Microfluidic Cassette

Abstract

Disclosed herein is a microfluidic cassette comprising a microfluidic cassette body comprising a fluid flow path, a first piercing member comprising a wall extending outwardly from the microfluidic cassette body, the wall surrounding a first fluid opening in fluid communication with the fluid flow path, and a second piercing member comprising a wall extending outwardly from the microfluidic cassette body adjacent to the first piercing member, the wall surrounding a second fluid opening in fluid communication with the fluid flow path, the first piercing member comprising a further fluid opening located on a portion of the wall of the first piercing member facing away from the second piercing member.

Description

[Technical Field]

[0001] The present invention relates to microfluidic cassettes and associated microfluidic diagnostic systems that use such cassettes. [Background technology]

[0002] Microfluidic diagnostic devices are used to provide rapid point-of-care diagnosis of health conditions based on fluid samples provided by patients. The microfluidic diagnostic devices include components that interact with the fluid samples contained within microfluidic cassettes to enable diagnostic tests to be performed.

[0003] Microfluidic cassettes typically include a plurality of fluid flow paths that allow a fluid sample provided by a patient to pass through the cassette and interact with various reagents contained within the cassette. Such microfluidic cassettes typically include an imaging / sensing region where a microfluidic diagnostic device can perform imaging and / or sensing on the fluid sample within the cassette.

[0004] To help ensure accurate and reliable results from microfluidic diagnostic devices, it is desirable that the reagents within the cassettes be well maintained, away from moisture and other contaminants. Moisture can be an issue when using dry or wet reagents. However, moisture is particularly problematic when using lyophilized reagents because such reagents are hydrophilic, meaning that even small amounts of moisture can interact with such reagents and potentially reduce their effectiveness.

[0005] It is known to deposit reagents directly onto the fluid flow paths of a microfluidic cassette during cassette manufacturing. However, in this configuration, even if the microfluidic cassette is sealed during manufacturing, moisture from the atmosphere or vapors from fluids intentionally stored in the cassette can contact and degrade the reagents over time. This can reduce the effectiveness of diagnostic tests performed using the cassette and / or shorten the shelf life of the cassette.

[0006] Patent Document 1 discloses a microfluidic cassette configuration including an insert with a reagent-containing chamber. The reagent-containing chamber is sealed with a layer of foil. This seal can be broken in situ within the cassette by forcing the insert into contact with a seal-breaking structure of the microfluidic cassette. A portion of the cassette adjacent to the seal-breaking structure is in fluid communication with the cassette's fluid flow path, and when the seal of the reagent-containing chamber is broken, fluid can flow from the cassette's fluid flow path to the reagent-containing chamber.

[0007] This configuration allows the reagents to remain in a sealed chamber until use, thus preventing outside materials from contacting and potentially degrading the reagents.

[0008] However, under certain conditions of use, this configuration can result in erratic and uncontrollable flow of the fluid sample through the microfluidic cassette, and incomplete mixing of the fluid sample with the reagents.

[0009] For example, under certain conditions, the foil seal of a reagent-containing chamber may partially block the seal-breaking structure after being broken in situ within the cassette. This may be caused by the reagent within the chamber being compressed behind the foil seal. When the foil seal partially blocks the seal-breaking structure, this may slow the rate of fluid flow through the cassette, potentially reducing the degree of mixing between the fluid sample and the reagent. This reduction in fluid velocity may cause pressure to build up behind the fluid sample as it is forced through the cassette. If a dried reagent is used in the chamber, this built-up pressure may be suddenly released as the reagent is rehydrated. This sudden pressure release may result in a loss of control and disruption of the fluid sample.

[0010] It is an object of certain embodiments of the present invention to provide a microfluidic cassette configuration that avoids or mitigates one or more of the above-mentioned problems. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] International Publication No. 2020109797 Summary of the Invention

[0012] According to a first aspect of the present invention, there is provided a microfluidic cassette comprising a microfluidic cassette body, the microfluidic cassette body comprising a fluid flow path, a first piercing member comprising a wall extending outward from the microfluidic cassette body, the wall surrounding a first fluid opening in fluid communication with the fluid flow path, and a second piercing member comprising a wall extending outward from the microfluidic cassette body adjacent to the first piercing member, the wall surrounding a second fluid opening in fluid communication with the fluid flow path, the first piercing member comprising a further fluid opening located on a portion of the wall of the first piercing member facing away from the second piercing member.

