Claims:We claim:
1. A microfluidic cartridge (100), comprising:
at least one fluid flow channel (101) to facilitate flow of biological samples; and
a fluid distribution region (102) in fluid communication with the at least one fluid flow channel (101), the fluid distribution region (102) comprising:
a plurality of passages (103) arranged concentrically to one another; and
a plurality of connecting channels (104), interconnecting the plurality of passages (103), wherein the number of connecting channels (104) extending from an outermost passage of the plurality of passages (103) is less than the number of connecting channels (104) extending from an innermost passage of the plurality of passages (103).

2. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in the form of spokes.

3. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in equal volumes.

4. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in varied volumes.

5. The microfluidic cartridge (100) as claimed in claim 1 comprises a collection chamber (105) interconnecting the connecting channels (104) extending from the innermost passage of the plurality of passages (103) to collect the fluid mixture.

6. The microfluidic cartridge (100) as claimed in claim 1 comprises a divergent nozzle (106) in fluid communication with the collection chamber (105).

7. The microfluidic cartridge (100) as claimed in claim 6, wherein the divergent nozzle (106) is configured to accelerate the exit of fluid mixture from the collection chamber (105).

8. The microfluidic cartridge (100) as claimed in claim 1 comprises a filter unit (107) in fluid communication with the fluid flow channel (101), the filter unit (107) is configured to filter the fluid mixture based on size of particles of interest.

9. The microfluidic cartridge (100) as claimed in claim 8 comprises a mixing chamber (108) in fluid communication with the filter unit (107), the mixing chamber (108) is configured to mix biological sample and at least one reagent to form the fluid mixture.

10. The microfluidic cartridge (100) as claimed in claim 9, wherein an inlet of the mixing chamber (108a) is fluidly connected to a biological sample container (109) and at least one reagent container (110).

11. The microfluidic cartridge (100) as claimed in claim 9, wherein the biological sample and the at least one reagent is supplied to the mixing chamber (108) through at least one pump (111).

12. The microfluidic cartridge (100) as claimed in claim 9, wherein the mixing chamber (108) comprises a fluid flow stream (112).

13. The microfluidic cartridge (100) as claimed in claim 12, wherein geometry of the fluid flow stream (112) is at least one of serpentine geometry and sudden expansion geometry.

14. The microfluidic cartridge (100) as claimed in claim 1 is fabricated by at least one of photo-lithography and soft-lithography techniques using Polydimethylsiloxane (PDMS).

15. A microscopy system for analyzing fluids comprising a microfluidic cartridge (100) as claimed in claim 1.

16. The microscopy system as claimed in claim 15, wherein the fluid distribution region (102) between the innermost passage of the plurality of passages (103) and the collection chamber (105) is configured as an imaging region (113) to analyze fluids.

17. The microscopy system as claimed in claim 16, wherein a low frame rate camera is used for capturing images in the imaging region (113).
, Description:TECHNICAL FIELD

The present disclosure generally relates to a field of Bio-Medical devices. Particularly but not exclusively, the present disclosure relates to microscopic system used for performing morphological analysis of biological samples. Further embodiments of the present disclosure, discloses a microfluidic cartridge for use in the microscopic system.

BACKGROUND OF THE DISCLOSURE

Morphological analysis is a method used for studying form and structure of biological cells and their specific structural features. This includes aspects of the outward appearance (shape, structure, color, pattern), i.e., external morphology as well as the form and structure of the internal parts like bones and organs, i.e., internal morphology or anatomy. The study of structural features of the biological samples can be used to diagnose the disease condition in subject.

Presently, clinical microscopy serves as a gold standard diagnostic method for numerous diseases. The morphological details provided by this method have proven useful in successful diagnosis. However, this is a highly tedious process involving long durations and requires skilled technicians to perform medical analysis. In addition the number of cells analysed is limited and lacks the ability to perform single cell analysis as the sample is smeared on a glass slide. Another disadvantage is improper slide or smear preparation and handling, results in generation of wrong diagnosis.

