An analysis of electric fields developed inside microchannels of microfluidic devices

An analysis of electric fields inside microchannels of microfluidic (MF) devices is reported in this paper. Microchannel-based MF devices using electric fields are of recent research interest for various purposes, including on-chip manipulation of biological elements (cell, DNA, proteins and other macromolecules). To determine electric field strengths inside the microchannels of such devices, the uniform electric field equation (eg. E = deltaV/deltal) is commonly used. However, this can lead to a significant estimation error, especially for smaller dimensions of the microchannel, which is the future trend. Finite element method (FEM) analysis should be performed for such smaller dimensions. However, this method is time consuming and computationally expensive, particularly during design phases, as there exist many unbound parameters. In this paper, analytical expressions to determine electric fields and other parameters of interest are developed for a simplistic model, and then compared the FEM simulation results to that of MF devices for a range of microchannel dimensions. The results show that significant estimation errors can occur. For example, more than 10% overestimation of electric field results in microchannel lengths smaller than 2.5 mm. The analysis and graphs can aid MF device designers during design phases.