Microfluidic Device for Passive Blood Clotting Time Determination
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Solution Overview
Problem
Current point-of-care coagulometers for determining blood clotting time are costly, complex, and require large blood samples, making them inconvenient for patients and difficult to manufacture as disposable units.
Innovation Solution
A low-cost, passive microfluidic device with a two-layer assembly that uses capillary flow to monitor the position and velocity of a fluid front in a microfluidic channel, allowing for accurate clotting time determination with minimal blood sample volume, integrated quality controls, and simple manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional point-of-care coagulometers are used, then clotting time can be determined, but the devices are costly and complex
Solution Approach 1:
The device is divided into two separate layers: a passive microfluidic chip layer for fluid handling and a detection layer for monitoring. This segmentation allows the complex detection functions to be isolated from the simple fluid handling, reducing overall device complexity while maintaining measurement accuracy
Solution Approach 2:
A passive microfluidic channel acts as an intermediary between the blood sample introduction and the detection system. This intermediary component simplifies the direct interaction complexity by providing a controlled, passive fluid pathway that requires no active pumping or complex control mechanisms
2Measurement precision
If traditional coagulometers are used, then clotting time can be measured, but large blood sample volumes are required
Solution Approach 1:
The invention transitions from conventional large-volume fluid handling to micro-scale two-dimensional channel flow. By confining the blood sample to a thin microfluidic channel with controlled cross-section, the required sample volume is dramatically reduced while maintaining sufficient fluid for accurate clotting time measurement
3Reliability
If traditional coagulometers are used, then clotting time determination is possible, but manufacturing as disposable units is difficult
Solution Approach 1:
The microfluidic chip is designed as a disposable single-use component that can be easily manufactured using standard microfabrication techniques. The passive channel structure requires no complex assembly or calibration, making it ideal for cost-effective disposable production while ensuring reliable test results for each use
Solution Approach 2:
The passive microfluidic channel performs fluid handling automatically through capillary action and pressure-driven flow without requiring external pumps or complex control systems. This self-service capability simplifies manufacturing and eliminates the need for calibration, making disposable production straightforward
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 accurate and portable clotting time measurement with reduced blood sample volume, integrated quality controls, and cost-effective production, facilitating patient self-testing and reducing production complexity.
Implementation Method 1
uses capillary flow to monitor the position and velocity of a fluid front in a microfluidic channel
Data Source
AI summary
A microfluidic passive device and a method for determining clotting time are described, of a fluid medium such as blood, of low production cost which can therefore be disposable. When optimized to determine blood clotting time, it requires a minimal whole blood sample (<5 μL) and it is particularly suited to INR and PT determination, which can be used to autonomously by patient without venipuncture. Monitoring and processing means to interpret the results are comprised in an external coagulometer device. A production method for the manufacture of the microfluidic device is also provided.