Evidences of Changes in Surface Electrostatic Charge Distribution during Stabilization of HPV16 Virus-Like Particles

Abstract

The stabilization of human papillomavirus type 16 virus-like particles has been examined by means of different techniques including dynamic and static light scattering, transmission electron microscopy and electrophoretic mobility. All these techniques provide different and often complementary perspectives about the aggregation process and generation of stabilized virus-like particles after a period of time of 48 hours at a temperature of 298 K. Interestingly, static light scattering results point towards a clear colloidal instability in the initial systems, as suggested by a negative value of the second virial coefficient. This is likely related to small repulsive electrostatic interactions among the particles, and in agreement with relatively small absolute values of the electrophoretic mobility and, hence, of the net surface charges. At this initial stage the small repulsive interactions are not able to compensate binding interactions, which tend to aggregate the particles. As time proceeds, an increase of the size of the particles is accompanied by strong increases, in absolute values, of the electrophoretic mobility and net surface charge, suggesting enhanced repulsive electrostatic interactions and, consequently, a stabilized colloidal system. These results show that electrophoretic mobility is a useful methodology that can be applied to screen the stabilization factors for virus-like particles during vaccine development.

Hydrodynamic and Electrophoretic Properties of Trastuzumab/HER2 Extracellular Domain Complexes as Revealed by Experimental Techniques and Computational Simulations

“…Other experimental details concerning size exclusion chromatography (SEC), dynamic light scattering (DLS) and electrophoretic mobility (EM) were reported in our previous articles [ 21 , 35 ]. For the sake of clarity, a brief resume taken from reference 35 is given in what follows:…”

“…Interesting reviews about the results were published by Harding [ 14 , 15 ]. It is well known that the hydrodynamics of proteins may be altered by ligands [ 16 ], phospholipids [ 17 ], polyelectrolytes [ 18 ] and by the formation of both complexes [ 19 , 20 ] and assemblies [ 21 ]. The importance of protein hydrodynamics is also especially interesting in the field of biotechnology.…”

Hydrodynamic and electrophoretic properties of Trastuzumab/HER2 complexes. Experiments and modeling.

“…The TZM Herceptin © (stock solution at 21 mgml -1 ) was kindly provided by one Experimental details concerning size exclusion chromatography (SEC), dynamic light scattering (DLS) and electrophoretic mobility (EM) were reported in our previous articles (21,35). The sample concentration in both SEC and EM measurements were 1-3 mg·ml -1 .…”

“…It is well known that the hydrodynamics of proteins may be altered by ligands (16), phospholipids (17), polyelectrolites (18) and by the formation of both complexes (19) , (20) and assemblies (21). The importance of protein hydrodynamics is also especially interesting in the field of biotechnology.…”

Theoretical Analysis of the Induction of Forced Resonance Mechanical Oscillations to Virus Particles by Microwave Irradiation:Prospects as an Anti-virus Modality

“…Also, Elasticity Theory methods applied to draw conclusions on the mechanical properties of virus particles 4 . Electric charge distributions of virus have been also studied by several researchers 5,6,7,8,9 . It is observed that under physiological conditions of salinity and acidity, virus capsid assembly requires the presence of genomic material that is oppositely charged to the core proteins 10 .…”