This invention relates generally to a method for fluid transfer and a micro peristaltic pump based upon the method.
Microfluidic devices have been widely used in biomedical, biochemical and trace analysis, etc. On the great demand of the reliability for bioanalytical devices, disposable cartridges or chips are more and more welcomed as the carrier for reaction and detection. Sometimes fluid is injected into the cartridge or chip manually but this will result in low reliability. On the other hand, a micropump is often not easy and too expensive to be integrated into the disposable part.
Many kinds of micropumps have been studied in the recent years. Unlike conventional peristaltic pumps which commonly comprise a flexible tube and three or more rollers (See e.g., U.S. Pat. Nos. 6,062,829 and 6,102,678, and European Patent Nos. 1,078,879 and 1,099,154), micro pumps generally consist of three or more chambers among which fluid is transferred from one to another (See e.g., U.S. Pat. Nos. 5,085,562 and 5,759,015, and WO01/28,682). For example, in WO01/28,682, three identical chambers are connected in tandem and driven independently by three drives in a peristaltic time sequence and then fluid is transferred.
This invention addresses the above and other related concerns in the art by presenting a method for fluid transfer and a micro peristaltic pump based upon the method.
In one aspect, the present invention is directed to a method for fluid transfer, which comprises: a) an actuating part comprising a motor and a first force effector driven by the motor; b) a cartridge part comprising an elastic membrane attached to a cartridge body, wherein said elastic membrane attached to said cartridge body forms an enclosed space within the cartridge body comprising at least three chambers, and the cartridge also comprising a second force effector which interacts with the first force effector; c) at least three said chambers have inlets and outlets, which are sealingly connected in tandem; and d) means for controlling movement of the first force effector to and from said cartridge part in a plane substantially parallel to the plane comprising said cartridge part, whereby said chambers covered by the first force effector are open or close by the interaction of the first and second force effector.
Said first force effector is unsymmetrically attached to the motor and is rotated by the motor to interact with the second force effectors configured along the circular track.
Said first force effector is attached to the motor and is moved straightly by the motor to interact with the second force effectors configured along the linear track.
When said first force effector is not in close proximity to said second force effector, said chamber are kept closed or open by said second force effector, and when said first force effector is in close proximity to said second chamber, said chamber are kept open or closed by the interaction of said first and second force effector.
Either the first force effector or the second force effector is ferromagnetic, and the other is ferromagnetic, paramagnetic or any type of magnetic substrate that can generate magnetic force with ferromagnet.
Both said first and second force effector are electrically charged and thus interact by electrostatic force.
In another example, the working surface of the first force effector has a wave shape circumfenrentially. The movement of the first force effector into close proximity to the cartridge part results in contact between the first and second force effector and the contact opens the chambers the actuating part covers. When the first force effector moves away, the contact between the first and second force effector disappears and thus the chambers are close again. Preferably, the flat spring comprises a metal, a plastic or another flexible material.
In still another example, a third force effector was set in the cartridge refering to and interacts with said second force effector.
The movement of the first force effector into close proximity to the cartridge part results in contact between the first and second force effector and the contact opens the chambers the actuating part covers. When the first force effector moves away, the contact between the first and second force effector disappears and thus the chambers are close again.
When said first force effector is not in close proximity to said chambers, the chambers are kept closed or open by the interaction of said second and third force effector, and when said first force effector is in close proximity to said chambers, the chambers are kept open or closed by the strong interaction between said first and second force effector over said third force effector.
Said third force effector is driven along with the first force effector, alternatively and oppositely, by the motor in the actuating part.
Said third force effector is ferromagnetic, paramagnetic or any type of magnetic substrate that can generate magnetic force with the second force effector, which prevents the chambers from being kept close or open by the second force effector.
Both the second and third force effector are electrically charged and thus interact by electrostatic force, which prevents the chambers from being kept close or open by the second force effector.