[0013] Optionally, the further fluid opening is a slot in the wall of the first piercing member.

[0014] Optionally, the slot extends through the wall in a direction from the distal end of the wall towards the proximal end of the wall.

[0015] Optionally, the slot is substantially V-shaped, decreasing in width in a direction from the distal end of the wall to the proximal end of the wall.

[0016] Optionally, the further fluid opening is located on the wall at or near the portion of the wall that extends furthest from the microfluidic cassette body.

[0017] Optionally, the wall of the first piercing member and / or the wall of the second piercing member are substantially annular.

[0018] Optionally, the distal end of the wall of the first piercing member and / or the distal end of the wall of the second piercing member are substantially beveled.

[0019] Optionally, the microfluidic cassette further comprises an insert comprising a reagent-containing chamber, the reagent-containing chamber comprising a seal pierceable by the first piercing member and the second piercing member.

[0020] Optionally, the insert is fixed within the microfluidic cassette body and is movable from a first position within the microfluidic cassette body in which the seal of the reagent-containing chamber is not in contact with the first piercing member and the second piercing member to a second position within the microfluidic cassette body in which the seal is in contact with the first piercing member and the second piercing member.

[0021] Optionally, the microfluidic cassette body further comprises an outer wall surrounding the first piercing member and the second piercing member, the outer wall being shaped to guide movement of the insert between the first position and the second position.

[0022] Optionally, the microfluidic cassette further comprises a cover element arranged to provide a sealed chamber enclosing the first piercing member, the second piercing member and the insert.

[0023] Optionally, the insert is secured to an inner surface of the cover element.

[0024] Optionally, the second piercing member comprises a further fluid opening located on a portion of the wall of the second piercing member facing away from the first piercing member.

[0025] According to a second aspect of the present invention, there is provided a microfluidic diagnostic system comprising a microfluidic cassette according to the first aspect and a microfluidic diagnostic device adapted to receive the microfluidic cassette, the microfluidic diagnostic device comprising one or more actuators adapted to break seals of reagent-containing chambers of an insert in the microfluidic cassette.

[0026] Advantageously, embodiments of the present invention provide a microfluidic cassette configuration that allows reagents to be protected within a sealed chamber prior to use, thereby preventing external substances from contacting and potentially degrading the reagents, while during diagnostic testing, ensuring that the fluid sample flows through the chamber in an orderly and controllable manner, properly mixing the fluid sample with the reagents contained within the chamber.

[0027] The microfluidic cassette includes a first piercing member and a second piercing member, each having a wall extending outward from the microfluidic cassette body, the wall surrounding a respective fluid opening that fluidly communicates with the fluid flow path of the microfluidic cassette. The first piercing member has an additional fluid opening located on a portion of the wall of the first piercing member facing away from the second piercing member. Thus, relative to the second piercing member, the additional fluid opening is located on the back side of the first piercing member. Fluid passing through the additional fluid opening travels away from the second piercing member.

[0028] In certain embodiments, the additional fluid opening is located immediately adjacent to the distal end of the wall of the first piercing member, in such embodiments, the additional fluid opening and the opening formed by the wall of the first piercing member at the distal end of the first piercing member together form a larger opening.

[0029] The further fluid opening in the first piercing member provides a material-free region in the first piercing member. In use, when the first piercing member engages with the reagent-containing chamber, the further fluid opening provides a further path for fluid to flow into and out of the reagent-containing chamber. This allows fluid to flow through the reagent-containing chamber even when the end of the piercing member is partially or completely blocked, for example, by a seal of the reagent chamber partially or completely overlapping the distal end of the piercing member.

[0030] Furthermore, the location of the further fluid opening on a portion of the wall of the first piercing member facing away from the second piercing member improves mixing of the fluid sample with the reagent contained in the reagent-containing chamber. The location of the further fluid opening ensures that the fluid sample follows a path through the reagent-containing chamber, resulting in improved mixing of the fluid sample with the reagent.

