Multichannel cuvette

Abstract

Devices and methods for optically measuring fluid flow are disclosed. The devices and methods include a multi-component, multichannel cuvette associated with a fluid circuit. The multi-component, multichannel cuvette includes a molded body and first and second transparent walls.

Description

Attorney Docket No. F-7020 PCT (9362-0815)MULTICHANNEL CUVETTEThe present application claims the benefit of and priority to U.S. Provisional Application 63 / 736,052, filed December 19, 2024, which is hereby incorporated herein by reference.FIELD OF DISCLOSURE

[0001] The present disclosure relates generally to optical monitoring of fluids. More particularly, the present disclosure relates to a multi-component, flow-through cuvette configured to be associated with and / or part of a disposable fluid circuit typically used in, but not limited to the processing of biological fluids. Even more particularly, the present disclosure relates to a multichannel flow-through cuvette.BACKGROUND

[0002] In the field of biological fluid processing, it is known to employ an optical detection assembly to monitor the flow of blood, blood components, and / or other biological fluids through a fluid flow circuit to determine various characteristics of the flow. A typical optical detection assembly includes a light source (e.g., a laser or a light-emitting diode) configured to emit light into a transparent or translucent fluid-containing vessel of the fluid flow circuit, with a light detector (e.g., a photodiode) configured to receive light exiting the vessel. The light detector transmits a signal to a coupled controller based upon the light received, with the controller using the signal to determine one or more properties of the fluid (and, if necessary, adjusting or otherwise initiating certain actions in the biological fluid processing procedure).

[0003] A conventional optical detection assembly may have any of a number of possible shortcomings, depending on its exact configuration. For example, it is common for an optical detection assembly to monitor flow of a biological fluid through flexible plastic tubing of a fluid flow circuit. When light is incident upon plastic tubing, the transport of light into the tubing lumen may vary according to Snell’s Law depending on the refractive indices of the materials and incident light angles formed by the tubing surface. The refractive index of air (which is approximately 1 ) and the refractive index of plastic (which may typically be approximately 1 .3 to 1 .5) are quite different, and when combined with inconsistencies in the tubing surface fromAttorney Docket No. F-7020 PCT (9362-0815) procedure to procedure or from fluid circuit to fluid circuit and, thus, varying incident angles, light transmission through the tubing will vary among procedures, leading to inconsistent measurements of fluid properties.

[0004] Therefore, there exists a need for improved optical detection assemblies that at least substantially eliminate or reduce inconsistencies in the measurement of fluid properties.SUMMARY

[0005] There are several aspects of the present subject matter which may be embodied separately or together in the devices, systems, and methods described and / or claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto or later amended. For purposes of this description and claims, unless otherwise expressly indicated, “blood” is intended to include whole blood and blood components, such as concentrated red cells, plasma, platelets and white cells, whether with or without anticoagulant or additives.

[0006] In one aspect, a flow-through cuvette is provided. The cuvette includes a body including a first end, a second end, a first face, and an opposing second face. The body also includes a plurality of fluid channels extending between the first end and the second end. A fluid channel of the plurality of fluid channels defines a fluid flow path. Additionally, each of the first face and the second face includes a transparent wall.

[0007] In another aspect, a system for optically sensing a fluid in a fluid circuit is provided. The system includes a flow-through cuvette including a body with a first end, a second end, a first face, and an opposing second face. The body also includes a plurality of fluid channels extending between the first end and the second end. A fluid channel of the plurality of fluid channels defines a fluid flow path. Each of the first face and the second face includes a transparent wall. The system also includes an optical sensing system including a light source and a detector.

[0008] In another aspect, a method of optically sensing multiple fluid streams in a fluid circuit is provided. The method includes attaching a first line of a fluid circuitAttorney Docket No. F-7020 PCT (9362-0815) to a first inlet port and first outlet port of a cuvette and attaching a second line of a fluid circuit to a second inlet port and a second outlet port of the cuvette. The method also includes flowing a fluid through the first and second lines into the cuvette. The cuvette includes a body including a first end, a second end, a first face, and an opposing second face. The first and second inlet ports are located at the first end and the first and second outlet ports are located at the second end. The body also includes a first channel in fluid communication with the first inlet port and the first outlet port and a second channel in fluid communication with the second inlet port and the second outlet port. The first and second channels extend between the first end and the second end. Additionally, each of the first face and second face include a transparent wall. The method further includes passing light from a light source through the first and second channels perpendicular to a longitudinal axis of the first and second channels.

[0009] These and other aspects of the present subject are set forth in the following detailed description of the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a perspective view of an embodiment of a multichannel cuvette.

[0011] FIG. 2 is an exploded perspective view of the multichannel cuvette of FIG.1.

[0012] FIG. 3 is a top view of the multichannel cuvette of FIG. 1 .

[0013] FIG. 4 is a side view of the multichannel cuvette of FIG. 1 .

