Test Card Fluid-Microchannel Imaging for Bubble-Aware PCR Detection
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Solution Overview
Problem
Current point-of-care (POC) diagnostic immunoassays lack the sensitivity and specificity of nucleic acid amplification methods, particularly during the early stages of infection, and require complex equipment and processes, while POC NAATs are cumbersome.
Innovation Solution
A device and method for performing PCR at the point-of-care that includes a current source for heating, a camera imaging device for recording images, and a controller to analyze images by distinguishing wanted and unwanted objects, determining positivity or negativity based on fluorescence values adjusted for bubble presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If NAAT is used to detect infectious agents, then sensitivity and specificity are improved, but device complexity and operational difficulty increase
Solution Approach 1:
The device segments the PCR process into distinct functional zones: a heating zone for thermal cycling, a detection zone with fluorescence imaging, and a microfluidic sample handling system. This segmentation allows each component to be optimized independently while maintaining overall simplicity for point-of-care use.
Solution Approach 2:
The patent replaces complex mechanical PCR systems with a simplified thermal heating mechanism and optical detection system. The PCR amplification is achieved through controlled heating cycles rather than complex mechanical manipulation, and detection is performed through fluorescence imaging rather than complex signal processing equipment.
2Ease of operation
If immunoassay is used for diagnostic testing, then ease of operation is improved, but sensitivity and specificity deteriorate
Solution Approach 1:
The device performs self-service through automated thermal cycling and optical detection. The system automatically controls heating cycles, captures fluorescence images, and processes signals without requiring skilled laboratory personnel, thereby maintaining ease of operation while achieving NAAT-level sensitivity.
3Speed
If PCR is performed at point-of-care, then detection speed is improved, but unwanted bubbles interfere with the reaction
Solution Approach 1:
The patent converts the harmful effect of bubbles into a detectable signal characteristic. By capturing fluorescence images during PCR, the system can distinguish between bubbles and actual nucleic acid amplification signals based on their optical properties, allowing rapid detection while compensating for bubble presence.
Solution Approach 2:
The system incorporates real-time optical feedback during thermal cycling to monitor reaction progress and detect bubble formation. This feedback allows the system to adjust heating parameters or compensate for bubble interference, maintaining detection speed and accuracy despite the presence of bubbles.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid, high sensitivity and specificity diagnostics in low-resource settings with minimal user training, capable of detecting infectious agents early in infection and handling bubbles during PCR, ensuring accurate test results.
Implementation Method 1
a current source configured to cause the polymerase chain reaction by heating the fluid sample within a target zone
Implementation Method 2
a camera imaging device configured to record a plurality of images of the fluid sample in the target zone
Implementation Method 3
wanted objects in the plurality of images from an unwanted object in the plurality of images, and (ii) determine whether the fluid sample tests positive or negative for a bacteria or virus based on the wanted objects
Data Source
AI summary
An apparatus and method for image analysis of a fluid sample on a test card are disclosed. An example apparatus for analyzing a fluid sample includes a camera imaging device configured to record a plurality of images of the fluid sample while located within a target zone of a fluid microchannel of a test card. The example apparatus also includes a controller configured to perform a cytometry analysis on the fluid sample to determine whether the fluid sample tests positive or negative for a bacteria or virus.