Colloid particle and protein deposition — Electrokinetic studies

Controlling protein–particle adsorption by surface tailoring colloidal alumina particles with sulfonate groups

“…We assume that, at a given ionic strength and pH, the variation of zeta potential of particles after protein adsorption Df is a function of (i) h the degree of occupancy of the particle surface with the proteins, (ii) f part the particles' zeta potential and (iii) f prot the zeta potential of the protein, in line with previous studies [35,36,51].…”

“…Local positively and negatively charged regimes on the protein surface could be involved in the adsorption mechanism, although the net charge suggests an electrostatic repulsion according to Refs. [8,19,35]. However, the number of accessible ionizable groups and charge distributions may be slightly different if protein conformational changes occur in solution or in the adsorbed state [48].…”

“…An empirical approach to estimate the zeta potential of protein-particle complexes is the correlation between the degree of particle surface covered by proteins and the zeta potential of the particles and proteins separately [35,36]. This approach was employed to prove how surface functional groups and adsorbed proteins contribute to the zeta potential of protein-particle complexes.…”

Mechanism of immunoglobulin G adsorption on polystyrene microspheres

“…In the case where the charge density is known, the zeta potential can be calculated from the following equation [27,38]   However, for high ionic strength, a significant part of adsorbed IgG molecules is located above the shear plane, which is in accordance with the assumptions of the threedimensionalelectrokinetic (3D) model developed in Refs. [38,41].…”

“…In each case,the zeta potential increases with the IgG coverage and As previously done for fibrinogen [26,27] and rHSA [28], the experimental datapresented in Fig. 3 were interpreted in terms of the mean-field Gouy-Chapman model and the three-dimensional (3D) model.According to the GC model,the net charge density of the latex covered by IgG can be calculated from the formula [31,37,38] σ= σ 0 + q e (Av/M w ) Γ…”