[0014] FIG. 5 is a cross-sectional end view of the multichannel cuvette of FIG. 1 .

[0015] FIG. 6 is a perspective view of the multichannel cuvette of FIG. 1 including a schematic view of an optical detection system associated with the multichannel cuvette.

[0016] FIG. 7 is a top view of an example of the multichannel cuvette including tubing of a fluid flow circuit.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The embodiments disclosed herein are for the purpose of providing an exemplary description of the present subject matter. They are, however, only exemplary and not exclusive, and the present subject matter may be embodied inAttorney Docket No. F-7020 PCT (9362-0815) various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.

[0018] FIG. 1 illustrates an example of a multichannel cuvette 10. The multichannel cuvette can be a multi-component, flow-through cuvette 10. The multichannel cuvette 10 allows for concurrent fluid flow within the cuvette 10 and optical measurement of the biological fluid flowing therethrough. In an example, the multichannel cuvette 10 allows for the concurrent fluid flow of more than one stream therethrough and for the optical measurement of the fluid streams flowing through the cuvette 10. As such, the multichannel cuvette 10 is configured to be attached to the tubing of a fluid circuit, such that the cuvette 10 is in line with the tubing of the fluid circuit. For instance, cuvette 10 can be attached to the tubing of a disposable fluid circuit configured for blood processing procedures, such as, but not limited to, apheresis. In particular, the cuvette 10 can be attached to a fluid flow circuit configured to be used with the hardware component of a system of the type described in U.S. Publication No. 2025 / 0147003 A1 , the contents of which are incorporated by reference herein in its entirety.

[0019] The multichannel cuvette 10 can be associated with more than one line of a disposable fluid circuit. In other words, the multichannel cuvette 10 can be associated with tubing such that the cuvette 10 is configured to receive multiple streams of fluid. In a particular example, the multichannel cuvette 10 can be associated with as many lines as channels included in the multichannel cuvette 10. The different lines can include the same or a different biological fluid flowing therethrough. The different fluids may flow through the channels of the cuvette 10 simultaneously or sequentially. Accordingly, the cuvette 10 can be configured to receive the flow of blood, separated blood component(s), blood product(s), or other fluid (bodily or non-bodily). In a particular example, the multichannel cuvette 10 can be associated with a platelet concentrate (PC) line and a platelet poor plasma (PPP) line of a fluid circuit. As such, concentrated platelets can travel through a first channel of the cuvette and platelet poor plasma can travel through a second channel of the cuvette 10.

[0020] Additionally, the cuvette 10 can be associated with an optical sensing system / assembly of a biological fluid processing system. For instance, the cuvetteAttorney Docket No. F-7020 PCT (9362-0815)10 can be used with an optical sensing system configured to measure light transmission or reflection through fluid. For example, cuvette 10 can be used in conjunction with the optical sensing systems / assemblies and methods as described in U.S. Publication No. 2023 / 0243746 A1 and U.S. Publication No. 2025 / 0147003 A1 , the disclosures of which are incorporated by reference in their entireties herein.

[0021] Turning to FIGS. 1 -5, the figures illustrate an example of a multichannel cuvette 10. The multichannel cuvette 10 includes a molded body 12. In an example, the molded body 12 includes a first end 18 and a second end 20. The body 12 additionally includes a first face 22 (shown in FIGS. 2 and 5) and an opposing second face 23 (shown in FIG. 5). The molded body 12 can have a generally flat, rectangular shape. As illustrated in the figures, the perimeter of the body 12 is generally rectangular. Without departing from the scope of the disclosure, the body 12 can be any suitable shape.

[0022] Additionally, the molded body 12 includes a plurality of fluid channels 13 extending therethrough and a transparent wall on each of the first face 22 and second face 23. For instance, as shown in FIG. 1 , the body 12 can include two fluid channels 13, but it will be understood that more channels 13 can be included without departing from the scope of the disclosure. Furthermore, in an example, as shown in FIG. 1 , body 12 includes a first transparent wall 14 at the first face 22 and a second transparent wall 16 at the second face 23 (FIG. 2). Because the walls are transparent, the fluid channels 13 are visible to a user.

[0023] In an example, the channels 13 are defined by central passages 30 in the body 12 and by the transparent walls 14 and 16, as shown in FIG. 2.Accordingly, fluid can flow through the flow path defined by the channels 13 through cuvette 10. As shown in FIGS. 1 -3, the passages 30 extend between the first end 18 and the second end 20 of the body 12. The passages 30 additionally include a central passage inlet 33 (shown in FIG. 5) at the passage first end 31 and a central passage outlet (not shown) at the passage second end 32. The passage inlet 33 and the passage outlet are in fluid communication with ports 26 located at the body first end 18 and ports 28 located at the body second end 20, as described in greater detail below.Attorney Docket No. F-7020 PCT (9362-0815)

[0024] The dimensions of the passages 30 can vary based on the fluid to be flowed therethrough and / or the optical sensing system 40 to be employed with the cuvette 10. In an example, the central passages 30 can include similar dimensions or, optionally, the central passages 30 can include varying dimensions from one another. It will be understood that because the central passages 30, including the first transparent wall 14 and the second transparent wall 16, define the visible channels 13, the fluid channels 13 include the dimensions of the central passages 30.

