A Novel In-Plane Microfluidic Mixer Using Vortex Pumps for Fluidic Discretization

Anovel in-plane microfluidic mixer based on fluidic discretization using vortex micropumps integrated in an optically transparent microfluidic substrate is presented in this article. The design, fabrication, simulation, and experimental results are described of this integrated micromixer. The basic working principle of the discretized fluidic mixer is to manipulate fluids as discretized volumes and inject them to an expansion chamber. Due to increase interfacial surface area of the discretized fluid “chunks,” the diffusion between these fluids can be completed in a shorter time, and the fluids can be mixed instantly without additional external energy. A numerical simulation was performed to emulate the flow field and mixing phenomenon to understand the results obtained by various flow experiments. Experimental results of discretized mixing have been successfully shown to have almost an ideal mixing performance and shown reasonably good match with the simulation results. Moreover, a dimensionless governing parameter (mixing index) was used to estimate the mixing performance in our system. This parameter is shown to be useful for the design and analyses of discretized mixing systems. Because this discretized mixing system requires simple mechanical structures, it provides flexibility for integrate with other microfluidic components. Also, optically transparent and biocompatible material was used to fabricate the microfluidic system, hence this micromixing system could be used to develop future fully automated biomedical and chemical “lab-on-chip” systems.