Over past few decades, microscopy has greatly evolved, from being able to resolve micro-scale features to nano-scale features with the use of some advanced illumination techniques. The research efforts in the field of microscopy have predominantly focused on improving the resolution of the technique. However, the prospect of enhancing imaging throughput had not been fully explored previously. In view of necessity for detection of extremely rare cells like circulating tumor cells (CTCs), the problem of low throughput in microscopy has recently surfaced. Consequently, some of the most recent efforts have focused on developing high-throughput microscopy techniques. Among the recent efforts, a method has been developed to perform rapid single cell analysis by flow cytometry which correlates the cell size and granularity based on the forward and side scattered light. Although it is possible to achieve high throughputs by the flow cytometry method, this method does not give morphological information of the cell and these flow cytometers are very expensive.
With the on-going research, Imaging flow cytometry (IFC) has emerged as technique which fuses advantages of both clinical microscopy and flow cytometry. Morphological analysis of cells can be performed in suspension at a faster rate with the use of IFC. Further, achievable throughputs in imaging systems depend on several parameters like the exposure time, frame rate of camera, field of view of the camera and the flow velocity of the biological particles. The frame rate of the camera goes down with increase in the field of view.

Conventionally, various IFC’s are developed, and used for Morphological analysis of cells. The conventional IFC’s have demonstrated an imaging throughput ranging from about 1000 cells per second to about 5000 cells per second. However these throughputs were achieved by employing expensive cameras having high frame rates of several tens-of-thousands frames per second. This limits the use of such systems, in point of care diagnostic settings.

Typically, the conventional microfluidic device or the IFC uses a microfluidic cartridge for channelizing a mixture of biological sample and a reagent. The microfluidic cartridge generally comprises of three zones – mixing zone, filter zone and imaging zone. A pump injects biological samples and reagents into the mixing zone where it forms a mixture. The mixture is then let into the filter for filtering the fluid mixture depending on its size. The imaging zone of the microfluidic cartridge is configured with multiple straight parallel channels. With the use of straight parallel channels in IFC, though throughputs increase considerably, maximum possible channels are not accommodated in the distribution zone which limits the imaging throughput of the biological cells. In addition, with straight parallel channels design, the velocity of mixture of biological samples and reagents is very high. Due to high velocity of this mixture, high frame rate cameras have to be employed to capture images, which lead to significant rise in cost.

In light of the foregoing discussion, it is necessary to develop an improved microfluidic cartridge to overcome one or more limitations stated above.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the prior arts are overcome by device as claimed and additional advantages are provided through the provision of device as claimed in the present disclosure.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In one non-limiting embodiment of the disclosure there is provided a microfluidic cartridge. The microfluidic cartridge comprises at least one fluid flow channel to facilitate flow of biological samples. A fluid distribution region is provided in the cartridge in fluid communication with the at least one fluid flow channel. The fluid distribution region comprises a plurality of passages arranged concentrically to one another. The fluid distribution region also comprises a plurality of connecting channels, interconnecting the plurality of passages. The number of connecting channels extending from an outermost passage of the plurality of passages is less than the number of connecting channels extending from an innermost passage of the plurality of passages.

In an embodiment of the disclosure, the plurality of connecting channels extending from the innermost passage of the plurality of passages is configured in the form of spokes. Further, in an embodiment the plurality of connecting channels extending from the innermost passage is configured in equal volumes. Alternatively, the plurality of connecting channels extending from the innermost passage is configured in varied volumes.

In an embodiment of the disclosure, the microfluidic cartridge comprises a collection chamber interconnecting the connecting channels extending from the innermost passage of the plurality of passages to collect the fluid mixture.

In an embodiment of the disclosure, the microfluidic cartridge comprises a divergent nozzle in fluid communication with the collection chamber. The divergent nozzle is configured to accelerate the exit of fluid mixture from the collection chamber.

In an embodiment of the disclosure, the microfluidic cartridge comprises a filter unit in fluid communication with the fluid flow channel. The filter unit is configured to filter the fluid mixture based on size of particles of interest.

