Microstructured Substrate for Centrifuge-Free Red Blood Cell Separation
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Solution Overview
Problem
Existing methods struggle to efficiently separate red blood cells from small volumes of blood, such as those obtained from finger pricks, which interfere with biomarker detection due to light scattering, absorbance, and chemical interference, and are not feasible with point-of-care analyzers lacking centrifugation capabilities.
Innovation Solution
A microstructured substrate with capillary action-enabled microstructures and apertures is used to settle and retain red blood cells within its open volumes, allowing for their separation from small blood volumes through capillary filling and pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centrifugation is used to separate red blood cells from blood, then separation effectiveness is improved, but device complexity and requirement for large blood volumes increases
Solution Approach 1:
The patent replaces the complex mechanical centrifugation system with a simple microstructured substrate device that uses capillary action and gravity-based settling. The microstructured substrate with controlled pore sizes and surface properties enables red blood cell separation without requiring centrifugal force, thereby eliminating the need for complex centrifugation equipment while maintaining separation effectiveness.
Solution Approach 2:
The patent employs a microstructured substrate with specific pore size distribution that allows plasma to pass through while retaining red blood cells. The porous structure is designed with孔径 (pore sizes) that match the size differential between plasma and red blood cells, enabling passive separation based on physical filtration and settling principles rather than mechanical centrifugation.
2Reliability
If centrifugation is used to separate red blood cells, then separation effectiveness is improved, but time consumption increases
Solution Approach 1:
The patent replaces time-consuming centrifugation with a rapid passive settling process. By using a microstructured substrate that promotes immediate red blood cell aggregation and settling through capillary action and gravity, the separation process is accelerated from minutes (centrifugation) to seconds, enabling point-of-care testing where rapid results are critical.
Solution Approach 2:
The microstructured substrate is pre-designed with surface properties and pore structures that immediately promote red blood cell settling upon blood contact. This preliminary preparation of the separation interface eliminates the need for extended centrifugation time, as the structural features are already in place to guide and accelerate the separation process as soon as the blood sample is applied.
3Ease of operation
If small blood volumes from finger pricks are used, then ease of operation is improved, but separation effectiveness deteriorates
Solution Approach 1:
The patent applies local quality by designing the microstructured substrate with spatially varying pore sizes, densities, and surface properties optimized for small volume samples. The substrate includes regions with different microstructural characteristics that work together to enhance settling efficiency in microliter-scale samples, ensuring effective separation even when only finger-prick volumes are available.
Solution Approach 2:
The patent transitions from bulk separation approaches to micro-scale dimensional control. By engineering the substrate at the microscale with precise pore dimensions and surface features, the device optimizes separation physics for small volumes. The microstructured geometry creates enhanced surface-to-volume ratios and capillary forces that are particularly effective when only small blood volumes from finger pricks are used.
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
Effectively separates red blood cells from microliter volumes of blood, minimizing interference in biomarker detection without hemolysis or significant blood loss, suitable for point-of-care analysis.
Implementation Method 1
At least a portion of an exterior surface of the plurality of microstructures are configured to allow capillary action
Implementation Method 2
waiting for a time sufficient for at least a portion of the red blood cells to settle within the first open volume of the plurality of microstructures
Data Source
AI summary
The present disclosure provides methods and devices for removing particles from fluids. A method for removing red blood cells includes obtaining a device having a microstructured substrate including microstructures extending across a first surface, where at least a portion of an exterior surface of the microstructures are configured to allow capillary action. The device also includes a cover disposed a selected distance apart from a top of the first surface of the microstructured substrate and at least one sidewall that attaches the cover to the first surface of the microstructured substrate along a perimeter of the first surface of the microstructured substrate. The method further includes filling the device with a volume of blood through the first aperture via capillary action, waiting for a time sufficient for at least a portion of the red blood cells to settle within the first open volume of the microstructures, and applying pressure to the device, thereby causing some of the initial volume of blood, from which at least some of the red blood cells have been retained within the first open volume of the microstructures, to flow out of the device.