Aspects of the present disclosure generally relate to assay devices, and more particularly, to assay devices including microfluidic channels and colorimetric testing components.
Capillary-driven microfluidic devices have gained popularity in the last decade as alternatives to traditional microfluidics. Instead of using an external pump to induce flow, capillary-driven devices utilize the surface tension of a fluid acting on channel walls (e.g., hydrophilic channel walls or fibers in the case of paper) to drive flow. Without the need for a pump, these devices can be operated outside of a centralized lab in resource limited settings without a power source, among other advantages. Pregnancy tests are just one example of capillary-driven analytical devices and their widespread utility as platforms for at-home diagnostics.
Immunoassays are a widely used technology for applications ranging from clinical diagnostics to environmental monitoring. The basis of the immunoassay is the binding reaction between antigen and antibody, typically performed on a surface. Either the antigen or the antibody can be the target analyte. After this reaction, the presence of the analyte is detected by one of several methods, including colorimetry, electrochemistry, fluorescence, and chemiluminescence. Immunoassays unfortunately rely heavily on laboratory instrumentation and thus, do not work well at the point-of-care or point-of-need. A related technology, the lateral flow assay (LFA) simplifies workflow but lacks the sensitivity and specificity of traditional immunoassays.
Considering the foregoing, a need exists for testing devices with the ease of use of LFAs and similarly immunoassays and the increased sensitivity associated with assays that conventionally require laboratory instrumentation.
In one aspect of the present disclosure, an assay device includes a colorimetric testing assembly including a detection area, a fluid inlet, and a microfluidic network. The microfluidic network includes a first path extending to the detection area and a second path extending to the detection area. The assay device further includes a first dried reagent disposed along the first path and a second dried reagent disposed along the second path. When a fluid is provided to the fluid inlet, a first portion of the fluid rehydrates the first dried reagent to produce a first rehydrated reagent, a second portion of the fluid rehydrates the second dried reagent to produce a second rehydrated reagent, and the first rehydrated reagent and the second rehydrated reagent are sequentially delivered to the detection area by capillary-driven flow.
In certain implementations, the assay device includes a pad. The pad may be disposed within the first path and contain the first dried reagent, or the pad may be disposed within the second path and contains the second dried reagent.
In another implementation, the first path includes a first surface on which the first dried reagent is disposed, or the second microfluidic path includes a second surface on which the second dried reagent is disposed.
In certain implementations, when fluid is provided to the fluid inlet, the first rehydrated reagent arrives at the detection area before the first rehydrated reagent.
In another implementation, the assay device includes a sample inlet separate from the fluid inlet and in communication with the microfluidic network. The sample inlet may include a filtration membrane.
In yet another implementation, the first path may be shorter than the second path.
In another implementation, the microfluidic network is configured such that the fluid arrives at the detection area by the first path before the fluid arrives at the detection area by the second path.
In still another implementation, the assay device includes a body formed from alternating layers of film and double-sided adhesive and the alternating layers of film and double-sided adhesive form the microfluidic network.
In another implementation, the assay device includes a vent in communication with the microfluidic network.
In another implementation, the assay device includes a second colorimetric testing assembly including a second detection area and a second microfluidic network in communication with each of the fluid inlet and the second detection area.
In another aspect of the present disclosure, a method of performing a colorimetric assay includes receiving a fluid at an inlet of an assay device. The assay device includes a microfluidic network in communication with each of the fluid inlet and a colorimetric assembly including a detection area. The method further includes rehydrating a first dried reagent disposed along a first path of the microfluidic network to produce a first rehydrated reagent, rehydrating a second dried reagent disposed along a second path of the microfluidic network to produce a second rehydrated reagent, and sequentially delivering the first rehydrated reagent and the second rehydrated reagent to the detection area by capillary flow.
In certain implementations, the assay device includes a device body formed from alternating layers of film and double-sided adhesive, and the alternating layers of film and double-sided adhesive define the microfluidic network.
In other implementation, the first rehydrated reagent includes an enzyme label, second rehydrated reagent includes a substrate, and the enzyme label is delivered to the detection area before the substrate.
In still other implementations, the fluid is a buffer fluid, and the method further includes receiving a sample at a sample inlet of the assay device, the sample inlet being in communication with the microfluidic network and separate from the fluid inlet. In such implementations, the method may further include transporting the sample by capillary action to the detection area such that the sample arrives at the detection area before each of the first rehydrated reagent and the second rehydrated reagent.
