Integrated microfluidic system for efficient DNA extraction using on-disk magnetic stirrer micromixer

Abstract

Micromixers are essential microfluidic modules for fabricating integrated lab-on-chip devices for point-of-care applications. Ease of fabrication and integration with other fluidic modules, practicability for different viscosities of the solutions, and high mixing efficiencies are the most important characteristics of a suitable micromixer. In this study, a magnetic stirrer on a rotating micro-structured disk is presented to mix liquids of a wide range of viscosities (up to 42 mPa.s) in low rotational velocities (less than 600 rpm). The concept relies on implementing a small stainless steel rotor aligned on a circular chamber and actuating that by stationary magnets located on the lab frame. The on-disk magnetic stirrer can be implemented in integrated microfluidic platforms without affecting other modules, e.g., valves, to rapidly prepare a homogenous solution in less than 2 s. Moreover, high mixing indexes and the considerable viscous stresses generated in solutions make this approach a convenient choice for the cell lysis process. Observations show that DNA yields in the order of 100 ± 15% relative to conventional lysis protocols can be achieved when the stirrer spins at 200 rpm for 1 min