[0025] The length and width of the passages 30 can vary depending on the type of optical sensing system 40 employed with the multichannel cuvette 10. For example, the cuvette 10 can be molded to be used with an optical sensing system 40 including a linear photodiode array sensor. In this instance, the passages 30 can be about 51 mm long and about 4 mm wide. In a particular example, the passages 30 can be 51 mm long and 4 mm wide. In another example, the optical sensing system 40 may include a single photodiode sensor and the passages 30 can be shorter. Accordingly, the passages 30 can be molded to a suitable size to be used with a variety of optical sensing systems without departing from the scope of the disclosure.

[0026] The thickness of the central passages 30 can be at least about 0.5 mm, such as at least 0.5 mm. In an embodiment, the thickness of the central passages 30 can be about 0.5-4 mm, such as in the range of 0.5-4 mm. Preferably, the central passages 30 include a thickness of about 2-4 mm. In another embodiment, the central passages 30 include a thickness of 2 mm. Additionally, the thickness of the central passages 30 can be determined based on the contents of the fluid to be evaluated flowing through the cuvette 10. For example, in an embodiment, cuvette 10 is configured to allow for measurement of a fluid containing platelets (e.g., platelet-rich plasma or platelet concentrate) and at least one of the passages 30 includes a thickness of about 2-4 mm, such as in the range of 2-4 mm. In another embodiment, the cuvette 10 is configured for measurement of larger (cellular) and higher concentration components such as a fluid containing red blood cells. In this instance, due to the increased optical density of red blood cells, the thickness of at least one of the central passages 30 is less than 1 mm.Attorney Docket No. F-7020 PCT (9362-0815)

[0027] In an example, the multichannel cuvette 10 is configured to receive streams of different biological fluid. In this instance, the dimensions of the central passages 30 can vary from one another to accommodate the different streams that flow therethrough.

[0028] As illustrated in FIGS. 1 -2, 4, 6, and 7, channels 13 can have an elongated shape, such as a generally oval shape or elongated octagonal shape, but other shapes can be used without departing from the scope of the disclosure. For instance, passage 30 can have a generally oval shape. Depending on the shape of the passages 30, the ends 31 and 32 of the central passage 30 may include a tapered width. For example, the first end 31 and second end 32 of the central passages 30 can be tapered or rounded and, accordingly, are narrower at the ends than elsewhere on the passage 30. The tapered / rounded ends 31 and 32 assist with providing consistent fluid flow from a tubing segment to the channels 13. Particularly, this assists with low flow rates or with filling the channel 13 with fluid as the tapered / rounded ends 31 and 32 direct fluid across the entire width of the channel 13. Additionally, the tapered / rounded ends 31 and 32 assist in removing air from the channel 13 such that only fluid remains after priming.

[0029] As disclosed above, the molded body 12 further includes at least one port. For instance, body 12 includes at least one port 26 located at the first end 18 of the body 12 and at least one port 28 located at the second end 20 of the body 12. The first end ports 26 and second end ports 28 are configured to receive tubing segments (as shown in FIG. 7) associated with a fluid circuit and the ports 26 and 28 are in fluid communication with the passages 30 (and thus, the fluid channels 13).

[0030] In an example, tubing segments can be releasably attached to the first end ports 26 and second end ports 28. For instance, tubing segments can be attached to the first end ports 26 and second end ports 28 via a push fit, a friction fit, or with a luer fitting, among other suitable releasable attachment means. Alternatively, tubing segments can be irreversibly attached to the first end and second end ports 26 and 28. For instance, tubing segments can be attached to the first end and second end ports 26 and 28 via welding, adhesion, or any other suitable irreversible attachment or bonding method. Accordingly, after tubing isAttorney Docket No. F-7020 PCT (9362-0815) attached to the first end ports 26 and the second end ports 28, the tubing is in fluid communication with the central passages 30.

[0031] In an example, as shown in FIGS. 1 -3 and 5-7, the cuvette 10 can include multiple first end ports 26 and multiple second end ports 28. In a particular example, the cuvette 10 can include a first end port 26 and a second end port 28 for each fluid channel 13. For instance, as shown in the figures, cuvette 10 can include two first end ports 26 and two second end ports 28. A fluid channel 13 can be associated with a single first end port 26 and a single second end port 28. Alternatively, a first end port 26 and a second end port 28 can be associated with multiple passages 30. In this instance, a stream can enter the cuvette 10 from one port 26 or 28 and can branch off into and be in fluid communication with multiple central passages 30, allowing a fluid to travel through the cuvette at a faster rate.

