Vertical Fluidics Cartridge for Sequencing
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Solution Overview
Problem
Conventional fluidics cartridges are limited by a 3-mm head height restriction, making it difficult to handle large volumes of reagents in sequencing by synthesis applications, and are sensitive to tilt, which is not suitable for mobile applications and efficient air bubble elimination.
Innovation Solution
A fluidics cartridge designed for use in a vertical or substantially vertical position, featuring a droplet operations gap between substrates with electrodes configured for vertical droplet transport, U-shaped reservoirs, and an aqueous/oil exchange process to manage reagent volumes and prevent flooding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional horizontal fluidics cartridges are used, then the cartridge structure is simple and easy to manufacture, but the head height is restricted to about 3 mm which limits reagent volume
Solution Approach 1:
The patent transitions from horizontal cartridge operation to vertical operation, changing the gravitational reference frame. This dimensional change allows reservoirs to extend vertically without increasing the cartridge's horizontal footprint, enabling larger reagent volumes while maintaining a compact overall structure.
Solution Approach 2:
The cartridge is divided into distinct functional zones: reservoirs positioned at the bottom for liquid storage, a droplet operations gap in the middle for electrowetting operations, and air bubble venting paths at the top. This segmentation allows each zone to be optimized independently for its specific function.
2Ease of operation
If horizontal fluidics cartridges are used, then air bubble elimination is difficult, but vertical design requires reconfiguring the entire cartridge structure
Solution Approach 1:
Instead of trying to eliminate air bubbles from the bottom up in a horizontal configuration, the patent inverts the approach by positioning reservoirs at the bottom and allowing air bubbles to naturally rise to the top through gravity-assisted venting paths, eliminating bubbles through the natural buoyancy direction.
Solution Approach 2:
The patent introduces hydrophobic coating as an intermediary layer on the inner surfaces of venting paths and reservoirs. This coating prevents liquid from adhering to walls while allowing air bubbles to pass through, facilitating efficient bubble elimination without requiring complex mechanical mechanisms.
3Adaptability or versatility
If horizontal fluidics cartridges are used, then the cartridge is sensitive to tilt, but vertical design requires overcoming gravitational effects on droplet transport
Solution Approach 1:
The patent uses electrowetting forces generated by electrode arrays as a counteracting force to balance gravitational effects on droplets. By applying controlled electrical fields across the droplet operations gap, the system can move droplets vertically against gravity and maintain position regardless of cartridge tilt angle.
Solution Approach 2:
The electrowetting electrode system provides dynamic control over droplet position and movement. The applied voltage can be adjusted in real-time to compensate for gravitational variations caused by different tilt angles, enabling the cartridge to operate adaptively in various orientations.
4Quantity of substance
If reservoir height is increased to hold large reagent volumes, then reagent volume capacity increases, but liquid pressure exceeds electrowetting pad capacity causing flooding
Solution Approach 1:
The patent introduces hydrophobic barriers as intermediary structures at the interface between reservoirs and the droplet operations gap. These barriers create capillary pressure that prevents liquid from flooding into the electrowetting zone while still allowing controlled droplet formation and transfer, effectively decoupling reservoir height from operating pressure.
Solution Approach 2:
The patent replaces direct mechanical pressure transmission from tall liquid columns with surface tension-based hydrophobic barriers. This substitution allows tall reservoirs to hold large volumes without transmitting excessive hydrostatic pressure to the electrowetting pads, as the hydrophobic interface maintains pressure equilibrium.
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 vertical design eliminates the 3-mm head height restriction, allows for larger reagent volumes, reduces sensitivity to tilt, and facilitates easier air bubble elimination, enhancing the cartridge's usability in sequencing by synthesis and mobile applications.
Implementation Method 1
Some fluidics cartridges use droplet actuators to move individual droplets within the fluidics cartridge, for example by electrowetting
Implementation Method 2
In some electrowetting devices, the gap between the substrates is filled with a filler fluid such as oil that is immiscible with the liquid that forms the droplets
Data Source
AI summary
Disclosed herein are devices, systems and methods for conducting a reaction using electrowetting in a vertical or substantially vertical position. Some embodiments disclosed herein provide fluidic cartridges for use in a substantially vertical position comprising: (a) a front substrate; (b) a back substrate; (c) a droplet operations gap formed between the front substrate and the back substrate; and (d) a plurality of electrodes on the front substrate or the back substrate, wherein the plurality of electrodes are configured to transport a droplet along a substantially vertical plane defined by the front substrate and the back substrate.