In an embodiment of the disclosure, the microfluidic cartridge comprises a mixing chamber in fluid communication with the filter unit. The mixing chamber is configured to mix biological sample and at least one reagent to form the fluid mixture. Further, an inlet of the mixing chamber is fluidly connected to a biological sample container and at least one reagent container. The biological sample and the at least one reagent is supplied to the mixing chamber through at least one pump. Furthermore, the mixing chamber comprises a fluid flow stream and the geometry of the fluid flow stream is at least one of serpentine geometry and sudden expansion geometry.

In an embodiment of the disclosure, the microfluidic cartridge is fabricated by at least one of photo-lithography and soft-lithography techniques using Polydimethylsiloxane (PDMS).

In another non-limiting embodiment of the disclosure, there is provided a microfluidic cartridge in a microscopy system for analyzing fluids. The fluid distribution region between the innermost passage of the plurality of passages and the collection chamber is configured as an imaging region to analyze fluids and a low frame rate camera is used for capturing images in the imaging region.

It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

FIG.1 illustrates a schematic representation of a microfluidic cartridge, according to an embodiment of the present disclosure.

FIGS.2A and 2B illustrates schematic representations of different geometries of mixing chamber in microfluidic cartridge of FIG.1, according to some embodiment of the present disclosure.

FIG.3 illustrates schematic representation of an exemplary filter unit provided in microfluidic cartridge of FIG.1, according to some embodiment of the present disclosure.

FIG.4A illustrates schematic representation of fluid distribution region in the microfluidic cartridge of FIG.1, according to some embodiment of the present disclosure.

FIG.4B illustrates schematic representation of exemplary imaging region in the fluid distribution region of FIG.4A with connecting channels, according to some embodiment of the present disclosure.

FIG.5 illustrates pictorial representation of a microsystem employed with microfluidic cartridge of FIG.1, for performing morphological analysis of biological sample, according to some embodiment of the present disclosure.

FIG.6 illustrates a schematic representation of the microfluidic cartridge of FIG.1 comprising a collection unit to collect the biological samples, according to some embodiment of the present disclosure.

The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other device for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the disclosure.

The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.

Embodiments of the present disclosure relates to a microfluidic cartridge for use in a microscopy system for performing morphological analysis on biological samples.

To overcome one or more drawbacks mentioned in the background, the present disclosure provides a microfluidic cartridge for use in an Imaging Flow Cytometry (IFC) system which is also referred as microscopy system. The IFC combines features of clinical microscopy and a conventional cytometer. The IFC can perform automated morphological analysis at sufficiently modest speeds. For instance, conventional flow cytometers have detection speeds in the range of 50000 cells/second as opposed to the 5000 cells/second provided by an IFC system. The existing IFC either have very low throughputs or use expensive cameras rendering them unfit for point care diagnostic applications.

The present disclosure discloses a microfluidic cartridge for use in microscopy device which improves the imaging throughout of the biological samples to enhance morphological analysis. The microfluidic cartridge comprises a plurality of flow passages for distributing the flow of biological samples. The flow passages are arranged concentric to one another, and are interconnected by a plurality of connecting channels. In other words, the plurality of passages are arranged radially towards a collection chamber of the fluid distribution region. Further, the plurality of connecting channels extending from an innermost passage of the plurality of passages converges into a collection chamber, where the mixture of biological samples and reagents are imaged. This configuration, improves flow of biological samples in the imaging region of the IFC, and thereby significantly increases the number of biological samples that can be assessed by imaging within a given field of view. Hence, the microfluidic cartridge improves the throughput of the IFC by introducing a fluid distribution region designed ideally to suit the low frame rate cameras and could be easily used in any resource limited localities. The present disclosure also enhances the performance of various imaging based particle counters.

