Fluidic Test Cassette With Integrated Resistive Heating
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Solution Overview
Problem
Current nucleic acid testing technologies are unsuitable for field use due to their requirement for elaborate and costly instrumentation, specialized laboratory materials, and user intervention, limiting their utility in rapid point-of-use applications, especially in remote or austere settings where logistical constraints prevent the transportation of bulky equipment.
Innovation Solution
A disposable cassette with integrated chambers, vent pockets, and a heat labile material for sealing, along with a flexible circuit and resistive heating elements, allows for programmable fluid control and reagent mixing, enabling nucleic acid detection without external instrumentation, suitable for small clinics and remote settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If external instrumentation is used to accomplish fluid movement, amplification temperature control and detection, then many engineering challenges are simplified, but tremendous economic barriers are imposed and instrument availability becomes a bottleneck
Solution Approach 1:
The patent extracts the complex external instrumentation functions and integrates them directly into the disposable cartridge. The cartridge now contains integrated heating elements for temperature control, fluid reservoirs for reagent delivery, and mixing chambers, eliminating the need for separate external instruments and reducing economic barriers while maintaining functional complexity management.
Solution Approach 2:
The disposable cartridge is designed to be self-sufficient with all necessary components for fluid movement, temperature control, and detection integrated within the cartridge itself. The cartridge performs its own heating, fluid management, and mixing functions without requiring external instrument support, enabling widespread distribution to remote settings.
2Volume of moving object
If smaller reaction volumes are used in microfluidic devices, then device size is reduced, but the volume of specimen that can be added is reduced and capacity to accommodate sufficient specimen volume is reduced
Solution Approach 1:
The patent transitions from traditional horizontal microfluidic layouts to a vertical three-dimensional cartridge architecture. Multiple reaction chambers are stacked vertically, allowing sufficient specimen volume to be accommodated in the vertical dimension while maintaining compact overall device footprint. The cartridge includes a sample reservoir, reaction chambers, and detection zones arranged in vertical layers.
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
The solution enables rapid, sensitive, and specific nucleic acid testing with minimal user intervention, accommodating specimen volumes similar to traditional laboratory assays, and allows for surge capacity during increased demand without external instrument bottlenecks, reducing costs and logistical challenges.
Implementation Method 1
a heat labile material for sealing one or more of the vent pockets
Implementation Method 2
The protrusion preferably comprises a dimple or an asperity and preferably sufficiently prevents molten heat labile material from attaching to a heat stable material
Implementation Method 3
a flexible circuit and resistive heating elements
Data Source
AI summary
A disposable cassette for detecting nucleic acids or performing other assays. The cassette can be inserted into a base station during use. The cassette has numerous features to ensure correct operation of the device under gravity, such as vent pockets for enabling the flow of sample fluid from one chamber to the next when the vent pocket is unsealed. The vent pockets have protrusions to help prevent accidental resealing. The cassette also can have a gasket to ensure free air movement between open vent pockets. A flexible circuit with patterned metallic electrical components disposed on a heat stable material can be in direct contact with fluid in the chambers and has resistive heating elements aligned with the vent pockets and the chambers. Recesses in the cassette channels or chambers can have structures such as ridges or grooves to direct fluid flow to enhance rehydration of lyophilized reagents disposed in the recess. Flow diverters in the chambers can reduce the flow velocity of the sample fluid and increase the effective fluid flow path length, enabling more accurate control of fluid flow in the cassette. The roof of each chamber can have a projection that prevents capillary fluid flow across the top of the chamber, thus reducing or preventing sequestration of newly resuspended reagent from the bulk of the reaction solution volume.