Abstract:
A microfluidic connector comprises an enclosure, a fluidic inlet port and a fluidic outlet port, in the enclosure, in which the inlet and outlet ports are movable with respect to each other, for example, mutual spacing between the inlet and outlet ports is variable. A port is in a fixed part of the enclosure, and another port is in a part of the enclosure which slides with respect to the fixed part. There may be multiple inlet ports and/or multiple outlet ports. Also, there may be an auxiliary port for introduction of fluid into the enclosure or removal of fluid from the enclosure.

Description:
FIELD OF THE INVENTION 
       [0001]    The invoice relates to a connector between fluidic conduits such as channels or tubes. The invention relates particularly to the microfluidic scale. 
         [0002]    PRIOR ART DISCUSSION 
         [0003]    A frequent requirement in microfluidics is to make a temporary but sound connection between two tubes or channels. Examples are, for instance, where a part with fluidic connections to other parts needs to be removed, may need to be disregarded because of contamination, or it may need to be refilled with reagents. Another example is when the connection between two or more tubes needs to be changed automatically, where for instance the contents of a well is delivered sequentially to many tubes. 
         [0004]    It is known to provide a connector that is manually disconnected and reconnected. It is also known to use valves so that a fluidic line is closed and another opened to redirect the fluid flow. 
         [0005]    The invention is directed towards providing an improved fluidic connector. 
       SUMMARY OF THE INVENTION 
       [0006]    According to the invention, there is provided a microfluidic connector comprising an enclosure, a fluidic inlet port, and a fluidic outlet port in the enclosure, in which the inlet and outlet ports are movable with respect to each other. 
         [0007]    In one embodiment, the mutual spacing between the inlet and outlet ports is variable. 
         [0008]    In one embodiment, a port is in a fixed part of the enclosure, and another port is in a part of the enclosure which is movable with respect to said fixed part. 
         [0009]    In one embodiment, the movable part slides within the fixed part. 
         [0010]    In one embodiment, the connector comprises a plurality of inlet ports. 
         [0011]    In one embodiment, the connector comprises a plurality of outlet ports. 
         [0012]    In one embodiment, the connector further comprises an auxiliary port for introduction of fluid into the enclosure or removal of fluid from the enclosure. 
         [0013]    In one embodiment, the inlet ports and/or the outlet ports extend through a movable support for changing mutual alignment of ports. 
         [0014]    In one embodiment, the connector comprises a single inlet port and a plurality of outlet ports, the enclosure being configured as a manifold. 
         [0015]    In one embodiment, the connector comprises a single outlet port and a plurality of inlet ports, the enclosure being configured as a mixer. 
         [0016]    In one embodiment, the enclosure is an inner enclosure mounted within an outer enclosure. 
         [0017]    In one embodiment, there is a port in the inner enclosure for flow of fluid between the inner enclosure and the outer enclosure. 
         [0018]    In one embodiment, the outer enclosure has an outlet port. 
         [0019]    In one embodiment, there are a plurality of inner enclosures within the outer enclosure. 
         [0020]    In another aspect, the invention provides a method of controlling fluidic flow through any connector defined above, the method comprising the steps of directing flow of a carrier fluid carrying discrete plugs or droplets of a different fluid so that the plugs or droplets transfer from the inlet port to the outlet port. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
       Brief Description of the Drawings 
         [0021]    The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which: 
           [0022]      FIG. 1  is a cross-sectional diagram of a fluidic connector of the invention; 
           [0023]      FIG. 2  is a cross-sectional diagram of the connector in use as a two-phase inlet and outlet across a liquid bridge; 
           [0024]      FIG. 3  is a cross-sectional diagram of a connector with two inlets and outlets; 
           [0025]      FIG. 4  is a cross-sectional diagram of a connector with a flowing bath liquid; 
           [0026]      FIG. 5  is a cross-sectional diagram of a fluidic connector in which the connection may be changed by moving one set of ports relative to the others; 
           [0027]      FIG. 6  is a cross-sectional diagram and an end view of a fluidic connector which acts as a manifold by connecting multiple outlet ports to a single inlet port; 
           [0028]      FIG. 7  is a cross-sectional diagram of fluidic connectors in a bath of immiscible fluid; 
           [0029]      FIG. 8  is a cross-sectional diagram of a fluidic bath containing an array of fluidic bridges with a common outlet port and in which the bridges do not need to be sealed from each other; and 
           [0030]      FIG. 9  is a cross-sectional diagram of a fluidic bath containing a lattice of tubes arranged as fluidic bridges with a common outlet port. 
