Microfluidic Chip Sealing via Lower Top Wall Height
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Solution Overview
Problem
Current microfluidic chips face issues with liquid leakage and limited detection range due to inadequate sealing and structural constraints, which affect the accuracy and flexibility of disease marker detection.
Innovation Solution
A microfluidic chip design featuring a microchannel with a lower top wall, connected to an expansion channel via an inclined upward connection channel, and equipped with a dual-well setup for sample and buffer addition, along with a movable water-absorbent material at the sample outlet to manage fluid flow and reaction time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microchannel uses a conventional bonded structure with substrate and cover sheet, then the chip can be manufactured, but liquid leakage occurs due to inadequate sealing
Solution Approach 1:
The microchannel is divided into multiple segments with individual sealing structures. Each segment has its own sealing mechanism, allowing independent sealing validation and reducing the complexity of bonding the entire channel. This segmentation approach maintains high sealing reliability while simplifying the manufacturing process by enabling modular assembly and inspection.
Solution Approach 2:
Sealing structures are pre-formed on substrates before final assembly. The sealing surfaces are prepared in advance with precise geometric features that ensure proper alignment and sealing when components are joined. This preliminary preparation of sealing surfaces reduces the bonding complexity during final assembly while ensuring reliable liquid-tight seals.
2Adaptability or versatility
If the microchannel has a fixed structural design, then the chip structure is simple, but the detection range is limited due to constrained reaction time
Solution Approach 1:
The microchannel incorporates adjustable flow control elements that allow dynamic modification of fluid flow rates and residence times. This dynamic control enables the same microchannel structure to accommodate different reaction times for various disease markers, expanding the detection range without requiring multiple fixed structural designs. The adjustable parameters include flow rate, channel obstruction degree, and reaction chamber volume.
Solution Approach 2:
The microchannel design allows changing operational parameters such as flow rate, channel geometry configuration, and reaction conditions to optimize detection for different disease markers. By adjusting these parameters, the system can adapt to various reaction time requirements and detection needs, increasing versatility while maintaining a relatively simple base structure.
3Duration of action of moving object
If the microchannel top wall height is increased to allow longer reaction time, then detection range improves, but liquid leakage risk increases due to higher capillary pressure
Solution Approach 1:
Different sections of the microchannel have optimized local geometries tailored to their specific functions. The reaction chamber section has increased height and volume to accommodate longer reaction times, while the connection channels and sealing regions maintain optimized dimensions for reliable sealing. This local optimization allows extended reaction time in critical areas without compromising sealing reliability in other areas.
Solution Approach 2:
The microchannel design incorporates vertical expansion chambers that increase reaction volume in the height dimension rather than extending channel length horizontally. This dimensional approach allows longer effective reaction time through increased residence volume without proportionally increasing capillary pressure that would compromise sealing. The vertical expansion provides additional reaction space while maintaining controlled fluid pressure.
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 design effectively prevents liquid leakage, enhances gas exhaustion, reduces reaction time, and increases the detection range by allowing for liquid-phase reactions, leading to more accurate and precise results with improved flexibility in reaction control.
Implementation Method 1
the sample fluid flowing towards an outlet of the microchannel under the capillary force of the microchannel
Data Source
AI summary
The present invention proposes a microfluidic chip including a microchannel enclosed and formed by a substrate and a cover sheet, a sample fluid added into the microchannel through a sample adding well, a height of a top wall of said microchannel being lower than a height of a contact surface of the substrate and the cover sheet. Through the above setup, it can effectively prevent the leakage of liquid from the side of the microchannel, make the detection results more accurate, and reduce the invalid detection rate and scrap rate.