Said third force effector is a flat spring with one end fixed to the cartridge and the other end prevents the chambers from being kept close or open by the second force effector.
A spacing cover was fixed to the cartridge between the first and second force effector to define the extent to which the chamber is open.
A micro peristaltic pump, which comprises: a) an actuating part compring a motor and a first force effector driven by the motor; b) a cartridge part comprising an elastic membrane attached to a cartridge body, wherein said elastic membrane attached to said cartridge body forms an enclosed space within the cartridge body comprising at least three chambers, and the cartridge also comprising a second force effector which interacts with the first force effector; c) at least three said chambers have inlets and outlets, which are sealingly connected in tandem.
There are three chambers within said cartridge, wherein every chamber has its inlet and outlet, and all inlets and outlets are connected in tandem with the inlet of the first chamber and the outlet of the third chamber serving as the inlet and outlet for the fluidic system in the cartridge.
A spacing cover was fixed to the cartridge between the first and second force effector.
Said spacing cover, elastic membrane and cartridge were fixed together by screws.
A third force effector was set in the cartridge refering to and interacts with said second force effector.
Either the first force effector or the second force effector is ferromagnetic, and the other is ferromagnetic, paramagnetic or any type of magnetic substrate that can generate magnetic force with ferromagnet.
Both said first and second force effector are electrically charged and thus interact by electrostatic force.
Said third force effector is a flat spring with one end fixed to the cartridge and the other end interacts with said second force effector by contact.
The working surface of said first force effector has a wave shape circumfenrentially, where the first force effector interacts with the second force effector.
According to the first force effector, a third force effector is set in the cartridge with the second force effector, and has some convex parts in order to interact mechanically with the first force effector by contact.
Said third force effector is a flat spring which has a convex part.
Said first force effector is a sector permanent magnet which is unsymmetrically attached by a flange to the rotor of said motor, and all chambers within the cartridge are configured along the circular track of the first force effector.
Said first force effector was fixed to a linear motor, and all chambers within the cartridge are configured along the linear track of the first force effector.
Said first force effector is manufacturered as a part of said motor.
Said elastic membrane is made of rubber or poly-siloxane, and is attached to said cartridge by adhesion, welding or ultrasonic welding.
The inlet and outlet of said chambers are connected via external tubings or via fabricated channels on the cartridge part.
Said second force effector is fabricated to the interior of said elastic membrane.
Said second force effector is attached to the elastic membrane by adhesion, welding or mechanical means.
An exemplary micro peristaltic pump comprises two separate parts: a cartridge (or chip) and an actuator. They can work together with or without physical contact.
The cartridge comprises at least three valve-shaped chambers each of which has a valve seat, valve membrane on which the second force effector is attached to interact with the first force effector. The chamber is enclosed by the elastic membrane and the structure of the cartridge, wherein a pair of inlet/outlet ports was fabricated. All ports of the chambers are connected in tandem and the left two serve as the inlet and outlet ports for the whole system. A flat spring may be mounted on the cartridge for every chamber to generate the deformation force that will press the valve membrane onto the valve seat. A spacing cover may also be necessary to ensure a unified stroke of all membranes. The actuator part comprises a motor and a sector working part and they are linked mechanically by a flange on the rotor of the motor. The sector working part can be a sector permanent magnet and interact with another magnet attached to the elastic membrane. In this case the sector permanent magnet is the first force effector and the magnet on the membrane is the second force effector while the flat spring is the third force effector.
The fluid transfer is realized in this invention by means that when said sector permanent magnet is in close proximity, but not necessarily with physical contact, to said chambers, the elastic membrane is dragged up from or pressed onto the valve seats. On the other hand, the elastic membrane will be tightly pressed on the valve seats by the deformation force of the flat springs. The vertical displacement of the elastic membrane is defined by the spacing cover. Since the three chambers are fabricated within the cartridge in a deliberate pattern, the rotating sector permanent magnet will cover every chamber and consequently lead to the alternative open and close states for every chamber in a peristaltic time sequence. Thus the fluid is transported from one chamber to another in the peristaltic manner. The flow rate as well as direction can be changed simply by controlling the rotation speed and direction of the sector magnet.
