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.

The reorientation of poly(2-dimethylamino ethyl methacrylate) after environment stimuli improves hydrophilicity and resistance of protein adsorption

“…Poly(2-dimethylamino ethyl methacrylate) is a weak polyelectrolyte, whose degree of ionization can be switched at around neutral pH. PDMAEMA is a stimuli-responsive polymer; there is a conformation transition of PDMAEMA from stretched to shrunk states after changes of temperature, pH, and ionic strength in aqueous solutions [16][17][18][19][20][21]. PDMAEMA was able to condense the structure of plasmid DNA yielding polymer/plasmid complex, which has the highest transfection efficiency and cytotoxicity [19,20].…”

Directed Motion of Proteins along Tethered Polyelectrolytes

“…Very often, charged and uncharged polymers attached to surfaces are used to tune the interaction with proteins. Tethered chains of poly(ethylene oxide) are now widely used to prevent protein adsorption [7] while polyelectrolyte multilayers [8,9] or dense layers of polyelectrolytes [9][10][11] are utilized to immobilize proteins on surfaces.Despite numerous studies, little is known about the kinetics of protein adsorption and the self-organization of biomolecules with tethered polymer chains on a molecular level. Evidently, the kinetics of protein adsorption plays a major role in these processes [4,5,8,10 -13] and it is necessary to determine the position of the protein molecules on a molecular scale as a function of time.…”

“…Very often, charged and uncharged polymers attached to surfaces are used to tune the interaction with proteins. Tethered chains of poly(ethylene oxide) are now widely used to prevent protein adsorption [7] while polyelectrolyte multilayers [8,9] or dense layers of polyelectrolytes [9][10][11] are utilized to immobilize proteins on surfaces.…”

Effect of cosolvent on the phase behavior of binary and ternary mixture for the poly(2-dimethylaminoethyl methacrylate) in supercritical solvents

“…Particularly, research into the experimental data of methacrylate monomers in SCF solvents has been valuable for the chemical plant design by providing information on polymer processes and polymerization conditions [11,12]. Poly(2-dimethylaminoethyl methacrylate) [P(2-DMAEMA)] has numerous potential uses, including a nonviral gene delivery vector [13] in water purification [14] and in drug delivery [15], as well as a coating for soil-resistant surfaces [16] and for wettability of surfaces [17], and an ion exchange media for protein separation [18]. In addition, 2-dimethylaminoethyl methacrylate (2-DMAEMA) is used as a component of copolymers in the polymer industry, in coatings and in paper agents [19].…”