Many biochemical processes are carried out on the basis of mixing different liquids. The liquids are generally mixed in a mixing chamber.
For example, document WO 2007066783 describes a microchip which comprises a mixing chamber. The mixing chamber contains particles which are moved under the effect of a centrifugal force.
The publication “Batch-mode mixing on centrifugal microfluidic platforms”, Grumann et al., The Royal Society of Chemistry, 2005, describes a plate having a plurality of mixing chambers. The mixing chambers are filled with magnetic particles. The magnetic particles are moved to and fro by means of permanent magnets, which are arranged along a circular path, so as to mix liquids in the mixing chambers whilst the plate rotates.
Compared to conventional solutions, the cartridge, the centrifuge, and the method have the advantage that the cartridge containing the first and second components is inserted into the centrifuge and, hereafter, the components can be mixed easily under the effect of the electromagnetic force. This can occur at a constant or varying rotational speed, that is to say the mixing operation can be carried out independently of the rotational speed and the associated effective centrifugal force.
Advantageous embodiments of the disclosure will emerge from the dependent claims.
In the present case, “component” means a liquid, a gas, or a particle. “First and second component” can also be understood to mean merely two different states of the same substance: For example, the first component may be formed as a clumped fraction, and the second component may be formed as a liquid fraction of the same substance.
In the present case, “electromagnetic force” means the force acting on an electrically charged material in an electric field, or on a magnet, in particular a permanent magnet, or a live conductor, in particular a coil, in a magnetic field.
The “means for producing the electromagnetic force” can be formed as a permanent magnet, coil or capacitor. The corresponding magnetic fields typically have a field strength of 10 to 300 mT.
In the present case, “electromagnetic particles” are understood to be particles which contain an electrically charged material or a magnetic or magnetizable material, for example iron or nickel.
According to one embodiment, the cartridge further has: a first drum, which has a first chamber, a displacement device, which is designed to rotate the first drum about the center axis thereof when the centrifugal force exceeds a predetermined threshold value so as to thus conductively connect the first chamber to a second chamber, the first and/or second chamber being formed as the mixing chamber. With appropriate selection of the rotational speed of a rotor of a centrifuge containing the cartridge, the first and/or second component can therefore advantageously be transferred between the first and second chamber. Depending on whether the first and/or second chamber is/are formed as a mixing chamber, the corresponding components can be mixed effectively in the first and/or second chamber. In the present case, “conductive(ly)” means so as to conduct liquid, gas and/or particles.
According to a further embodiment of the cartridge according to the disclosure, the displacement device comprises a first slanted edge, which cooperates with a second slanted edge of the first drum so as to bring the drum out of a first position, in which it engages with a positive fit with a housing of the cartridge in the direction of rotation about the center axis, and into a second position along the center axis, against the action of a restoring means, the positive fit being annulled in said second position and the first drum rotating about the center axis. A simple mechanism is thus provided so as to displace the first drum between at least two defined positions in the direction of rotation about the center axis.
According to a further embodiment of the cartridge according to the disclosure, the second chamber and/or a third chamber is/are arranged upstream or downstream of the first drum, based on the center axis, the first chamber preferably being connectable selectively and conductively to the second chamber or to the third chamber by means of the adjustment device. The mixing chamber can thus be arranged upstream and/or downstream of the first drum, or can be provided in the first drum itself. In addition, the mixing chamber can preferably be connected selectively to different further chambers as required.
According to a further embodiment of the cartridge according to the disclosure, a second drum, which has the second chamber, and/or a third drum, which has the third chamber, is/are provided. However, the second drum may just as equally also have the second chamber and the third chamber for example. The same applies to the third drum. Since a plurality of drums, in particular with a plurality of chambers which are displaced relative to one another, are provided, a wide range of different processes can be carried out automatically by means of the cartridge.
According to a further embodiment of the cartridge according to the disclosure, said cartridge further comprises a means for producing the electromagnetic force. Since the means is an element of the cartridge, the means can be adapted to a respective cartridge type and connected securely to the corresponding cartridge. For example, the means can be formed as a coil or as a permanent magnet.
According to a further embodiment of the cartridge according to the disclosure, the means is integrated into a housing of the cartridge, into the first, second and/or third drum. The means can thus be arranged easily in the region of the mixing chamber.
