title: Design, Implementation, Simulation, and Visualization of a Highly Efficient RIM Microfluidic Mixer for Rapid Freeze-Quench of Biological Samples.
abstract: 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 submillisecond 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 (RIM) 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 a RFQ setup that involves copper wheels, show this new mixer can in practice provide reaction deadtimes as low as 100 microseconds.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208.
authors.forename: Bryan
authors.initials: B
authors.lastname: Schmidt
authors.forename: Goher
authors.initials: G
authors.lastname: Mahmud
authors.forename: Siowling
authors.initials: S
authors.lastname: Soh
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Taylor
authors.initials: T
authors.lastname: Page
authors.forename: Thomas V
authors.initials: TV
authors.lastname: O'Halloran
authors.forename: Bartosz A
authors.initials: BA
authors.lastname: Grzybowski
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hoffman