Ampholytic ion-exchange materials coated with small zwitterions for high-efficacy purification of ionizable soluble biomacromolecules.

Abstract For the purification of soluble proteins and nucleic acids through ion-exchange, the ampholytic ion-exchange materials (AIEMs) were designed, which possessed both short aliphatic carboxyl and short aliphatic amines/imidazole at optimized ratios on solid supports coated with high density of small zwitterions; under optimized conditions, the soluble ionizable biomacromolecules were adsorbed on those AIEMs via electrostatic attractions and eluted effectively through electrostatic repulsions. As the proof-of-concept, magnetic submicron particles bearing short aliphatic carboxyl and the coats of small zwitterion served as the starting solid supports, which were conjugated with lysine alone, or with lysine plus glycine or N , N ‑dimethylethylenediamine, to yield magnetic AIEMs whose surfaces possessed zero net charges at different pH. Such magnetic AIEMs exhibited ideal efficacy to release acid red 13 as an anion at the elution pH optimized for strong electrostatic repulsions; those magnetic AIEMs were proven absorbing under optimized conditions for the purification of soluble proteins stable at pH close to their isoelectric points and solid-phase extraction of nucleic acids in applicable biological mixtures. Therefore, the designed AIEMs are promising for the high-efficacy purification of ionizable soluble biomacromolecules. [ABSTRACT FROM AUTHOR]