The present invention relates to a micro fluidic device comprising a plurality of chambers and a flow path for at least one magnetic particle which is subsequently moved through the plurality of chambers.
In recent years, several types of microfluidic devices have been developed for e.g. biochemical processing, biochemical synthesis, and/or biochemical detection. For example, U.S. Pat. No. 6,632,655 B1 describes several types of microfluidic devices which can e.g. be used for biochemical analysis.
According to one type of such micro fluidic devices which is for instance suited for sequencing-by-synthesis, magnetic particles are subsequently driven or actuated through a plurality of chambers, wherein e.g. a plurality of different physical, chemical, or biochemical processes is performed in the plurality of chambers. The magnetic particles may for instance be provided with a (biological) component to be analyzed. In this type of microfluidic device, several chambers through which the magnetic particles are subsequently moved are connected by channels defining a flow path for the magnetic particles. The plurality of chambers and the interconnecting channels define a processing module. Since different fluids may be provided in the plurality of chambers, valve-like structures are typically provided in the channels connecting the chambers. These valve-like structures are adapted for enabling passing-through of the magnetic particles and prevent (at least substantially) mixing of the fluids present in the different chambers. For example, such valve-like structures may contain a visco-elastic medium through which the magnetic particles can travel. The magnetic particles are actuated through the plurality of chambers by means of an applied magnetic field (or several applied magnetic fields) generated by a magnetic-field generating unit. In such a system, the dynamics of magnetic particles such as the traveling speed, the position in the micro fluidic device at a predetermined time after the start of a process, and/or the residence time in the respective components of the micro fluidic device may deviate from an ideal (or planned) behavior due to e.g. manufacturing tolerances. For example, the magnetic particles, e.g. formed by magnetic beads, may show varying properties such as varying susceptibility, size, or surface coating. Further, the valve-like structures separating the plurality of chambers may have varying properties such as varying roughness, surface tension, or size. As another reason for deviations in the dynamics of the magnetic particles, the magnetic field for actuating the magnetic particles through the microfluidic device may comprise spatial non-uniformities.
In many cases, microfluidic devices for high-throughput and/or high-multiplex applications are desired. In such devices, processing should be performed simultaneously in a plurality of (substantially) identical processing modules in parallel. For example,
It is an object of the present invention to provide a microfluidic device enabling control of the movement of at least one magnetic particle.
This object is solved by a microfluidic device according to claim 1. The microfluidic device comprises: a plurality of chambers adapted for performing chemical, biochemical, or physical processes; a flow path connecting the plurality of chambers adapted for accommodating at least one magnetic particle subsequently moving through the plurality of chambers; the plurality of chambers being separated by at least one valve-like structure adapted to enable passing-through of the at least one magnetic particle from one of the plurality of chambers to another one of the plurality of chambers; and at least one delaying structure adapted to delay movement of the at least one magnetic particle along the flow path. Since at least one delaying structure for delaying movement of the at least one magnetic particle is provided in the microfluidic device, in case of the magnetic particle moving too fast (e.g. as compared to magnetic particles in other processing modules), the magnetic particle (or particles) can be delayed such that it is brought to a desired time-position relation in the microfluidic device. The magnetic particle (or several magnetic particles) can be delayed appropriately to bring the microfluidic device in a well-defined state. If several processing modules are present, magnetic particles which are moving faster through the respective processing module as compared to magnetic particles in other processing modules can be slowed down by the delaying structure such that the movement of the respective particles becomes synchronized. The magnetic particle can be controllably delayed, e.g. by application of a suitable magnetic field. As a result, it can be ensured that magnetic particles in different processing modules undergo the same processing simultaneously.
The term valve-like structure means a structure which is adapted for allowing passing of one type of substance (e.g. magnetic particles in the embodiments) while (at least substantially) preventing passing of another type or other types of substances (e.g. different fluids in the embodiments).
Preferably, the delaying structure is adapted to delay the movement of the at least one magnetic particle by application of a magnetic field. In this case, the delaying structure can be suitably constructed e.g. exploiting the capability of an already present magnetic-field generating unit (which is present for actuating the at least one magnetic particle along the flow path) to generate different magnetic fields (e.g. different magnetic field amplitudes, different magnetic field directions, etc.). The response of magnetic particles to magnetic fields is exploited to delay the particles.
