Smartphone-Based Microfluidic Blood Coagulation Testing
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Solution Overview
Problem
Current methods for monitoring blood coagulation, particularly for patients on vitamin K antagonists like warfarin, require frequent and costly hospital visits for PT/INR testing, and existing alternatives like fixed-dose anticoagulants are expensive and not suitable for all patients.
Innovation Solution
A portable and cost-effective system for fluid-mechanical blood coagulation testing using a microfluidic cartridge and a smartphone-based monitoring device, which records a video of a blood sample flowing through a microchannel and processes it to determine the flow stopping time, thereby calculating the PT/INR value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard PT/INR testing is performed in hospitals, then accurate coagulation measurement is achieved, but frequent hospital visits and high costs are required
Solution Approach 1:
The patent replaces complex mechanical/optical coagulation measurement systems with a simple fluid-mechanical approach. Blood flow through a microchannel is captured via capillary action, and coagulation is detected by monitoring flow cessation using a smartphone camera, eliminating the need for expensive hospital-based mechanical testing equipment
Solution Approach 2:
The system enables patients to perform their own coagulation testing at home using a portable device and smartphone. The microfluidic cartridge automatically draws blood via capillary forces without manual intervention, and the smartphone processes the video to determine coagulation time, making the patient self-sufficient for monitoring
2Loss of time
If fixed-dose anticoagulants are used, then frequent blood tests are eliminated, but medication cost increases significantly
Solution Approach 1:
The patent substitutes expensive fixed-dose anticoagulant medications with an affordable diagnostic tool. By providing an inexpensive portable testing device that costs a fraction of the medication, patients can maintain warfarin therapy at low cost while performing frequent self-testing, eliminating the need to pay premium prices for fixed-dose drugs
3Ease of operation
If commercial INR self-testing platforms are used, then hospital visits are reduced, but device cost and test strip cost are prohibitively high
Solution Approach 1:
The patent employs a disposable microfluidic cartridge that is inexpensive to manufacture and use. The cartridge contains all necessary reagents and microchannels for a single test, eliminating the need for expensive reusable devices and costly test strips. The low cost enables widespread adoption and frequent testing without financial burden
Solution Approach 2:
The patent replaces expensive commercial testing platforms with a simple portable device using basic components: a microfluidic cartridge, LED illumination, and a smartphone camera. This substitution of complex commercial systems with simple, readily available components dramatically reduces both device and consumable costs
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 system provides accurate and accessible blood coagulation testing, reducing the need for frequent hospital visits and lowering costs, while being suitable for point-of-care and self-testing applications.
Implementation Method 1
The microchannel in the cartridge is configured to draw the sample into the channel via capillary forces, e.g., from a sample loading zone likewise defined in the cartridge
Implementation Method 2
the camera may be positioned and oriented relative to the cartridge to capture illumination that undergoes total internal reflection at a boundary surface of the microchannel
Implementation Method 3
Filling of the microchannel with the sample increases the refractive index in the channel and thus the critical angle associated with the total internal reflection, causing a reduction in the intensity of the reflected light
Data Source
AI summary
Blood coagulation testing can be performed by measuring, based on video of a blood sample flowing in a microfluidic channel, the time it takes until flow stops due to clotting. In various embodiments, such measurements are enabled by a low-cost testing system that includes a microfluidic cartridge and uses a smartphone or similar device for video acquisition, in conjunction with a lighting module for illuminating the microfluidic channel and a 3D-printed platform for holding and positioning and orienting the cartridge, lighting module, and smartphone in fixed special relation to each other.