[0032] Body 12 can be formed as a molded unitary component. For instance, the body 12, first end ports 26, and second end ports 28 can be a single, unitary component. The passages 30 can be formed during manufacture of the molded body 12 or the passages 30 can be cut out, punched out, or otherwise formed by any suitable means, after molding the body 12. Alternatively, the molded body 12 can be assembled of separate molded parts. For instance, the body 12, the first end tubing ports 26, and the second end tubing ports 28 can be separately molded and then attached to one another. In one example, the portions of body 12 comprising first and second faces 22 and 23, respectively, can be molded as separate halves that are joined together by bonding, welding or the like with subsequent attachment of ports 26 and 28.

[0033] The molded body 12 can be made of any suitable moldable material. For instance, the molded body 12 between the transparent walls 14 and 16 can be made of a non-transparent material. In an example, the molded body 12 can be made of a material conducive to laser welding, such as plastic with laser absorbing colorant. The molded body 12 can be made of acrylic, polycarbonate, cyclic olefin copolymer (COC), or any other suitable biocompatible material.

[0034] As disclosed herein, the first transparent wall 14 and the second transparent wall 16, together with the central passages 30, define a window or visible channel 13. The first and second transparent walls 14 and 16 can be made of aAttorney Docket No. F-7020 PCT (9362-0815) molded or non-molded, optically transparent material, such that the material transmits light from a light source without significant optical interference. The optically transparent material may exhibit a luminance transmittance of greater than 85% per 3.2 mm and a haze of less than 10% per 3.2 mm. Preferably, the optically transparent material may exhibit a luminance transmittance of greater than 90% per 3.2 mm and a haze of less than 1% per 3.2 mm. The first and second transparent walls 14 and 16 can be made of polycarbonate, acrylic, glass, cyclic olefin copolymer (COC) , plastic, and / or any combination of optically transparent material. Other suitable optically transparent materials can be used without departing from the scope of the disclosure.

[0035] The first and second transparent walls 14 and 16 can be attached to the first face 22 and second face 23, respectively. In an example, the molded body 12 can include at least one raised ring 34 extending around the perimeter of a central passage 30. In particular, the molded body 12 can include a raised ring 34 extending around the perimeter of each central passage 30, as shown in FIG. 2. The molded body 12 can include rings 34 located on the first face 22 extending around the perimeter of the passages 30 and rings 34 located on the second face 23 extending around the perimeter of the passages 30. The ring(s) 34 can be integrally formed on the molded body 12 during manufacturing or the ring(s) 34 can be attached to the molded body 12. Ring 34 provides a raised surface for the first and second transparent walls 14 and 16 to be welded to the body 12. For instance, the first and second transparent walls 14 and 16 can be laser or hot plate welded to the ring(s) 34.

[0036] Alternatively, in an example, the first and second transparent walls 14 and 16 can be attached to the first face 22 and the second face via adhesion. Any other suitable welding or attachment means to attach the transparent walls 14 and 16 to the body 12 can be employed without departing from the scope of the disclosure.

[0037] The first and second transparent walls 14 and 16 can be shaped to cover at least the central passages 30. In an example, as shown in FIGS. 1-3, the shape of the first and second transparent walls 14 and 16 can substantially correspond to the shape of the molded body 12. For instance, the first and secondAttorney Docket No. F-7020 PCT (9362-0815) transparent walls 14 and 16 can be rectangularly shaped and are configured to fit within the perimeter of the molded body 12. In an example, a ridge 36 can extend around the perimeter of body 12. In this instance, the first and second transparent walls 14 and 16 can be shaped to fit within the ridge(s) 36 of the molded body 12 As shown in FIGS. 1 and 5, the ridge 36 can assist in holding the first and second transparent walls 14 and 16 in place on the faces of the body 12. The first and second transparent walls 14 and 16 can extend beyond the height of the ridge 36. For example, the first and second transparent walls 14 and 16 are about 0.5 mm, such as 0.5mm, taller than the ring(s) 34 such that the first and second transparent walls 14 and 16 extend beyond the ridge 36. In another example, the first and / or second transparent walls 14 and 16 can be shaped to only cover the central passages 30. For instance, the first and second transparent walls 14 and 16 can have a generally oval shape corresponding to the shape of the central passages 30. The shape of the first and second transparent walls 14 and 16 can vary without departing from the scope of the disclosure.

[0038] As disclosed herein, the multichannel cuvette 10 can be used with and / or incorporated into a disposable fluid circuit associated with an optical sensing system 40 (shown in FIG. 6) of a hardware component of a biological fluid processing system or device. As schematically illustrated in FIG. 6, the optical sensing system 40 can include a light source 42 and a light detector 44. The light source 42 and light detector 44 are located adjacent to opposite faces of the cuvette 10. For example, as shown in FIG. 6, the light source 42 can be located adjacent to first face 22 and the light detector 44 can be located adjacent to second face (not shown), or vice versa.

