Microfluidic Temperature Control via Segmented Thermal Contact
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Solution Overview
Problem
Existing microfluidic devices face challenges in achieving precise temperature control, particularly in creating linear temperature gradients, due to complex designs, non-linearity, large physical size, and high manufacturing costs, which limits their performance and applicability in Lab-on-a-Chip applications.
Innovation Solution
A temperature control system for microfluidic devices that utilizes a single controllable heating and/or cooling element with strategically arranged passive thermal contact elements and a thermally resistive material to create a desired spatial temperature profile within the device, allowing for uniform or non-uniform heat transfer and achieving a high degree of control over temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature elements are used to create a spatial temperature gradient, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The single temperature element is segmented into multiple discrete contact regions that are spatially distributed across the substrate. Each contact region acts as an independent thermal source, enabling precise temperature gradient control without requiring multiple separate heating elements. This segmentation approach maintains temperature control precision while significantly reducing device complexity.
Solution Approach 2:
Different regions of the single temperature element are assigned different thermal characteristics through varying contact region properties (size, shape, thermal resistance). This allows each local region to provide the specific temperature control needed at that location, achieving precise spatial temperature gradients while using a single integrated element rather than multiple complex components.
2Manufacturing precision
If a spatial temperature gradient is created using conventional methods, then temperature profile control is improved, but manufacturing cost increases
Solution Approach 1:
Multiple temperature control functions are merged into a single temperature element with multiple contact regions. This consolidation reduces the number of components that need to be manufactured and assembled, thereby reducing manufacturing cost while maintaining the ability to create precise temperature profiles through the spatial distribution of contact regions.
Solution Approach 2:
The single temperature element serves multiple functions simultaneously: it provides overall heating, creates spatial temperature gradients, and enables precise temperature control at multiple locations. This multi-functionality eliminates the need for separate heating elements and temperature control systems, reducing manufacturing complexity and cost while maintaining temperature profile control precision.
3Stability of the object's composition
If external heating means are used to control device temperature, then temperature uniformity is improved, but temperature change rate decreases
Solution Approach 1:
The temperature element is segmented into multiple contact regions that can be independently controlled or selectively activated. This allows rapid temperature changes in specific regions without requiring the entire device to be heated or cooled uniformly, thereby increasing the temperature change rate while maintaining temperature uniformity in the fluid gap through proper contact region design.
Solution Approach 2:
The invention transitions from external heating (heating the entire device housing) to internal heating through direct contact regions on the substrate. This dimensional change from external to internal heating enables faster heat transfer to the fluid gap while maintaining temperature uniformity through the distributed contact region arrangement.
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 solution simplifies temperature control, reduces complexity, and enables the creation of both linear and non-linear temperature gradients with high precision, while minimizing device size and cost, making it suitable for disposable Lab-on-a-Chip applications.
Implementation Method 1
passive thermal contact elements arranged to be disposed, in use, against a first substrate of the microfluidic device so as to provide thermal transfer between the heating/cooling element and the first substrate of the microfluidic device at a plurality of discrete contact regions
Implementation Method 2
a first thermally resistive material disposed between the heating and/or cooling element and at least some of the passive thermal contact elements
Data Source
AI summary
A heating system for an EWOD device using a single, spatially-structured temperature control element, used to create a zone with a specific temperature profile. The heating system uses multiple contact regions between the temperature control element and the device. One or more contact regions are separated from the temperature control element by one or more thermally resistive layers that restrict heat flow from the temperature control element to the device, and further restrict lateral flow of heat between adjacent contact regions. The heating system can use materials with different thermal resistance to alter the heat flow to different regions. The spatial location of the contact regions is also used to determine the temperature profile within the device. The device has an optional temperature control element which offsets the low temperature point from the inlet temperature. This invention includes methods to process multiple droplets within the multiple temperature zones.