Method for strengthening micro-mixing by using low-frequency intermittent magnetic fields in microchannel

Abstract

The invention discloses a method for strengthening micro-mixing by using low-frequency intermittent magnetic fields in a microchannel. The method comprises the following steps: processing a tiny soft magnet array on a side wall surface of the microchannel; injecting two strands of fluid into the microchannel, wherein the two strands of fluid are same in initial velocity and flow, and the two strands of fluid are a superparamagnetic bead containing suspension and a biochemical sample solution; exerting an intermittent uniform magnetic field on the outside of a chip, so that a soft magnet generates a new magnetic field under the excitation of the external uniform magnetic field. Because of the mutual superposition of magnetic fields generated by the magnets in the soft magnet array and the superposition of external magnetic fields, a magnetic force exerted on magnetic beads in the microchannel presents a positive-negative alternate space change along the axis direction of the microchannel, the magnetic force presenting a positive-negative alternate space change is sporadic with the external intermittent magnetic field so as to induce the magnetic beads in the microchannel to carry out a transverse motion and an axial motion which occur alternately, and the motions of the magnetic beads disturb the laminar flow in the microchannel, thereby achieving the purpose of strengthening micro-mixing.

Description

technical field [0001] The invention relates to a method in the technical field of microelectronics, in particular to a method for enhancing the micro-mixing effect by exciting an integrated soft magnet array on a microfluidic chip through a low-frequency intermittent magnetic field. Background technique [0002] With the rapid development of science and technology, micro-nano technology has rapidly penetrated into various disciplines, and due to the interdisciplinary development of multiple disciplines, emerging cutting-edge scientific and technological fields have emerged. Microfluidic technology has emerged and developed under such a background. This technology integrates basic operations such as sampling, mixing, reaction, separation, detection, and cell culture, sorting, and lysis involved in the fields of chemistry, biology, and medicine into a chip that is several centimeters square, thereby replacing traditional biochemical experiments. The function of the chamber ha...

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Problems solved by technology

Through literature research, it is found that the current method of using magnetic field to enhance micro-mixing efficiency still has the following deficiencies: (1) The method of magnetic field disturbance mostly adopts alternating magnetic field or even a constant magnetic field, but in fact, the magnetic force received by the magnetic beads does not change with the external force. The direction of the magnetic field changes and changes, but is the same as the direction of the magnetic field gradient, so the intermittent magnetic field disturbance is more conducive to strengthening the mixing effect in the microchannel than the alternating magnetic field; (2) the magnetic field in the current micro-mixer is composed of electric Coil generation is limited by Joule heat, and the magnetic field generated is generally weak. When the flow rate is high, the magnetic field force is not enough to disturb the flow field, so that the purpose of intensified mixing cannot be achieved.

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