Micropost Array for Measuring Cell Traction Forces Under Shear Flow
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Solution Overview
Problem
Current technologies lack effective methods to expose cells to controlled fluid shear forces, specifically to measure changes in internal cell forces, which are crucial for understanding mechanotransduction responses in endothelial cells under different flow conditions.
Innovation Solution
A fluidic device with a flow unit and a fluid channel that induces both laminar and disturbed flow, using an array of microposts to simulate physiological fluid shear stresses, and includes detection means to measure deflection and calculate traction forces, allowing for the analysis of intercellular forces and adherens junction assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current technologies are used to expose cells to fluid shear forces, then the ability to maintain vascular barrier integrity is compromised, but there is no effective method to measure changes in internal cell forces
Solution Approach 1:
The patent introduces flexible microposts as intermediary elements that mediate between the fluid flow environment and the endothelial cells. These microposts serve as mechanical transducers that convert fluid shear forces into measurable deflections, enabling indirect measurement of internal cell forces while maintaining physiological flow conditions that preserve barrier integrity.
Solution Approach 2:
The patent replaces direct mechanical measurement methods with an optical detection system. By substituting mechanical force sensors with optical detection of micropost deflections, the system enables non-invasive measurement of cellular traction forces without compromising the mechanical environment or barrier function of the endothelial cells.
2Stability of the object's composition
If laminar flow is applied to endothelial cells, then adherens junction assembly is promoted and barrier integrity is maintained, but the ability to quantify these mechanical effects is lacking
Solution Approach 1:
The patent employs fluorescent labeling of cellular components (actin filaments, adherens junctions) that undergo color intensity changes in response to mechanical stimulation. This optical signal change provides quantitative information about adherens junction assembly and cytoskeletal reorganization under laminar flow conditions.
Solution Approach 2:
The patent substitutes direct mechanical measurement of cellular forces with optical detection methods. By measuring micropost deflections optically and correlating them with cellular traction forces, the system recovers quantitative mechanical information that would otherwise be lost in traditional visual inspection methods.
3Measurement precision
If disturbed flow is applied to endothelial cells, then mechanosensor activation leads to cytoskeletal disorganization and barrier disruption, but there is no way to measure the magnitude of these mechanical changes
Solution Approach 1:
The flexible microposts serve as intermediary sensors that capture and transmit disturbed flow forces to the endothelial cells while simultaneously providing a measurable record of the mechanical stimulus. The micropost deflections quantify the magnitude of disturbed flow forces, enabling precise measurement of mechanical changes even as they induce cytoskeletal disorganization.
Solution Approach 2:
The patent employs dynamic micropost arrays that can respond to transient and oscillating flow patterns characteristic of disturbed flow conditions. The flexible posts capture temporal variations in mechanical forces, enabling measurement of dynamic mechanical changes as they occur during disturbed flow exposure.
4Measurement precision
If traditional flow chambers are used without micropost arrays, then the device complexity is low, but the ability to detect and measure cellular traction forces is insufficient
Solution Approach 1:
The patent divides the flow chamber substrate into an array of discrete flexible micropost elements. This segmentation allows independent measurement of traction forces at multiple locations simultaneously, providing spatially resolved mechanical data without requiring a monolithic complex sensor system.
Solution Approach 2:
The patent uses simplified micropost structures that replicate the essential mechanical function of complex force sensors. By copying the force-sensing capability into simple flexible posts with optical readout, the system achieves precise force measurement while maintaining device simplicity and ease of fabrication.
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 the quantitative measurement of intercellular tension and cytoskeletal forces, demonstrating how laminar flow increases traction and intercellular forces, promoting adherens junction assembly, while disturbed flow weakens these forces and leads to disassembly, providing insights into vascular barrier integrity.
Implementation Method 1
Laminar flow occurs in straight vessels and produces a steady shear stress on the cells
Implementation Method 2
Disturbed flow forms downstream of obstructions, bends, or bifurcations, and produces a time-averaged, low shear stress due to eddies in the flow
Implementation Method 3
detection means configured to measure a degree of deflection of one or more flexible structures in the array
Data Source
AI summary
The present technology relates generally to devices to expose cells to fluid shear forces and associated systems and methods. In particular, several embodiments are directed toward devices to expose cells to fluid shear forces in order to measure changes in internal cell forces. In some embodiments, a fluidic device includes a flow unit configured to induce fluid flow through the device. The device further includes a fluid channel configured to accept a biological sample dispersed on an array of flexible structures. The flow unit can be configured to induce disturbed and/or laminar flow in the fluid channel. The device can further include optical or magnetic detection means configured to measure a degree of deflection of one or more flexible structures in the array.