The microfluidic cartridge also comprises a mixing chamber configured to receive biological samples and at least one reagent, and is adapted to mix the biological samples with the at least one reagent to form a fluid mixture. The inlet of the mixing chamber is fluidly connected to a biological sample container and at least one reagent container. A pump is used to supply the biological samples and at least one reagent to the mixing chamber. The mixing chamber comprises a fluid flow stream, wherein geometry of the fluid flow stream is at least one of serpentine geometry and sudden expansion geometry. Further, a filter unit in fluid is provisioned in the microfluidic cartridge in fluid communication with the mixing chamber. The filter unit receives the fluid mixture from the mixing chamber and filters the fluid mixture based on size of particles of interest. The microfluidic cartridge comprises a fluid flow channel interconnecting the filter unit and the fluid distribution region, the fluid distribution region fluidly connected to the fluid flow channel. The fluid distribution region comprises a plurality of passages arranged concentrically to one another and comprises a plurality of connecting channels interconnecting the plurality of passages. The number of connecting channels extending from an outermost passage of the plurality of passages is less than the number of connecting channels extending from an innermost passage of the plurality of passages. An imaging region is formed between the innermost passage and the collection chamber of the fluid distribution region, wherein low frame rate cameras could be used to capture images of the fluid mixture. In an embodiment of the disclosure, the plurality of connecting channels in the imaging region is configured in the form of spokes. These channels are made in equal sizes or can vary in dimensions according to the size of particles flowing in the imaging region. In one embodiment, the microfluidic cartridge comprises a collection unit to collect the fluid mixture after imaging in the imaging region. The collection unit is fluidly connected to the divergent nozzle. The collection unit is surrounded by a thin membrane which allows diffusion of air molecules through it. In one embodiment, the membrane is a PDMS membrane. The diffusion of air molecules creates a differential pressure and allows suction of fluid mixture into the collection unit.

Henceforth, the present disclosure is explained with the help of figures of a microfluidic cartridge which is used in an Imaging Flow Cytometry (IFC) system, to improve the throughput of the IFC system and to provide a design that suits imaging by a low frame rate camera. However, such exemplary embodiments should not be construed as limitations of the present disclosure. A person skilled in the art can envisage various such embodiments without deviating from scope of the present disclosure.

FIG.1 is an exemplary embodiment of the present disclosure, which illustrates a schematic representation of the microfluidic cartridge (100) for use in an Imaging Flow Cytometry (IFC) system which is also referred as microscopy system. The microfluidic cartridge (100) comprises a fluid distribution region (102) which improves throughput of biological samples, and thereby facilitates use of low frame rate cameras for imaging, and hence microscopy system could be easily used in any resource limited localities. The present disclosure substantially increases the number of channels that can be accommodated across the field of view of the camera as opposed to the conventional multiple straight parallel channels. Thereby ensures that images are captured without any motion blur for further morphological analysis.

As shown in FIG. 1 the microfluidic cartridge (100) comprises a mixing chamber (108). The mixing chamber (108) comprises an inlet (108a), and is configured to receive biological samples and at least one reagent. In an embodiment of the disclosure, the biological samples include but are not limited to blood, urine, saliva and any other fluids, which require visualization of microscopic specimen like pollen, particles in aerosols etc. The essential reagents may include, but not limited to anti-coagulants, staining dyes, nano-particles needed for sample preparation. In an embodiment of the present disclosure, the biological samples and the reagents are stored in containers such as sample container (108), and reagent container (109). The inlet of the mixing chamber (108) is fluidly connected to the biological sample container (109) and the reagent container (110) to receive the biological sample and the regent stored in the containers (108 and 109). A pump (109) [shown in FIG. 5] such as but not limiting to syringe pump is fluidly connected to the inlet (108a) of the mixing chamber (108) to inject the biological samples and at least one reagent into mixing chamber (108).

In an embodiment of the present disclosure, the mixing chamber (108) comprises a plurality of fluid flow streams (112) [best shown in FIGS. 2a and 2b] for mixing the biological sample with the at least one reagent. The fluid flow stream (112) with a predetermined geometry improves the mixing of the biological sample with the at least one regent. The geometry of the fluid flow stream (112) is selected on the basis of biological cells and the reagents used. In an embodiment of the present disclosure, the geometry of the fluid flow stream (112) is at least one of serpentine geometry and sudden expansion geometry. The geometry of the fluid flow stream (112) is configured to mix the biological samples and the reagents to form a fluid mixture. The ratio of the fluid mixture i.e. the ratio of biological samples and reagents is regulated according to requirements of the tests to be carried out.

