Microfluidic Cartridge Off-Board Actuation
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Solution Overview
Problem
Traditional microfluidic devices for medical diagnostics face challenges in precision due to fluid loss, capillary effects, gravity, and trapped air, especially in disposable formats requiring on-board fluidic controls, which complicates assays like mixing and incubation.
Innovation Solution
A microfluidic test device with no onboard fluid control mechanisms, where precision control is moved to the instrument, allowing for reusable and cost-effective disposable consumables that use off-board actuation and optical detection for assays, utilizing smaller microchannels and on-board reagents and calibrators for precise analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-board fluid control mechanisms are used in disposable microfluidic devices, then fluid transport precision can be achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts fluid control functions from the disposable microfluidic device and relocates them to the reusable instrument. The disposable device retains only passive fluid handling capabilities while the instrument provides active pumping, metering, and control, thereby reducing device complexity while maintaining precision.
Solution Approach 2:
The patent introduces an intermediary connection system between the disposable device and the instrument that enables precise fluid control without requiring complex on-board mechanisms in the disposable. The instrument acts as an intermediary that provides the necessary control functions externally.
2Measurement precision
If on-board fluid control mechanisms are included in disposable microfluidic devices, then assay precision can be maintained, but manufacturing cost increases
Solution Approach 1:
The patent applies the disposable principle by making the microfluidic device single-use and simple in construction, while relocating expensive precision control mechanisms to the reusable instrument. This allows the disposable device to be manufactured economically without complex valves and pumps.
Solution Approach 2:
The instrument is designed to work with multiple disposable devices and perform multiple assay functions, amortizing the cost of precision control mechanisms across many uses and many different disposable devices, thereby reducing the per-unit manufacturing cost.
3Device complexity
If passive fluid handling is used in disposable microfluidic devices, then device complexity is reduced, but fluid transport precision deteriorates due to fluid loss, capillary effects, and trapped air
Solution Approach 1:
The patent replaces passive capillary-based fluid handling with active instrument-controlled fluid delivery systems. The instrument uses controlled pumping and metering mechanisms to deliver precise fluid volumes, overcoming the limitations of passive fluid handling while keeping the disposable device simple.
4Reliability
If on-board mixing and incubation mechanisms are included, then assay performance is maintained, but device complexity and cost increase
Solution Approach 1:
The patent extracts mixing and incubation functions from the disposable device and relocates them to the instrument. The disposable device is designed to be simple without these complex on-board functions, while the instrument provides the necessary mixing and incubation capabilities externally.
Data Source
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AI summary
A microfluidic test device and analyzer, the test device includes a sample well, at least one reaction well and a calibrator well fluidicly connected to a waste well which in turn is connected to a pump port. When vacuum pressure from the analyzer is applied through the pump port, fluid from the reaction well and the calibrator well are moved to the waste well via transparent flow paths. The analyzer detects objects in the flow paths and calibrates its measurement of the objects in the sample utilizing beads from the calibrator well.