[0031] This helps to avoid the fluid bypassing some or all of the reagents, for example by passing along the surface of the microfluidic cassette through the shallowest part of the chamber without fully mixing with the reagents in the chamber.

[0032] In certain embodiments, both the first piercing member and the second piercing member may include additional openings configured as described herein. Providing additional openings in both piercing members may further improve fluid flow and mixing of reagents.

[0033] Advantageously, in certain embodiments, the distal ends of the piercing members may be beveled. In this way, in use, a portion of the distal ends of the piercing members extends further into the reagent-containing chamber. In such embodiments, the further opening may be located on or near the "tip" of the beveled distal ends of one or both of the piercing members. Advantageously, the combination of a beveled distal end and another opening located at the tip of the bevel may further enhance the ability of the annular wall to effectively pierce the seal of the chamber while providing desirable fluid flow characteristics through the chamber.

[0034] Various further features and aspects of the present invention are defined in the following claims. [Brief explanation of the drawings]

[0035] [Figure 1] 1 is a simplified schematic diagram of a microfluidic diagnostic system in accordance with certain embodiments of the present invention. [Figure 2a] 1 illustrates an exterior surface of a portion of a microfluidic cassette according to certain embodiments of the present invention. [Figure 2b] FIG. 2b is a further view of the microfluidic cassette of FIG. 2a. [Figure 3] 1 is a cross-sectional view of an insert according to a particular embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a cover element according to a particular embodiment of the present invention. [Figure 5a] FIG. 1 is a cross-sectional view of an assembled cassette configuration within a microfluidic diagnostic device. [Figure 5b] FIG. 1 is a cross-sectional view of an assembled cassette configuration within a microfluidic diagnostic device. [Figure 5c] FIG. 1 is a cross-sectional view of an assembled cassette configuration within a microfluidic diagnostic device. [Figure 5d] FIG. 1 is a cross-sectional view of an assembled cassette configuration within a microfluidic diagnostic device. DETAILED DESCRIPTION OF THE INVENTION

[0036] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which like parts have corresponding reference numerals, and in which:

[0037] 1 is a simplified schematic diagram of a microfluidic diagnostic system 100 in accordance with certain embodiments of the present invention. System 100 includes a microfluidic cassette 101, which includes a microfluidic cassette body 102 and at least one chamber 103. Microfluidic cassette 101 may be of a type described in more detail herein.

[0038] System 100 further includes a microfluidic diagnostic device 104 adapted to receive cassette 101. Diagnostic device 104 includes a cassette receiving area that allows cassette 101 to be inserted into diagnostic device 104. Diagnostic device 104 further includes components that can interact with cassette 101 to perform diagnostic tests on the fluid sample contained within cassette 101. For example, diagnostic device 104 can include one or more diagnostic sensing and / or imaging components for performing diagnostic sensing and / or imaging on the fluid sample contained within cassette 101. Diagnostic device 104 may also include components for heating and / or cooling the fluid sample.

[0039] The diagnostic device 104 includes one or more actuators 105 adapted to break seals of chambers of the cassette 101 in situ, as described in more detail below.

[0040] In use, cassette 101 is inserted (indicated by the large arrow) into diagnostic device 104. After cassette 101 is inserted into diagnostic device 104, the seal of chamber 103 is broken in situ via one or more actuators 105. A fluid sample is then introduced into the fluid flow path of cassette 101, and a diagnostic test is performed on the sample.

[0041] The one or more actuators 105 can comprise one or more movable actuation members that are movable from a position out of contact with the microfluidic cassette 101 to a position in contact with the microfluidic cassette 101. The actuation members can apply a force to a portion of the cassette 101 to break the seal of the chamber 103 in situ after the cassette 101 is inserted into the diagnostic device 104.

[0042] Figure 2a shows the exterior of a portion of a microfluidic cassette 200 in accordance with certain embodiments of the present invention. Microfluidic cassette 200 may be of the type described with reference to Figure 1. Microfluidic cassette 200 includes a microfluidic cassette body 201. As will be appreciated, microfluidic cassette body 201 includes one or more fluid flow paths that allow a liquid fluid sample, typically provided by a patient, to pass through microfluidic cassette 200 as diagnostic tests are performed on the sample.

