CA-3088509-C - MICROFLUIDIC DEVICE WITH VENTED MICROCHAMBERS

CA3088509CCA 3088509 CCA3088509 CCA 3088509CCA-3088509-C

Abstract

A microfluidic device with a microfluidic circuit including an array of fluidly coupled microchambers. Each microchamber includes a reaction chamber and an associated vent chamber. The microfluidic circuit may be arranged so that a fluid sample introduced to microfluidic device flows into the reaction chamber and air or other gas present in the reaction chamber is vented from the microchamber through the vent chamber. The microchamber may be configured to allow only the flow of air into the vent chamber from the reaction chamber until the air has been displaced from the reaction chamber by the fluid sample and/or a predefined volume of the fluid sample has been received in the reaction chamber. The microchamber may be further configured to release the fluid sample to thereafter flow from the reaction chamber into the vent chamber.

Inventors

Kabir James Yamana
Sean Yamana-Hayes

Assignees

QIAGEN SCIENCES, LLC

Dates

Publication Date: 20260505
Application Date: 20181220
Priority Date: 20180117

Claims (2)

CLAIMS: 1. A microfluidic device for handling a fluid sample comprising: at least one microfluidic well configured to receive the fluid sample, the at least one microfluidic well comprising a primary inlet fluidly coupled to an inlet microfluidic channel, the inlet microfluidic channel fluidly coupled to a plurality of parallel microfluidic channels at inlet ends of the parallel microfluidic channels, each microfluidic channel comprising a plurality of microchambers arranged in series that are fluidly coupled, via an outlet end, to an outlet microfluidic channel, the outlet microfluidic channel fluidly coupled to a primary vent configured to vent gas from the parallel microfluidic channels, wherein each microchamber comprises a reaction chamber configured to receive the fluid sample and a vent chamber configured to vent gas from the reaction chamber as the fluid sample flows into the reaction chamber, wherein the reaction chamber is fluidly coupled to a corresponding microfluidic channel via an inlet and the vent chamber is fluidly coupled to said corresponding microfluidic channel via an outlet, wherein the reaction chamber is configured to flow the fluid sample to the vent chamber after the gas has been vented to the outlet.
2. The microfluidic device according to claim 1, wherein the reaction chamber is larger than the vent chamber. 25 3. The microfluidic device according to claim 1, wherein the vent chamber is configured with a narrow hydrophobic stricture to initially prevent flow of the fluid sample from the reaction chamber while allowing flow of gas from the reaction chamber as the fluid sample flows into the reaction chamber. 30 4. The microfluidic device according to claim 3, wherein the vent chamber is configured to release flow of the fluid sample from the reaction chamber when the gas has been vented from the reaction chamber. 17 Date Re9ue/Date Received 2023-12-21 86750451 5. The microfluidic device according to claim 1, wherein the reaction chamber has a diameter D and the vent chamber has a length L extending in a direction along the plurality of micro:fluidic channels arranged in parallel and a width W extending in a direction perpendicular to the length, 5 wherein the vent chamber has a diameter-to-width ratio based on the diameter (D) of the reaction chamber compared to the width (W) of the vent chamber ofD/W 2::. 2 and length-towidth ratio based on the length (L) and width (W) of the vent chamber ofL/W 2::. 0.7. 6. The micro:fluidic device according to claim 5, the vent chamber has a length-to- 10 width ratio ofL/W 2::. 0.8. 7. The micro:fluidic device according to claim 6, the vent chamber has a length-towidth ratio of L/W 2::. 0.9. 15 8. The micro:fluidic device according to claim 7, the vent chamber has a length-towidth ratio of L/W 2::. 1. 9. The micro:fluidic device according to claim 5, wherein the reaction chamber has a depth d and a depth-to-diameter ratio of d/D ::::; 2. 10. The microfluidic device according to claim 9, wherein the reaction chamber has a depth-to-diameter ratio d/D of about 1.5. 11. The microfluidic device according to claim 5, wherein the reaction chamber has a 25 diameter D ::::; 600 μm. 12. The microfluidic device according to claim 11, wherein the reaction chamber has a diameter D of at least 60 μm. 13. The microfluidic device according to claim 1, wherein each reaction chamber has a depth d and each microfluidic channel comprising a plurality of microchambers has segments connecting the plurality of microchambers, wherein the segments have a depth d2, a ratio d/d2 of the reaction chamber depth to the micro:fluidic channel segment depth being no more than 2: 1. 