A typical structure of the exemplary pump comprises a cartridge part and an actuating part as shown in
The main components within the cartridge include the cartridge body 4, elastic membrane 3, magnet 7 attached to the membrane 3 for each chamber within cartridge 4, a spacing cover 2 and may also include screws 6 and 11 and a flat spring 5 for each chamber if it is designed to generate the pre-tightening and restoring forces (See
As illustrated in
The inlet and outlet ports for all valve structures within the cartridge are connected in tandem to enable a fluidic pipeline except the very beginning and end of the pathway. As depicted in
The following states come forth one by one in a whole rotation cycle of magnet 1:
(a) The initial state, shown in
(b) See
(c) See
(e) See
(a) When the sector magnet keeps rotating, the system returns to the initial state.
Following the procedures described above, fluid can be transferred from the inlet port 9 to the outlet port 14. Flow rate can be increased by the speedup of the rotation of sector magnet 1 and pumping direction can be altered when the magnet rotates reversibly.
In
Not only can all the valve chambers work in the same manner as stated above, but also they can be actuated variously. Electrostatic force may be employed to open the valves as the substitution of the magnetic force in the previously mentioned method. The elastic force from the membrane itself can be used to restore the valve. Also, deformation force from the flat spring can serve to open the valve which is totally dependent on its initial shape.
As still another embodiment, the permanent magnet can move straightly to generate the peristaltic time sequence. Of course in this case the permanent magnet is not a sector. All phases during the movement of the permanent magnet are shown in
There are still some other types of force that can be used to actuate vertically to substitute the magnetic force and flat spring force in the stated embodiment. In fact, the essence of the present embodiment is the peristaltic movement formed by the single rotation of the sector working part 1, regardless of whatever type of vertical actuation. ureThe left end of flat spring 5 is fixed and the other end is free. For the free end of the flat spring, a displacement y will be generated by the externally applied force P and vice versa. Also, the restoring force can be provided by the elastic membrane 3 as depicted in
Electrostatic force is generated between any two separate objects with electric charges. If the charges are both positive or negative, the two objects repel each other. If the charges are opposite, they attract each other. As another embodiment of the invention, 1 and 7 are charged to generate the electrostatic force. Therefore, electrostatic force actuates vertically in the same time sequence, formed by the rotating sector working part 1, as the one in the typical embodiment. it can be noticed that physical contact is absent for electrostatic actuation.
Any suitable number of chambers in the present peristaltic pumps can be sealingly connected to an inlet and an outlet. For example, more than 50% of the chambers in the present peristaltic pumps can be sealingly connected to an inlet and an outlet. Preferably, each chamber is sealingly connected to an inlet and an outlet. The inlet and outlet of any suitable number of chambers in the present peristaltic pumps can be connected. For example, the inlet and outlet of at least three chambers are connected. Preferably, the inlet and outlet of all chambers are connected.
In another specific embodiment, when the first force effector is not in close proximity to the chamber within the cartridge, the chamber are kept closed, and when the first force effector moves into close proximity to the chamber, the interaction between the actuating part and the cartridge part opens the chamber.
In still another specific embodiment, when the first force effector is not in close proximity to the chamber within the cartridge, the chamber are kept open, and when the actuating part moves into close proximity to the chamber, the interaction between the actuating part and the cartridge part closes the chamber. In this situation, a repelling, rather than an attractive, magnetic force can be used.
The above examples are included for illustrative purposes only and are not intended to limit the scope of the invention. Many variations to those described above are possible. Since modifications and variations to the examples described above will be apparent to those of skill in this art, it is intended that this invention be limited only by the scope of the appended claims.
For clarity of disclosure, and not by way of limitation, the nonmenclature with regard to this invention is provided below.
1. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this invention belongs. All patents, applications, published applications and other publications referred to herein are incorporated by reference in their entirety. If a definition set forth in this section is contrary to or otherwise inconsistent with a definition set forth in the patents, applications, published applications and other publications that are herein incorporated by reference, the definition set forth in this section prevails over the definition that is incorporated herein by reference.
2. As used herein, “a” or “an” means “at least one” or “one or more”.
3. As used herein, “a plane substantially parallel to the plane comprising said cartridge part” means that the angle between the plane wherein the actuating part moves from and to the cartridge part and the plane comprising the cartridge part is less than 45 degrees or more than 135 degrees. Preferably, the angle between the plane wherein the actuating part moves from and to the cartridge part and the plane comprising the cartridge part is less than 30, 15, 10, 5, 2, 1 or less than 1 degree(s), or more than 150, 165, 170, 175, 178, 179 or more than 179 degrees. More preferably, the angle between the plane wherein the actuating part moves from and to the cartridge part and the plane comprising the cartridge part is 0 or 180 degrees, i.e., the two planes are completely parallel.
4. As used herein, “the actuating part is in close proximity to the cartridge part” means that the actuating part and the cartridge part are brought sufficiently close to achieve the desired opening or closing of chamber(s). Normal, the distance between the actuating part and cartridge part is about several micrometers to a few millimeters, e.g., from about 10 μm to about 5 mm.
5. As used herein, “magnetic substance” refers to any substance that has the properties of a magnet, pertaining to a magnet or to magnetism, producing, caused by, or operating by means of, magnetism.
6. As used herein, “magnetizable substance” refers to any substance that has the property of being interacted with the field of a magnet, and hence, when suspended or placed freely in a magnetic field, of inducing magnetization and producing a magnetic moment. Examples of magnetizable substances include, but are not limited to, paramagnetic, ferromagnetic and ferrimagnetic substances.
7. As used herein, “paramagnetic substance” refers to the substances where the individual atoms, ions or molecules possess a permanent magnetic dipole moment. In the absence of an external magnetic field, the atomic dipoles point in random directions and there is no resultant magnetization of the substances as a whole in any direction. This random orientation is the result of thermal agitation within the substance. When an external magnetic field is applied, the atomic dipoles tend to orient themselves parallel to the field, since this is the state of lower energy than antiparallel position. This gives a net magnetization parallel to the field and a positive contribution to the susceptibility. Further details on “paramagnetic substance” or “paramagnetism” can be found in various literatures, e.g., at Page 169-page 171, Chapter 6, in “Electricity and Magnetism” by B. I Bleaney and B. Bleaney, Oxford, 1975.
8. As used herein, “ferromagnetic substance” refers to the substances that are distinguished by very large (positive) values of susceptibility, and are dependent on the applied magnetic field strength. In addition, ferromagnetic substances may possess a magnetic moment even in the absence of the applied magnetic field, and the retention of magnetization in zero field is known as “remanence”. Further details on “ferromagnetic substance” or “ferromagnetism” can be found in various literatures, e.g., at Page 171-page 174, Chapter 6, in “Electricity and Magnetism” by B. I Bleaney and B. Bleaney, Oxford, 1975.
9. As used herein, “ferrimagnetic substance” refers to the substances that show spontaneous magnetization, remanence, and other properties similar to ordinary ferromagnetic materials, but the spontaneous moment does not correspond to the value expected for full parallel alignment of the (magnetic) dipoles in the substance. Further details on “ferrimagnetic substance” or “ferrimagnetism” can be found in various literatures, e.g., at Page 519-524, Chapter 16, in “Electricity and Magnetism” by B. I Bleaney and B. Bleaney, Oxford, 1975.
Number | Date | Country | Kind |
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03101875.0 | Jan 2003 | CN | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CN03/00563 | 7/14/2003 | WO | 5/15/2006 |