbers. An energy analysis is used to provide insight into the mechanism by which the topography stabilizes the flow. Because the stabilizing effect of the topographical features is only weakly sensitive to the governing parameters and particular temperature profile, the use of such features could be a simple alternative in applications to more complicated methods of stabilization.

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Interfacial Phenomena

Cited by 104 publications

References 0 publications

Rapid and sensitive biosensor for Salmonella

Rapid and sensitive biosensor for Salmonella

Effect of pH and Monovalent Cations on the Ionization State of Phosphatidylglycerol in Monolayers

Stabilization of thin liquid films flowing over locally heated surfaces via substrate topography

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