The microfluidic cartridge (100) further comprises a filter unit (107) fluidly connected to the mixing chamber (108). The filter unit (107) is configured to receive the fluid mixture from the mixing chamber (108) and filter the fluid mixture based on size of particles of interest. The particles of interest are further let into the fluid distribution region (102), other particles of the fluid mixture are filtered out of the microfluidic cartridge (100). In an embodiment of the present disclosure, the filter unit (107) is a microfluidic spatial filter [best illustrated in the FIG.3]. Microfluidic spatial filter provide a convenient way to filter out different sized particles. In general, spatial filters comprise different spatial obstacles in the fluid path. The size, placement and distribution of these obstacles are designed, so that particles with size of interest are allowed to flow through, while particle with sizes out of interest range are filtered out.

Further, the throughput of the microscopy system is determined by factors like – concentration of the biological sample, frame-rate of the image sensor, particle flow velocity and number of microfluidic channels simultaneously imaged. The concentration of the sample suspension determines the number of cells that enter and exit the region of the microfluidic device that is under microscopic surveillance. Hence, increasing the concentration of the sample would increase the throughput. However, increasing the concentration beyond certain limit would result in the reduced spatial separation between individual cells. Reduced spatial separation may lead to failure of the image processing algorithms to distinguish individual cells. Coming to the aspect of frame rate; the throughput of system increases with increase in frame rate. However, the frame rate cannot be increased indefinitely. Some of the fastest cameras available today enable frame rates up to few thousand frames per second. Although apparent, increasing the frame rate may not be the most ideal choice for throughput enhancement in all scenarios. For example, in cases where system cost is an important design parameter, increasing frame rate would proportionally raise the cost of the system.

In the present disclosure, a low frame-rate image sensor have been employed as they are cost-
effective. Particle flow velocity is another important parameter, which determines the throughput. As the exposure time of the image sensor is finite, the particle flow velocity is limited to a range; wherein motion-blur would be minimal. It is important to image the particle without motion-blur, as the blur due to motion would result in loss of morphological information. On the other hand, very low particle flow velocity would result in the particle taking longer duration of time to exit the system field of view. This would lead to the particle being imaged in several frames of the recorded video. Thereby, leading to a redundancy in the acquired images; this reduces the effective throughput of the system. Thus, the ideal particle flow velocity would strike a balance between redundancy and motion-blur. The number of microfluidic channels transporting the specimen sample across field of view also determines the throughput. As simultaneously imaging cells passing through multiple channels would proportionally multiply the throughput of the system. By balancing out the trade-offs between these parameters, the imaging throughput of the microfluidic microsystem can be optimized.

The microfluidic cartridge (100) comprises at least one fluid flow channel (101) fluidly connected to the filter unit (107). The fluid flow channel (101) interconnects the filter unit (107) with the fluid distribution region (102). The fluid flow channel (101) receives the filtered fluid mixture from the filter unit (107) and transfers this mixture into the fluid distribution region (102) for further distribution. In one embodiment of the present disclosure, a single fluid flow channel (101) interconnects the filter unit (107) and fluid distribution region (102). In another embodiment of the present disclosure, two or more fluid flow channels (101) with a common input at the filter unit (107) and common output at the fluid distribution region (102) interconnects the filter unit (107) and the fluid distribution region (102).

