Microfluidic Constriction for Size-Selective Cell Delivery
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Solution Overview
Problem
Current methods for intracellular delivery of materials are often indiscriminant and fail to selectively target cells based on their physical properties, such as size, which is crucial for effective research, diagnosis, and therapeutic applications, especially in identifying and isolating circulating tumor cells (CTCs) responsible for cancer metastasis.
Innovation Solution
A microfluidic device and method that selectively delivers materials to cells based on their physical properties by deforming cells in a channel constriction, allowing larger cells to undergo membrane disruption and take up markers or therapeutics while smaller cells do not, enabling size-dependent tagging and isolation of tumor cells from blood cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing delivery technologies (nanoparticles, electrical fields, pore-forming chemicals) are used to deliver materials to cells, then delivery capability is achieved, but selectivity based on cell physical properties is lost
Solution Approach 1:
The patent applies local quality by creating a spatial gradient of mechanical stress within the microfluidic channel. Cells at different positions experience different levels of deformation, with larger cells experiencing sufficient stress to induce membrane disruption and material uptake, while smaller cells pass through without significant deformation. This spatially differentiated mechanical environment enables selective delivery based on cell size.
Solution Approach 2:
The patent changes the physical parameter of cell size as the basis for selective delivery. By controlling the constriction geometry and flow conditions, the system transforms the physical property difference (size) into a functional difference (membrane disruption threshold), enabling size-dependent material uptake without requiring cell-specific biological markers.
2Quantity of substance
If indiscriminant delivery methods are used, then delivery to all cells is achieved, but purity of target cell population is reduced
Solution Approach 1:
The patent applies partial action by delivering material to only a subset of cells (those exceeding a size threshold) within the population. The constriction is designed to cause membrane disruption in larger target cells while leaving smaller non-target cells unaffected. This partial delivery approach achieves high purity enrichment of target cells without requiring complete delivery to all cells in the sample.
3Productivity
If cell membrane disruption is used for material delivery, then intracellular delivery efficiency is improved, but cell damage and loss increase
Solution Approach 1:
The patent segments the cell population based on size, creating distinct outcomes for different cell size ranges. Larger target cells undergo membrane disruption and efficient material uptake, while smaller non-target cells pass through the constriction intact without damage. This segmentation approach concentrates the mechanical stress effect on the intended target population, reducing overall cell damage in the sample.
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 approach enhances the purity of tumor cells by 100 to 10,000 times compared to peripheral blood, allowing for the effective identification and isolation of CTCs, which is clinically relevant for early cancer detection and treatment.
Implementation Method 1
A cell suspension containing differentially sized cells can be run through a device in the presence of the target delivery material and these materials can be selectively delivered to the larger cells within the population. The mechanism of delivery in the data being through selective disruption of the cell membrane of larger cells as they are deformed in a channel constriction
Data Source
AI summary
Isolating or identifying a cell based on a physical property of said cell can include providing a cell suspension; passing said suspension through a microfluidic channel that includes a constriction; passing the cell suspension through the constriction; and, contacting said cell suspension solution with a compound. The constriction can be sized to preferentially deform a relatively larger cell compared to a relatively smaller cell.