Controller/detector interfaces for microfluidic systems

Abstract

The present invention is generally directed to improved methods, structures and systems for interfacing microfluidic devices with ancillary systems that are used in conjunction with such devices. These systems typically include control and monitoring systems ( 620 ) for controlling the performance of the processes carried out within the device, e.g., monitoring and controlling environmental conditions and monitoring results of the processes performed, e.g., detection.

1 . An electrically controlled microfluidic system, comprising: 
 a microfluidic device comprising a body structure having an interior portion and at least a first exterior surface, a plurality of intersecting microscale channels disposed in the interior portion of the body structure, and a plurality of ports disposed in the body structure, communicating the exterior surface with the interior portion, each of the ports being in fluid communication with at least one of the plurality of intersecting channels;    an electrical control system comprising a plurality of electrical leads, each of the leads being operably coupled to a power source, the electrical control system-concomitantly delivering a voltage to each of the plurality of electrical leads;    an electrical interface array, for separately and removably coupling each of the electrical leads with each of the plurality of ports, whereupon each of the leads is in electrical communication with a fluid disposed in each of the ports.    
   
   
       2 . The system of  claim 1 , wherein the electrical interface array comprises a cover having at least a first surface, and a plurality of electrode pins mounted thereon, the electrode pins being oriented for insertion into the plurality of ports, each of the electrode pins being electrically coupled to a separate one of the electrical leads.  
   
   
       3 . The system of  claim 2 , wherein the electrical interface array further comprises a base having adapted for receiving the microfluidic device, wherein an edge of the cover is attached to the base by a hinge, whereby the cover is capable of being rotatably closed over the microfluidic device mounted on the base, to insert the plurality of pins into the plurality of ports.  
   
   
       4 . The system of  claim 3 , wherein the base includes one or more alignment structures for receiving the microfluidic device in a predetermined orientation.  
   
   
       5 . The system of  claim 4 , wherein the alignment structure comprises a nesting well on the base sized to receive the microfluidic device.  
   
   
       6 . The system of  claim 2 , wherein the first surface of the cover comprises raised regions disposed between adjacent electrode pins.  
   
   
       7 . The system of  claim 1 , wherein the microfluidic device further comprises a hydrophobic layer on the exterior portion of the microfluidic device disposed around each of the ports.  
   
   
       8 . The system of  claim 7 , wherein the hydrophobic layer is a hydrophobic coating on the exterior surface of the microfluidic device.  
   
   
       9 . The system of  claim 7 , wherein the hydrophobic layer is a gasket mated with the exterior surface of the microfluidic device.  
   
   
       10 . The system of  claim 2 , wherein the first surface of the cover element comprises a plurality of recessed regions disposed in the first surface of the cover, around each of the electrode pins and extending toward an edge of the cover, providing an air vent for each of the ports when the electrode pins are inserted into the ports.  
   
   
       11 . The system of  claim 2 , wherein the plurality of electrodes are arranged in a grid orientation of at least two rows of electrodes, wherein each row comprises at least two electrodes.  
   
   
       12 . The system of  claim 2 , wherein the plurality of electrode pins are arranged in a gridded orientation of at least three rows of electrodes, wherein each row comprises at least three electrodes.  
   
   
       13 . The system of  claim 1 , wherein: 
 the body structure is planar and has at least one edge;    the electrical interface array comprises a plurality of electrical contact pads disposed along the at least one edge of the microfluidic device, each of the electrical contact pads being electrically coupled to at least one of the plurality of ports; and    each of the plurality of electrical leads is positioned to contact a separate one of the plurality of contact pads.    
   
   
       14 . The system of  claim 13 , further comprising a cover having at least a first surface and a plurality of electrical contacts mounted thereon, each of the electrical contacts being electrically coupled to a separate electrical lead, and wherein each of the electrical contacts is oriented to contact a separate contact pad when the cover is placed over the exterior surface of the microfluidic device.  
   
   
       15 . The system of  claim 14 , wherein the electrical interface array further comprises a base having adapted for receiving the microfluidic device, wherein an edge of the cover is attached to the base by a hinge, whereby the cover is capable of being rotatably closed over the microfluidic device mounted on the base, to contact the plurality of electrical contacts with the plurality of electrical contact pads.  
   
   
       16 . The system of  claim 13 , wherein: 
 the body structure comprises a top layer and a bottom layer, the channels being disposed between the top layer and the bottom layer, and the ports being disposed through the top layer, and wherein at least a portion of the bottom layer extends beyond the top layer along at least one edge; and    the electrical contact pads are disposed upon a portion of the bottom layer that extends beyond the top layer.    
   
   
       17 . The system of  claim 16 , wherein the electrical interface array comprises a coupler having an opening disposed therein, and wherein each of the electrical leads is disposed within the slot and positioned to contact a different contact pad when the extended portion of the bottom layer is inserted into the slot.  
   
