Fast Characterization of Polyplexes by Taylor Dispersion Analysis

Abstract

In a single procedure, Taylor dispersion analysis (TDA) was used for the size characterization of polyplexes and the quantification of free polycation contained in excess within the polyplex sample. TDA analysis was carried out in frontal mode for a better sensitivity of detection. The proof of concept was established using a model polyplex generated from the mixture of linear polylysine (DP 20) and DNA from salmon testes at nitrogen to phosphate (N/P) ratio of 12. Polyplex hydrodynamic radius was compared to the values obtained by dynamic light scattering measurements. TDA was found to give access to the weight-average hydrodynamic radius, while DLS basically gives an intensityaverage (harmonic z-average) value. The method was next applied to the study of various polyplexes issued from polylysines of various DP (50, 100) and different topologies (dendrigraft polylysines of generation 2 and 3). This new methodology should greatly contribute to the physicochemical characterization of polyplexes used for gene transfection.

Hydrodynamic size characterization of a self-emulsifying lipid pharmaceutical excipient by Taylor dispersion analysis with fluorescent detection

“…This means that, at least for these Labrasol samples, the kinetics of exchange of the hydrophobic marker between the droplets of different size is very fast compared to the average elution time (few min). Of course, in the case of slow kinetics, elution profile corresponding to the superposition of two Gaussian peaks (for plug mode) or two erf functions would be obtained, as previously observed for bimodal mixture (Cottet et al, 2010;Leclercq et al, 2015).…”

Supramolecular Self‐Assembly of DNA with a Cationic Polythiophene: From Polyplexes to Fibers

“…TDA is based on the analysis of band broadening under a laminar Poiseuille flow in an open tube. In the case of polycation mixtures, TDA give access to the weight‐average hydrodynamic radius ( R h ) of the polyplex, and to the free polycation concentration at equilibrium in the mixture . Figure displays the taylorgram obtained for salmon DNA ( sDNA ) and P3HT‐PMe 3 polyplex (N/P=12 molar ratio) in frontal mode (continuous injection of the equilibrated mixture in the capillary).…”

“…In the case of polycation mixtures, TDA give access to the weightaverage hydrodynamic radius (R h ) [13] of the polyplex, and to the free polycation concentration at equilibrium in the mixture. [14] Figure 1 displays the taylorgram obtained for salmon DNA (sDNA) and P3HT-PMe 3 polyplex (N/P = 12 molar ratio) in frontal mode (continuous injection of the equilibrated mixture in the capillary). The taylorgram is the combination of two erf contributions (see experimental part): one pertaining to the free polycation in solution, and the other belonging to the polyplex.…”

Antigen-Adjuvant Interactions in Vaccines by Taylor Dispersion Analysis: Size Characterization and Binding Parameters

“…In the case of mixtures composed of two populations of different sizes, which are both stable at the time scale of the analysis, TDA signal is the sum of two Gaussian peaks. The fitting of the elution profile allows to get the hydrodynamic radius of the two individual populations constituting the mixture and their relative proportions 20,21 . The access to the free ligand proportion allows to determine the isotherm of adsorption, and by curve fitting, the parameters of interaction (intrinsic binding constant and stoichiometry of interaction) 22 .…”

“…From the elution profile, it is possible to determine the molecular diffusion coefficient ( D ) and therefore the hydrodynamic radius ( R h ) of solutes ranging from angstroms to submicrons. , In the case of mixtures composed of two populations of different sizes, which are both stable at the time scale of the analysis, TDA signal is the sum of two Gaussian peaks. The fitting of the elution profile allows one to get the hydrodynamic radius of the two individual populations constituting the mixture and their relative proportions. , The access to the free ligand proportion allows one to determine the isotherm of adsorption and, by curve fitting, the parameters of interaction (intrinsic binding constant and stoichiometry of interaction) . TDA can also be used to study substrate/ligand interactions at equilibrium, when the two entities in the interaction are in fast exchange at the time scale of the analysis.…”