In certain implementations, the method may further include receiving a sample at a sample inlet of the assay device, the sample inlet in communication with the microfluidic network, and filtering the sample using a filtration membrane of the sample inlet. Such implementations may further include transporting the sample by capillary action to the detection area such that the sample arrives at the detection area before each of the first rehydrated reagent and the second rehydrated reagent.
In other implementations, the method may further include transporting a wash portion of the fluid by capillary action to the detection area before delivery of at least one of the first rehydrated reagent and the second rehydrated reagent to the detection area.
In another implementation, the method may include transporting a wash portion of the buffer fluid by capillary action to the detection area after delivery of the first rehydrated reagent and before delivery of the second rehydrated reagent.
In another aspect of the current disclosure, an assay device includes a colorimetric testing assembly including a detection area and a microfluidic network in communication with the colorimetric testing assembly. The microfluidic network is defined within a device body formed from alternating layers of film and double-sided adhesive. The assay device further includes a fluid inlet in communication with the microfluidic network, a first path extending to the detection area, and a dried enzyme label disposed along the first path. The assay device also includes a second path extending to the detection area, the second path being longer than the first path, and a dried substrate disposed along the second path.
In certain implementations, the fluid inlet is a buffer fluid inlet and the assay device further includes a sample inlet in communication with the microfluidic network.
The patent application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of necessary fee.
The present disclosure is described in conjunction with the appended figures.
In the appended figures, similar components and/or features can have the same reference label. Further, various components of the same type can be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
Aspects of the present disclosure are directed to capillary-driven microfluidic devices and, more specifically, such devices for performing colorimetric testing. In general, the devices disclosed herein include a microfluidic network through which fluid is transported by capillary action and that automatically sequences the delivery of reagents and washes to a test/detection zone. Sequencing is achieved, at least in part, by varying the geometry and/or other flow driving characteristics of pathways through the microfluidic network. For example, the microfluidic network may include paths of varying length between a buffer inlet and the detection zone such that fluid transported along longer paths is delivered to the detection zone after fluid transported along shorter paths. Dried reagents may be disposed along certain paths of the microfluidic network such that the reagents may be rehydrated and delivered to the detection zone. The flow-driving characteristics of the paths (e.g., the geometry of the paths) relative to each other may therefore be used to control the timing and sequencing of delivery of the rehydrated reagents. Flow through the devices and subsequent sequencing of reagent delivery to the detection zone is substantially automatic and generally requires only that a user provide each of a sample and buffer solution or a combined sample and buffer to the device, depending on the particular test to be conducted using the device.
Enzyme linked immunosorbent assays (ELISAs) are used to detect a wide range of analytes with good sensitivity and specificity. These analytes include whole cells, proteins, antibodies, and small molecules, among other things. The high sensitivity of ELISAs is enabled by stringent washing steps to mitigate non-specific adsorption of non-targets and using an catalytic label such as an enzyme to amplify a signal, while the high specificity is enabled using a “sandwich” immunoassay that captures an analyte between two highly specific probes.
An example of a conventional ELISA system 100 is illustrated in
Control line 106 may be optional but is generally included in ELISA systems to verify proper device functionality. In general, control line 106 includes an anti-label 120 adapted to bond with an enzyme label 122. Test line 104, on the other hand, includes a capture probe 108 configured to bond with a target analyte 110, to which enzyme label 122 bonds. Following delivery of target analyte 110 and enzyme label 122, an enzyme substrate 124 is provided that reacts with enzyme label 122 to produce a product and a corresponding colorimetric or other visual change of the corresponding line.
Both enzymatic detection and the sandwich assay format require multiple washing steps and sequential delivery of reagents (e.g., the enzyme label and the substrate). These washing and reagent delivery steps yield robust analytical performance from ELISAs, but they are complicated to perform and relegate the assay to a centralized laboratory with expensive equipment and trained laboratory technicians. In many testing situations the time and financial resources needed for ELISAs are not available. There are more affordable point-of-care alternatives, but they often lack the analytical performance needed.
One of the most common alternatives to an ELISA is the lateral flow immunoassay. Lateral flow strips are inexpensive and easy to use in comparison to the ELISA. They generally require only that the end user provide a sample and the results are easy to interpret in most settings. The pregnancy test is the most widespread example of a lateral flow device, having an estimated global market of $1.3 billion per year. Although they are easy to use, lateral flow strips perform poorly compared to ELISAs, with well-documented reports of high false positive and negative rates and unreliable quantification. Substandard sensitivity and specificity in lateral flow assays stem from the inability to use enzymes as labels and sequentially wash and add reagents, which limits the scope of possible target analytes (e.g. disease biomarkers, antibodies, whole cells).
