Neutral Coatings for the Study of Polycation/Multicharged Anion Interactions by Capillary Electrophoresis: Application to Dendrigraft Poly-l-lysines with Negatively Multicharged Molecules

Abstract

The study of interactions between oppositely multicharged (macro)molecules remains a challenging issue. In frontal analysis capillary electrophoresis (FACE), it is difficult to avoid the adsorption of one of the interacting partners onto the capillary wall. In this work, we demonstrate the possibility to use FACE and affinity capillary electrophoresis (ACE) on a neutrally coated capillary for the study of interactions between a polycationic dendrigraft (or linear) poly-l-lysines, on one hand, and a multicharged anionic biomolecule (adenosine monophosphate, AMP, or adenosine triphosphate, ATP), on the other hand. A systematic comparison of four different neutral coatings (hydroxypropyl cellulose, polydimethylacrylamide, polyacrylamide, polyethylene glycol) has been performed based on the repeatability of the electrophoretic migration of the dendrigraft poly-l-lysines at pH close to neutrality. Both FACE and ACE methodogies were then used to study the interactions and to get the association constants and the stoichiometry of the complex. Multisite interactions, with two classes of independent sites, were determined. The specificity of the dendritic polylysine structure compared with linear polylysine in the interaction with ATP or AMP is also emphasized.

Layer-by-layer assembled hydrophobic coatings for cellulose nanofibril films and textiles, made of polylysine and natural wax particles

“…It was previously reported that adsorption of PLL on various substrates is controlled by the balance of electrostatic and nonelectrostatic interactions (Choi et al, 2015). In the current work, the adsorption was most likely driven by the entropy gain due to release of counterions during adsorption of oppositely charged components, but hydrophobic interactions between PLL and wax particles may have also played a role (Choi et al, 2015;Zou, Oukacine, Le Saux, & Cottet, 2010). Upon rinsing with water, a slight decrease in sensed mass of PLL was observed, likely deriving from the removal of some loosely bound molecules.…”

Pressure‐assisted capillary electrophoresis frontal analysis for faster binding constant determination

“…However, the adsorption of the interacting species on the capillary wall has been identified as a major concern . To overcome this problem, CE‐FA in capillary with a neutral coating has been developed . Since there is a very weak or none existing EOF in a neutral coated capillary, it is impossible to let all interacting species migrate with only an electrical potential applied to the capillary.…”

Evaluation of three neutral capillary coatings for the determination of analyte-cyclodextrin binding constants by affinity capillary electrophoresis. Application to N , N ⿲-disubstituted piperazine derivatives.

“…Among the neutral polymers, four have proven their high efficiency to coat the capillary and then to avoid protein adsorption: the cellulose derivatives, the polyvinylalcohol (PVA), the polyethylene oxide (PEO) and the acrylamide-based polymers [27,28] or copolymers [29]. We chose to study the performance of a covalently-linked HPC capillary, previously used in our laboratory [30], and two physically adsorbed coated capillaries using PEO and PDMA.…”