[0039] In an example, the light source 42 can be a laser or a light emitting diode. The light detector 44 can be a photodiode or an array of photodiodes. In another example, the optical sensing system 40 can be any other suitable optical sensing system including, but not limited to, the system(s) disclosed in U.S. Publication No. 2023 / 0243746 A1 and U.S. Publication No. 2025 / 0147003 A1 , which have been previously incorporated by reference herein. The light source 42 is configured to emit and transmit light through the visible fluid channel 13 and the light detector 44 is configured to detect the light transmitted through the visible fluidAttorney Docket No. F-7020 PCT (9362-0815) channel 13. In particular, the optical sensing system 40 is configured to optically measure the fluid within a centrally located viewing window 54 (shown in broken lines in FIG. 7) within the visible fluid flow path. The size of the viewing window 54 can be determined by the size of the light source beam and the size of the light sensor / detector and can vary without departing from the scope of the disclosure.

[0040] It will be understood that the configuration of the optical sensing system 40 can vary without departing from the scope of the disclosure. For instance, the optical sensing system 40 can include a single light source 42 and a single detector 44 configured to monitor the multiple channels 13 of the cuvette.Alternatively, the optical sensing system 40 can include multiple light sources 42 and / or detectors 44. For instance, in an example, the optical sensing system 40 can include a separate light source 42 associated with each respective channel 13 and a single detector 44 configured to monitor fluid flowing through each channel 13. In another example, the optical sensing system 40 can include a single light source 42 and a separate detector 44 associated with each respective channel 13.

[0041] The optical sensing system 40 includes a controller 46 or can be coupled or connected to a controller of the hardware component of the biological fluid processing system or device configured to record and analyze the information received from the light detector 44. Additionally, the controller 46 can be configured to transmit the information to a computing device via a wired or wireless connection.

[0042] Turning to FIG. 7, the figure illustrates an example of the cuvette 10 in use. Cuvette 10 can be connected to two separate lines of a fluid circuit. For instance, as shown in FIG. 7, cuvette 10 is connected to a first line, including tubing segments 46a and 48a and a second line including tubing segments 46b and 48b. The tubing segments forming a line are connected to a pair of first end and second end ports 26 and 28 that are in fluid communication with one another. For instance, tubing segment 46a is connected to a first end port 26a and tubing segment 48a is connected to a second end port 28a, which are in fluid communication with a first channel 13a. Tubing segment 46b is connected to first end port 26b and tubing segment 48b is connected to second end port 28b, which are in fluid communication with a second channel 13b. As such, fluid traveling through the first and second lines travel through separate channels 13a and 13b. As described herein, the biologicalAttorney Docket No. F-7020 PCT (9362-0815) fluid travelling through the lines may be the same or may be different. For instance, the first line, and accordingly, channel 13a can be configured to accommodate a platelet concentrate, and the second line, and accordingly, channel 13b can be configured to accommodate platelet poor plasma.

[0043] In some instances, air bubbles 50 within the fluid may interfere with obtaining an accurate optical reading of the fluid flowing through the cuvette 10. For instance, if the longitudinal axis 47 (shown with a dotted line) of the cuvette 10, extending from the first end 18 to the second end 20 of the body 12, is parallel to the direction of gravity 49 (also shown with a dotted line), the natural buoyancy of air can cause air bubbles to flow upwards through the viewing window 54, causing inaccurate optical readings. Additionally, if the longitudinal axis 47 is perpendicular with the direction of gravity ( / .e., the cuvette 10 is placed horizontally), the natural buoyancy of air may cause the air bubbles to travel above the viewing window 54, but the air bubbles 50 may not exit the outlet passage because the outlet passage may include a smaller width than the passage 30. In this instance, the air bubbles 50 may build up at the passage second end 32 due to a lack of strong convective force from fluid flow (due to low flow rates) acting against the buoyancy of air required to move any bubbles 50 downward and out of the outlet passage. The air bubbles 50 can accumulate and interfere with fluid flow and optical measurements within the viewing window 54.

[0044] Accordingly, after attachment to a fluid flow circuit, to effectively sense the fluid flowing through the cuvette 10, the cuvette 10 is placed in a predetermined angled orientation with respect to the direction of gravity 49. In other words, the longitudinal axis 47 extending from the first end 18 to the second end 20 of the body 12 of the fluid flow path is oriented at an angle relative to gravity. For instance, in an example, as shown in FIG. 7, the axis 47 can be oriented at a 45° angle. The axis 47 can be oriented at any other suitable angle greater than 0° ( / .e., the axis 47 being aligned with the direction of gravity) and less than 90° ( / .e., the axis 47 being perpendicular to the direction of gravity) without departing from the scope of the disclosure.