To address the foregoing issues, among others, this disclosure introduces a system that can be as easy to use as a pregnancy test or other lateral flow assay, but with the same analytical capabilities of an ELISA. The system relies on a capillary driven immunoassay device to sequentially add and wash reagents and competing/non-target species from a test zone with minimal steps by an end user. The assay device generally includes a microfluidic network with channels that are specifically configured to provide sequential flow of reagents and washing fluids to a detection zone. Operation of the assay device is substantially automatic, with an end user only being required to provide a sample and a buffer fluid or a sample/buffer combination. In certain implementations, flow through the assay device is achieved by capillary driven flow, which may be facilitated by hydrophilic channels of the microfluidic network and a passive pump mechanism, such as a paper/nitrocellulose pump. Notably, assay devices according to the present disclosure are capable of performing tests similar to conventional ELISAs, enabling quick and accurate detection of target analytes in at-home and other settings and by untrained users that were previously undetectable outside a centralized laboratory.
In certain implementations, the assay device is made of film sheets (e.g., transparency sheets, polyester film) and double-sided adhesive layers. Each layer may be laser cut or otherwise manufactured such that, when the layers are assembled by stacking and laminated, a microfluidic network is defined within the resulting laminated body.
The microfluidic network includes multiple channels/paths, each configured to transport fluid (e.g., a buffer fluid) by capillary flow from one or more fluid inlets to a testing area/detection zone. Certain of the channels may include dried reagents that are rehydrated by fluid transported through the channels for subsequent delivery to the testing area. Other channels may not include reagents such that fluid transported through such channels is delivered to the testing area without substantially altering the composition of the fluid. As a result, fluid transported through channels furnished with a dried or otherwise stabilized reagent may be used to deliver the reagent to the testing area. Washes may be provided, for example, by fluid portions that do not include rehydrated reagent or that are provided by other paths/channels of the microfluidic network that do not include dried reagents. By varying the length, size, and similar characteristics of the channels of the microfluidic network and including other flow control mechanisms, delivery of fluid via different channels to the testing area/detection cone may be sequenced. So, for example, delivery of reagents and washes may be alternated or otherwise sequenced to follow a particular testing protocol.
Dried reagents may be provided by conjugate release pads disposed along channels of the microfluidic network. Such pads may be formed, e.g., from glass fiber or nitrocellulose. Alternatively, dried reagent may be disposed along a given channel, e.g., by being dried onto a surface of the channel.
In certain implementations, the testing area may be provided by a nitrocellulose membrane connected to or otherwise in communication with the microfluidic network. The nitrocellulose membrane may contain a capture probe specific to the target analyte. The capture probe may be striped onto the nitrocellulose membrane to form a test line. During operation, an enzyme-labeled detection antibody specific to the target analyte may be delivered to the test line (e.g., by rehydrating a dried antibody disposed in a channel of the microfluidic network) followed by subsequent delivery of a substrate (e.g., by rehydrating a dried antibody disposed in a channel of the microfluidic network) that reacts with the enzymatic label to produce a colorimetric signal at the test line.
The assay device may include a specific sample inlet and related components for processing a sample for testing, such as a filtration membrane for filtering the sample. When performing an assay based on whole blood, for example, the filtration membrane may be a plasma separation membrane and may be sealed over the sample inlet. In such cases, the assay device may further include a separate fluid/buffer inlet for introducing a fluid buffer to initiate subsequent testing of the sample. For less viscous or less complex sample matrices (e.g., nasal swab samples diluted in an extraction buffer) a single sample inlet/buffer inlet with no filtration membrane could be used. In such application, a separate membrane or similar element may not be necessary, and the sample may also supply the buffer for the rest of the assay. In general, however, the same reagent addition and washing steps may be accomplished with single-inlet assay device as with multi-inlet devices by configuring the microfluidic network accordingly.