       
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       [0031]    In a microfluidic system, a liquid bridge forms a connection between inlet and outlet ports. This works in a two or more phase flow where one of the phases is attached to the end of the inlet and outlet ports and therefore can be made to bridge between these ports, with the boundaries of these bridges defined by the region of interfacial tension between the two phases. By this means a solid connection between two tubes is replaced by a liquid one. The connection may therefore be broken and remade without effort for many connections, many times. 
         [0032]    The following are aspects and advantages:
       The connector does not bring the connecting channels or tubes into contact but instead immerses them in a fluid well.   It allows a two phase fluid to flow across a junction with the second phase in droplets bridging across the junction.   There may be many inlets and outlets with each inlet connecting with an outlet so that for a multiple phase inlet multiple bridges will be formed. In this arrangement there may be a fluid flow into a fluid bath so that a single aqueous phase at inlet will be segmented at exit. Also, there may be fluid flow from the bath so that the aqueous phase droplets can mix. In addition the inlet ports may be moved relative to the outlet ports so that a variety of inlet/outlet combinations can be formed.   There may be fewer inlets than outlets and the inlet bridges the outlet when the aqueous phase is present at the bridge, forming a manifold that distributes the aqueous phase between the outlets. With the addition of an out of plane tube or channel this fluidic connector can be converted into a segmenter.   There may be fewer outlets than inlets and the inlet bridges the outlet when the aqueous phase is present at the bridge, forming a mixer that combines the phases entering from the inlets into a single mixed phase exiting through the outlet. With the addition of an out-of-plane tube or channel this fluidic connector can be converted into a segmenter.   There may be one or more fluidic connectors contained in an immiscible fluid so as to eliminate the problem of leakage from the connector to the surroundings.   There may be an array of fluidic bridges with a common outlet port, and where each bridge does not need to be sealed from each other. In this aspect the fluidic bridges may be replaced by means of a lattice of tubes.       
 
         [0040]      FIG. 1  shows a connector  1  fluidically joining a tube  2  to a tube  3  across a bath  4  of fluid  5 . Two parts  6  and  7  are attached to the tubes  2  and  3  respectively, and are sealed. Part  7  can be removed from part  6 , making the device a reusable connector. 
         [0041]    For single phase fluid connections, of either a gas or a liquid, the tubes and bath are continuously filled with that fluid. For a two-phase liquid flow, where one phase is in the form of plugs or droplets separated by the second immiscible phase, one phase continuously fills the bath and the second phase periodically bridges the ends of tubes  2  and  3 , as shown in  FIG. 2 . The connector  1  may also be configured such that an immiscible phase fills the bath  4  and a second phase flows continuously from  2  to  3  across a permanent liquid bridge. 
         [0042]      FIG. 3  shows multiple inlets and outlets configured in a connector  20 , in which two are shown. A connector  20  has a bath  21 , two inlets  22  and  23 , and two outlets  24  and  25 . The bath  21  is composed of two parts,  27  and  28 . 
         [0043]    The connector  20  may be used as follows:
   (1) The same fluid fills tubes  22 ,  23 ,  24  and  25  and the bath  21 . Here, an advantage is that very many connections can be made by simply connecting  27  to  28  and the connections may be made and remade many times without damage to the tubes.   (2) A two-phase fluid flows in and out of the ports in the same manner as described with reference to  FIG. 2 . The same advantage given in (1) above applies.   (3) A different fluid flows in at  22  and  23  and out at  24  and  25  respectively with the bath  21  filled with an immiscible liquid. There is thereby no cross contamination between the streams. The same advantage given in (1) above applies.   
 
         [0047]      FIG. 4  shows a connector  40  having two inlets  41  and  42 , two outlets  43  and  44 , an auxiliary port  45 , and parts  47  and  48  of the bath  46 . In this diagram only two inlets and two outlets are shown however multiple inlets and outlets may be used. It has the same configuration as that of  FIG. 3  but with the addition of the port  45  to allow flow into or out of the bath. When flow is taken from the port  45 , two phase flows at the inlets  41  and  42 , in the form of plugs or droplets can be merged in the bath and delivered either as a continuous phase from the ports  43  and  44 , or as two phases, but with the most closely spaced droplets or plugs mixed into one. The connector may therefore also be used to mix two fluids. When flow is fed in at  45 , if the flow rates are correctly matched, a continuous phase at ports  41  and  42  can be segmented into droplets or plugs for delivery at outlet ports  43  and  44 . 
         [0048]    The ports can be arranged in various embodiments in lines opposite each other or in a cylinder with the tubes running axially, or in any geometrical configuration which allows for the ends of tubes to be arranged on the same axis. The tubes at inlet and outlet can also be of any internal and external diameter to facilitate the bridging. With regard to  FIG. 4 , the most common requirement would be for all inlet and outlet ports to operate under the same conditions. The flow into port  45  would therefore need to be suitably distributed so that it is divided equally between the ports that it delivers to, or takes from. The fluidic bridge connections are somewhat forgiving of misalignment of the axis of the bridge inlet and outlet tubes. 
