Enhanced saturation coverages in adsorption–desorption processes

Tassel, Paul R. Van; Viot, Pascal; Tarjus, Gilles; Ramsden, Jeremy J.; Talbot, J.

doi:10.1063/1.480715

Cited by 13 publications

(14 citation statements)

References 25 publications

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“…Other, more complex, adsorption models have been developed that more appropriately characterize protein adsorption processes, which include the effects of surface crowding and subsequent protein‐protein interactions, such as the random sequential adsorption (RSA) process as presented by Ramsden and coworkers, as well as effects due to protein cooperativity, clustering, and aggregation, as summarized in the excellent review article by Rabe et al These more appropriate models should be considered for the characterization of protein adsorption behavior rather than the Langmuir model.…”

Section: Actual Protein Adsorption Behaviormentioning

confidence: 99%

The langmuir isotherm: A commonly applied but misleading approach for the analysis of protein adsorption behavior

Latour

2014

J Biomedical Materials Res

185

150

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The Langmuir adsorption isotherm provides one of the simplest and most direct methods to quantify an adsorption process. Because isotherm data from protein adsorption studies often appear to be fit well by the Langmuir isotherm model, estimates of protein binding affinity have often been made from its use despite that fact that none of the conditions required for a Langmuir adsorption process may be satisfied for this type of application. The physical events that cause protein adsorption isotherms to often provide a Langmuir-shaped isotherm can be explained as being due to changes in adsorption-induced spreading, reorientation, clustering, and aggregation of the protein on a surface as a function of solution concentration in contrast to being due to a dynamic equilibrium adsorption process, which is required for Langmuir adsorption. Unless the requirements of the Langmuir adsorption process can be confirmed, fitting of the Langmuir model to protein adsorption isotherm data to obtain thermodynamic properties, such as the equilibrium constant for adsorption and adsorption free energy, may provide erroneous values that have little to do with the actual protein adsorption process, and should be avoided. In this article, a detailed analysis of the Langmuir isotherm model is presented along with a quantitative analysis of the level of error that can arise in derived parameters when the Langmuir isotherm is inappropriately applied to characterize a protein adsorption process.

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Section: Actual Protein Adsorption Behaviormentioning

confidence: 99%

The langmuir isotherm: A commonly applied but misleading approach for the analysis of protein adsorption behavior

Latour

2014

J Biomedical Materials Res

185

150

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“…These considerations motivate us to study the deposition and evaporation of hard objects with rigid boundaries on a substrate. While a deposition-only system, of the type studied in random sequential adsorption [9], can end up in a non-evolving jammed configuration, with the addition of evaporation, the system eventually reaches an equilibrium steady state with a density governed by the rates of deposition and evaporation [12][13][14][15][16][17]. While most of these studies have focussed on the kinetics of approach to steady state, in this paper, we are interested in the properties of the steady state itself.…”

Section: Introductionmentioning

confidence: 99%

Orientational correlations and the effect of spatial gradients in the equilibrium steady state of hard rods in two dimensions: A study using deposition-evaporation kinetics

Khandkar

Barma

2005

Phys. Rev. E

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Deposition and evaporation of infinitely thin hard rods (needles) is studied in two dimensions using Monte Carlo simulations. The ratio of deposition to evaporation rates controls the equilibrium density of rods, and increasing it leads to an entropy-driven transition to a nematic phase in which both static and dynamical orientational correlation functions decay as power laws, with exponents varying continuously with deposition-evaporation rate ratio. Our results for the onset of the power-law phase agree with those for a conserved number of rods. At a coarse-grained level, the dynamics of the nonconserved angle field is described by the Edwards-Wilkinson equation. Predicted relations between the exponents of the quadrupolar and octupolar correlation functions are borne out by our numerical results. We explore the effects of spatial inhomogeneity in the deposition-evaporation ratio by simulations, entropy-based arguments, and a study of the additional terms introduced in the free energy. The primary effect is that needles tend to align along the local spatial gradient of the ratio. A uniform gradient thus induces a uniformly aligned state, as does a gradient which varies randomly in magnitude and sign, but acts only in one direction. Random variations of deposition-evaporation rates in both directions induce frustration, resulting in a state with glassy characteristics.

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“…Our objective was to independently establish three key model parameters (C E Max , k a , k d ) using experimental data for the adsorption and desorption of enzyme from the rubisco stain bound to the dyed surface. Although there are more advanced and complex models for protein adsorption [48][49][50], for simplicity we used the Langmuir isotherm and found it to be adequate, particularly in light of the observed reversibility of enzyme adsorption (e.g., Fig. 4 washout).…”

Section: Resultsmentioning

confidence: 99%