According to a further embodiment of the cartridge according to the disclosure, the mixing chamber comprises a flexible membrane, which divides the container into a first and a second volume, the at least one first and second components being receivable in the first volume and the electromagnetic particles being receivable in the second volume, the membrane being deformable by means of the electromagnetic particles under the effect of the electromagnetic force so as to mix the at least one first and second components. The particles are thus separated from the first and second components at all times, and therefore the particles can also be formed of non-sterile materials for example.
According to a further embodiment, the cartridge according to the disclosure further comprises the first and second components as well as the electromagnetic particles, the first component being formed as a biochemical probe and the second component being formed as a receptor molecule which binds the biochemical probe, the electromagnetic particles carrying the first or second component. The receptor molecules thus bind to the biochemical probes within a minimal period of time.
According to a further embodiment of the centrifuge according to the disclosure, the at least one means is designed to produce an electromagnetic force which acts against the centrifugal force, perpendicular to the centrifugal force and/or in the same direction as the centrifugal force. Different mixing effects can thus be achieved.
According to a further embodiment of the centrifuge according to the disclosure, at least one first and at least one second means are provided, the first means being arranged on one side of a circular path along which the cartridge is movable during centrifugation, and the second means being arranged on the other side of said circular path, and the first and second means being distanced from one another along the circular path. The particles can thus easily move to and fro in a direction perpendicular to the plane of the circular path.
According to a further embodiment of the centrifuge according to the disclosure, the at least one means is integrated into a housing of the centrifuge, in particular into a base and/or cover thereof. A simple design is thus produced.
According to an embodiment of the method according to the disclosure, the electromagnetic force changes whilst the cartridge is centrifuged. The electromagnetic force can change in terms of its amount and/or its direction.
Exemplary embodiments of the disclosure are illustrated in the figures of the drawing and will be explained in greater detail in the following description.
In the figures:
In the figures, like or functionally like elements are denoted by like reference signs, unless stated otherwise.
The cartridge 100 comprises a housing 102 in the form of a tube. For example, the housing 102 may be formed as a 15 mL centrifuge tube, 1.5 mL or 2 mL Eppendorf tube, or alternatively as a micro titer plate (for example 20 μl per well). The longitudinal axis of the housing 102 is denoted by 104.
For example, a first drum 108, a second drum 106 and a third drum 110 are received in the housing 102. The drums 106, 108, 110 are arranged in succession and with their respective center axes coaxially with the longitudinal axis 104.
The housing 102 is closed at one end 112. A restoring means, for example in the form of a spring 114, is arranged between the closed end 112 and the third drum 110 arranged adjacent thereto. The spring 114 can be formed as a spiral spring or as a polymer, in particular an elastomer. The other end 116 of the housing 102 is sealed by means of a seal 118. The seal 118 can preferably be removed so as to remove the drums 106, 108, 110 from the housing 102.
According to a further exemplary embodiment, the spring 114 is arranged between the seal 118 and the drum 106, and therefore the spring 114 is extended to produce a restoring force. Other arrangements of the spring 114 are also conceivable.
A respective drum 106, 108, 110 can have one or more chambers:
For example, the second drum 106 thus comprises a plurality of chambers 120 for reagents and a further chamber 122 for receiving a sample, for example a blood sample, which has been taken from a patient.
The first drum 108, which is arranged downstream of the second drum 106, comprises a mixing chamber 124, in which the reagents from the chambers 120 are mixed with the sample from the chamber 122. In addition, the first drum 108 comprises a further chamber 126 for example, in which the mixture from the mixing chamber 124 is separated into a liquid and a solid phase 128 and 130 respectively.
The third drum 110, again arranged downstream of the first drum 108, comprises a chamber 132 for receiving a waste product 134 from the chamber 126. Furthermore, the third drum 110 comprises a further chamber 136 for receiving the desired end product 138.
The cartridge 100 has an external geometry such that it can be inserted into a seat in a rotor of a centrifuge, in particular into a seat in a swing-out rotor or fixed-angle rotor of a centrifuge. During the centrifugation process, the cartridge 100 is rotated at high speed about a center of rotation 140 indicated schematically in
The objective is to control different processes within the cartridge 100 by means of suitable control of the rotational speed. For example, the mixing chamber 124 is first to be connected fluidically to the chamber 122 so as to receive the sample from the chamber 122. Hereafter, the mixing chamber 124 is to be connected to the chambers 120 so as to receive the reagents therefrom. The reagents and the sample are then to be mixed in the mixing chamber 124. The processes in the chambers 126, 132 and 136 are also to be controlled in a similar manner.
