Structural Evolution of an Interpolyelectrolyte Complex of Charged Dendrimers Interacting with Poly(l-glutamate)

Abstract

The size and molecular mass of water-soluble interpolyelectrolyte complex (PEC) formed between poly(l-glutamate) and poly(amido amine) dendrimer in aqueous solution were estimated as a function of the decreasing pH from the turbidities (τ) and their wavelength dependence, by comparison with numerical τ calculations by applying the Rayleigh−Debye−Gans and Mie scattering theories. Close to the pK a of the peripheral amino groups of the dendrimer, PECs with densities comparable to that of fractal clusters from a reaction limited colloid aggregation process collapsed to dense particles with ∼1 μm diameter. At a pH close to the pK a of the amino groups in the interior of the dendrimer, systems with carboxylate excess over amino/ammonium groups formed compact particles, and ion pairing likely extended to the ammonium groups in the dendrimer interior. PECs with the highest polymer density were formed at the stoichiometric ratio: They appeared to be stable against dissociation at pH 3 in contrast to PECs formed with high dendrimer excess.

Bioinspired control of colloidal silica in vitro by dual polymeric assemblies of zwitterionic phosphomethylated chitosan and polycations or polyanions

“…In contrast, literature reports show that small molecules with functional groups possessing cationic charge, such as proline, lysine, aspartate and serine, exert some, albeit minor, catalytic effect on silicic acid condensation [97]. Amine-terminated PAMAM dendrimers at low dosages (40 ppm is the optimum) stabilize silicic acid, but at the same time, due to their cationic charge from protonated surface amine groups at pH 7 [98,99], interact with anionic colloidal silica particles (originating from the inability of the dendrimer to achieve quantitative inhibition) to form PAMAM-SiO 2 composite precipitates. The propensity of the dendrimeric inhibitor to be entrapped within the silica 3D matrix is alleviated by addition of anionic polyelectrolytes (e.g.…”

Effects of topology and size on statics and dynamics of complexes of hyperbranched polymers with linear polyelectrolytes

“…Complex formation involving a polyelectrolyte and a macroion ͑e.g., between proteins and DNA or between colloidal particles and synthetic polyelectrolytes͒ is a usual phenomenon in living matter and plays a significant role in several novel nanoscale applications. 1 Recently, the ability of HPs to form complexes with DNA and other biological molecules has been experimentally and computationally explored, [2][3][4] and they were recognized as promising systems for targeted gene transfer. 3,5 Complexes formed by HP molecules and linear synthetic polyelectrolytes demonstrated their capacity to act as solubility enhancer, cytotoxicity reducer, and stabilizer against the enzymatic degradation agents for drug delivery purposes.…”

The Structure of Dendrimers with Charged Terminal Groups: Monte Carlo Simulations

“…Some examples of their use include lithographic materials, nanoscale catalysts, drug delivery systems, rheology modifiers, bioadhesives, and magnetic resonance imaging (MRI) contrast agents [3]. Though experimental studies [4][5][6][7][8][9], theory and simulations [10][11][12][13][14] have already brought about some insight into the way charged dendrimers react to various conditions, the research on them is far from being completed. For instance, the number of simulation papers is still very limited and some predictions reported in them contrast with experimental results.…”