[0045] By placing the cuvette 10 in an angled orientation, as fluid flows through the cuvette 10, the natural buoyancy of any air bubbles 50 within the fluidAttorney Docket No. F-7020 PCT (9362-0815) will cause the bubbles 50 to float towards the top of the fluid flow path. For example, as shown in FIG. 7, the air bubbles 50 will travel through the fluid flow path along the highest / top wall of the fluid flow path. At an angled orientation, the convective force of the fluid flow is great enough to act against the buoyancy of the air bubbles 50 at the passage second end 32 to push the bubbles through the outlet passage. An optical sensing system can then be configured to take an optical measurement of the flow path in the viewing window 54. For instance, as illustrated in FIG. 7, the light source is configured to emit a beam 52 through the center of the longitudinal axis 47 of the fluid flow path, thus avoiding potential interference from the air bubbles 50. In addition to preventing interference, the angled orientation of the fluid flow path also prevents the air bubbles 50 from accumulating near the outlet passage of the passage 30, assisting the bubbles in exiting the visible fluid flow path therefrom.

[0046] There are additional aspects to the devices and methods described herein including, without limitation the following aspects.

[0047] Aspect 1 . A flow-through cuvette including a body including a first end, a second end, a first face, and an opposing second face, a plurality of fluid channels extending between the first end and the second end, wherein a fluid channel of the plurality of fluid channels defines a fluid flow path, and each of said first face and said second face including a transparent wall.

[0048] Aspect 2. The cuvette of Aspect 1 , wherein the body includes at least one port located at the first end and at least one tubing port located at the second end, wherein the at least one first end port and at least one second end port are in fluid communication with the plurality of fluid channels.

[0049] Aspect 3. The cuvette of Aspect 2 including multiple first end ports and multiple second end ports.

[0050] Aspect 4. The cuvette of Aspect 3, wherein a single fluid channel of the plurality of fluid channels is in fluid communication with a single first end port of the multiple first end ports and with a single second end port of the multiple second end ports.

[0051] Aspect 5. The cuvette of any one of Aspects 1 -4 wherein the body between the transparent walls is made of a molded non-transparent material.Attorney Docket No. F-7020 PCT (9362-0815)

[0052] Aspect 6. The cuvette of any one of Aspects 1 -5, wherein the body between the transparent walls is made of a molded plastic.

[0053] Aspect 7. The cuvette of any one of Aspects 1 -6, wherein the transparent walls are made of a molded or non-molded material.

[0054] Aspect 8. The cuvette of any one of Aspects 1 -7, wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

[0055] Aspect 9. The cuvette of any one of Aspects 1 -8, wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

[0056] Aspect 10. The cuvette of any one of Aspects 1 -9, wherein the fluid flow path is about 51 mm.

[0057] Aspect 11 . The cuvette of any one of Aspects 1 -10, wherein the width of the fluid flow path is about 4 mm.

[0058] Aspect 12. The cuvette of any one of Aspects 1 -11 , wherein the thickness of the fluid flow path between the first face and the second face is at least 0.5 mm.

[0059] Aspect 13. The cuvette of any one of Aspects 1 -12, wherein the thickness of the fluid flow path is about 2-4 mm.

[0060] Aspect 14. The cuvette of any one of Aspects 1 -13, wherein the thickness of the fluid flow path is 2 mm.

[0061] Aspect 15. A system for optically sensing a fluid in a fluid circuit including a flow-through cuvette including a body including a first end, a second end, a first face and an opposing second face, a plurality of fluid channels extending between the first end and the second end, wherein a fluid channel of the plurality of fluid channels defines a fluid flow path, and each of said first face and said second face including a transparent wall, and an optical sensing system including a light source and a detector.

[0062] Aspect 16. The system of Aspect 15, wherein the body includes at least one port located at the first end and at least one port located at the second end, wherein the at least one first end port and at least one second end port are in fluid communication with the plurality of fluid channels.Attorney Docket No. F-7020 PCT (9362-0815)

[0063] Aspect 17. The system of Aspect 16 including multiple first end ports and multiple second end ports.

[0064] Aspect 18. The system of Aspect 17, wherein a single fluid channel of the plurality of fluid channels is in fluid communication with a single first end port of the multiple first end tubing ports and with a single second end port of the multiple second end tubing ports.

[0065] Aspect 19. The system of any one of Aspects 15-18 wherein the body between the transparent walls is made of a molded non-transparent material.

[0066] Aspect 20. The system of any one of Aspects 15-19, wherein the body between the transparent walls is made of a molded plastic.

[0067] Aspect 21 . The system of any one of Aspects 15-20, wherein the transparent walls are made of a molded or non-molded material.

[0068] Aspect 22. The system of any one of Aspects 15-21 , wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

[0069] Aspect 23. The system of any one of Aspects 15-22, wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

[0070] Aspect 24. The system of any one of Aspects 15-23, wherein the fluid flow path is about 51 mm.