   
       18 . The system of  claim 16 , wherein: 
 the top layer comprises a plurality of recessed regions along at least one edge of the body structure, exposing the extended portion of the bottom layer; and    the electrical contact pads are disposed within the recessed regions.    
   
   
       19 . The system of  claim 18 , wherein the electrical interface array comprises: 
 a body structure having a cavity disposed therein, the cavity being adapted for receiving the body structure;    a plurality of electrical contacts disposed along at least one edge of the opening, each electrical contact being positioned to contact a separate electrical contact pad and a separate electrical lead.    
   
   
       20 . The system of  claim 13 , wherein each of the electrical contact pads is electrically coupled to at least one of the plurality of ports by electrical circuitry in electrical contact with the electrical contact pad at a first point and with the at least one port at a second point, and wherein the electrical circuitry is disposed between the top layer and the bottom layer.  
   
   
       21 . The system of  claim 20 , wherein the electrical circuitry has a thickness between about 800 and about 1400 Å.  
   
   
       22 . The system of  claim 20 , wherein the electrical circuitry comprises a metal layer that comprises a metal selected from the group consisting of Tungsten, Palladium, Ruthenium, Iridium, Osmium and Rhodium.  
   
   
       23 . The system of  claim 22 , wherein the electrical circuitry comprises titanium/tungsten.  
   
   
       24 . The system of  claim 23 , wherein the electrical circuitry comprises an adhesion layer that comprises titanium/tungsten and a conductive layer that comprises platinum.  
   
   
       25 . A microfluidic system, comprising: 
 a clam shell comprising:    a base having at least one edge and at least an upper surface, the upper surface being adapted for receiving a microfluidic device; and    the cover having at least a lower surface and at least one edge, the edge of the cover being connected to the edge of the base by a hinge, and the lower surface having at least a first electrical interface component; and    a microfluidic device mounted on the upper surface of the base, the microfluidic device comprising a body structure having an exterior surface, an interior portion defining a plurality of microscale channels, and a second electrical interface component disposed on the exterior surface and providing a plurality of separate electrical connections between the second electrical interface component and a plurality of separate points in the plurality of intersecting microscale channels, the second electrical interface component being complementary to the first electrical interface component and oriented to contact the first electrical interface component when the cover is closed over the microfluidic device.    
   
   
       26 . The microfluidic system of  claim 25 , wherein the first electrical interface array component comprises a plurality of electrode pins mounted on the lower surface of the cover, and the second electrical interface array component comprises a plurality of ports disposed in the exterior surface of the microfluidic device and in fluid communication with the separate points of the plurality of intersecting microscale channels.  
   
   
       27 . The microfluidic system of  claim 25 , wherein the first electrical interface array component comprises an array of electrical contacts mounted on the lower surface of the cover and the second electrical interface array component comprises a plurality of electrical contact pads on the exterior surface of the microfluidic device, each electrical contact pad being in electrical communication with a separate point in the plurality of intersecting microscale channels.  
   
   
       28 . The microfluidic system of  claim 25 , wherein the upper surface of the base includes one or more alignment structures for maintaining the microfluidic device mounted thereon in at least a first predetermined orientation.  
   
   
       29 . The microfluidic system of  claim 28 , wherein the alignment structure comprises a nesting well in the upper surface of the base, sized for receiving the microfluidic device mounted thereon.  
   
   
       30 . A microfluidic system comprising: 
 a base unit having a mounting surface adapted for receiving a microfluidic device, and a first electrical interface array component, the first electrical interface array component providing a plurality of electrical contacts, each of the electrical contacts being separately coupled to a different electrical lead from an electrical controller;    a microfluidic device mounted on the mounting surface, the microfluidic device comprising a body structure having an exterior surface, an interior portion defining a plurality of microscale channels, and a second electrical interface component disposed on the exterior surface and providing a plurality of separate electrical connections between the second electrical interface component and a plurality of separate points in the plurality of intersecting microscale channels, the second electrical interface component being complementary to the first electrical interface component and oriented to contact the first electrical interface component when the microfluidic device is mounted on the mounting surface.    
   
   
       31 . A microfluidic system comprising: 
 a microfluidic device comprising a body structure having at least first and second separate channel networks disposed therein, each channel network comprising a plurality of intersecting microscale channels, a first interface component on the body structure capable of delivering energy to the first channel network, and a second interface component on the body structure capable of delivering energy to the second channel network; and    a controller, comprising an energy source and a first surface adapted for mounting the body structure thereon in at least first and second fixed orientations, and including at least a third interface component operably coupled to the energy source, the third interface component being capable of transmitting energy from the energy source to the first interface component when the body structure is mounted on the mounting surface in the first orientation, and from the energy source to the second interface component when the body structure is mounted on the mounting surface in the second orientation.    
   
