Single-sheath microfluidic chip

Abstract

Microfluidic devices and methods for focusing components in a fluid sample are described herein. The microfluidic device has at least one flow focusing channel where the components are focused or re-oriented by the geometry of the channel. From an upstream end of the flow focusing channel to a downstream end of the flow focusing channel, at least a portion of the flow focusing channel has a reduction in height and at least a portion of the flow focusing channel narrows in width, thereby geometrically constricting the flow focusing channel. The devices and methods can be utilized in sex-sorting of sperm cells to improve performance and increase eligibility.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]This application is a continuation and claims benefit of U.S. Non-Provisional application Ser. No. 16 / 396,138 filed Apr. 26, 2019, the specification(s) of which is / are incorporated herein in their entirety by reference.BACKGROUND OF THE INVENTIONField of the Invention[0002]The present invention relates to a microfluidic chip design, in particular, to a microfluidic chip for isolating particles or cellular materials using laminar flow from a single sheath and geometric focusing.Background Art[0003]Microfluidics enables the use of small volumes for preparing and processing samples, such as various particles or cellular materials. When separating a sample, such as the separation of sperm into viable and motile sperm from non-viable or non-motile sperm, or separation by gender, the process is often a time-consuming task and can have severe volume restrictions. Current separation techniques cannot, for example, produce the desired yield, or p...

AI Technical Summary

Benefits of technology

[0007]One of the unique and inventive technical features of the present invention is the physical restriction of the channel geometry at the flow focusing region. Without wishing to limit the invention to any theory or mechanism, it is believed that the technical feature of the present invention advantageously eliminates the second sheath flow structure from the microfluidic device such that the use of a secondary sheath fluid to focus / orient sperm cells becomes unnecessary, thus reducing the volume of sheath fluid used as compared to existing devices that have two focusing regions using sheath fluids for stream compression. This provides an additional benefit of reducing operational costs for equipment and supplies, and further simplifying system complexity. None of the presently known prior references or work has the unique inventive technical feature of the present invention.

[0008]The inventive technical feature of the present invention surprisingly resulted in equivalent purity, better performance, and improved functionality for Y-skewed sperm cells as compared to the prior devices having two focusing regions using sheath fluids. For instance, the microfluidic device of the present invention unexpectedly improved the orientation of the sperm cells, which is believed to have increased the eligibility, i.e. higher number of cells detected, sorted, and ablated. In addition, the device of the present invention was able to enhance resolution between the Y-chromosome bearing sperm cells and the X-chromosome bearing sperm cells, which resulted in effective discrimination of Y-chromosome-bearing sperm cells.

Problems solved by technology

When separating a sample, such as the separation of sperm into viable and motile sperm from non-viable or non-motile sperm, or separation by gender, the process is often a time-consuming task and can have severe volume restrictions.

Current separation techniques cannot, for example, produce the desired yield, or process volumes of cellular materials in a timely fashion.

Furthermore, existing microfluidic devices do not effectively focus or orient the sperm cells.

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