Digital Microfluidic Dilution Using Fractional Electrodes
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Solution Overview
Problem
Digital microfluidic dilution methods using serial dilutions are imprecise and limited in achieving non-integer dilution ratios due to the repetitive merging and splitting of droplets, leading to errors and inefficiencies in manipulating large droplets within analytical devices.
Innovation Solution
The use of electrodes with fractional areas based on a binary sequence allows for precise control of droplet volumes, enabling the selective merging and mixing of sample and diluent droplets to achieve a wide range of dilution ratios without repetitive splitting, thereby reducing surface tension effects and increasing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If serial dilution methods are used with repetitive merging and splitting of droplets, then dilution can be achieved, but precision deteriorates due to accumulation of errors and difficulty in manipulating large droplets
Solution Approach 1:
The patent segments the dilution process into discrete digital operations using individually addressable electrodes. Instead of manipulating large droplets through multiple merging and splitting cycles, the system divides the sample and diluent into smaller discrete droplet volumes that can be precisely controlled and combined in a single step, thereby eliminating cumulative errors from repetitive operations.
Solution Approach 2:
The patent replaces mechanical droplet manipulation (merging and splitting physical droplets) with electrical control through electrode arrays. By applying voltages to specific electrodes, the system digitally controls droplet formation, movement, and combination, substituting complex mechanical operations with precise electrical signals that eliminate manual manipulation errors.
2Adaptability or versatility
If serial dilution with repetitive merging and splitting is performed, then dilution ratio can be adjusted, but time consumption increases due to multiple repetitive steps
Solution Approach 1:
The patent prepares multiple individually addressable droplets with predetermined volumes on separate electrodes before the dilution operation. By pre-positioning sample and diluent droplets on different electrodes, the system enables immediate combination without requiring sequential merging and splitting steps, significantly reducing the time required to achieve various dilution ratios.
Solution Approach 2:
The patent merges multiple droplet manipulation operations into a single combined action. By controlling electrode voltages, the system can simultaneously combine sample and diluent droplets in the correct proportions to achieve the desired dilution ratio in one step, rather than requiring multiple sequential merging and splitting operations that consume time.
3Quantity of substance
If large droplets are created through merging sample and diluent, then dilution ratio can be achieved, but manipulation difficulty increases and surface tension effects worsen
Solution Approach 1:
The patent segments the final diluted droplet into smaller component droplets that are manipulated separately on individual electrodes. Instead of creating and manipulating one large droplet that is difficult to control, the system maintains smaller discrete droplets on addressable electrodes throughout the process, making them easier to position, combine, and transfer while reducing surface tension-related manipulation difficulties.
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 approach enables the achievement of precise and efficient dilution ratios, reducing errors and improving the manipulation of droplets, allowing for more accurate sample preparation within analytical devices.
Implementation Method 1
Digital microfluidics allows for manipulation of discrete volumes of fluids, including electrically moving, mixing, and splitting droplets of fluid disposed in a gap between two surfaces, at least one of the surfaces of which includes an electrode array coated with a hydrophobic and/or a dielectric material.
Data Source
AI summary
Example methods, apparatus, systems for diluting samples are disclosed. An example method includes depositing a first fluid droplet on a first electrode of a plurality of electrodes. The first electrode has a first area. The first fluid droplet has a first volume associated with the first area. The example method includes depositing a second fluid droplet on a second electrode of the plurality of electrodes. The second electrode has a second area. The second fluid droplet has a second volume associated with the second area. The second volume is different than the first volume. The example method includes forming a combined droplet by selectively activating at least one of the first electrode or the second electrode to cause one of the first fluid droplet or the second fluid droplet to merge with the other of the first fluid droplet or the second fluid droplet.