[0043] The microfluidic cassette body 201 includes a first piercing member 202. The first piercing member 202 is hollow. In this embodiment, the first piercing member 202 is an annular wall extending outward from a surface 203 of the microfluidic cassette body 201. The first piercing member 202 includes a proximal end 204 located directly adjacent to the surface 203 and a distal end 205 located away from the surface 203.

[0044] The first piercing member 202 surrounds an opening (not shown) in the surface 203 of the microfluidic cassette body 201. The opening is in fluid communication with the fluid flow paths of the microfluidic cassette 200. In this manner, a fluid flow path is formed from the fluid flow paths of the cassette to the hollow interior region of the first piercing member 202.

[0045] In use, the distal end 205 is positioned to pierce the breakable seal of the reagent-containing chamber.

[0046] More specifically, the microfluidic cassette body 201 is arranged to provide an interface with an insert, such as an insert of the type described with reference to FIG. 3 . Such an insert includes a sealed reagent-containing chamber. As the insert moves toward the first piercing member 202, the first piercing member 202 pierces the seal of the reagent-containing chamber. A fluid flow path is then formed between the reagent-containing chamber and the fluid flow path of the cassette through the hollow interior region of the first piercing member 202 and the opening that it surrounds. This allows a fluid sample to flow through the reagent-containing chamber and mix with the reagent contained therein.

[0047] In this embodiment, the distal end 205 of the first piercing member 202 is sloped such that a portion of the distal end 205 extends further from the surface 203. The slope is continuous around the periphery of the distal end 205 and follows a plane that is offset from the surface 203 of the microfluidic cassette body 201. The slope of the distal end 205 enhances the ability of the first piercing member 202 to pierce the seal.

[0048] The first piercing member 202 includes a further fluid opening 206. The further fluid opening 206 provides a further path for fluid to exit the first piercing member 202 (i.e., in addition to exiting the distal end 205), thereby allowing fluid to flow through the reagent-containing chamber even if the end of the first piercing member 202 is partially or completely blocked, for example, by a portion of the seal partially or completely overlapping the distal end 205 of the piercing member 202 after the seal has been pierced.

[0049] In this embodiment, the fluid opening 206 is a slot. The slot is an elongated region of the first annular wall 202 that is free of material. The slot begins at the distal end 205 and extends partially through the piercing member toward the proximal end 204. The slot is substantially V-shaped. The slot is wider at the distal end 205 and narrows toward the proximal end 204.

[0050] In this embodiment, the further fluid opening 206 is located on or near a portion of the first piercing member 202 that is furthest from the surface 203 of the microfluidic cassette body 201. In this embodiment, the portion of the first piercing member 202 that is furthest from the surface 203 of the microfluidic cassette body 201 is the tip of the beveled distal end 205. By locating the further fluid opening 206 in this position, the further fluid opening 206 is located on a portion of the first piercing member 202 that extends furthest into the reagent-containing chamber in use, thereby improving fluid flow through the reagent-containing chamber.

[0051] By locating the additional fluid opening 206 at the tip of the beveled distal end of the first piercing member 202, the ability of the first piercing member 202 to effectively pierce the seal of the chamber can be further enhanced while ensuring desirable fluid flow characteristics through the chamber.

[0052] In this embodiment, the additional fluid opening 206 is located immediately adjacent the distal end 205 of the wall of the first piercing member 202. In such an embodiment, the additional fluid opening and the opening formed by the wall of the first piercing member at its distal end together form a larger opening.

[0053] 2b is a further view of the microfluidic cassette 200 of FIG. 2a. In addition to the first piercing member 202, the microfluidic cassette body 201 includes a second piercing member 207. The second piercing member 207 substantially corresponds to the first piercing member 202 and includes a further fluid opening substantially corresponding to the further fluid opening 206 of the first piercing member 202.

[0054] As best shown in Figure 2b, the further fluid opening 206 of the first piercing member 202 is located on a part of the wall of the first piercing member 202 that faces away from the second piercing member 207. Thus, relative to the second piercing member 207, the further fluid opening 206 is located on the rear side of the first piercing member 202.