Example implementations discussed herein focus on non-competitive immunoassays; however, implementations of the present disclosure are not limited to such assays. Rather, this disclosure is intended to describe a more general assay device that may be used in a range of applications. Stated differently, this disclosure is intended to describe a general assay device capable of sequential delivery of reagents and washes to a colorimetric test assembly. Although specific tests (including specific sample types, reagents, buffers, etc.) may be described, such tests should be considered illustrative only and non-limiting regarding other applications for the present disclosure. For example, while most examples discussed herein focus on testing of bodily fluids, assay devices according to this disclosure may be adapted for environmental or chemical testing (e.g., water testing). As another example, while the examples disclosed herein generally focus on non-competitive immunoassays, assay devices according to the present disclosure may be adapted to perform competitive immunoassays. Competitive immunoassays are more commonly used for small molecules, like hormones, THC, and other small molecular weight molecules where an antibody pair is not available. In a competitive immunoassay, a capture antibody is deposited in a detection area (e.g., on a nitrocellulose strip). A detection reagent in the system would be a labeled version of the analyte (e.g., the analyte labelled with an enzyme, metal, nanoparticle, etc.). When the sample runs through the system with no analyte, the labeled detector analyte binds to the capture antibody and gives a signal, e.g., a color change at the test line. If analyte is present in the sample, it competes with the detector analyte binding at the detection area and reduces the resulting signal. Therefore, a reduction in signal is observed in the presence of specific analyte. So, for example, in implementations of the present disclosure, an assay device may be configured to deliver a capture antibody to a detection area followed by a sample, followed by a labeled version of the analyte, with optional washes between each delivery. More generally, while specific assay devices are described herein, such devices may be readily adapted for different applications by modifying the placement and type of reagents included in the assay device as required for the assay to be performed.
The foregoing introduces certain concepts related to assay device devices. Other features and aspects of such devices and related technology are described below with reference to various example implementations.
As illustrated, assay device 200 includes a device body 202 defining a microfluidic network 204. Assay device 200 includes a sample inlet 206 and a buffer inlet 208 in communication with microfluidic network 204. Microfluidic network 204 generally includes microfluidic pathways or channels for transporting fluids provided via sample inlet 206 and buffer inlet 208 to a test strip 210 (e.g., a colorimetric test strip). In general, the channels of microfluidic network 204 are configured to transport fluids by capillary action. Such transportation may be facilitated by forming device body 202 from or otherwise applying hydrophilic materials to surfaces of the channels of microfluidic network 204. Transportation may be further facilitated by a nitrocellulose or similar “wicking” substrate of test strip 210 alone or in combination with a passive pump 212. As shown in
Assay device 200 is generally configured to perform a test like a conventional enzyme linked immunosorbent assay (ELISA). To facilitate such testing, assay device 200 includes dried reagents disposed along channels of microfluidic network 204. Specifically, assay device 200 includes a dried enzyme label pad 214 and a dried substrate pad 216 disposed within microfluidic network 204. In other implementations, assay device 200 may be adapted to perform other assays by changing, adding, removing, or otherwise modifying the specific reagents included in microfluidic network 204. Such modification may include adding additional paths of microfluidic network 204 for delivery of additional reagents.
As described below in further detail in the context of
In certain implementations, a sample may require processing as part of the testing process. In such cases, sample inlet may include a filtration membrane or similar component for processing the sample. For example, when testing blood, sample inlet 206 may include a plasma or similar membrane to separate blood components.
As previously noted,
In
A discussion of the use of assay device 200 is now provided with reference to
Referring first to
Referring next to
As shown in FIG. 5D, buffer fluid 232 rehydrates dried substrate pad 216 to produce rehydrated substrate 235. Rehydrated substrate 235 is transported through microfluidic network 204 to test strip 210. In assay device 200, such transportation includes transporting rehydrated substrate 235 by capillary action along a path/channel of microfluidic network 204 that extends through a lower layer of device body 202 and that emerges upstream of test strip 210. When rehydrated substrate 235 ultimately arrives at test strip 210, it reacts with the previously delivered rehydrated enzyme label 233 and sample 230, resulting in a colorimetric change in the test strip 210 (e.g., the appearance of a stripe 234).
Notably, and as previously discussed in the context of
The sequential reagent delivery and washing illustrated in
As illustrated in
During delivery of enzyme label from dried enzyme label pad 714, an excess of enzyme label may be delivered to test strip 710. Accordingly, FIG. 9D illustrates assay device 700 during a wash after delivery of rehydrated enzyme label 754. More specifically, microfluidic network 704 is generally shaped and configured such that at least a portion of the test fluid is delivered to test strip 710 after rehydrated enzyme label 754 but before rehydrated substrate 756. By doing so, excess of the enzyme label can be removed from test strip 710 before arrival of rehydrated substrate 756, generally improving the response of test strip 710.