[0071] Aspect 25. The system of any one of Aspects 15-24, wherein the width of the fluid flow path is about 4 mm.

[0072] Aspect 26. The system of any one of Aspects 15-25, wherein the thickness of the fluid flow path between the first face and the second face is at least 0.5 mm.

[0073] Aspect 27. The system of any one of Aspects 15-26, wherein the thickness of the fluid flow path is about 2-4 mm.

[0074] Aspect 28. The system of any one of Aspects 15-27, wherein the thickness of the fluid flow path is 2 mm.

[0075] Aspect 29. The system of any one of Aspects 15-28, wherein the optical sensing system is configured to monitor the flow of fluid through the plurality of channels.Attorney Docket No. F-7020 PCT (9362-0815)

[0076] Aspect 30. The system of any one of Aspects 15-28, wherein the light source is located adjacent to the first or second face and the detector is located adjacent to the other of the first or second face.

[0077] Aspect 31 . A method of optically sensing multiple fluid streams in a fluid circuit including attaching a first line of a fluid circuit to a first inlet port and a first outlet port of a cuvette and attaching a second line of a fluid circuit to a second inlet port and a second outlet port of the cuvette, flowing a fluid through the first and second lines into the cuvette, wherein the cuvette includes a body including a first end, a second end, a first face, and an opposing second face, the first and second inlet ports being located at the first end and the first and second outlet ports being located at the second end, a first channel in fluid communication with the first inlet port and the first outlet port and a second channel in fluid communication with the second inlet port and the second outlet port, wherein the first and second channels extend between the first end and the second end, each of said first face and said second face including a transparent wall, and passing light from a light source through the first and second channels perpendicular to a longitudinal axis of the first and second channels.

[0078] Aspect 32. The method of Aspect 31 , including orienting the longitudinal axis of the first and second channels at an angle relative to the direction of gravity.

[0079] Aspect 33. The method of Aspect 32, wherein the longitudinal axis of the first and second channels is oriented at a 45° angle relative to the direction of gravity.

[0080] Aspect 34. The method of any one of Aspects 31 -33, including measuring the absorption of the light passing through the first and second channels.

[0081] Aspect 35. The method of any one of Aspects 31 -34, wherein the fluid flowing through the first and second channels is a biological fluid.

[0082] Aspect 36. The method of Aspect 35, wherein the fluid flowing through the first and second channels is the same biological fluid.

[0083] Aspect 37. The method of Aspect 35, wherein the fluid flowing through first and second channels includes different biological fluids.Attorney Docket No. F-7020 PCT (9362-0815)

[0084] Aspect 38. The method of any one of Aspects 31 -37, wherein the body between the transparent walls is made of a molded non-transparent material.

[0085] Aspect 39. The method of any one of Aspects 31 -38, wherein the body between the transparent walls is made of molded plastic.

[0086] Aspect 40. The method of any one of Aspects 31 -39, wherein the transparent walls are made of a molded or non-molded material.

[0087] Aspect 41 . The method of any one of Aspects 31 -40, wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

[0088] Aspect 42. The method of any one of Aspects 31 -41 , wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

[0089] It will be understood that the embodiments and examples described above are illustrative of some of the applications or principles of the present subject matter. Numerous modifications may be made by those skilled in the art without departing from the spirit and scope of the claimed subject matter, including those combinations of features that are individually disclosed or claimed herein. For these reasons, the scope hereof is not limited to the above description but is as set forth in the following claims, and it is understood that the claims may be directed to the features thereof, including as combinations of features that are individually disclosed or claimed herein.

Claims

Attorney Docket No. F-7020 PCT (9362-0815)CLAIMS:1 . A flow-through cuvette comprising: a body including a first end, a second end, a first face, and an opposing second face; a plurality of fluid channels extending between the first end and the second end, wherein a fluid channel of the plurality of fluid channels defines a fluid flow path; and each of said first face and said second face comprising a transparent wall.

2. The cuvette of Claim 1 , wherein the body includes at least one port located at the first end and at least one tubing port located at the second end, wherein the at least one first end port and at least one second end port are in fluid communication with the plurality of fluid channels.

3. The cuvette of Claim 2 comprising multiple first end ports and multiple second end ports.

4. The cuvette of Claim 3, wherein a single fluid channel of the plurality of fluid channels is in fluid communication with a single first end port of the multiple first end ports and with a single second end port of the multiple second end ports.

5. The cuvette of any one of Claims 1 -4 wherein the body between the transparent walls is made of a molded non-transparent material.

