Synthesis of porous zwitterionic sulfobetaine monoliths and characterization of their interaction with proteins

New synthesis routes for incorporation of zwitterionic sulfobetaine groups into porous polymeric monoliths have been developed. The first approach inv olved photoinitiated copolymerization of N,N-dimethyl-N-methacryloxyethyl-N -(3-(sulfopropyl)ammonium betaine (SPE) and ethylene dimethacrylate. (EDMA) as cross-linker. Alternatively, the internal surfaces of porous poly(trime thylolpropane trimethacrylate) (poly-TRIM) monoliths were provided with zwi tterionic "combs" by thermally initiated grafting of poly-SPE chains. The g rafted monoliths exhibited an electrolyte responsive flow permeability, whe reas the permeability of the copolymerized monoliths was unaffected by chan ges in ionic strength in the interval tested. Both synthesis routes yielded polymers capable of interacting reversibly with proteins in aqueous soluti ons, thus paving the way for novel selectivity dimensions in the field of b ioseparations. This report also reveals the possibility of modulating the p rotein-polymer interaction strengths over a wide range on monolithic zwitte rionic sorbents, by addition of low concentrations of a chaotropic ion to t he aqueous phase.