Notably, operation of any of the foregoing devices and others in accordance with the present disclosure is straightforward from the perspective of an end user and substantially automated. More specifically, in double- or multi-inlet assay device devices, a sample is added to an inlet (which may include a filtration membrane or similar element) and buffer is subsequently added to a buffer inlet. The addition of the buffer starts the sequential reagent delivery and washing cycles without any further intervention by the user. Accordingly, the only substantive steps to be performed by the end-user to execute an assay are the addition of the sample and buffer. Similarly, in single-inlet devices, the assay is initiated by adding a combined sample and buffer (e.g., a sample diluted in a sample buffer) to an inlet. Accordingly, the only step to be performed by the end-user to perform the assay is the addition of the sample and buffer to the assay device.
As previously discussed, in at least certain implementations, after sample and buffer addition, all channels of the microfluidic network may be filled with buffer (or combined buffer and sample) due to capillary action. Notably, the microfluidic network may include vents or similar openings (e.g., above the dried reagent pads) to ensure proper filling of the assay device and to ensure venting of air to prevent bubbles that may impede flow through the microfluidic network. Once the channels are filled, passive pump (e.g., a waste pad, nitrocellulose body of a test strip, etc.) may be coupled to the microfluidic network or otherwise made to contact the fluid within the microfluidic network, thereby pumping/drawing fluid through the microfluidic network to a testing or detection zone (e.g., of a test strip). In at least certain implementations, the sample inlet is placed immediately upstream of the detection zone such that the sample is delivered to the detection zone first.
Assay devices according to this disclosure may include two or more dried reagents, which may be stored on pads within the microfluidic network or otherwise disposed within the microfluidic network. In certain implementations, a first of the dried reagents may be an enzyme or nanozyme label while a second of the dried reagents may be a substrate. The microfluidic network is generally configured such that after introduction of a sample, the sample may be transported to the detection zone by capillary action. The user may then introduce a buffer fluid to the assay device, which substantially fills the microfluidic network and, in some instances, further drives flow of the sample to the detection zone. A portion of the buffer fluid may follow, thereby washing away excess sample that may interfere with the remaining assay. Following introduction of the buffer fluid, dried reagent stored within the microfluidic network may be rehydrated by the buffer fluid and generally permitted to flow toward the detection zone. In a two-reagent configuration, the pressure differential or other parameter impacting flow is such that rehydrated reagent from the first reagent pad (e.g., enzyme label) arrives at the detection zone before rehydrated reagent from the second reagent pad. As a result, target analyte captured in the detection zone may captures the rehydrated reagent form the first reagent pad.
Following delivery of the first reagent, the second reagent (e.g., rehydrated substrate) may be delivered to the detection zone. The rehydrated substrate may be preceded at the detection zone by additional buffer fluid, which washes away excess of the first reagent. When the rehydrated second reagent reaches the detection zone, the rehydrated second may react with the first reagent, producing a visible color change or similar effect.
In certain implementations, after flow is substantially complete in the device, the color change may generally be detectable with the naked eye for qualitative detection, imaged (e.g., using a smartphone camera) for quantitative information, or otherwise interpreted.
As noted above,
For the serology assay, a nitrocellulose membrane (e.g., test strip 610) was striped with SARs-CoV-2 nucleocapsid protein (NP). A first reagent pad (generally corresponding to dried enzyme label pad 614 of assay device 600) was prepared with dried anti-mouse-Horse radish peroxidase (HRP) while a second reagent pad (generally corresponding to dried substrate pad 616 of assay device 600) contained dried p-dimethylaminoazobenzene (DAB), a colorimetric substrate for HRP. The nitrocellulose membrane was blocked with StabilGuard and the buffer used in the buffer inlet contained 0.01% hydrogen peroxide to activate the HRP.
As noted above, the antigen assay was completed with a single-inlet device, such as assay device 700. The only changes that needed to be made to transition to the antigen assay were switches in the capture and detection antibodies so that SARs-CoV-2 N protein was the target. HRP was still used as the label, but tetramethylbenzidine (TMB) was used as the colorimetric substrate instead of DAB, providing more sensitive results. The antigen assay was compared to a laboratory ELISA and to a traditional lateral flow assay using gold nanoparticles as a label. The results of this comparison are illustrated in
As discussed herein, the device body and microfluidic network defined by the device body generally includes various pathways and dried reagents along the pathways to facilitate sequential delivery of rehydrated reagent to test strip 1308. Housing 1302 may be configured to be unsealed, thereby permitting venting of the microfluidic network as previously described.
