The invention relates to a microfluidics system comprising:
The invention further relates to a device comprising such a micro fluidics system.
The invention further relates to a method for using such a microfluidics the system.
An embodiment of a microfluidics system as referred to above is known from US 2005/0019898 A1. This document describes a fluid mixing device comprising a chamber comprising two diaphragm regions. The diaphragm regions are displaced into and out of the chamber by inflation and deflation of two mixing bladders to generate fluid movement within the chamber. Mixing results from the fluid movement obtained by operating the mixing bladders and diaphragm regions. It is a drawback of the known device that the mixing can be improved and that the mixing bladders and associated means for inflating and deflating the mixing bladders take-up volume. The fluid cannot be removed from the mixing chamber except by replacing with another fluid (air) which requires another fluid source and additional sealing measures.
It is an object of the invention to provide a microfluidics system that has improved mixing characteristics.
The invention is based on the recognition that by having a channel through which one or more fluids enter a closed, expandable volume closed by a flexible membrane, a chaotic flow pattern is created near the membrane inside the expandable volume when fluids to be mixed are transported through the channel into the expandable volume. The chaotic flow pattern leads to an efficient mixing of the fluid entering the expandable volume. The invention enables homogenizing a single fluid entering the closed, expandable volume or mixing two or more different fluids. For the current invention homogenizing and mixing are regarded as a single concept indicated by the term mixing. In a preferred embodiment the tension occurring in the flexible membrane as a result of the expansion of the membrane as the expandable volume fills with fluid tends to push the fluid back towards the channel through which the fluid entered the expandable volume. No external actuation is required for this tendency to push back the fluid. However, external actuation may be applied with or without a flexible membrane. The filling and emptying of the expandable volume can be repeated as often as required for a certain quality of mixing, the degree of filling can be varied as desired so the same design can be used for different volumes, depending on the application.
Consequently, the micro fluidics system according to the invention provides improved mixing as compared to the mixing obtained in the prior art described above. Moreover, the present invention does not require a reservoir, venting of gas which is displaced by moving fluid, or an extra volume. By making the closed volume expandable no extra volume is required and all fluid can be recovered into the system without venting or using a displacing fluid.
It is an additional advantage of the invention that the device according to the invention is compact. When there is no fluid in the closed, expandable volume, the dead volume is essentially zero.
An embodiment of the microfluidics system according to the invention is characterized in that the flexible membrane covers the second channel opening.
This embodiment has the advantage that the expandable volume is completely defined by the flexible membrane allowing simple and easy assembly of a microfluidics system according to the invention. Alternatively, the flexible membrane may be located in the channel at the second channel opening.
A further embodiment of the microfluidics system according to the invention is characterized in that the flexible membrane is elastic.
This embodiment has the advantage that the membrane upon expansion generates a force tending to push liquid out of the expandable volume. This means that no separate actuation of the fluid is absolutely necessary to remove fluid from the expandable volume after (a single cycle of) mixing.
A further embodiment of the microfluidics system according to the invention is characterized in that the microfluidics system comprises a plurality of channels to the closed, expandable volume. This embodiment has the advantage that it allows chaotic flow patterns different from those attainable by use of a single channel.
A further embodiment of the microfluidics system according to the invention is characterized in that at least one of the channels out of the plurality of channels comprises a directional valve.
This embodiment has the advantage that providing at least one but not all channels out of a plurality of channels fluidically coupling the first side of the surface to the closed, expandable volume with a directional valve allows enhancement of mixing by forcing fluid out of the expandable volume along a path different from the path along which the fluid entered the expandable volume.
A further embodiment of the microfluidics system according to the invention is characterized in that the geometry of the channel is adapted for enhancing mixing.
This embodiment has the advantage that it allows enhancement of mixing. A well-known structure for enhancing mixing is a so-called herring bone structure which leads to a rotation of the flow field dependent on the flow direction.
A further embodiment of the microfluidics system according to the invention is characterized in that the closed, expandable volume comprises a structure for enhancing mixing.
This embodiment has the advantage that it allows enhancement of mixing. A possibility that can be optionally combined with a structure such as a herring bone structure (see the previous embodiment), is formed by one or more grooves over the bottom of the chamber which act as extended openings of the channel.
A further embodiment of the microfluidics system according to the invention is characterized in that the flexible membrane is pre-shaped for enhancing mixing.
This embodiment has the advantage that it allows enhancement of mixing. One embodiment of a pre-shaped a flexible membrane is a membrane pre-shaped like a folded bag also called a faltenbalg. Moreover, the membrane may be pre-shaped in the sense that it is nonsymmetric with respect to the opening or openings of the channel or channels communicating fluid to the closed, expandable volume.
The object of the invention is further realized with a device comprising a microfluidics system according to any one of the previous embodiments.
A device comprising a micro fluidics system according to the invention would benefit from any one of the previous embodiments.
An embodiment of a device according to the invention is characterized in that the device is a cartridge, the cartridge being insertable into an instrument for into acting with the cartridge.
This embodiment has the advantage that cartridges, for instance there was used in molecular diagnostics, sometimes require mixing of fluids. Consequently, a cartridge comprising a microfluidics system according to the invention would benefit from any one of the previous embodiments of the invention.
A further embodiment of a device according to the invention is characterized in that the device is a device for molecular diagnostics.
This embodiment has the advantage that a device for molecular diagnostics may require mixing of fluids. Consequently, such a device, potentially comprising a cartridge according to the previous embodiment, would benefit from any one of the previous embodiment of the invention.
The object of the invention is further realized with a method for mixing fluids comprising the following steps:
providing a micro fluidics system comprising:
An embodiment of a method according to the invention is characterized in that the steps of transporting and returning are repeated as often as necessary to achieve a desired level of mixing.
This embodiment has the advantage that mixing can be repeated by going through a plurality of mixing cycles until a desired level of mixing has been achieved.
b shows the same setup as
c shows a top view of the setup shown in
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In the system claims enumerating several means, several of these means can be embodied by one and the same item of computer readable software or hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Number | Date | Country | Kind |
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09158646 | Apr 2009 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB2010/051671 | 4/16/2010 | WO | 00 | 10/21/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/122464 | 10/28/2010 | WO | A |
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Number | Date | Country | |
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20120100630 A1 | Apr 2012 | US |