Preferably, the delaying structure is adapted to stop in a controlled manner the movement of the at least one magnetic particle and to controllably release the at least one magnetic particle again. In this case, the position of the at least one magnetic particle at a certain point in time can be exactly adjusted by the delaying structure by capturing the at least one magnetic particle and releasing it again at a predetermined point in time. Thus, the movement of the at least one magnetic particle can be exactly synchronized to the movement of magnetic particles in other processing modules. If the delaying structure is adapted such that stopping and releasing is performed by changing a magnetic field, the synchronization can be achieved by an (already present) magnetic-field generation unit. Generated magnetic fields and resulting magnetic forces/torques can be easily controlled in amplitude, orientation, and time such that reliable synchronization can be achieved.
Preferably, the delaying structure comprises a geometrical structure and is adapted such that the at least one magnetic particle is moved against the geometrical structure by application of a magnetic field. In this case, the delaying structure can be realized in a particularly easy manner even in microfluidic devices comprising very narrow flow paths. The geometrical structure can e.g. be formed by an indentation, a protrusion, an edge, a wall, etc. provided in the flow path of the at least one magnetic particle. The at least one magnetic particle can for instance be driven against the geometrical structure by the magnetic field such that it is held there. The geometrical structure has the shape of a stop. The magnetic particle (or particles) can be released again driven by thermal/diffusive movement as well as by magnetic/drift movement, or by other forces on the magnetic particle (or particles).
Preferably, the at least one delaying structure is formed separate from the valve-like structure. In this case, the reliability of the device is improved, since the valve-like function and the delaying function do not interfere.
According to an aspect, valve-like structures are each provided between chambers of the plurality of chambers which are adjacent with respect to the flow path. In this case, the at least one magnetic particle has to travel through a valve-like structure for each movement from one chamber to another chamber. Thus, the chambers are reliably separated with respect to each other.
Preferably, the microfluidic device comprises a magnetic-field generating unit adapted for moving the at least one magnetic particle through the plurality of chambers by means of a magnetic field. This enables controlled movement of the at least one magnetic particle along the flow path. If the magnetic-field generating unit is adapted for applying the magnetic field for delaying the at least one particle, both movement of the at least one magnetic particle along the flow path and delaying of the at least one magnetic particle can be achieved by a single structure. As a consequence, a miniaturized implementation is possible.
According to one aspect, the microfluidic device is structured such that the direction of movement from a first of the plurality of chambers to a subsequent second of the plurality of chambers is in a first direction and the movement from the second of the plurality of chambers to a subsequent third of the plurality of chambers is in a second direction, the first direction and the second direction being different. Such a structure provides a phased/controlled way to move magnetic particles between the different chambers which is particularly suited for micro fluidic devices comprising a large number of processing modules in parallel and a single magnetic-field generating unit. Thus, a concerted movement of magnetic particles in the processing modules can be achieved.
Preferably, the microfluidic device comprises a plurality of processing modules each comprising a plurality of chambers and a respective flow path connecting the respective plurality of chambers adapted for accommodating magnetic particles simultaneously moving through the respective plurality of chambers. In this case, high-throughput and/or high-multiplex applications are possible. If a common magnetic-field generating unit is provided for the plurality of processing modules, effective miniaturization is possible even for high numbers of processing modules. For example, the processing modules can have a similar or identical structure.
Preferably, the processing the processing modules of the microfluidic device are identical. In this case, the same processes are performed in corresponding chambers of the processing modules and the device is particularly suited for high-throughput and/or high-multiplex applications.
Preferably, the individual chambers of the plurality of chambers are adapted for performing a plurality of different chemical or biochemical processes. In this case, the microfluidic device is particularly suited for sequencing by synthesis and other complex chemical and/or biochemical processes.
Further features and advantages of the present invention will arise from the detailed description of embodiments with reference to the enclosed drawings.
a and 2b schematically show two examples for delaying structures.
a to 3c schematically indicate exemplary positions of delaying structures with respect to a chamber.
