Stair-Step Membrane Array for Whole Blood Analysis
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Solution Overview
Problem
Current analytical devices for detecting analytes in fluid samples, particularly whole blood, face challenges in achieving rapid and high sensitivity detection with minimal hemolysis and background interference, especially when using small sample volumes.
Innovation Solution
A membrane array comprising three or more porous membranes arranged in a stair-step configuration, where the first membrane contains a detection reagent, the second membrane has a lower porosity to further retard red blood cells, and the third membrane contains a capture reagent, facilitating capillary flow and minimizing hemolysis for efficient analyte detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single membrane or two-membrane system is used, then the device complexity is reduced, but the sensitivity and detection efficiency are insufficient
Solution Approach 1:
The device divides the detection function into three separate porous membranes with different porosity values, where each membrane performs a specific function in the detection process. This segmentation allows for optimized analyte capture and detection at each stage, improving overall sensitivity while maintaining manageable device complexity through modular design
Solution Approach 2:
Each porous membrane is assigned a specific local function based on its porosity: the first membrane (higher porosity) allows sample penetration and initial analyte capture, the second membrane (intermediate porosity) provides additional capture capacity, and the third membrane (lowest porosity) enables concentrated detection. This local quality differentiation optimizes detection sensitivity across the membrane array
2Speed
If the sample flow rate is increased to achieve rapid detection, then the detection speed is improved, but hemolysis and background interference increase
Solution Approach 1:
The device changes the porosity parameter across the three membranes to control sample flow dynamics. The gradient in porosity (decreasing from first to third membrane) creates optimal flow resistance at each stage, allowing rapid analyte transport while preventing excessive shear forces that would cause hemolysis. This parameter variation enables fast detection without the harmful effects of high flow rates
3Quantity of substance
If smaller sample volumes are used, then the sample volume requirement is reduced, but the detection sensitivity decreases
Solution Approach 1:
The three porous membranes are arranged in a nested configuration where the sample flows sequentially through each membrane layer. This nested structure allows the analyte to be captured and concentrated across multiple stages within a compact volume, enabling high sensitivity detection from small sample volumes by progressively enriching the analyte signal at each membrane level
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
This configuration enables rapid, highly efficient, and sensitive detection of analytes in small volumes of whole blood with minimal hemolysis, providing stable and accurate results within a short time frame.
Implementation Method 1
The presence of an analyte in the sample can be detected either visually or by using reflectance or fluorescence based detection systems and instruments. Oftentimes, the label is an enzyme label or a particulate direct label, for instance a gold sol label.
Implementation Method 2
Immunoassay devices and procedures currently exist for detecting the presence of an analyte in a sample of biological fluid. Typically, immunochemical reactions involving antigen/antibody reactions take place on dry porous carriers such as cellular membranes
Implementation Method 3
The membrane array comprises a two membrane system including a first separation membrane and an analytical capture membrane
Data Source
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AI summary
A membrane array used to detect one or more analytes from a small sample of fluid with high sensitivity is provided. The membrane array can be employed in various analytical devices and is especially useful for identifying analytes from whole blood with minimal or negligible background interference.