Microdroplet Manipulation via Dual Optical Assemblies
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Solution Overview
Problem
Current optically mediated electrowetting-on-device (oEWOD) techniques face limitations in processing large numbers of microdroplets in parallel, particularly in applications requiring handling of millions of droplets, such as in the pharmaceutical industry for cell line development and antibody screening, due to the practical limit of droplets that can be processed within a single field of view.
Innovation Solution
The use of two individually controllable optical assemblies capable of generating fixed but switchable arrays of light spots on the oEWOD chip allows for high-throughput and flexible loading and processing of microdroplets, enabling the formation of transient oEWOD traps to create arrays, inspect, and select microdroplets, while maintaining the entire array in place for sequential inspection and manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single optical assembly is used to process microdroplets, then the device complexity is reduced, but the productivity is limited due to the practical field of view constraint
Solution Approach 1:
The system divides the optical processing task into multiple independent optical assemblies, each capable of addressing a specific field of view. This segmentation allows parallel processing of microdroplets across multiple fields of view simultaneously, thereby increasing overall productivity without requiring a single overly complex optical system.
Solution Approach 2:
Each optical assembly is designed to be multi-functional, capable of performing multiple operations (manipulation, inspection, sorting) on microdroplets within its field of view. This universality allows the system to maintain high productivity while avoiding the need for additional specialized components for each function.
2Productivity
If multiple optical assemblies are used to increase processing capacity, then the productivity is improved, but the device complexity increases
Solution Approach 1:
The system employs dynamic coordination between multiple optical assemblies, where assemblies can be independently activated, deactivated, or have their fields of view adjusted based on processing needs. This dynamic control allows the system to optimize throughput for different processing scenarios while managing complexity through flexible, adaptive configuration rather than fixed rigid structures.
3Productivity
If the field of view is increased to process more microdroplets, then the productivity is improved, but the measurement precision deteriorates
Solution Approach 1:
Instead of using a single large-field optical assembly that would compromise measurement precision, the system segments the total field of view into multiple smaller fields, each handled by a dedicated optical assembly. This segmentation allows each assembly to maintain high measurement precision within its smaller field while the collective system achieves high productivity by processing multiple fields in parallel.
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 configuration enhances operational flexibility, allowing for the efficient handling and manipulation of thousands to millions of microdroplets without losing contact, enabling detailed inspection and selection, and optimizing optical performance by handing off responsibilities between optical assemblies.
Implementation Method 1
optically mediated electrowetting (oEWOD) techniques to manipulate and interrogate the contents of large numbers of microdroplets in parallel on a surface of a microfluidic chip
Implementation Method 2
selectively illuminating an area of a semiconductor layer buried within. By selective illumination of the layer with light from a separate light source, controlled by an optical assembly, a virtual pathway of virtual electrowetting electrode locations can be generated transiently
Implementation Method 3
Electrowetting-on-dielectric (EWOD) is a well-known effect in which an electric field applied between a liquid and a substrate makes the liquid more wetting on the surface than the natural state. The effect of electrowetting can be used to manipulate (e.g., move, divide, or change shape of) fluids by applying a series of spatially varying electrical fields on a substrate to increase the surface wettability following the spatial variations in a sequence.
Implementation Method 4
each having a photoconductive layer, a conductive layer and a dielectric layer, the exposed surfaces of the dielectric layers being disposed apart to define a microfluidic space adapted to contain microdroplets
Data Source
AI summary
The present invention provides methods and apparatus for manipulating and interrogating the contents of large numbers of microdroplets in parallel on a surface of a microfluidic chip. According to one aspect of the invention a method is provided for manipulating and inspecting microdroplets on a microfluidic chip by optically- mediated electrowetting (oEWOD), the method comprising forming, using a first optical assembly, a plurality of oEWOD traps on a surface of the chip and forming, using a second optical assembly, a second array of oEWOD traps on the surface of the chip, and making an adjustment to the first optical assembly whilst one or more of the microdroplets are held in place by second array of oEWOD traps. Apparatus comprising a microfluidic chip and first and second optical assemblies is also provided.