Simulations of sieving characteristics of macromolecules in porous membranes at high concentrations

Cifra, Peter; Bleha, Tomáš

doi:10.1016/j.memsci.2005.04.036

Cited by 4 publications

(7 citation statements)

References 28 publications

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“…As a random coiled polymer is much more flexible, it can change its shape to the pore where it is diffusing. Thus, values of the effective diffusivity significantly higher than zero are obtained even though the radius of gyration of the polymer is bigger than the pore size (Cifra and Bleha, 2005).…”

Section: Introductionmentioning

confidence: 91%

“…Transport of polymers in porous materials is usually described as hindered diffusion. This diffusion is much influenced by the existence of interactions (Davidson and Deen, 1988;Smith and Deen, 1983) and the type of polymer: hard sphere (Smith and Deen, 1983) or random coiled polymer (Cifra and Bleha, 2005). As a random coiled polymer is much more flexible, it can change its shape to the pore where it is diffusing.…”

Section: Introductionmentioning

confidence: 99%

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Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Ladero

Santos

Garcı́a-Ochoa

2007

Chemical Engineering Science

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Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Ladero

Santos

Garcı́a-Ochoa

2007

Chemical Engineering Science

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“…Then using the Stokes-Einstein equation, one gets: (12) Since for the plasmid pUC19, nbp = 2686, therefore r s = 77.9 nm, r g = 122 nm and h 2 1/2 = 298 nm. These values can be compared with those estimated by a different approach, using the WLC model, which is often applied for modeling DNA (since DNA is a molecule of considerable stiffness).…”

Section: Specification Of the Molecular Size Of The Prototypesmentioning

confidence: 99%

“…For this purpose, stochastic methods, involving computational simulation, have been developed [10][11][12] in order to avoid the excessive complexity of obtaining an analytical solution. In these algorithms it is estimated the probability of a certain event to occur, for instance, the probability of a molecule to enter inside a pore, by testing that occurrence several times (typically more than 10 5 times are required to obtain a satisfactory approach to actual probability of the event).…”

Section: Introductionmentioning

confidence: 99%

“…This model, and other more sophisticated models, have been used for studying the possibility of the macromolecules to adopt conformations and enter into confined regions, namely pores and slits [10][11][12], yet never in the case of s 1. Predictions of partition coefficients can be made by determining the probability of the molecule to adopt such conformations, if one assumes no deformation induced by the convective flow through the pores.…”

Section: Introductionmentioning

confidence: 99%

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Development of a model for membrane filtration of long and flexible macromolecules: Application to predict dextran and linear DNA rejections in ultrafiltration

Morão

Nunes

Sousa

et al. 2009

Journal of Membrane Science

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a b s t r a c tA model is proposed for predicting the intrinsic rejections of linear flexible molecules, of high molecular dimensions, in microfiltration and ultrafiltration membranes. The developed model is based on the available theory of hindered transport of solutes through narrow pores, assuming that convection is the only relevant transport mechanism. For the application of the model, partition coefficients of the solutes between the solution and the membrane were estimated by a stochastic simulation, assuming suction of the macrosolutes into the pore. In these simulations, the macromolecules were modeled as freely jointed chains. Different methods for the estimation of the molecular dimensions of the solutes are discussed. The validity of the model was tested using dextran T2000 and plasmid pUC19 in its linear isoform, as model solutes; the tests were performed using membranes of different pore size, that include two ultrafiltration membranes previously characterized, having 4.1 and 10.5 nm of pore radius, and two track-etched polycarbonate membranes, having 15 and 40 nm of pore radius. Filtration was performed in a stirred cell, at controlled permeate flux. Different conditions of stirring speed and permeate flux were tested to check the consistency of the model. The results show that very satisfactory predictions are obtained, considering the simplicity of the model, especially in the case of the plasmid.

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Optimizing collagen transport through track-etched nanopores

Bueno¹,

Ruberti²

2008

Journal of Membrane Science

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Polymer transport through nanopores is a potentially powerful tool for separation and organization of molecules in biotechnology applications. Our goal is to produce aligned collagen fibrils by mimicking cell-mediated collagen assembly: driving collagen monomers in solution through the aligned nanopores in track-etched membranes followed by fibrillogenesis at the pore exit. We examined type I atelo-collagen monomer transport in neutral, cold solution through polycarbonate track-etched membranes comprising 80-nm-diameter, 6-μm-long pores at 2% areal fraction. Source concentrations of 1.0, 2.8 and 7.0 mg/ml and pressure differentials of 0, 10 and 20 inH 2 O were used. Membrane surfaces were hydrophilized via covalent poly(ethylene-glycol) binding to limit solute-membrane interaction. Collagen transport through the nanopores was a non-intuitive process due to the complex behavior of this associating molecule in semi-dilute solution. Nonetheless, a modified open pore model provided reasonable predictions of transport parameters. Transport rates were concentration-and pressure-dependent, with diffusivities across the membrane in semi-dilute solution two-fold those in dilute solution, possibly via cooperative diffusion or polymer entrainment. The most significant enhancement of collagen transport was accomplished by membrane hydrophilization. The highest concentration transported (5.99±2.58 mg/ml) with the highest monomer flux (2.60±0.49 ×10 3 molecules s -1 pore -1 ) was observed using 2.8 mg collagen/ml, 10 inH 2 O and hydrophilic membranes.

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Simulations of sieving characteristics of macromolecules in porous membranes at high concentrations

Cited by 4 publications

References 28 publications

Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Hindered diffusion of proteins and polymethacrylates in controlled-pore glass: An experimental approach

Development of a model for membrane filtration of long and flexible macromolecules: Application to predict dextran and linear DNA rejections in ultrafiltration

Optimizing collagen transport through track-etched nanopores

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