   
       32 . The microfluidic system of  claim 31 , wherein the first surface is adapted for mounting the body structure thereon in at least four fixed orientations.  
   
   
       33 . A microfluidic system comprising: 
 a microfluidic device comprising a body structure having at least first and second separate channel networks disposed therein, each channel network comprising a plurality of intersecting microscale channels, a first interface component on the body structure capable of transmitting energy from the first channel network, and a second interface component on the body structure capable of transmitting energy from the second channel network; and    a detection system, comprising an energy detector and a first surface adapted for mounting the body structure thereon in at least first and second fixed orientations, and including at least a third interface component operably coupled to the energy detector, the third interface component being capable of transmitting energy from the first interface component to the detector when the body structure is mounted on the mounting surface in the first orientation, and from the second interface component to the detector when the body structure is mounted on the mounting surface in the second orientation.    
   
   
       34 . The microfluidic system of  claim 33 , wherein the first surface is adapted for mounting the body structure thereon in at least four fixed orientations.  
   
   
       35 . An electrically controlled microfluidic system comprising: 
 a microfluidic device having an exterior portion and an interior portion defining a plurality of ports disposed at unintersected termini of a plurality of microscale channels, each port being electrically coupled to a different one of a plurality of electrical contacts on the exterior portion of the microfluidic device;    a power source comprising a plurality of electrical leads, the power source being capable of delivering a different voltage to each of the leads;    an electrical interface component, for reversibly electrically coupling each of the leads to at least one of the plurality of electrical contacts.    
   
   
       36 . The microfluidic system of  claim 35 , wherein each port is electrically coupled to a different one of the electrical contacts via an electrical conduit disposed within the interior portion of the microfluidic device, the electrical conduit comprising: 
 a thickness less than 1500 Å;    at least a first metal component selected from the group of tungsten, palladium, ruthenium, iridium, osmium and rhodium; and    wherein the electrode does not substantially degrade at a metal/fluid interface under applied current densities greater than 10 μA/cm 2 .    
   
   
       37 . The microfluidic system of  claim 36 , wherein the electrical conduit does not substantially degrade at a metal/fluid interface, under applied currents of greater than 0.1 mA/cm 2 .  
   
   
       38 . The microfluidic system of  claim 36 , wherein the electrical conduit does not substantially degrade at the metal/fluid interface under applied currents of greater than 1 mA/cm 2 .  
   
   
       39 . The microfluidic system of  claim 36 , wherein the electrical conduit does not substantially degrade at temperatures between about 500° C. and about 1400° C.  
   
   
       40 . The microfluidic system of  claim 36 , wherein the first metal component is titanium/tungsten alloy.  
   
   
       41 . The microfluidic system of  claim 36 , further comprising a platinum conductive layer overlaying the first metal component.  
   
   
       42 . The microfluidic system of  claim 41 , wherein the first metal component is between about 50 and about 600 Å thick and the conductive layer is between about 400 and about 1200 Å thick.  
   
   
       43 . The microfluidic system of  claim 36 , wherein the electrode is disposed between opposing surfaces of two solid planar substrates that are bonded together.  
   
   
       44 . An electrode for applying a current to a fluid, the electrode comprising: 
 a thickness less than 1500 Å;    at least a first metal component selected from the group of tungsten, palladium, ruthenium, iridium, osmium and rhodium; and    wherein the electrode does not substantially degrade at a metal/fluid interface under applied current densities greater than 10 μA/cm 2 .    
   
   
       45 . The electrode of  claim 44 , wherein the electrode does not substantially degrade at applied current densities of greater than 0.1 mA/cm 2 .  
   
   
       46 . The electrode of  claim 44 , wherein the electrode does not substantially degrade at applied current densities of greater than 1 mA/cm 2 .  
   
   
       47 . The electrode of  claim 44 , wherein the electrode does not substantially degrade at applied current densities of greater than 10 mA/cm 2 .  
   
   
       48 . The electrode of  claim 44 , wherein the electrode does not substantially degrade at temperatures between about 500° C. and about 1400° C.  
   
   
       49 . The electrode of  claim 44 , wherein the first metal component is titanium/tungsten.  
   
   
       50 . The electrode of  claim 44 , further comprising a platinum conductive layer overlaying the first metal component.  
   
   
       51 . The electrode of  claim 50 , wherein the first metal component is between about 50 and about 600 Å thick and the conductive layer is between about 400 and about 1200 Å thick.  
   
   
       52 . The electrode of  claim 44 , wherein the electrode is disposed between opposing planar surfaces of two solid planar substrates that are bonded together.  
   
   
       53 . The electrode of  claim 52 , wherein the opposing surfaces of the two solid planar substrates define a microscale channel network, the electrode being in electrical contact with the channel network.  
   