[0055] The further fluid opening 206 is positioned such that it faces away from the second piercing member 207. In this manner, the further fluid opening 206 is located on the first piercing member 202 at a point at or near the part of the first piercing member 202 that is furthest from the second piercing member 207. Fluid passing through the further fluid opening 206 travels in a direction away from the second piercing member 207.

[0056] Similarly, the second piercing member 207 includes a further fluid opening (not shown) located on a portion of the wall of the second piercing member 207 facing away from the first piercing member 202. Relative to the first piercing member 202, the further fluid opening of the second piercing member 207 is located on a rear surface of the second piercing member 207.

[0057] The location of the additional fluid opening improves mixing of the fluid sample with the reagent contained in the reagent-containing chamber because the location of the additional fluid opening ensures that the fluid sample follows a path through the reagent-containing chamber, thereby improving mixing between the fluid sample and the reagent. In particular, this configuration helps prevent the fluid sample from bypassing some or all of the reagent in the chamber by passing through the shallowest part of the chamber (i.e., the part closest to the surface 203 of the cassette body 201) without fully mixing with the reagent in the chamber.

[0058] The microfluidic cassette body 201 also includes an outer wall 208. The outer wall 208 surrounds the first piercing member 202 and the second piercing member 207 and acts as a guide for movement of the insert toward and away from the first piercing member 202 and the second piercing member 207.

[0059] It will be appreciated that in certain embodiments, either the first piercing member 202 or the second piercing member 207, or both the first piercing member 202 and the second piercing member 207, may include additional fluid openings configured as described herein.

[0060] In this embodiment, the first piercing member 202 and the second piercing member 207 are substantially annular in shape, although it will be appreciated that other suitable shapes may be used in other embodiments.

[0061] In this embodiment, the distal ends of both piercing members 202, 207 are substantially beveled, however, in other embodiments, the distal ends 205 of either or both piercing members can be substantially flat.

[0062] In this embodiment the further opening is a slot, however it will be appreciated that in other embodiments the further opening may take another suitable form such as a through hole.

[0063] Figures 3 and 4 illustrate further components that may be provided as part of a microfluidic cassette configuration including the microfluidic cassette described with reference to Figures 2a and 2b.

[0064] FIG. 3 is a cross-sectional view of an insert according to a particular embodiment of the present invention.

[0065] The insert 300 includes a body 301. The body 301 includes a first enclosed area 302. Prior to use, the first enclosed area 302 is filled with a reagent and sealed to provide a reagent-receiving chamber.

[0066] The term reagent is used herein to refer to a substance or mixture used in a chemical analysis or other reaction. In certain embodiments, a reagent may be a dried or lyophilized substance. In certain embodiments, a reagent may be a liquid or a gas.

[0067] The body 301 also includes a second closed region 303. In this embodiment, the second closed region 303 is located opposite the first closed region 302 and is substantially conformal in shape to the first closed region 302, such that the body 301 has a substantially H-shaped cross section. The second closed region 303 can be used to secure the insert 300 to another structure, such as the cover described with reference to FIG. 4.

[0068] After the first enclosed area 302 is filled with reagent to provide a reagent-containing chamber, a seal (not shown) is provided to enclose the reagent within the chamber.

[0069] In certain embodiments, the seal is made of foil (e.g., including aluminum), thermoplastic, or polypropylene (PP) foil composite. Typically, the seal is secured (i.e., sealed) by heat staking, laser welding, or using a suitable adhesive, such as a thin adhesive. In certain embodiments, the seal is about 20 microns thick. The seal is breakable when a mechanical piercing force is applied to the seal.

[0070] FIG. 4 is a cross-sectional view of a cover element according to a particular embodiment of the present invention.

[0071] A cover element 400 is secured via a fluid-tight seal and positioned to form part of the microfluidic cassette body. The cover element 400 is generally sealed at end portions 401 to provide an interior chamber 402. The cover element 400 is shaped to enclose an area of ​​the cassette body and an insert, such as an insert of the type described with reference to FIG. 3.

[0072] The cover element 400 is elastically deformable and is typically constructed from a material such as a thermoplastic elastomer.