Embodiments of the present invention will now be described with reference to the drawings. First, the general structure will exemplarily be explained with respect to
The chambers 3, 4, 5, and 6 are connected in series and interconnected by channels 9. The channels 9 and chambers 3, 4, 5, and 6 are structured such that magnetic particles 7 can be subsequently transported through the different chambers 3, 4, 5, and 6. In
It has been described that different chemical, biochemical, or physical processes may be performed in the respective chambers 2, 3, 4, and 5. For this purpose, the chambers 2, 3, 4, and 5 may e.g. be filled with different fluids (which in many cases should not mix). In order to achieve separation of the chambers 2, 3, 4, and 5 with respect to each other, valve-like structures 10 are provided in the channels 9 interconnecting respective two neighboring chambers. The valve-like structures 10 are structured such that fluids contained in adjacent chambers do not mix (or at least substantially do not mix), i.e. do not pass through the valve-like structures 10. On the other hand, the valve-like structures 10 are formed such that the magnetic particles 7 actuated by the applied magnetic field can pass from one chamber to an adjacent one. For example, the valve-like structure can be formed by a visco-elastic medium arranged in the channel 9.
In general, in operation of the microfluidic device, the magnetic particles 7 are substantially simultaneously moved subsequently through the chambers 2, 3, 4, and 5 by application of a magnetic field by the magnetic-field generation unit 8, and different processes are performed in the different chambers 2, 3, 4, and 5. However, as has been described above, due to e.g. manufacturing tolerances, without further measures the magnetic particles 7 in the plurality of processing modules 2a, 2b, and 2c will not be actuated absolutely synchronously. Thus, some dispersion will arise, i.e. variations in speed, position, time, etc. in the various processing modules 2a, 2b, and 2c.
According to the embodiment, a delaying structure for delaying movement of the magnetic particles 7 is provided which enables synchronization of the dynamics of the magnetic particles 7 in different processing modules 2a, 2b, 2c.
a to 3c schematically show different possible positions of the geometrical structures 11, 111 as the delaying structure with respect to the chamber 4. As schematically indicated in the top view in
After the synchronization phase, the magnetic particles 7 are further actuated in the microfluidic device to move to the next chamber (via a channel 9). The release of the magnetic particles 7 from the delaying structure may be achieved in different ways. For example, the release can be driven by thermal/diffusive movement after the magnetic field holding the magnetic particle at the delaying structure is changed, by magnetic/drift movement, or by other forces acting on the particles such as e.g. fluidic shear forces. Release of the magnetic particle 7 from the geometrical structure 11/111 of the delaying structure is schematically indicated by an arrow R in
Although with respect to the embodiments above a linear arrangement of the chambers of each processing module 2a, 2b, 2c has been described, other arrangements are also possible.
Although with respect to
With respect to all examples/embodiments, several magnetic particles, e.g. formed by magnetic beads, may be provided in each processing module to increase the processing/sequencing speed and/or reduce the total device size and/or costs. As has been described above, different chambers can host different (bio)chemical processes, e.g. in the case of sequencing by synthesis, different chambers can host A-C-T-G incorporation processes, detection processes, quenching processes (e.g. by apyrase), and washing processes. One or more intermediate wash chambers may be provided to reduce contamination of a subsequent chamber which can e.g. be important in sequencing by synthesis (e.g. the wash of apyrase to avoid contamination of subsequent chambers). Each chamber can be attached to a fluid reservoir so that the chambers in the module can be refilled and/or refreshed with a fluid required for the respective processing, e.g. to avoid contamination and/or depletion. For example, the microfluidic device can be realized in a planar construction, i.e. with all channels and chambers arranged in a single plane. However, the micro fluidic device can also be realized with the channels and chambers arranged in different three-dimensional geometries, with in-plane and out-of-plane orientations.
It has been described above that a delaying structure forming a synchronization structure is provided in at least one of the chambers. The delaying structure is shaped as a stop to which the magnetic particle (or particles) is driven by the magnetic force. In a synchronization step, magnetic particles (in one module or in several modules) are actuated toward the delaying structures by application of a magnetic force such that the system is brought to a well-defined state. Synchronization of magnetic particles is achieved by slowing the fastest moving magnetic particles down such that the many-particle system is synchronized and controlled.
The disclosed microfluidic device and method enable high-density processing of actuated magnetic particles in a biochemical processing, synthesis and/or detection device. The microfluidic device is suited for e.g. multiplexed in-vitro diagnostics, multiplexed molecular diagnostics, and highly-parallel sequencing by synthesis.
Number | Date | Country | Kind |
---|---|---|---|
08165887.4 | Oct 2008 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/IB2009/054294 | 10/1/2009 | WO | 00 | 3/23/2011 |