Enhancement in mixing efficiency by ridges in straight and meander microchannels

Abstract We present an analysis of the effect of incorporating ridges in straight and meander shaped pressure-driven Y-type micromixers. Triangular and rectangular ridges were incorporated on the inner walls of straight and meandered microfluidic channels, and their effect on mixing was evaluated. The incorporation of ridges greatly enhances mixing in the flow path due to strong laminar perturbations. Also, the effect of the geometry of ridges and their arrangement pattern in the microchannel was studied extensively. Incorporation of ridges in the microchannels resulted in enhanced performance of the mixer in terms of reduction in mixing time and length. Meander channels with ridges provided greater than 90% mixing in less than 2 mm, whereas straight channels with ridges required a mixing length of 10 mm. The optimum design was fabricated using direct-laser write photolithography followed by soft lithography. The performance of the micromixer was validated using coloured solutions and biosensors. The micromixer is compact, simple in fabrication and operation, and easy-to-integrate with other microfluidic components enabling them for real-time applications. Its scope for the development of microfluidic devices where mixing is crucial has been demonstrated using glucose biosensors.