[0073] Cover element 400 is positioned so that an insert can be secured to the inner surface of cover element 400. In this embodiment, cover element 400 includes an area 403 that is shaped to correspond to the shape of a portion of the insert to provide a friction fit between cover element 400 and the insert.

[0074] Use of a microfluidic cassette configuration 501 will now be described with reference to Figures 5a-5d according to an embodiment of the present invention.

[0075] Figures 5a-5d are cross-sectional views of an assembled cassette arrangement 501 in use after insertion into a microfluidic diagnostic device. Cassette arrangement 501 includes microfluidic cassette 200, insert 300, and cover element 400, as described with reference to Figures 2, 3, and 4, respectively. Numbering has been omitted from Figures 5a-5d for clarity.

[0076] Figure 5a shows the cassette configuration 501 prior to use. The movable actuation member 500 of the microfluidic diagnostic device is also shown in Figure 5a.

[0077] The insert 300 is secured to the inside surface of the cover element 400 , which is sealed to the remainder of the cassette body 200 .

[0078] The insert 300 is initially in a first position before the seal is broken, not in contact with the piercing member, as shown in Figure 5a.

[0079] The movable actuating member 500 then moves towards the cover element 400. The actuating member 500 contacts the cover element 400 and the insert 300 and begins to displace them towards the cassette body 200. The direction of movement of the cover element 400 and the insert 300 towards the cassette body 200 is guided by the outer wall of the cassette body 200 which contacts the insert 300.

[0080] As the insert 300 moves, the piercing member of the cassette body 200 contacts and pierces the seal of the insert 300. This is shown in Figure 5b.

[0081] The actuating member 500 continues to displace the cover element 400 and the insert 300 towards the cassette body 200 until a second position is reached where the insert 300 comes into contact with the cassette body 200. This is shown in Figure 5c.

[0082] In this configuration, the insert 300 is sealed to the cassette body 200 and the reagent-containing chambers of the insert 300 are in fluid communication with the fluid flow paths of the microfluidic cassette through the fluid openings in the cassette body 200 .

[0083] In this configuration, microfluidic tests can be performed by a microfluidic diagnostic device in which fluid flows through the insert 300 and interacts with reagents contained therein.

[0084] 5c includes arrows representing exemplary fluid flow of a fluid sample into and out of the chamber of insert 300 during a microfluidic test. In certain embodiments, fluid can flow in either direction through the chamber at different stages of a diagnostic test.

[0085] As described herein, in certain embodiments, when the seal is pierced by the piercing member, the seal often partially or completely blocks the end of the piercing member. As described herein, the presence of additional openings on one or both sides of the piercing member provides an additional fluid flow path for the fluid sample to bypass the end of the piercing member and enter the chamber. This allows the fluid sample to pass through the insert even when the end of the piercing member is blocked. Furthermore, the location of the additional openings can improve mixing of the fluid sample with the reagents in the chamber by increasing the distance the fluid needs to travel between the first and second piercing members and by preventing the fluid sample from bypassing portions of the chamber further away from the surface of the cassette body (i.e., the "deeper" portions of the chamber), where the majority of the reagents are typically present.

[0086] After the diagnostic test is completed, the actuating member 500 moves away from the cassette body 200, as shown in Figure 10d. The resilience of the cover element 400 causes it to return to its original shape, which also moves the insert 300 away from the cassette body 200.

[0087] A fluid-tight seal between the cover element 400 and the cassette body 300 ensures that the cassette remains sealed throughout and prevents fluid from leaking from the cassette interior.

[0088] All structures disclosed in this specification (including any accompanying claims, abstracts, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such structures and / or steps are mutually exclusive. Each structure disclosed in this specification (including any accompanying claims, abstracts, and drawings) may be replaced by an alternative structure serving the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each structure disclosed is only an example in a generic series of equivalent or similar structures. The invention is not limited to the details of the foregoing embodiments. The invention extends to any novel one or any novel combination of structures disclosed in this specification (including any accompanying claims, abstracts, and drawings), or to any novel one or any novel combination of steps of any method or process so disclosed.

[0089] With respect to the use of virtually any plural and / or singular term herein, those skilled in the art can translate from plural to singular and / or from singular to plural as appropriate to the context and / or application. For clarity, various singular / plural permutations may be expressly defined herein.