         [0049]      FIG. 5  shows a connector  60  having inlet ports  61  and  62 , outlet ports  63  and  64 , and a bath  65  defined between moveable supports  66  and  67 . Parts  65  and  67  may exist as one part where only part  6  is moveable. The connections between ports may be changed by simply moving one set of ports relative to another so as to line up different inlets with different outlets in the bath. The two inlet ports  61  and  62  are shown with corresponding outlet ports  63  and  64 . By rotating part  66  relative to  67 . The connections may be changed between  61 - 63  and  62 - 64  to  61 - 64  and  62 - 63 . This may be done many times for many connections. Turning on an axis is only one method of achieving relative movement of ports. Part  66  may be driven by an orthogonally orientated stepper motor, hydraulic drives or pneumatic drives so that any inlet port maybe positioned adjacent to any outlet port. The transition is best completed in a two phase flow, where the phase in the bath is passed between ports during the transition and the bridging phase is transmitted when the support  66  is stationery relative to support  67 . By this means fast, reliable, repeatable and near zero maintenance connections may be made for many inlet and outlet ports. 
         [0050]      FIG. 6  shows a connector  80  having a single inlet port  81 , a bath  82  with enclosure parts  86  and  87 , and multiple outlet ports  83 . An inlet port can be used to feed equal flow to multiple outlets. The inlet port  81  is centred with the outlet ports  83  circumferentially positioned at equidistance from each other. When fluid flows from the inlet, the aqueous phase bridges with all multiple outlet ports simultaneously. The outlet flow in each tube is equal with the connector acting as a manifold. With the addition of an out-of-plane tube or channel of fluid flow into the bath this fluidic connector can be converted into a segmenter. 
         [0051]    Also, if the flow through the system is reversed with the existence of one outlet port with many inlets, the fluidic connector becomes a mixer where multiple phases entering simultaneously through the inlets bridge with the single outlet and thus create one single phase. Again, with the addition of an out of plane tube or channel of fluid flow into the bath this fluidic connector can be converted into a segmenter. 
         [0052]    As illustrated in  FIG. 7  the fluidic connectors  90  can also sit in a bath  91  of immiscible fluid. Two bridges are shown in the diagram however any number of fluidic connectors can be used. The bridges have two inlet tubes or channels  93  and  94  entering into the bath and join with the fluidic connector while two outlet tubes or channels  95  and  96  extend out from the bridge and out of the bath. In this embodiment instead of the bridges being set in a solid material they are in a bath of the same immiscible fluid as used in the bridges. There is then no need to be concerned about sealing the bridge tubes. This overcomes the problem of ensuring that no liquid will leak from the bridge. 
         [0053]      FIG. 8  shows a connector  100  having a main bath  101  within which are two baths  102 , each having an inlet port  103 , an outlet port  104 , and an auxiliary inlet port  105 . In this embodiment only two bridges are shown, for illustration. Instead of connecting outlet ports  109  to a separate withdrawal system, the withdrawal is to a common reservoir from which fluid is withdrawn from the one port  110 . Only the immiscible fluid is drawn from the ports  109  while aqueous phase arriving at either of the inlet ports  103  and  105  exits to the lower outlet ports  104 . Because of this the bridges can all be fully immersed and sealed in a bath of the immiscible fluid, but they do not need to be sealed from each other, making their manufacture and assembly considerably easier. 
         [0054]    The potential for further simplification is shown in  FIG. 9 , in which like parts have the same reference numerals. Here, the structure of the withdrawal bridges is removed to leave only a lattice of tubes in a bath of oil phase (2). Internal structures, not shown, are only important here to support the two inlets  103  and  105  and one outlet port  104  for each bridge. The outlet port  110  is configured and positioned so that the withdrawn flow rate is the same for each of the constituent bridges. The network of bridges may be repeated many times and may be constructed at very small length scales (&gt;10 μm), to form a compact microfluidic circuit. If the problem of equal extraction of the immiscible fluid from the outlet ports  104  is difficult to solve then individual ports, local to each bridge, can be used to extract the immiscible fluid from the reservoir. 
         [0055]    It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. It will be appreciated that the invention provides excellent versatility in bridging of microfluidic flows. The mutual positions of the ports may be changed to optimum positions according to fluidic characteristics and desired outlet flow parameters. For example, there may be adjustment to provide a desired droplet size in outlet flow. 
         [0056]    The invention is not limited to the embodiments described but may be varied in construction and detail.