Fluid mixing in low aspect ratio chambers

Abstract

A method and system for performing mixing in a low volume, low aspect ratio microfluidic chamber (3) is described. Two or more mixing bladders (13,15) formed adjacent the microfluidic chamber are inflated and deflated in reciprocating fashion to cause inward and outward deflection of discrete regions of the chamber wall to mix fluid within the chamber. Mixing bladders are actuated by air or another gas, or by a liquid such as water, pumped in and out of the bladders with a pump which may be located remote from the microfluidic device including the microfluidic chamber. In an alternative embodiment, mixing is generated by applying alternating mechanical forces to a surface of a flexible chamber forming device. The microfluidic chamber may be a hybridization chamber formed on a microarray (25) slide with the use of a microarray interface device, or it may be a microfluidic chamber formed in various other types of microfluidic devices.

Description

RELATED APPLICATIONS [0001] This application is a continuation-in-part of PCT Application PCT / US02 / 07113, filed Mar. 8,2002, which application claims the benefit of U.S. Provisional Application 60 / 274,389, filed Mar. 9, 2001, U.S. Provisional Application 60 / 284,427, filed Apr. 17, 2001, U.S. Provisional Application 60 / 313,703, filed Aug. 20, 2001, and U.S. Provisional Application 60 / 339,851, filed Dec. 12, 2001. It is also a continuation-in-part of PCT Application PCT / US02 / ______, filed Aug. 2, 2002 and identified by Attorney Docket No. 3153.2.17. The foregoing applications are incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the area of microfluidic devices. In particular, it. relates to methods and systems for agitating or mixing fluids in chambers of microfluidic devices. More particularly, it relates to methods and systems for generating agitation or mixing in low aspect ratio chambers formed on substr...

AI Technical Summary

Benefits of technology

[0014] Bladders are activated by positive and negative air (or other gas) pressures that may be generated remote to the microfluidic device. Alternatively, water or other liquid may be pumped in and out of the bladders to generate deflections of the chamber wall. Bladders and associated air (fluid) lines can be incorporated into the design of microfluidic devices relatively simply and inexpensively, and therefore are suitable for use in devices intended for one-time use.

Problems solved by technology

However, some of the current limitations of microarrays are the time and care required to process slides, the difficulty in obtaining consistent, high quality results, and limited sensitivity, which makes detection of low-expression genes difficult.

The need for high quality microarray processing is particularly pronounced because individual microarray slides are expensive and only limited quantities of the samples used in the reactions may be available, making it particularly important to obtain good results consistently.

However, when small quantities of sample fluid are spread out over the area of the microarray, the fluid layer is very thin, leading to the possibility that, if no mixing is provided, the sample fluid will become locally depleted of a particular sequence over the spot binding that sequence.

This is a greater problem for low-abundance sequences.

However, these methods depend on the use of relatively large sample volumes, large hybridization chambers, and inconvenient or complicated equipment, and in some cases require the use of specially designed slides or other substrates.

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