Microfluidic chip for rapid mixing and uniform distribution of multiple reagents using commercial pipettes

Abstract

The mixing and distribution of reagents are fundamental processes in most biochemical experiments; however, they can be time-consuming when they are executed with manual pipettes, the efficiency of the process majorly depends on the experience of the user. This study developed an integrated microfluidic chip to improve the efficiency of mixing and distribution of multiple reagents and reduce the risk of cross-contamination in cases where reagents would be manipulated using manual pipettes. The proposed microfluidic chip is able to mix multiple reagents rapidly and distribute them with a high degree of uniformity, and it integrates four major components: a pipette connector, a reagent storage reservoir, a micromixer, and a reagent distributor. The micro-scale features of the functional components are not planar structures; therefore, four different manufacturing methods are required for fabrication, including additive manufacturing, micromilling, epoxy casting, and PDMS casting. Sixty experiments using liquid food dyes were conducted to characterize the performance of the integrated microfluidic chip. Experiment results demonstrate the effectiveness of the proposed device in the mixing and distribution of multiple reagents with minimal pipette operations. Overall mixing performance after distribution is 97.41% with a standard deviation of 0.19%, uniformity in the distribution of daughter plugs is 9.07%, and the overall reagent loss is 8.2%.