18 Date Re9ue/Date Received 2023-12-21 86750451 14. The microfluidic device according to claim 13, wherein the vent chamber has a depth which is at least 50% of the reaction chamber depth. 15. A microfluidic device for handling a fluid sample, the microfluidic device compnsmg: at least one microfluidic well configured to receive the fluid sample; and a microfluidic circuit provided in the at least one microfluidic well, the microfluidic circuit configured to distribute the fluid sample within the at least one microfluidic well; 10 the microfluidic circuit including a plurality ofreaction chambers, at least one microfluidic channel fluidly coupling the plurality of reaction chambers, and a plurality of microfluidic valves associated with the plurality of reaction chambers, each microfluidic valve being fluidly coupled to an associated reaction chamber; each reaction chamber configured to receive a fluid sample from the at least one 15 microfluidic channel and each microfluidic valve configured to vent gas from a corresponding reaction chamber via the at least one microfluidic channel as the fluid sample flows into the reaction chamber, wherein each reaction chamber is arranged in the microfluidic circuit to receive fluid from an upstream segment of the at least one microfluidic channel and each microfluidic valve is 20 arranged in the microfluidic circuit to deliver fluid to a downstream segment of the at least one microfluidic channel. 16. The microfluidic device according to claim 15, wherein the plurality of reaction chambers includes first and second reaction chambers, one of the plurality ofmicrofluidic valves 25 being located between the first and second reaction chambers. 17. The microfluidic device according to claim 16, wherein the first reaction chamber is fluidly coupled to the microfluidic valve and the microfluidic valve is fluidly coupled to the second reaction chamber, the microfluidic circuit being arranged to direct the fluid sample to 30 flow from the first reaction chamber through the microfluidic valve to the second reaction chamber. 19 Date Re9ue/Date Received 2023-12-21 86750451 18. The microfluidic device according to claim 17, wherein the microfluidic valve is configured to restrict the flow of the fluid sample from the first reaction chamber until the first reaction chamber is essentially free of air. 5 19. The microfluidic device according to claim 15, wherein each microfluidic valve is configured to be a passive valve. 20. The microfluidic device according to claim 15, wherein each microfluidic valve is formed of a hydrophobic material. 21. The microfluidic device according to claim 20, wherein each microfluidic valve is formed from one or more of polypropylene, polyethylene and PTFE. 22. (a) A method of handling a fluid sample, the method comprising acts of: delivering a fluid sample to a microfluidic device including a plurality of microchambers and at least one microfluidic channel fluidly coupling the plurality of microchambers, each microchamber including a reaction chamber and a vent chamber fluidly coupled to the reaction chamber; (b) directing the fluid sample into the reaction chamber of each microchamber 20 through a first segment of the at least one microfluidic channel; and ( c) venting gas from the reaction chamber via the vent chamber through a second segment of the at least one microfluidic channel as the fluid sample flows into the reaction chamber, directing the fluid sample to flow from the reaction chamber to the vent chamber, and directing the fluid sample to flow from the vent chamber to the second segment of the at least 25 one microfluidic channel. 23. The method according to claim 22, wherein during act (c), the fluid sample is released from the reaction chamber into the vent chamber when the gas has been vented from the reaction chamber and the reaction chamber is essentially free of air. 24. The method according to claim 22, wherein the plurality of microchambers includes first, second and third microchambers fluidly coupled by the at least one microfluidic channel, the first segment of the at least one microfluidic channel fluidly coupling the first and Date Re9ue/Date Received 2023-12-21 86750451 second microchambers and the second segment of the at least one microfluidic channel fluidly coupling the second and third microchambers. 25. The method according to claim 22, further comprising act (d) of performing 5 digital PCR in the microfluidic device after :filling the reaction chambers with the fluid sample. 21 Date Re9ue/Date Received 2023-12-21

