@article {1225,
	title = {Entropic interaction chromatography: Separating proteins on the basis of size using end-grafted polymer brushes},
	journal = {Biotechnology and Bioengineering},
	volume = {90},
	number = {1},
	year = {2005},
	note = {ISI Document Delivery No.: 909ETTimes Cited: 9Cited Reference Count: 48},
	month = {Apr},
	pages = {1-13},
	type = {Article},
	abstract = {Partitioning of a macromolecule into the interfacial volume occupied by a grafted polymer brush decreases the configurational entropy (Delta S(c)brush) of the terminally attached linear polymer chains due to a loss of free volume. Self-consistent field theory (SCF) calculations are used to show that Delta S(c)brush is a strong function of both the size (MW,) of the partitioning macromolecule and the depth of penetration into the brush volume. We further demonstrate that the strong dependence of Delta S(c)brush on MW, provides a novel and powerful platform, which we call entropic interaction chromatography (EIC), for efficiently separating mixtures of proteins on the basis of size. Two EIC columns, differing primarily in polymer grafting density, were prepared by growing a brush of poly(methoxyethyl acrylamide) chains on the surface of a widepore (1,000-angstrom pores, 64-mu m diameter rigid beads) resin (Toyopearl AF-650M) bearing surface aldehyde groups. Semipreparative 0.1-L columns packed with either EIC resin provide reduced-plate heights of 2 or less for efficient separation of globular protein mixtures over at least three molecular-weight decades. Protein partitioning within these wide-pore EIC columns is shown to be effectively modeled as a thermodynamically controlled process, allowing partition coefficients (K-p) and elution chromatograms to be accurately predicted using a column model that combines SCF calculation of Kp values with an equilibrium-dispersion type model of solute transport through the column. This model is used to explore the dependence of column separation efficiency on brush properties, predicting that optimal separation of proteins over a broad MW, range is achieved at low to moderate grafting densities and intermediate chain lengths. (c) 2005 Wiley Periodicals, Inc.},
	keywords = {ADSORPTION, CHAIN MOLECULES, CONSISTENT-FIELD THEORY, entropic interaction chromatography, equilibrium dispersion, EXCLUSION CHROMATOGRAPHY, GEL FILTRATION, grafted polymer brush, HUMAN SERUM-ALBUMIN, LIQUID-CHROMATOGRAPHY, MODEL, MOLECULAR-WEIGHT, MONTE-CARLO, protein purification, size exclusion chromatography, STATISTICAL-THEORY},
	isbn = {0006-3592},
	url = {<Go to ISI>://000227843800001},
	author = {Pang, P. and Koska, J. and Coad, B. R. and Brooks, D. E. and Haynes, C. A.}
}
@article {3703,
	title = {Interfacial thickness of liposomes containing poly(ethylene glycol)-cholesterol from electrophoresis},
	journal = {Biophysical Journal},
	volume = {70},
	number = {1},
	year = {1996},
	note = {ISI Document Delivery No.: TY683Times Cited: 29Cited Reference Count: 33},
	month = {Jan},
	pages = {313-320},
	type = {Article},
	abstract = {The electrophoretic mobilities of liposomes incorporating a polyethylene glycol (PEG) headgroup coupled to cholesterol for PEG of average chain index 3.0, 13.2, and 22.3 have been determined as a function of PEG-cholesterol mole fraction between 5\% and 40\% and ionic strength between 2 and 200 mM. The liposome compositions were 40 mole \% cholesterol plus PEG-cholesterol, 10 mole \% 1,2-dipalmitoyl-sn-glyerco-3-phosphoglycerol and 50 mole \% egg phosphatidylcholine. The mobilities were fit to a model in which the PEG forms a surface layer of polymer subject to viscous drag arising I from electroosmotic flow within this layer. The model provides estimates of the average layer thickness that are comparable to those determined from contemporary models of surface-attached polymer.},
	keywords = {CELLS, CHAINS, grafted polymer brush, mobility, PARTICLES},
	isbn = {0006-3495},
	url = {<Go to ISI>://A1996TY68300026},
	author = {Janzen, J. and Song, X. and Brooks, D. E.}
}
