Efficient micromixing of a highly viscous biosample with water using orbital shaking and microchannels.

Micromixing of a highly viscous biosample with water using orbital shaking and microchannels is considered. Existing methods mix biosamples by only shaking microwells or by specially designed microstirrers which are ineffective or inapplicable for highly viscous materials, let alone small volumes at microliter or nanoliter levels. Our method mixes a viscous biosample with water in microwells using orbital shaking plus an innovative block which divides the microwells into two compartments and is built in with microchannels. The mixing method with the block in the microwell is efficient compared to mixing in the microwell without the block. In this paper, the design of the block is presented, the model of the flow of the biosamples in the microchannel is developed, the Reynolds number of the flow in the microchannel is calculated, and the dynamics of the mixing process is analyzed. Furthermore, a miniature wireless video sensor system is used to observe the mixing process which verifies the model of the flow in the analysis. Finally, x-ray diffraction experiments on mixing monoolein with water are presented. In each trial, x-ray diffraction is used to evaluate the results of mixing which confirms that the proposed approach is effective for mixing a highly viscous biosample with water.