Dendritic Polyelectrolytes Research Articles

Tuning the Density Profile of Dendritic Polyelectrolytes

Using Monte Carlo simulations, we demonstrate that the shape of the intramolecular density profile of dendritic polyelectrolytes in solution can be tailored by varying the ionic strength of the solvent. Further, we find that a reversible transition between a “dense core” and a “dense shell” dendritic structure may be observed as the ionic strength is cycled from high to low. We present the necessary conditions in terms of salt concentration and various molecular variables such as generation number, spacer length, and number of charges, for realizing the potential of dendrimers as hosts in controlled-release and similar applications.

Ion-exchange displacement chromatography of proteins Dendritic polymers as novel displacers

While the ability to carry out simultaneous concentration and purification in a single displacement step has significant advantages for downstream processing of biopharmaceuticals, a major obstacle to the implementation of displacement chromatography has been the lack of appropriate displacer compounds. All protein displacement separations reported to date have employed relatively high-molecular-mass (> 2000) polyelectrolyte displacers. In this paper, results are presented on the discovery that low-molecular-mass dendritic polymers can be successfully employed as efficient displacers for protein purification in ion-exchange systems. Pentaerythritol-based dendritic polyelectrolytes ranging in molecular mass from 480 to 5100 were investigated as potential displacers for the purification of proteins in cation-exchange systems. The adsorption properties of these dendrimers were investigated using the steric mass action (SMA) model of non-linear ion-exchange chromatography. An analysis of the resulting SMA parameters using a dynamic affinity plot indicated that these dendrimers should have sufficient affinity to act as protein displacers. Displacement separations of protein mixtures in cation-exchange systems were carried out using zero-, first- and second-generation dendrimers. These experiments demonstrate that this new class of dendritic polyelectrolytes can indeed act as efficient protein displacers. The ability of a low-molecular-mass compound such as the “zero”-generation dendrimer ( M r 480) to displace proteins is very significant in that it represents a major departure from the conventional wisdom that large polyelectrolyte polymers are required to displace proteins in ion-exchange systems. In addition to the fundamental interest generated by low-molecular-mass displacers, it is likely that these displacers will have significant operational advantages as compared to large polyelectrolyte displacers.