Device for analyzing a fluid sample and use of test card with same
Inventors
Revilla, Ryan Alan • Heltsley, Roy James • Lee, Steve Hoe • Izadi Kharazi, Farzad • Patel, Tej Rushikesh
Assignees
Publication Number
US-11371091-B2
Publication Date
2022-06-28
Expiration Date
2036-06-17
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Abstract
Apparatuses and methods related to a point-of-care portable assay device and the use thereof with a test card are described herein. In a general embodiment, a device for monitoring a polymerase chain reaction in a fluid sample includes a vacuum source configured to pull the fluid sample through a microchannel, a current source configured to cause the polymerase chain reaction while the fluid sample is located within the microchannel, a light source configured to illuminate the polymerase chain reaction while the current source causes the polymerase chain reaction, a camera imaging device configured to record an image of the polymerase chain reaction while the light source illuminates the polymerase chain reaction, and a controller configured to analyze the image of the polymerase chain reaction and output a resulting analysis of the polymerase chain reaction.
Core Innovation
The invention relates to a point-of-care portable assay device designed to monitor polymerase chain reactions (PCR) in fluid samples using disposable test cards. The device integrates a vacuum source to pull fluid through microchannels, a current source to cause and control heating for PCR within a target zone of the microchannel, a light source to illuminate the reaction, a camera imaging device to record images or video of the PCR, and a controller to analyze these images and provide assay results. The device is capable of automatically aligning its components with test card features and performing different types of assays based on the test card inserted.
The problem addressed by the invention stems from limitations of point-of-care (POC) diagnostic tests, particularly comparing nucleic acid amplification tests (NAAT) and immunoassay-based tests. Immunoassay tests lack the sensitivity and specificity of NAAT, especially during early infection stages, delaying pathogen detection. Though NAATs provide early detection with high specificity, they traditionally require complicated equipment and processes. This invention solves this by providing a low-complexity, portable diagnostic system that enables rapid, sensitive, and specific detection of infectious agents using microfluidic disposable test cards, facilitating early-stage diagnosis in low-resource settings.
The device further supports various assays beyond PCR including flow cytometry and ELISA by recognizing test card types via codes and adjusting its operation accordingly. The microfluidic disposable test cards include features such as inlet/outlet ports, capture ports to prevent sample loss, microchannels with target zones coated with electrodes, and fluid detection zones with capacitance sensors. The system ensures fluid sample flow, applies controlled heating for PCR, and captures fluorescence and optical data to analyze the presence of pathogens or other biomarkers.
Claims Coverage
The claims define eleven main inventive features of a system comprising a disposable test card and a corresponding assay device that together perform sensitive analyses on fluid samples using microfluidic channels, controlled heating, fluid detection, and optical imaging.
Test card with microchannel architecture including capture port and embedded electrodes
A test card structured with an inlet port for fluid sample reception, an outlet port for vacuum application, a microchannel connecting inlet and outlet with a target zone for assays, and a capture port located downstream of the target zone to accumulate fluid and prevent it from reaching the outlet port. The test card incorporates multiple electrical contacts connected to electrodes positioned beneath the target zone to heat the fluid sample.
Device configured to interface with test card including vacuum, electrical contacts, imaging, and controller
An assay device designed with a slot to receive the test card, a vacuum source aligned with the test card's outlet port to pull fluid through, an electrical contact device to contact the test card's electrical contacts and apply current for heating, a camera imaging device aligned with the test card's microchannel to record images, and a controller configured to control vacuum, heating, and imaging operations.
Controller feedback control for heating the fluid sample
The controller is programmed to adjust the current applied to the heating electrodes based on feedback from a sensor to maintain desired temperature conditions during the assay.
Illumination of microchannel during assay
Inclusion of a light source within the device configured to illuminate at least a portion of the microchannel when the test card is inserted to facilitate optical measurements such as fluorescence.
Imaging including still and video images during assay
The camera imaging device is capable of recording either a series of still images or video images over a period of time capturing the assay as it progresses within the microchannel.
Physical alignment features of vacuum and imaging components with test card surfaces
The vacuum source aligns with an outlet port located on the upper surface of the test card and includes a button to assist alignment and sealing. The camera imaging device aligns with an analysis port located on the test card’s upper surface.
Electrical contact alignment on test card bottom surface
Electrical contacts are located on the bottom surface of the test card and designed to align and mate with corresponding contacts on the device to enable electrical control of the assay.
Controlled heating with current adjustment to maintain temperature
The controller maintains a desired temperature over time by adjusting current applied to heating electrodes based on sensor feedback.
Spring-loaded retractable electrical contacts for reliable connection
Device electrical contacts protrude upward and retract as the test card is inserted to ensure secure electrical connection with test card contacts.
Dual-section electrodes on opposite sides of microchannel for heating
The heating electrode under the target zone includes two sections located on opposite sides of the microchannel, each connected to one of the two test card electrical contacts, enabling even heating when current is applied to both.
Fluid detection zones with sensing electrodes to verify fluid presence and chemical quantities
Microchannel includes upstream and downstream fluid detection zones with sensing electrodes connected to test card electrical contacts. The controller can apply current to these electrodes to determine fluid presence in the microchannel and quantify chemical species in the fluid sample. Heating is initiated only if fluid is detected in both zones.
Overall, the claims cover a coordinated system of a disposable test card and a portable assay device featuring microfluidic structures with heating electrodes and fluid detection, means for applying vacuum to move fluid through microchannels, optical imaging during assays, feedback-controlled heating, and physical arrangements facilitating accurate alignment and reliable electrical connections, thus enabling sensitive point-of-care assays including PCR.
Stated Advantages
High sensitivity and specificity of nucleic acid amplification tests (NAAT) for early and accurate detection of infectious agents.
Low complexity and portability suitable for point-of-care applications in low-resource settings.
Use of inexpensive disposable test cards enables multiple inexpensive assays without need for repeated use of the device.
Automated alignment and operation reduce user intervention and facilitate ease of use.
Capability to perform multiple types of assays (PCR, flow cytometry, ELISA) on the same device with different test cards.
Real-time imaging and analysis of assays through integrated camera and light source.
In-built fluid detection sensors ensure sample presence before analysis to improve reliability.
Feedback-based heating control maintains optimal assay conditions.
Documented Applications
Rapid point-of-care nucleic acid amplification tests (PCR) for early detection of infectious agents in bodily fluids.
Flow cytometry assays for analyzing cell characteristics such as size, count, morphology, and protein presence.
Enzyme-linked immunosorbent assays (ELISA) including colorimetric analyses to measure analyte concentrations in fluid samples.
Quantification of specific chemical species in fluid samples by measuring dielectric properties in microchannels.
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