title: High capacity, charge-selective protein uptake by polyelectrolyte brushes.
abstract: Surface plasmon resonance was used to measure binding of proteins from solution to poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes end-grafted from gold surfaces by atom transfer radical polymerization (ATRP). PDMAEMA brushes were prepared with a variety of grafting densities and degrees of polymerization. These brushes displayed charge selective protein uptake. The extent of uptake for net negatively charged bovine serum albumin (BSA) scaled linearly with the surface mass concentration of grafted PDMAEMA, regardless of grafting density. BSA was bound at a constant ratio of 120 DMAEMA monomer units per protein molecule for all brushes examined. The equivalent three-dimensional concentration of BSA bound in the brush (i.e., the bound BSA surface excess concentration divided by the brush thickness) decreased monotonically with decreasing grafting density. The concentration of BSA bound within brushes prepared at higher grafting densities was comparable with the aqueous protein solubility limit. BSA desorption from the brush required changes in solution pH and/or ionic strength to eliminate its net electrostatic attraction to PDMAEMA. Net positively charged lysozyme was completely rejected by the PDMAEMA brushes.
authors.affiliation: Department of Chemical Engineering, Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Andy
authors.initials: A
authors.lastname: Kusumo
authors.forename: Lindsay
authors.initials: L
authors.lastname: Bombalski
authors.forename: Qiao
authors.initials: Q
authors.lastname: Lin
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Matyjaszewski
authors.forename: James W
authors.initials: JW
authors.lastname: Schneider
authors.forename: Robert D
authors.initials: RD
authors.lastname: Tilton
mesh_terms: D000818:Animals; D002417:Cattle; D002627:Chemistry, Physical / Q000379:methods; D004573:Electrolytes / Q000737:chemistry*; D006046:Gold; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008689:Methacrylates / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry; D009757:Nylons / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D055672:Static Electricity; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D007477:Ions; D008689:Methacrylates; D009757:Nylons; D011108:Polymers; D011506:Proteins; C407037:poly(2-(dimethylamino)ethyl methacrylate); D012710:Serum Albumin, Bovine; D006046:Gold; D009113:Muramidase