As shown in
The protrusions 200, the slits 204, the slanted edges 206, the protrusions 212, the slanted edges 218, 220, the protrusions 240 and the slanted edges 242 form the above-mentioned displacement device 300, together with the restoring spring 114, for defined rotation of the first drum 108 relative to the further drums 106, 110 about the longitudinal axis 104.
If the rotational speed is then reduced again, which involves a corresponding reduction in centrifugal force, the spring 114 thus presses the first drum 108 by means of the third drum 110 back towards the center of rotation 140. The second drum 106, together with its slanted edges 220, is thus likewise moved back towards the center of rotation 140, whereby the slanted edges 242 of the first drum 108 come to lie against the slanted edges 206 of the housing 102 and slide along these slanted edges, thus implementing a further rotational movement of the first drum 108 into a third position, as illustrated in
The above-described process can be repeated as often as desired, so as to rotate the first drum 108 in a defined manner relative to the other drums 106 and 110.
The mixing chamber 124 comprises a container 500 for receiving at least two components 502, 504. Such components are preferably components which are provided by means of the second drum 106, for example by means of one or more of the chambers 120, 122. For example, the components 502, 504 can be formed as reagents or samples, in particular blood samples.
The mixing chamber 124 further comprises magnetic particles 506. The particles 506 may already be arranged in the mixing chamber 124 before the onset of centrifugation, for example before insertion of the cartridge 100 in the centrifuge. Alternatively, the particles 506 can be held in one or more chambers 120, 122 of the second drum 106 and introduced under controlled rotational speed at a specific moment. Reference is made in this regard to the above, where the function of the displacement device 300 is described. Furthermore, the particles 506 can be held in one or more chambers 120, 122, together with one of the liquids 502, 504, and can be later introduced together (that is to say the liquid 502 with the particles 506 for example) into the mixing chamber 124 by means of the displacement device 300. The particles 506 can still be fed from the chamber 120 for example, either before or after a blood sample has been introduced into the mixing chamber 124 from the chamber 122.
The particles 506 preferably have a permanently magnetic material, for example iron. The particles 506 further preferably have a density which is greater than that of the liquids 502, 504. The particles 506 typically have a diameter of approximately 200 μm.
The centrifuge or cartridge 100 has a means 508 for producing a magnetic force 510, which acts on a respective particle 506. The means 508 is preferably formed as a permanent magnet, coil or capacitor. In the present exemplary embodiment, the means 508 is arranged radially inwardly in relation to the mixing chamber 124 and the cartridge 100. An arrangement of the means 508 radially outwardly is also possible.
The produced magnetic force 510 preferably varies over time. For example, this can occur suddenly if the means 508 produces a magnetic field which varies over time. In addition, the means 508 is formed as a coil for example, to which current is supplied suitably by means of a control device. In this case, the coil 508 can be a stationary element of the centrifuge. Alternatively, the coil 508 can be moved, that is to say for example integrated into the rotor of the centrifuge, into a specific rotor holder, into the cartridge 100, into the first drum 108 or into the container 500, and in particular can be supplied with current wirelessly. Furthermore, the means 508 can be designed to produce a magnetic field which remains constant over time, wherein the mixing chamber 124, including the particles 506, is moved relative to said magnetic field. To this end, the means 508 is formed as a permanent magnet for example. In this case, the means 508 always deflects the particles 506 when the cartridge 100 passes the means 508 over its circular path.
According to the exemplary embodiment in accordance with
Alternatively, the movement of the particles 508 can also be controlled exclusively by means of the coil 508. That is to say, the coil 508 produces a magnetic force 510, which acts alternately against the centrifugal force 142 and in the direction of the centrifugal force 142. In this case, the density of the particles 506 and also the strength of the centrifugal force 142 do not play any part, or only play an insignificant part.
