Nguyen and Shklovskii explained that when the Ruxolitinib order surface charge of the particle is reduced by condensed oppositely charged polyions, the correlation-induced short-range attraction dominates the long-range electrostatic repulsion, leading to the cluster formation [52–54]. Close to the isoelectric point, such destabilization (and eventually the precipitation of the solid fraction) is observed [55]. However, symmetrically on both sides of the isoelectric point, the formation of long-lived, finite size aggregates overstays [56–58]. These aggregates have a size ranging from a few hundred nanometers to a few

microns, getting closer to the border of the ‘destabilization zone’. They form almost SB203580 supplier immediately when the polyelectrolyte is added to the colloidal suspension and then remain stable in time for

weeks, without showing any tendency toward further aggregation. Here, we presented complete experimental details and results of the electrostatic SN-38 clinical trial complexation between cationic homoPEs and negatively charged superparamagnetic iron oxide NPs. By using direct mixing method, we evidenced their ‘destabilization state’ at charges stoichiometry (isoelectric point) and ‘long-lived stable clusters state’ named arrested states apart of isoelectric point. Then, we applied the ‘desalting kinetic’ method to their complexation in the presence of an externally applied magnetic field (0.3 T). At isoelectric point, large and irregular aggregates with macroscopic sedimentation were obtained. Apart of isoelectric point (at arrested state), regular and elongated magnetic wires can be obtained. By tuning charges ratio, we can also select the overall surface charge (either positive or negative) of these magnetic wires. Moreover, we derive the probability distribution function of wire length and study their mechanisms of reorientations under the application of a magnetic field. The experimental observations lead us to the conclusion that the

wires formed with homoPEs are superparamagnetic as well as the wires made from polyelectrolyte-neutral block copolymers. Methods Building block materials The synthesis of the superparamagnetic NPs see more investigated here was elaborated by Massart et al. using the technique of ‘soft chemistry’ [59]. Based on the polycondensation of metallic salts in alkaline aqueous media, this technique resulted in the formation of magnetite (Fe3O4) NPs of sizes comprised between 4 and 15 nm. Magnetite crystallites were further oxidized into maghemite (γ-Fe2O3) and sorted according to their size. In the conditions of the synthesis (pH 1.8, weight concentration c ~ 10 wt.%), the magnetic dispersions were stabilized by electrostatic interactions arising from the native cationic charges at the surface of the particles.