Interfacial behavior of RNA-free MS2 bacteriophage particles
The effect of genomic material on the effective surface charge a viral capsid was investigated in this study. The RNA of bacteriophage MS2 was removed and the empty capsid characterized and compared to intact MS2. Transmission electron microscopy was used to ensure that the MS2 capsid was intact and RNA removed. Electrophoretic mobility, aggregation kinetics and kinetics of deposition on silica surface were studied for these two nanoparticles. The isoelectric point of MS2 and RNA-free MS2 were found to be 3.4 and 3.2 respectively, found by varying pH at a constant ionic strength. The electrophoretic softness, found by varying ionic strength and constant pH, found that MS2 was 2.1 nm and that RNA-free MS2 was 1.6 nm, a slightly harder particle. Electrophoretic mobility results of these two particles are similar in solution containing Na+ or Ca2+ or Mg2+ up to ionic strength of 600 mM. Similar aggregation kinetics of MS2 and RNA-free MS2 measured by time-resolved dynamic light scattering at increasing ionic strengths of Na+, Ca2+ and Mg2+ cations were observed. No significant aggregation was observed for both types of particles in solutions containing up to 600 mM NaCl. Insignificant aggregation at high ionic strength suggests an important role of steric repulsion. Using a Quartz Crystal Microbalance, RNA-free MS2 attachment efficiency was found to be higher than MS2. This can be explained by more steric repulsion by the untreated MS2 particles. Similarity in electrophoretic mobility and aggregation of these two particles suggest that for non-magnetic nanoparticles, surface properties are dominant.
Aggregation kinetics, Aquatic system, Bacteriophage MS2, Deposition Kinetics, Divalent Salt, Electrostatic interactions, Empty Capsid, Monovalent Salt, Negative charge, Steric repulsion, Time-resolved dynamics
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign