Paper Microfluidic Device Plasma Separation
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Solution Overview
Problem
Current diagnostic assays for diseases like sickle cell disease are inaccessible in resource-limited settings due to the need for expensive equipment and trained personnel, and they cannot perform plasma separation from whole blood, which interferes with colorimetric assays, making them unsuitable for point-of-care diagnostics.
Innovation Solution
A paper-based diagnostic device (μPAD) with an agglutination zone and test readout zone, functionalized with agglutinating agents, that separates plasma from red blood cells by forming large agglutinated RBCs, allowing for integrated plasma separation and analysis of whole blood samples without additional preparation steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional centrifugation or magnetic separation methods are used to separate plasma from whole blood, then plasma separation is achieved, but additional sample preparation steps and expensive bulky equipment are required
Solution Approach 1:
The patent combines plasma separation and diagnostic testing into a single integrated paper-based device. The separation zone and test zones are merged on one paper substrate, eliminating the need for separate centrifugation equipment and multiple preparation steps. Whole blood is applied directly to the device and separation occurs automatically through capillary action.
Solution Approach 2:
The patent extracts the plasma separation function from complex laboratory equipment and implements it directly within the paper-based diagnostic device. The separation zone on the paper substrate performs plasma separation using simple capillary flow and hydrophobic barriers, removing the need for external centrifuges or magnetic separators.
2Ease of operation
If colorimetric assays are performed on whole blood samples, then sample preparation is simplified, but the intense color of red blood cells interferes with detection of assay results
Solution Approach 1:
The patent extracts plasma from whole blood within the device using a separation zone with hydrophobic barriers that confine plasma while allowing red blood cells to be retained or diverted. This separates the colored RBCs from the plasma needed for colorimetric detection, enabling accurate optical measurement without complex sample preparation.
Solution Approach 2:
The patent segments the device into distinct functional zones: a separation zone that divides plasma from red blood cells, and test zones that receive only plasma. This spatial segmentation ensures that colorimetric assays are performed on plasma alone, eliminating interference from RBC color while maintaining operational simplicity.
3Reliability
If current diagnostic assays are used in resource-limited settings, then diagnostic capability is provided, but the requirement for expensive equipment and trained personnel makes them inaccessible
Solution Approach 1:
The patent uses inexpensive paper as the substrate for the diagnostic device, replacing expensive laboratory equipment. The paper-based device is disposable and can be manufactured at low cost, making it accessible for use in resource-limited settings without requiring expensive infrastructure or specialized equipment.
Solution Approach 2:
The patent replaces complex mechanical laboratory equipment (centrifuges, magnetic separators) with passive paper-based structures that use capillary action and hydrophobic barriers. This substitution eliminates the need for powered equipment and trained operators, enabling diagnostic testing in remote areas with minimal infrastructure.
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, low-cost, and portable diagnostics capable of analyzing whole blood samples directly, improving accessibility and accuracy for diseases like sickle cell disease, and allowing for automated quantification and differentiation between healthy and affected individuals.
Implementation Method 1
an agglutination zone, functionalized with an agglutinating agent... that separates plasma from red blood cells by forming large agglutinated RBCs
Implementation Method 2
The μPADs use the paper as a fluidic substrate, and utilize the wicking/capillary properties of the paper to transport the biological sample
Data Source
AI summary
The present invention relates to simple, low-cost, rapid paper-based diagnostic devices and their methods of use.