Philippe Cros

Adsorption of oligonucleotides onto negatively and positively charged latex particles

Adsorption behavior has been investigated with an oligonucleotide consisting of 27 nucleotides in the presence of anionic or cationic polystyrene latex particles and at pH between 4 and 9. The combined effects of electrical interactions and charge balance on the amount of adsorbed oligonucleotide were also examined. It was found that the negatively charged oligonucleotides were considerably more adsorbed onto the cationic latex than onto the anionic one; moreover, for both latexes, the affinity decreases on increasing the pH. The results were explained by the effect of charge balance on the accessibility of the oligonucleotide at the particle surface.

Characterization of the Grafting Reaction Between Oligodeoxyribonucleotides and N-Vinyl Pyrrolidone /N-Acryloxy Succinimide Copolymers by Size Exclusion Chromatography and Free Solution Capillary Electrophoresis

Abstract The grafting reaction of oligodeoxyribonucleotides (ODN) on N-vinyl pyrrolidone (NVP)/N-acryloxy succinimide (NAS) copolymers has been investigated. First, NVP/NAS copolymers were prepared by free-radical polymerization in N,N-dimethylformamide (DMF); characterization of the monomer sequence distribution by 13C NMR suggested a strongly alternating structure. Low-conversion copolymers were synthesized using azeotropic composition (60% molar NAS) and various overall monomer concentrations. These model copolymers were characterized by light scattering and viscosity measurements in a DMF-water (90/10 volume ratio) mixture. The covalent attachment of ODN (constituted of 20 bases terminated with a primary amine linker) onto one selected copolymer (60% molar NAS) was then examined. Size exclusion chromatography (SEC) and free solution capillary electrophoresis (FSCE) were performed in order to analyse the reaction products and to calculate the yield of grafting. After optimization of the immobilization ...