Design, Implementation, Simulation, and Visualization of a Highly Efficient RIM Microfluidic Mixer for Rapid Freeze-Quench of Biological Samples
Rapid freeze-quench (RFQ) trapping of short-lived reaction intermediates for spectroscopic study plays an important role in the characterization of biological reactions. Recently, there has been considerable effort to achieve sub-millisecond reaction deadtimes. We present here a new, robust, high-velocity microfluidic mixer that enables such rapid freeze-quenching. It is a based on the mixing method of two impinging jets commonly used in reaction injection molding of plastics. This method achieves efficient mixing by inducing chaotic flow at relatively low Reynolds numbers (Re = 140). We present the first mathematical simulation and microscopic visualization of mixing in such RFQ micromixers, the results of which show that the impinging solutions efficiently mix within the mixing chamber. These tests, along with a practical demonstration in an RFQ setup that involves copper wheels, show that this new mixer can in practice provide reaction deadtimes as low as 100 µs.
KeywordsReynolds Number Electron Paramagnetic Resonance Outlet Channel Freezing Time Inlet Stream
This work was supported by the National Institutes of Health (HL13531, BMH; GM54111, TVO’H), and the Non-Equilibrium Energy Research Center (BG).
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