Digital Microfluidics Disposable Cartridge Electrowetting Control
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Solution Overview
Problem
Existing digital microfluidics systems are not designed to accommodate disposable cartridges for manipulating samples in liquid droplets efficiently, particularly in terms of portability and simplicity of construction, as they often require complex electrical connections and large volumes of liquids.
Innovation Solution
A digital microfluidics system with a base unit, electrode array, and a movable or fixed cover plate that includes an electrically conductive material not connected to a specific electrical potential, allowing for electrowetting movements of liquid droplets within disposable cartridges that have a hydrophobic surface and no conductive layer, enabling simple and cost-effective manipulation of samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If disposable cartridges with hydrophobic surfaces are used for liquid droplet manipulation, then portability and ease of operation are improved, but device complexity increases due to the need for specialized cartridge structures
Solution Approach 1:
The system is divided into a reusable base unit containing the electrode array and disposable cartridges containing the hydrophobic surface and sample. This segmentation allows the complex electrowetting functionality to be contained in a simple reusable base while the disposable cartridges remain structurally simple despite requiring specialized materials.
Solution Approach 2:
The invention uses disposable cartridges that can be discarded after use, eliminating the need for complex cleaning and sterilization procedures. The cartridges are designed to be inexpensive and simple in structure, with the hydrophobic surface being the only specialized component needed for electrowetting operation.
2Ease of manufacture
If complex electrical connections are eliminated in disposable cartridges, then manufacturing cost and simplicity are improved, but electrowetting functionality may be compromised
Solution Approach 1:
The electrical connection complexity is extracted from the disposable cartridges and placed entirely in the reusable base unit. The cartridges contain only the hydrophobic surface and sample, with no electrical components, while the base unit's electrode array provides all necessary electrical connections for electrowetting operation.
Solution Approach 2:
The hydrophobic surface acts as an intermediary between the simple disposable cartridge structure and the complex electrical system in the base unit. This hydrophobic layer enables electrowetting functionality to be achieved without requiring any electrical components within the disposable cartridge itself.
3Ease of manufacture
If conductive layers are removed from cartridge top surfaces, then material costs and manufacturing simplicity are improved, but droplet manipulation control may be affected
Solution Approach 1:
The cartridges are designed as simple disposable items without expensive conductive layers or complex materials. The hydrophobic surface provides sufficient control for droplet manipulation when combined with the electrode array in the reusable base, eliminating the need for costly conductive materials in the disposable component.
Solution Approach 2:
The specialized hydrophobic property is applied locally to the cartridge surface where it is needed for droplet interaction, while the rest of the cartridge structure remains simple and non-conductive. This localized application of special material properties achieves droplet control without requiring expensive materials throughout the entire cartridge.
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 system allows for efficient and cost-effective manipulation of liquid droplets within disposable cartridges, enhancing portability and simplicity of construction by eliminating the need for complex electrical connections and reducing material costs, while maintaining effective electrowetting functionality.
Implementation Method 1
a central control unit for controlling the selection of individual electrodes of this electrode array and for providing them with individual voltage pulses for manipulating liquid droplets by electrowetting
Implementation Method 2
using arrays of microelectrodes, preferably covered by a hydrophobic layer. By applying a defined voltage to electrodes of the electrode array, a change of the surface tension of the liquid droplet, which is present on the addressed electrodes, is induced.
Data Source
AI summary
A digital microfluidics system manipulates samples in liquid droplets within disposable cartridges and has disposable cartridges each with a bottom layer, a top layer and a gap therebetween. A base unit with cartridge accommodation sites and at least one electrode array with electrodes works with a cover plate at the sites and a control unit for controlling selection of the electrodes and for providing them with voltage pulses for manipulating liquid droplets within the cartridges by electrowetting. The cover plate has an electrically conductive material that extends parallel to the array. A selection of disposable cartridges and a method for manipulating samples in liquid droplets that adhere to a hydrophobic surface can be used with the system.