The microfluidic cartridge (100) of the present disclosure comprises a fluid distribution region (102) in fluid communication with the fluid flow channel (101). The fluid distribution region (102) comprises a plurality of passages (103) arranged concentrically to one another to facilitate flow of fluid mixture. The fluid distribution region (102) further comprises a plurality of connecting channels (104) interconnecting the plurality of passages (103) to facilitate the flow of fluid mixture from an outermost passage of the plurality of passages (103) to an innermost passage of the plurality of passages. Further, the number of connecting channels (104) extending from the outermost passage of the plurality of passages (103) is less than the number of connecting channels (104) extending from an innermost passage of the plurality of passages (103). In an embodiment of the disclosure, the number of connecting channels (104) gradually increases from the outermost passage of the plurality of passages (103) to the innermost passage of the plurality of passages (103). The connecting channels (104) are configured in the form of multiple smaller cross section channels in gradual angular manner. Further, microfluidic cartridge (100) comprises a collection chamber (105) interconnecting the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) to collect the fluid mixture. In an embodiment of the present disclosure, the collection chamber (105) forms a substantially central part of the fluid distribution region (102). In one embodiment of the present disclosure, a region between the innermost passage of the plurality of passages (103) and the collection chamber (105) is selected as imaging region. In another embodiment of the disclosure, the plurality of passages (103) is arranged radially towards the collection chamber (105) of the fluid distribution region (102). A low frame rate camera is used for capturing images in the imaging region (113) [best illustrated in FIG.4B]. The plurality of connecting channels (104) in the imaging region (113) is configured in the form of spokes and fuse to a middle imaging region of interest. This design facilitates the biological samples present in the suspension flow through the imaging region (113) once before they exit from the collection chamber (105). Further, configuration of the fluid distribution region (102) i.e. branching of the connecting channels (104) from the plurality of passages (103) help reduce the velocity of the particles of biological samples and ensures that the imaging free of motion blur. Further, the arrangement of connecting channels (104) in the form of spokes will facilitate more connecting channels in a small area. In an embodiment of the disclosure, this small area is used as imaging region (113) to capture the images. As more connecting channels (104) are covered within the imaging region (113), efficiency of the imaging system increases. In an embodiment of the present disclosure, the microfluidic cartridge (100) further comprises a divergent nozzle (106) fluidly connected to the collection chamber (105). The divergent nozzle (106) emerging out of the collection chamber (105) is configured to accelerate the exit of fluid mixture from the collection chamber (105) in order to make sure that there is no redundancy of imaging in the imaging region (113) of the microfluidic cartridge (100). The imaging region (113) and the collection chamber (105) of the microfluidic cartridge (100) is best illustrated in FIG.4B. Configuration of imaging region (113) between innermost passage and the collection chamber (105) should not be construed as limitation to present disclosure, as one skilled in the art, may consider any portion of the fluid distribution region (102) as imaging region (113) for analysis.

In an embodiment of the disclosure, the microfluidic cartridge (100) is fabricated using photo-lithography and soft-lithography techniques. The connecting channels (104) are configured to facilitate the flow of fluid mixture for further analysis. In an embodiment, the connecting channels (104) provided in the imaging region are configured in uniform width to facilitate uniform distribution of the biological samples. In another embodiment of the present disclosure, the connecting channels (104) are of varying width and depth to facilitate variable distribution of the biological samples. In an exemplary embodiment, the connecting channel (104) width is 15 µm and depth of the connecting channel is 9 µm. In an embodiment, the depth of the channels is kept uniform. However, in case the suspension contains cells of varied sizes, the cartridge is fabricated with channels of different depth, so as to accommodate samples of different sizes. This is relevant for blood samples, wherein the cell sizes vary from 2 µm to 20 µm. Further, in accordance with the depth of the channels spatial filters can be incorporated within the redistribution network. The corresponding spatial filters allow appropriate re-direction of the species with appropriate size through channels of appropriate depth i.e., the bigger cells would be directed to flow through the channels of higher depth. So that channels do not get clogged. Further, the volumes include depths & widths of the channels. The volumes of channels are modified so as to control the equivalent hydraulic resistance of the redistribution network. This control over hydraulic resistance (during design phase), enables control over flow rate and therefore, control over particle flow speeds. In one embodiment, 27 connecting channels (104) are configured in the imaging region (113) of the microfluidic cartridge (100). These connecting channels (104) are arranged in the form of spokes. The microfluidic cartridge (100) is fabricated with the aid of Polydimethylsiloxane (PDMS). In an embodiment of the present disclosure, the microfluidic cartridge (100) is fabricated with any other materials like glass, Polymethylmethacrylate (PMMA).