Description

MICROFLUIDIC DEVICE WITH VENTED MICROCHAMBERS FIELD Aspects of the present disclosure relate generally to methods and devices for microfluidic handling. DISCUSSION OF RELATED ART Polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a single copy or a few copies of a segment of DNA across several orders of magnitude, generating millions to billions of copies of a particular DNA sequence. It is an easy, inexpensive, and 10 reliable way to repeatedly replicate a focused segment of DNA, a concept which is applicable to numerous fields in modem biology and related sciences. PCR is a common technique used in clinical and research laboratories for a broad variety of applications. Examples of such applications include DNA cloning for sequencing, gene cloning and manipulation, gene mutagenesis; construction of DNA-based phylogenies, or 15 functional analysis of genes; diagnosis and monitoring of hereditary diseases; amplification of ancient DNA; analysis of genetic fingerprints for DNA profiling (for example, in forensic science and parentage testing); and detection of pathogens in nucleic acid tests for the diagnosis of infectious diseases. PCR methods typically rely on thermal cycling, which involves exposing reactants to 20 cycles of repeated heating and cooling, permitting different temperature-dependent reactions, specifically DNA melting and enzyme-driven DNA replication, to quickly proceed many times in sequence. Primers (short DNA fragments) containing sequences complementary to the target region, along with a DNA polymerase, enable selective and repeated amplification. As PCR progresses, the DNA generated is itself used as a template for replication, setting in motion a 25 chain reaction in which the original DNA template is exponentially amplified. For example, when exposed to a relatively high temperature (e.g., greater than 90 C), double helix molecules of a DNA sample are separated into single strands. At a relatively lower temperature (e.g., 50-70 C), DNA primers attach at target sites to single strands of the DNA sample. At an intermediate range of temperature (e.g., 60-80 C), the polymerase facilitates 30 elongation of DNA fragments formed from the initial attachment of primers to the singlestranded DNA molecules. The double-stranded DNA products of one PCR cycle can then be 1 WO 2019/143440 PCT/0S2018/066706 split at the relatively high temperature range and bound to new primer strands, doubling the amount of DNA in every cycle until the reagents are exhausted. Thus, the concentration of a DNA sample containing a target DNA sequence, when subject to PCR, may increase exponentially. 5 Digital PCR (dPCR) is a type of PCR analysis that involves dividing a DNA sample into a large number of separate aliquots, and amplifying the aliquots to determine whether a molecule of target DNA was present within the aliquot. Based on the number of aliquots that have undergone exponential growth, the original concentration of DNA prior to partitioning may be determined. Digital PCR can provide increased detection specificity. In cases where the target is relatively rare compared to the amount of non-target DNA, the background DNA can compete for reagents and cause non-specific amplification. Partitioning the sample into many small chambers on a dPCR microplate increases the effective concentration of rare targets in the partitions. 15 It is an object of the invention to provide a microfluidic device for handling fluid samples which may undergo dPCR or other techniques associated with molecular biology. SUMMARY The present disclosure relates to a microfluidic device, such as a microplate, for handling 20 fluid samples which may be subjected to various techniques associated with molecular biology applications. According to one aspect, the microfluidic device comprises at least one microfluidic well configured to receive a fluid sample. The at least one microfluidic well includes a plurality of microchambers and at least one microfluidic channel fluidly coupling the plurality of 25 microchambers. Each microchamber includes a reaction chamber and a vent chamber, the reaction chamber configured to receive the fluid sample from the microfluidic channel and the vent chamber configured to vent gas from the reaction chamber via the microfluidic channel as the fluid sample flows into the reaction chamber. According to another aspect, the microfluidic device comprises at least one microfluidic 30 well configured to receive a fluid sample, and a microfluidic circuit provided in the at least one microfluidic well. The microfluidic circuit is configured to distribute the fluid sample within the microfluidic well. The microfluidic circuit includes a plurality of reaction chambers, at least one 2 WO 2019/143440 PCT/0S2018/066706 microfluidic channel fluidly coupling the reaction chambers, and a plurality of microfluidic valves associated with the plurality of reaction chambers. Each microfluidic valve