   
       54 . An interface for use with a microfluidic device, the microfluidic device having a plurality of intersecting microscale channels and a plurality of ports for receiving fluid, the interface comprising: 
 a base for receiving the microfluidic device;    a structure movable relative to the base between a first position and a second position;    a plurality of electrical interface elements a fixed to the structure, the electrical interface elements aligned so that each electrical interface element is electrically coupled to an associated port when the microfluidic device is received by the base and the structure is disposed in the first position.    
   
   
       55 . The interface of  claim 54 , wherein the plurality of electrical interface elements comprises at least three electrical interface elements.  
   
   
       56 . The interface of  claim 55 , wherein the structure comprises a rigid member, and wherein the electrical interface elements comprise electrodes, the electrodes extending from the structure into the fluid in the ports of the microfluidic device when the microfluidic device is received by the base and the structure is disposed in the first position.  
   
   
       57 . The interface of  claim 56 , wherein the structure is mechanically coupled to the base and the base fittingly receives the microfluidic device so as to maintain alignment between the electrodes and the ports when the structure moves between the first position and the second position, the electrodes being outside of the ports when the microfluidic device is received by the base and the structure is disposed in the second position.  
   
   
       58 . The interface of  claim 57 , wherein the structure is rotatably coupled to the base, the structure comprising a cover, the cover and base receiving the microfluidic device therebetween.  
   
   
       59 . An instrument comprising: 
 an electrical power supply operably coupled to the interface of  claim 54 .    
   
   
       60 . A microfluidic device comprising: 
 a body structure having an interior portion defining a plurality of intersecting microscale channels and a port for receiving fluid, wherein the interior portion blocks fluid communication between the channels and the port; and    an electrical interface component electrically coupling the fluid in the port to the channels, or to a port in fluid communication with the channels.    
   
   
       61 . The device of  claim 60 , wherein the electrical interface component extends from the port to an unintersected terminus of a microscale channel.  
   
   
       62 . The device of  claim 61 , further comprising a port disposed at the unintersected terminus.  
   
   
       63 . The device of  claim 61 , further comprising a plurality of electrical interface components, each of the electrical interface components extending from an associated port to an associated unintersected terminus so as to electrically couple the associated port to the associated unintersected terminus, wherein the interior portion of the body structure blocks fluid communication between the ports and the channels.  
   
   
       64 . The device of  claim 60 , wherein the body structure comprises a top layer and a bottom layer, the port extending through the top layer, the electrical interface component comprising an electrical conductor disposed between the top layer and the bottom layer.  
   
   
       65 . The device of  claim 64 , wherein the conductor extends along the bottom layer into the port for electrical coupling with the fluid in the port, the conductor having a width and a thickness and a which is less than the width.  
   
   
       66 . The device of  claim 65 , further comprising a first electrode extending into the port for delivering an electrical voltage to the channels, the electrode coupled to the channels via the fluid in the port and via the conductor, in series.  
   
   
       67 . The device of  claim 66 , further comprising an array of electrodes extending into an aligned array of ports, the electrodes coupled to a plurality of conductors via fluid in the conductors, the fluid in the conductors coupled to the channels only via the conductors.  
   
   
       68 . A microfluidic device comprising: 
 a body structure including an upper layer and a bottom layer, the body structure having an interior portion defining first and second intersecting microscale channels, the first channel having an unintersected terminus, the upper later having first and second ports therethrough, the first port disposed at the terminus of the first channel, the interior portion blocking fluid communication between the first port and the second port; and    an electrically conductive film disposed between the first and second layers, the film electrically coupling a first fluid in the first port with a second fluid in the second port, the first fluid being different than the second fluid.    
   
   
       69 . The device of  claim 68 , further comprising an electrode movable between a first position and a second position, the electrode in the first position being clear of the body structure, the electrode in the second position extending downward into the second port so that the second port electrically couples the electrode to the conductive film.  
   
   
       70 . The device of  claim 69 , wherein the second port defines an axis, wherein the conductive film extends along a plane at an angle to the port axis, wherein the electrode moves axially between the first position and the second position, and wherein the electrode in the second position is separated from the film so as to avoid damaging the film when the electrode moves.  
   
   
       71 . The use of an interface to connect a microfluidic device to an electrical controller, the interface having a structure that includes a plurality of fixed electrodes disposed thereon, the electrodes being operably coupled to the electrical controller, the plurality of fixed electrodes being positioned on the structure to be inserted into a plurality of ports on the microfluidic device when the structure is moved from a first position to a second position.  
   
   
       72 . The use of  claim 71 , wherein the ports have a fluid disposed therein.  
   
   
       73 . The use of  claim 71 , wherein the structure is rotably mounted on a base, the base being configured to receive the microfluidic device, and the structure rotating form the first position to the second position.  
   
   
       74 . The use of  claim 71 , wherein the electrodes comprise a plurality of conductive pins disposed on the structure.