In addition to the mixing of the liquids 502, 504, the described method can also be used to accelerate biochemical binding processes. At least one liquid 502, which contains at least one type of biochemical probe (for example DNA, antigens, antibodies, proteins, cells, gene sequences, amino acids) is then located in the mixing chamber 124. A type of receptor molecule (for example DNA, antigens, antibodies, proteins, cells, gene sequences, amino acids) is located on the particles 506 and binds precisely to this type of biochemical probe. Due to the movement of the particles 506 through the liquid 502, the particles 506 are charged in an accelerated manner by the biochemical probes.
In a further embodiment, the mixing of liquids 502, 504 and the binding of biochemical probes to the surface of a respective particle 506 take place in a single process step.
The cartridge 100, including the chamber 124, is moved in a holder (not illustrated) of the centrifuge 600 over a circular path 602 about the center of rotation 140. The centrifuge 600 has two permanent magnets 508, which are each stationary and are denoted by reference signs 604 and 606 for the sake of improved distinction. As can be seen in
If the cartridge 100, including the chamber 124, is then moved over the circular path 602 past the permanent magnets 604, 606, said permanent magnets each produce a magnetic force 510, which acts on a respective particle 506, not parallel, but in particular substantially perpendicular, to the centrifugal force 142. Since the permanent magnets 604, 606 are arranged on different sides of the circular path 602, the magnetic force 510 when the permanent magnets 604, 606 are passed acts once downwardly and once upwardly, which leads to a corresponding movement to and fro of the particles 506 downwardly and upwardly, perpendicular to the centrifugal force 142. In particular, the particles 506 move over the entire inner width 512 of the container.
For example, coils could also be used instead of the permanent magnets 604, 606, said coils being supplied with current and thus producing the magnetic force 508 when they are passed by the cartridge 100 and mixing chamber 124.
The mixing chamber 124 according to
The magnetic force 510, which changes over time, acts in conjunction with the centrifugal force 142, such that the particles 506 move to and fro in relation to the center of rotation 140, that is to say along the longitudinal axis 104, and deform the membrane 700. The membrane 700 thus acts on the liquids 502, 504 and thus mixes them.
In all of the above exemplary embodiments, mixing can advantageously be carried out independently of the rotational speed of the rotor of the centrifuge. For example, mixing can be carried out at constant, increasing or decreasing rotational speed. According to an exemplary embodiment, the rotational speed of the centrifuge can be selected in such a way that the corresponding centrifugal force 142 exceeds a predetermined threshold value, and therefore the displacement device 300 rotates the drum 108 with the mixing chamber 124, thus connecting the chamber 124 conductively to a further chamber 120, 122, 132, 136. At the same time, the particles 506 already move in the container 500, and the components 502, 504 can thus be mixed together whilst one or both components 502, 504 flow into the mixing chamber 124 or flow out therefrom.
The exemplary embodiments described in this case are particularly preferably combined with one another. In particular, this is possible for the exemplary embodiments according to
Furthermore, the mixing chamber 124 may have an obstruction structure (not illustrated), for example a screen or a lattice structure, which is designed to move through the liquids 502, 504 or to be passed through by the liquids 502, 504 (the latter in the case of a stationary obstruction structure) under the effect of a centrifugal force (that is to say when the rotational speed of the centrifuge exceeds a predetermined threshold value), so as to mix said liquids.
The housing 102 and the drums 106, 108, 110 can be produced from the same or from different polymers. The one or more polymer(s) is/are thermoplastics, elastomers, or thermoplastic elastomers in particular. Examples include cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polycarbonates (PCs), polyamides (PAs), polyurethanes (PUs), polypropylene (PP), polyethylene terephthalates (PETs) and poly(methyl methacrylates) (PMMAs).
One or both drums 106, 110 can be formed in one piece with the housing 102.
Although the disclosure has been described herein on the basis of preferred exemplary embodiments, it is in no way limited thereto, but can be modified in many ways. In particular, it is noted that the embodiments and exemplary embodiments described herein for the cartridge according to the disclosure are accordingly applicable to the centrifuge according to the disclosure and to the method according to the disclosure for mixing a first and a second component, and vice versa. It is also noted that “a” and “an” do not exclude a plurality in the present case.
Number | Date | Country | Kind |
---|---|---|---|
10 2011 077 134.4 | Jun 2011 | DE | national |
This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2011 077 134.4, filed on Jun. 7, 2011 in Germany, the disclosure of which is incorporated herein by reference in its entirety.