Microfluidic dialysis device

Abstract

A microfluidic dialysis device that has a first channel for receiving a biological sample, a second channel, and a series of adjacent channels extending between the first channel and the second channel. Each of the adjacent channels pin a meniscus of the sample that arrests capillary flow between the first channel and the second channel. A bypass channel between the first channel and the second channel, the bypass channel joining the second channel upstream of the adjacent channels and is configured for uninterrupted capillary driven flow from the first channel to the second channel. Flow from the bypass channel reaches the meniscus pinned at each of the adjacent channels after the meniscus has formed to sequentially remove each of the menisci and allow flow from the first channel to the second channel via the adjacent channels as well as the bypass channel.

1 . A microfluidic dialysis device for a test module configured to analyze a biological sample, the dialysis device comprising:
 a first channel for receiving the biological sample;   a second channel;   a series of adjacent channels extending between the first channel and the second channel, each of the adjacent channels being configured to pin a meniscus of the sample that arrests capillary flow between the first channel and the second channel; and,   a bypass channel between the first channel and the second channel, the bypass channel joining the second channel upstream of the adjacent channels and is configured for uninterrupted capillary driven flow from the first channel to the second channel such that flow from the bypass channel reaches the meniscus pinned at each of the adjacent channels after the meniscus has formed to sequentially remove each of the menisci and allow flow from the first channel to the second channel via the adjacent channels as well as the bypass channel.   
     
     
         2 . The dialysis device according to  claim 1  further comprising a plurality of apertures fluidically at an upstream end of the adjacent channels configured to allow pathogens in the biological sample flow from the first channel to the second channel and larger constituents in the biological sample remain in the first channel. 
     
     
         3 . A test module for analyzing a biological sample, the test module comprising:
 an outer casing with a receptacle for receiving the sample;   a dialysis device with a first channel in fluid communication with the receptacle for receiving the biological sample, a second channel, a series of adjacent channels extending between the first channel and the second channel, and a bypass channel between the first channel and the second channel, each of the adjacent channels being configured to pin a meniscus of the sample that arrests capillary flow between the first channel and the second channel, and the bypass channel joining the second channel upstream of the adjacent channels and is configured for uninterrupted capillary driven flow from the first channel to the second channel such that flow from the bypass channel reaches the meniscus pinned at each of the adjacent channels after the meniscus has formed to sequentially remove each of the menisci and allow flow from the first channel to the second channel via the adjacent channels as well as the bypass channel; and,   a lab-on-a-chip (LOC) device being in fluid communication with the dialysis device and configured to analyze the pathogens.   
     
     
         4 . The test module according to  claim 3  wherein the second channel supplies a target channel and the first channel supplies a waste channel, the target channel being configured for capillary driven flow to the LOC device. 
     
     
         5 . The test module according to  claim 4  wherein pathogens in the biological sample contain target nucleic acid sequences, and the LOC device has a nucleic acid amplification section for amplifying the target nucleic acid sequences. 
     
     
         6 . The test module according to  claim 5  wherein the LOC device has a lysis section for lysing the pathogens to release the target nucleic acid sequences therein. 
     
     
         7 . The test module according to  claim 5  wherein the LOC device has a hybridization section with an array of probes for hybridization with the target nucleic acid sequences to form probe-target hybrids. 
     
     
         8 . The test module according to  claim 7  wherein the probes are configured to form probe-target hybrids with the target nucleic acid sequences, the probe-target hybrids being configured to emit photons of light in response to an excitation electric current. 
     
     
         9 . The test module according to  claim 8  wherein the LOC device has CMOS circuitry for operative control of the PCR section, the CMOS circuitry having a photosensor for sensing photons emitted by the probe-target hybrids. 
     
     
         10 . The test module according to  claim 9  wherein the hybridization section has an array of hybridization chambers containing the probes for hybridization with the target nucleic acid sequences. 
     
     
         11 . The test module according to  claim 10  wherein the photosensor is an array of photodiodes positioned adjacent each of the hybridization chambers respectively. 
     
     
         12 . The test module according to  claim 11  wherein the CMOS circuitry has a digital memory for storing data relating to the processing of the fluid, the data including the probe details and location of each of the probes in the array of hybridization chambers. 
     
     
         13 . The test module according to  claim 12  wherein the CMOS circuitry has at least one temperature sensor for sensing the temperature at the array of hybridization chambers. 
     
     
         14 . The test module according to  claim 13  wherein the LOC device has a heater controlled by the CMOS circuitry using feedback from the temperature sensor for maintaining the probes and the target nucleic acid sequences at a hybridization temperature. 
     
     
         15 . The test module according to  claim 14  wherein the photodiodes are less than 1600 microns from the corresponding hybridization chamber. 
     
     
         16 . The test module according to  claim 15  wherein the probes have an electrochemiluminescent (ECL) luminophore that emits a photon when in an excited state. 
     
     
         17 . The test module of  claim 16  wherein the hybridization chambers have electrodes for exciting the ECL luminophores with electrical current. 
     
     
         18 . The test module according to  claim 17  wherein the ECL probes each have a luminophore and a quencher positioned proximate the luminophore for quenching photons emitted by the luminophore such that hybridization with one of the target nucleic acid sequences moves the quencher away from the luminophore such that the photons are not quenched. 
     
     
         19 . The test module according to  claim 18  wherein the CMOS circuitry has bond-pads for electrical connection to an external device, and is configured to convert output from the photodiodes into a signal indicative of the ECL probes that hybridized with the target nucleic acid sequences, and provide the signal to the bond-pads for transmission to the external device. 
     
     
         20 . The test module according to  claim 13  wherein the LOC device and the dialysis device are fluidically connected via a cap, the cap has at least one channel for fluid communication between the dialysis device and the LOC device, and a plurality of reservoirs for holding liquid reagents for addition to the sample.