FIG.5 is an exemplary embodiment which illustrates an Imaging Flow Cytometry (IFC) system or a microscopy system comprising the microfluidic cartridge (100) for imaging and performing morphological analysis of biological sample. As shown in FIG.5 the microscopy system comprises an illumination unit (501) including a light source such as LED and condenser lens used for illuminating a portion of interest of a microfluidic cartridge (100) which receives input through one or more connecting channels (104). A microfluidic pump (111) such as but not limiting to syringe pump is used to regulate the flow of input and mixture formed in the microfluidic cartridge (100). An optical enhancement unit (502) is configured in the microscopy system to enhance the image of microscopic elements of the mixture. Further, an imaging unit (503) capture plurality of images in the imaging region (113) of the microscopic elements of the mixture. The plurality of images is processed and morphological analysis is carried out by a computing unit (not shown in the figure) and the analysis results are displayed by the display unit. In one embodiment, the imaging unit can include, but is not limited to, a low frame rate digital camera. The microfluidic cartridge (100) is positioned in the sample plane of the imaging unit, which enables the imaging unit to image the biological sample flowing through the microfluidic connecting channels (104) of the device. The flow of the input sample through the microfluidic cartridge (100) is facilitated with the help of a syringe pump.

In an exemplary experimental embodiment, total of 37778 cells were imaged in duration of 18 seconds. The average throughput of the system was approximately found to be 2098 cells per second. The throughput achieved is comparable to the previous demonstrations of high throughputs with expensive cameras and high frame rate cameras.

FIG.6 is an exemplary embodiment of the present disclosure, which illustrates schematic representation of the microfluidic cartridge (100) comprising a collection unit (114) to collect the biological samples. The microfluidic cartridge (100) of FIG. 6 comprises all the components and ingredients, and functions in a way similar to as described in previous paragraphs. Further, the microfluidic cartridge (100) comprises a collection unit (114) fluidly connected to the divergent nozzle (106). The collection unit (114) is configured to collect the fluid mixture from the collection chamber (105). The collection unit (114) is surrounded by a thin membrane. In one embodiment, the thin membrane (115) is a Polydimethylsiloxane (PDMS) membrane. This thin membrane (115) surrounding the collection unit (114) allows diffusion of air molecules through it. The diffusion of air molecules creates a differential pressure which allows the fluid mixture to be collected in the collection unit (114) after it’s imaging in the imaging region (113). Once sufficient amount of biological samples are collected in the collection unit (114) the PDMS device can be unplugged and disposed. This design enables compatibility of the microfluidic cartridge (100) with vacuum suction based pumping methods which eliminates the need for replacing the tubing and the syringes that are connected to the divergent nozzle (106).

It is to be understood by a person of ordinary skill in the art would do various modifications and variations without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

Advantages:

The present disclosure provides a microfluidic cartridge with a fluid distribution region which enhances imaging throughput of the microfluidic microsystems and thus enabling point of care diagnostic testing of a wide variety of diseases.

The present disclosure provides a microfluidic cartridge fluid distribution region which ensures velocity of the biological samples is optimum for motion blur free imaging using a low cost low frame rate camera.

The present disclosure provides a microfluidic cartridge that enhances the performance of various bright field imaging based particle counters.