6. The cuvette of any one of Claims 1 -5, wherein the body between the transparent walls is made of a molded plastic.

7. The cuvette of any one of Claims 1 -6, wherein the transparent walls are made of a molded or non-molded material.

8. The cuvette of any one of Claims 1 -7, wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

9. The cuvette of any one of Claims 1 -8, wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

10. The cuvette of any one of Claims 1 -9, wherein the fluid flow path is about 51 mm.Attorney Docket No. F-7020 PCT (9362-0815)11 . The cuvette of any one of Claims 1-10, wherein the width of the fluid flow path is about 4 mm.

12. The cuvette of any one of Claims 1-11 , wherein the thickness of the fluid flow path between the first face and the second face is at least 0.5 mm.

13. The cuvette of any one of Claims 1-12, wherein the thickness of the fluid flow path is about 2-4 mm.

14. The cuvette of any one of Claims 1-13, wherein the thickness of the fluid flow path is 2 mm.

15. A system for optically sensing a fluid in a fluid circuit comprising: a flow-through cuvette comprising a body including a first end, a second end, a first face and an opposing second face; a plurality of fluid channels extending between the first end and the second end, wherein a fluid channel of the plurality of fluid channels defines a fluid flow path; and each of said first face and said second face comprising a transparent wall; and an optical sensing system including a light source and a detector.

16. The system of Claim 15, wherein the body includes at least one port located at the first end and at least one port located at the second end, wherein the at least one first end port and at least one second end port are in fluid communication with the plurality of fluid channels.

17. The system of Claim 16 comprising multiple first end ports and multiple second end ports.

18. The system of Claim 17, wherein a single fluid channel of the plurality of fluid channels is in fluid communication with a single first end port of the multiple first end tubing ports and with a single second end port of the multiple second end tubing ports.

19. The system of any one of Claims 15-18 wherein the body between the transparent walls is made of a molded non-transparent material.

20. The system of any one of Claims 15-19, wherein the body between the transparent walls is made of a molded plastic.Attorney Docket No. F-7020 PCT (9362-0815)21 . The system of any one of Claims 15-20, wherein the transparent walls are made of a molded or non-molded material.

22. The system of any one of Claims 15-21 , wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

23. The system of any one of Claims 15-22, wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

24. The system of any one of Claims 15-23, wherein the fluid flow path is about 51 mm.

25. The system of any one of Claims 15-24, wherein the width of the fluid flow path is about 4 mm.

26. The system of any one of Claims 15-25, wherein the thickness of the fluid flow path between the first face and the second face is at least 0.5 mm.

27. The system of any one of Claims 15-26, wherein the thickness of the fluid flow path is about 2-4 mm.

28. The system of any one of Claims 15-27, wherein the thickness of the fluid flow path is 2 mm.

29. The system of any one of Claims 15-28, wherein the optical sensing system is configured to monitor the flow of fluid through the plurality of channels.

30. The system of any one of Claims 15-28, wherein the light source is located adjacent to the first or second face and the detector is located adjacent to the other of the first or second face.31 . A method of optically sensing multiple fluid streams in a fluid circuit comprising: attaching a first line of a fluid circuit to a first inlet port and a first outlet port of a cuvette and attaching a second line of a fluid circuit to a second inlet port and a second outlet port of the cuvette; flowing a fluid through the first and second lines into the cuvette, wherein the cuvette includes a body including a first end, a second end, a first face, and an opposing second face, the first and second inlet ports being located at the first end and the first and second outlet ports being located at the second end;Attorney Docket No. F-7020 PCT (9362-0815) a first channel in fluid communication with the first inlet port and the first outlet port and a second channel in fluid communication with the second inlet port and the second outlet port, wherein the first and second channels extend between the first end and the second end; each of said first face and said second face comprising a transparent wall; and passing light from a light source through the first and second channels perpendicular to a longitudinal axis of the first and second channels.

32. The method of Claim 31 , comprising orienting the longitudinal axis of the first and second channels at an angle relative to the direction of gravity.

33. The method of Claim 32, wherein the longitudinal axis of the first and second channels is oriented at a 45° angle relative to the direction of gravity.

34. The method of any one of Claims 31 -33, comprising measuring the absorption of the light passing through the first and second channels.

35. The method of any one of Claims 31 -34, wherein the fluid flowing through the first and second channels is a biological fluid.

36. The method of Claim 35, wherein the fluid flowing through the first and second channels is the same biological fluid.

37. The method of Claim 35, wherein the fluid flowing through first and second channels comprises different biological fluids.

38. The method of any one of Claims 31 -37, wherein the body between the transparent walls is made of a molded non-transparent material.

39. The method of any one of Claims 31 -38, wherein the body between the transparent walls is made of molded plastic.

40. The method of any one of Claims 31 -39, wherein the transparent walls are made of a molded or non-molded material.41 . The method of any one of Claims 31 -40, wherein the transparent walls are made of plastic, polycarbonate, acrylic, glass, and / or cyclic olefin copolymer (COC).

42. The method of any one of Claims 31 -41 , wherein a first transparent wall is attached to the first face and a second transparent wall is attached to the second face.

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