[0090] In general, those of skill in the art will understand that the terms used in this specification, and particularly in the appended claims, are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," and the term "includes" should be interpreted as "includes but is not limited to"). Furthermore, where specific numerical introduced claim recitations are intended, such intention will be expressly set forth in the claim, and those of skill in the art will understand that in the absence of such recitation, no such intention exists. For example, as an aid to understanding, the following appended claims may include the use of the introductory phrases "at least one" and "one or more" to introduce the claim recitations. However, the use of such phrases should not be construed as indicating that the introduction of a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such an introduced claim recitation to embodiments containing only one such recitation. This is true even if the same claim includes the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should be interpreted to mean "at least one" or "one or more"), and similarly applies to the use of definite articles used to introduce claim recitations. In addition, even if specific numbers of introduced claim recitations are explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., a recitation that simply states "two recitations" without any other modifiers means at least two recitations or more than two recitations).

[0091] It will be understood that various embodiments of the present disclosure have been described herein for purposes of illustration and that various changes may be made without departing from the scope of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope being indicated by the following claims.

Claims

1. 1. A microfluidic cassette comprising a microfluidic cassette body, The microfluidic cassette body includes: a fluid flow path; a first piercing member comprising a wall extending outwardly from the microfluidic cassette body, the wall surrounding a first fluid opening in fluid communication with the fluid flow path; a second piercing member comprising a wall extending outwardly from the microfluidic cassette body adjacent to the first piercing member, the wall surrounding a second fluid opening in fluid communication with the fluid flow path; A microfluidic cassette, wherein the first piercing member comprises a further fluid opening located on a portion of the wall of the first piercing member facing away from the second piercing member.

2. The microfluidic cassette of claim 1 , wherein the further fluid opening is a slot in the wall of the first piercing member.

3. The microfluidic cassette of claim 2 , wherein the slot extends through the wall in a direction from a distal end of the wall toward a proximal end of the wall.

4. The microfluidic cassette of claim 3 , wherein the slot is substantially V-shaped and decreases in width in a direction from the distal end of the wall to the proximal end of the wall.

5. 5. A microfluidic cassette according to claim 1, wherein the further fluid opening is located on the wall at or near the part of the wall that extends furthest from the body of the microfluidic cassette.

6. The microfluidic cassette of any one of claims 1 to 5, wherein the wall of the first piercing member and / or the wall of the second piercing member are substantially annular.

7. 7. The microfluidic cassette of claim 1, wherein the distal end of the wall of the first piercing member and / or the distal end of the wall of the second piercing member are substantially beveled.

8. 8. The microfluidic cassette of claim 1, further comprising an insert comprising a reagent-containing chamber, the reagent-containing chamber comprising a seal pierceable by the first piercing member and the second piercing member.

9. 9. The microfluidic cassette of claim 8, wherein the insert is fixed within the microfluidic cassette body and is movable from a first position within the microfluidic cassette body in which the seal of the reagent-containing chamber is not in contact with the first piercing member and the second piercing member, to a second position within the microfluidic cassette body in which the seal is in contact with the first piercing member and the second piercing member.

10. 10. The microfluidic cassette of claim 9, wherein the microfluidic cassette body further comprises an outer wall surrounding the first piercing member and the second piercing member, the outer wall being shaped to guide movement of the insert between the first position and the second position.

11. 11. The microfluidic cassette of claim 8, further comprising a cover element arranged to provide a sealed chamber surrounding the first piercing member, the second piercing member and the insert.

12. The microfluidic cassette of claim 11 , wherein the insert is secured to an inner surface of the cover element.

13. 13. The microfluidic cassette of claim 1, wherein the second piercing member comprises a further fluid opening located on a portion of the wall of the second piercing member facing away from the first piercing member.

14. A microfluidic cassette according to any one of claims 1 to 13; a microfluidic diagnostic device adapted to receive the microfluidic cassette, A microfluidic diagnostic system, wherein the microfluidic diagnostic device comprises one or more actuators adapted to break seals of reagent-containing chambers of inserts of the microfluidic cassette.

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