Generalized numerical model for the simulation of electrophoretic methods in microfluidic chips

Abstract

Electrophoretic methods are separation techniques based on the mobility of ions under the action of an external electric field. These techniques, which are widely used in chemical and biochemical analysis, have been miniaturized in the last years and now represent one of the most important applications of the lab-on-a-chip technology. In this work, a generalized numerical model of electrophoresis on microfluidic devices is presented. The model is based on the set of equations that governs electrical phenomena (Poisson equation), fluid dynamics (Navier-Stokes equations), mass transport (Nerst-Planck equation) and chemical reactions. The model is said to be generalized because it covers different techniques such as capillary eletrophoresis and isoelectric focusing, and allows to simulate processes involving multiple analytes and complex electrolytes buffers. Moreover, the relationship between the buffer characteristics (ionic strength, pH) and physicochemical properties of channel walls is taken into consideration. The numerical simulation is carried out by using PETSC-FEM (Portable, Extensible Toolkit for Scientific Computation - Finite Elements Method), in a Python environment developed at CIMEC using high performance parallel computing and solving techniques based on domain decomposition methods. Finally, examples of interest involving electrophoresis on chips are considered as study cases.