Microchannel Apparatus Patterned Posts Rare Cell Recovery
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Solution Overview
Problem
Current methods for isolating rare cells from bodily fluids, such as fetal cells from maternal blood, face challenges due to non-specific binding issues, bead loss, and inefficiencies in capturing and releasing target cells, particularly in column-based separation methods.
Innovation Solution
A microchannel device with a substrate featuring a collection region containing transverse posts arranged in an irregular pattern to disrupt streamlined flow, allowing sequestering agents attached to the posts to effectively capture and release target biomolecules, including cells, through controlled fluid dynamics and surface interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If column-based separation methods using macrobeads are used to capture target cells, then target cell capture is achieved, but non-specific binding increases and bead loss occurs
Solution Approach 1:
The patent replaces the mechanical gravity-based macrobead settling system with a microfluidic system that uses controlled fluid dynamics and surface interactions. The microchannel device with patterned posts creates specific flow patterns that enhance target cell capture through hydrodynamic forces and affinity-based binding, eliminating the non-specific binding and loss issues associated with macrobeads.
Solution Approach 2:
The patent changes the scale and flow parameters from macroscopic column-based systems to microscopic microchannel systems. The microchannel dimensions, flow rates, and post patterns are optimized to create specific hydrodynamic conditions that enhance capture efficiency while reducing non-specific binding, representing a fundamental parameter change from the conventional approach.
2Measurement precision
If sequestering agents are attached to macrobeads for target cell capture, then selective binding is achieved, but release of target cells becomes difficult
Solution Approach 1:
The patent segments the binding and release functions spatially within the microchannel device. The patterned posts create distinct regions where sequestering agents are positioned for selective capture, while fluid flow paths and channel geometry facilitate easy release by directing released cells to collection regions, separating the capture and release operations.
3Speed
If streamlined flow is maintained through the collection region, then fluid flow efficiency is preserved, but capture efficiency of rare cells decreases
Solution Approach 1:
The patent introduces asymmetric patterned posts in the microchannel collection region that disrupt symmetric streamlined flow. The irregular arrangement and varying dimensions of the posts create asymmetric flow patterns with eddies and recirculation zones that increase cell-post interactions, enhancing capture efficiency while maintaining overall fluid flow through the device.
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
The microchannel device enhances the capture efficiency of rare cells by disrupting streamlined flow, reducing non-specific binding, and facilitating the release of target cells, achieving high capture rates and minimizing cell loss, as demonstrated in examples with fetal trophoblast cell separation.
Implementation Method 1
The posts are arranged in a particular irregular array pattern to disrupt straight-line flow therethrough and importantly to break-up regular streamlined flow through the array, thereby assuring collisions with the posts and promoting swirling and eddies in a bodily fluid or other liquid
Implementation Method 2
Cell separation is often achieved by targeting molecules on the cell surface with specific affinity ligands in order to achieve selective, reversible attachment of a target cell population to a solid phase. Such specific affinity ligands may be antibodies, lectins, receptor ligands, or other ligands that bind proteins, hormones, carbohydrates, or other molecules with biological activity.
Data Source
AI summary
A microflow apparatus for separating or isolating cells from a bodily fluid or other liquid sample uses a flow path where straight-line flow is interrupted by a pattern of transverse posts. The posts are spaced across the width of a collection region in the flow path, extending between the upper and lower surfaces thereof; they have rectilinear surfaces, have arcuate cross-sections, and are randomly arranged so as to disrupt streamlined flow. Sequestering agents, such as Abs, are attached to all surfaces in the collection region via a hydrophilic coating, preferably a hydrogel containing isocyanate moieties or a PEG or polyglycine of substantial length, and are highly effective in capturing cells or other targeted biomolecules as a result of such streamlined flow disruption.