Notably, assay device 1300 may be readily modified to accommodate multiple inlets and, as a result, to perform test that may require separate introduction of a sample and a buffer fluid. In such cases, assay device 1300 may be modified to have each of a sample inlet and a buffer inlet. The sample inlet may also include a filtration membrane or similar component for separating/processing the sample.
At operation 1504, a buffer fluid is received at a buffer fluid inlet of the assay device. The buffer fluid may substantially fill the microfluidic network and addition of the buffer fluid may generally initiate capillary-driven flow through the microfluidic network. Capillary-driven flow may also be facilitated by a passive pump in communication with the microfluidic network.
At operation 1506, the buffer fluid flows across the detection area, washing excess sample from the detection area.
At operation 1508, a first rehydrated reagent is delivered to the detection area. More specifically, a first dried reagent, such as a dried enzyme label, may be disposed along a first path of the microfluidic network (e.g., in the form of a pad onto which the first reagent is dried). When the buffer fluid is added, the buffer fluid may rehydrate the first dried reagent and may initiate transportation of the first rehydrated reagent to the detection area.
At operation 1510, another portion of the buffer fluid may be transported across the detection area, washing excess first reagent from the detection area.
At operation 1512, a second rehydrated reagent is delivered to the detection area. More specifically, a second dried reagent, such as a dried substrate, may be disposed along a second path of the microfluidic network (e.g., in the form of a pad onto which the second reagent is dried). When the buffer fluid is added, the buffer fluid may rehydrate the second dried reagent and may initiate transportation of the rehydrated second reagent to the detection area.
At operation 1514, a result of the assay is visually indicated. For example, a stripe, pattern, or similar indicator may appear at the detection area in response to a product produced by delivery of the substrate.
Notably, devices in accordance with the present disclosure are configured to perform operations 1506-1514 of
At operation 1604, the sample/buffer fluid flows across the detection area, delivering sample to the detection area.
At operation 1606, a first rehydrated reagent is delivered to the detection area. More specifically, a first dried reagent, such as a dried enzyme label, may be disposed along a first path of the microfluidic network (e.g., in the form of a pad onto which the first reagent is dried). When the sample/buffer fluid is added, the sample/buffer fluid may rehydrate the first dried reagent and may initiate transportation of the resulting rehydrated reagent to the detection area.
At operation 1608, another portion of the sample/buffer fluid may be transported across the detection area, washing excess first reagent from the detection area.
At operation 1610, a second rehydrated reagent is delivered to the detection area. More specifically, a second dried reagent, such as a dried substrate, may be disposed along a second path of the microfluidic network (e.g., in the form of a pad onto which the second reagent is dried). When the sample/buffer fluid is added, the sample/buffer fluid may rehydrate the second dried reagent and may initiate transportation of the rehydrated second reagent to the detection area.
At operation 1612, a result of the assay is visually indicated. For example, a stripe, pattern, or similar indicator may appear at the detection area in response to a product produced by delivery of the substrate.
Notably, devices in accordance with the present disclosure are configured to perform operations 1604-1612 of
Considering the foregoing, the assay device disclosed herein represents a substantial innovation in disposable assays. Like other at-home assays, it is easy to operate, and results can be clearly interpreted. However, the analytical performance is enhanced by its ability to sequentially and automatically add and wash reagents from a nitrocellulose test zone. This capability allows the device to function as a disposable ELISA, opening new applications for sensitive and selective at-home detection of biomolecules at low concentrations.
Various modifications and additions can be made to the exemplary implementations discussed without departing from the scope of the present invention. For example, while the implementations described above refer to specific features, the scope of this invention also includes implementations having different combinations of features and implementations that do not include all the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations together with all equivalents thereof.
This application is related to and claims priority under 35 U.S.C. § 119(e) from U.S. Patent Application No. 63/058,683 filed Jul. 30, 2020 and titled “Automated Disposable Enzyme-Linked Immunosorbent Assay,” the entire contents of which is incorporated herein by reference for all purposes.
This invention was made with government support under grant number HL152405 awarded by NIH and award number 2032222 by NSF. The government has certain rights in the invention.
Filing Document | Filing Date | Country | Kind |
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PCT/US21/71050 | 7/29/2021 | WO |
Number | Date | Country | |
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63058683 | Jul 2020 | US |