(167e) Numerical Simulations of Electrokinetically-Driven Capture of Viral Particles inside Media of High Ionic Strength

The increasing frequency of virus-related disease outbreaks creates a growing need for methods that permit rapid detection of infectious biological agents, such as viruses, within small sample volumes and without amplification of the agent. The ability of dielectrophoretic and AC electrohydrodynamic forces to cause accelerated capture of viral particles on microelectrode platforms has been recently demonstrated. The present study is concerned with the modeling and simulation of the phenomena that govern viral transport to, and capture on, a microelectrode surface inside media of physiological ionic strength under the influence of a spatially non-uniform AC electric field. Computer simulations that probe the effects of various system parameters, including applied voltage, frequency, medium conductivity and permittivity and electrode spacing are studied. More specifically, the effect of the above parameters on the resulting flow patterns (fluid streaming), dielectrophoretic force, temperature profile and particle capture time are assessed by using a finite element method-based simulation package (COMSOL Multiphysics®). The magnitude of dielectrophoretic and other forces acting on a virus particle is calculated at various conditions and a range of parameters that leads to effective particle trapping is identified. The calculations show that the time scales associated with the transport and capture of viral particles when a non-uniform AC field is used are smaller by at least one order of magnitude when compared with those corresponding to a diffusion-limited system. The validity of the computer simulations is confirmed through experiments involving electrokinetically-directed capture of fluorescent sub-micron latex beads under the same conditions.