Microfluidic Cartridge for Digital PCR with Reduced Dead Volume
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Solution Overview
Problem
Current digital PCR equipment faces challenges with fluid flow control, including dead volume and the ability to analyze only one sample at a time, which limits the efficiency and scalability of genetic analysis.
Innovation Solution
A microfluidic cartridge design featuring a lower and upper cartridge body with a biochip, where the fluid channels are defined by the substrates and O-rings, allowing for precise and automated fluid control, and the inclusion of reaction and inflow channels with spacers to manage fluid flow and sample injection, enabling multiple sample analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional PCR equipment is used, then one sample can be analyzed at a time, but the productivity is low and only single-sample analysis is possible
Solution Approach 1:
The cartridge is divided into multiple independent reaction chambers (e.g., 96 wells), each capable of holding separate samples. This segmentation allows parallel processing of multiple samples simultaneously, transforming a single-sample system into a multi-sample high-throughput system without requiring multiple separate devices.
Solution Approach 2:
The cartridge design integrates multiple functions into a single device: sample loading, reagent distribution, thermal cycling, and detection all occur within one cartridge. The standardized interface allows the same cartridge to be used across different analysis conditions and sample types, enabling both high productivity and adaptability.
2Extent of automation
If automated digital PCR equipment is used, then fluid flow control should be improved, but dead volume remains in the device
Solution Approach 1:
The cartridge employs vertical layering with the biochip positioned at the bottom and reagents delivered from above through vertically oriented channels. This three-dimensional arrangement allows precise control of fluid delivery to each well independently, minimizing residual volume in horizontal connecting channels while maintaining automated delivery capability.
Solution Approach 2:
The design extracts and eliminates unnecessary intermediate fluid reservoirs and connecting channels that create dead volume. Samples and reagents are delivered directly to the reaction chambers through minimized channel pathways, and the biochip design allows for complete fluid displacement, removing trapped volumes that would otherwise remain in traditional horizontal channel configurations.
3Manufacturing precision
If fluid channels are not well defined, then manufacturing is simpler, but fluid flow control precision is poor
Solution Approach 1:
The cartridge employs different structural characteristics in different regions: the upper portion uses molded plastic channels for reagent delivery, while the lower portion incorporates a precision biochip with micrometer-scale wells. This local differentiation allows each region to be optimized for its specific function while maintaining overall manufacturability through modular assembly.
Solution Approach 2:
The biochip is nested within the cartridge body, with the cartridge serving as an outer housing that provides structural support and fluid delivery infrastructure. This nesting allows the complex precision biochip to be integrated into a simpler molded cartridge structure, combining high manufacturing precision where needed with overall structural simplicity.
Data Source
AI summary
A microfluidic cartridge includes lower cartridge body, a biochip, and an upper cartridge body. The lower cartridge body includes a first substrate and an inlet column. The inlet column is protruding above the substrate and is hollow. The biochip has a plurality of microwells and is attached to the first substrate of the lower cartridge body. The upper cartridge is disposed over the lower cartridge body and includes a second substrate, a first opening, and a first O-ring. The first opening penetrates the second substrate, wherein the inlet column of the lower cartridge body is inserted into the first opening, and the inlet column and the first opening are assembled into an inlet port. The first O-ring is disposed in the first opening. The inlet port and the biochip are connected to by an inflow channel.