Equivalents:

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of 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,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Referral Numerals:

Reference Number Description
100 Microfluidic cartridge
101 Fluid flow channel
102 Fluid distribution region
103 Passages
104 Connecting channels
105 Collection chamber
106 Divergent nozzle
107 Filter unit
108 Mixing chamber
108a Inlet of the mixing chamber
109 Biological sample container
110 Reagent container
111 Pump
112 Fluid flow stream in mixing chamber
113 Imaging region
114 Collection unit
115 Membrane
501 Illumination unit
502 Optical unit
503 Imaging unit
504 Display unit

We claim:
1. A microfluidic cartridge (100), comprising:
at least one fluid flow channel (101) to facilitate flow of biological samples; and
a fluid distribution region (102) in fluid communication with the at least one fluid flow channel (101), the fluid distribution region (102) comprising:
a plurality of passages (103) arranged concentrically to one another; and
a plurality of connecting channels (104), interconnecting the plurality of passages (103), wherein the number of connecting channels (104) extending from an outermost passage of the plurality of passages (103) is less than the number of connecting channels (104) extending from an innermost passage of the plurality of passages (103).

2. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in the form of spokes.

3. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in equal volumes.

4. The microfluidic cartridge (100) as claimed in claim 1, wherein the plurality of connecting channels (104) extending from the innermost passage of the plurality of passages (103) is configured in varied volumes.

5. The microfluidic cartridge (100) as claimed in claim 1 comprises a collection chamber (105) interconnecting the connecting channels (104) extending from the innermost passage of the plurality of passages (103) to collect the fluid mixture.

6. The microfluidic cartridge (100) as claimed in claim 1 comprises a divergent nozzle (106) in fluid communication with the collection chamber (105).

7. The microfluidic cartridge (100) as claimed in claim 6, wherein the divergent nozzle (106) is configured to accelerate the exit of fluid mixture from the collection chamber (105).

8. The microfluidic cartridge (100) as claimed in claim 1 comprises a filter unit (107) in fluid communication with the fluid flow channel (101), the filter unit (107) is configured to filter the fluid mixture based on size of particles of interest.

9. The microfluidic cartridge (100) as claimed in claim 8 comprises a mixing chamber (108) in fluid communication with the filter unit (107), the mixing chamber (108) is configured to mix biological sample and at least one reagent to form the fluid mixture.

10. The microfluidic cartridge (100) as claimed in claim 9, wherein an inlet of the mixing chamber (108a) is fluidly connected to a biological sample container (109) and at least one reagent container (110).

11. The microfluidic cartridge (100) as claimed in claim 9, wherein the biological sample and the at least one reagent is supplied to the mixing chamber (108) through at least one pump (111).

12. The microfluidic cartridge (100) as claimed in claim 9, wherein the mixing chamber (108) comprises a fluid flow stream (112).

13. The microfluidic cartridge (100) as claimed in claim 12, wherein geometry of the fluid flow stream (112) is at least one of serpentine geometry and sudden expansion geometry.

14. The microfluidic cartridge (100) as claimed in claim 1 is fabricated by at least one of photo-lithography and soft-lithography techniques using Polydimethylsiloxane (PDMS).

15. A microscopy system for analyzing fluids comprising a microfluidic cartridge (100) as claimed in claim 1.

16. The microscopy system as claimed in claim 15, wherein the fluid distribution region (102) between the innermost passage of the plurality of passages (103) and the collection chamber (105) is configured as an imaging region (113) to analyze fluids.

17. The microscopy system as claimed in claim 16, wherein a low frame rate camera is used for capturing images in the imaging region (113).

Dated this 13th day of August, 2015 GOPINATH A S
IN/PA 1852
OF K&S PARTNERS
AGENT FOR THE APPLICANT

Title: “A MICROFLUIDIC CARTRIDGE”

ABSTRACT

The present disclosure discloses a microfluidic cartridge (100) for use in a microscopy system. The microfluidic cartridge (100) comprises at least one fluid flow channel (101) to facilitate flow of biological samples and a fluid distribution region (102) in fluid communication with the at least one fluid flow channel (101). The fluid distribution region (102) comprises a plurality of passages (103) arranged concentrically to one another. The fluid distribution region (102) also comprises a plurality of connecting channels (104), interconnecting the plurality of passages (103). The number of connecting channels (104) extending from an outermost passage of the plurality of passages (103) is less than the number of connecting channels (104) extending from an innermost passage of the plurality of passages (103).

FIG.1