Disposable Reagent Carriers for Digital Microfluidics
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Solution Overview
Problem
Digital microfluidics face challenges with biofouling and the 'world-to-chip' interface, limiting their application scope due to non-specific adsorption and cross-contamination, and the difficulty in delivering reagents and samples efficiently.
Innovation Solution
The development of removable, disposable plastic sheets pre-loaded with reagents, which are strategically positioned on digital microfluidic devices, allowing for easy replacement and reuse, preventing cross-contamination and facilitating reagent introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reagents are delivered to digital microfluidic devices using conventional microfluidic methods, then reagent introduction is achieved, but cross-contamination and biofouling occur due to non-specific adsorption on surfaces
Solution Approach 1:
The device is segmented into a permanent base structure and removable carrier sheets. The carrier sheets are separated into individual disposable units, each pre-loaded with reagents in microchannels. This segmentation allows the reagent-containing portions to be discarded after use, preventing cross-contamination while eliminating the need to clean the permanent electrode array between runs.
Solution Approach 2:
The invention employs disposable carrier sheets that are inexpensive and single-use. Each carrier is pre-loaded with reagents and discarded after one assay, eliminating biofouling accumulation and cross-contamination issues. The disposable nature ensures that no residual reagents or contaminants remain on the device for subsequent experiments.
2Productivity
If manual reagent loading is performed on digital microfluidic devices, then reagent introduction is achieved, but processing time increases and high-throughput capability is reduced
Solution Approach 1:
Reagents are pre-loaded into microchannels on the carrier sheets before the assay begins. This preliminary action eliminates the time-consuming step of manual reagent loading during the experiment. The pre-loaded carriers are ready for immediate use, enabling rapid setup and high-throughput batch processing of multiple samples.
Solution Approach 2:
The carrier sheets are designed to be self-contained units that require no manual manipulation for reagent introduction. The carriers automatically present their pre-loaded reagents to the reaction zones when positioned on the electrode array, eliminating the need for operator intervention in the reagent loading process and enabling unattended batch processing.
3Reliability
If the entire digital microfluidic device is made disposable, then cross-contamination is eliminated, but device complexity and cost increase significantly
Solution Approach 1:
The device is divided into permanent and disposable components. The permanent base contains the electrode array and control electronics, while the disposable carrier sheets contain the reagents and reaction zones. This segmentation allows only the contaminated portions (carriers) to be discarded, maintaining simplicity in the permanent structure while achieving cross-contamination prevention.
Solution Approach 2:
The permanent electrode array and base structure are designed to be universal and reusable across multiple assays. The same permanent device can accommodate different carrier sheets for various applications, eliminating the need for disposable entire devices while maintaining reliability through carrier replacement.
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 enables high-throughput batch processing in digital microfluidics while minimizing biofouling and cross-contamination, allowing for the use of digital microfluidics in a wide range of applications from laboratory analyses to point-of-care diagnostics.
Implementation Method 1
The pre-loaded carrier comprises an electrically insulating sheet having a front hydrophobic surface
Implementation Method 2
The electrically insulating sheet is attachable to a surface of the electrode array with an adhesive on a back surface of the sheet
Implementation Method 3
The electrode controller is capable of selectively actuating and de-actuating the discrete electrodes for translating liquid drops over the hydrophobic surface
Data Source
Figure 1A~1B
Figure 1C~2
Figure 3a~3d
AI summary
The present invention provides exchangeable, reagent pre-loaded carriers (10), preferably in the form of plastic sheets, which can be temporarily applied to an electrode array (16) on a digital microfluidic (DMF) device (14). The carrier (10) facilitates virtually un-limited re-use of the DMF devices (14) avoiding cross- contamination on the electrode array (16) itself, as well as enabling rapid exchange of pre-loaded reagents (12) while bridging the world-to-chip interface of DMF devices (14). The present invention allows for the transformation of DMF into a versatile platform for lab-on-a-chip applications.