Capillary Cavity Design for Centrifugal Plasma Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analyzing devices face challenges in accurately collecting a required amount of plasma component from a small sample liquid without mixing blood cells, precise measurement due to variations in optical path length, and efficient transfer of sample liquids with non-symmetrical liquid branch points.
Innovation Solution
The analyzing device employs a microchannel structure with a separating cavity, measurement channel, connecting channel, and capillary cavities to centrifugally separate and transfer the sample liquid, using a siphon structure and overflow cavity to manage fluid flow and prevent blood cell mixing, while correcting for optical path length variations through absorbance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capillary cavity is positioned to draw plasma component from a separating cavity during centrifugal separation, then the plasma component can be collected for analysis, but the separation interface position varies due to molding variations and individual differences, causing liquid transfer loss and requiring larger sample volume
Solution Approach 1:
The invention positions the capillary cavity to extend beyond the separation interface before centrifugal separation occurs. This preliminary positioning ensures that when separation happens, the plasma component can be drawn immediately without needing to precisely track the moving separation interface, thereby collecting the required plasma amount from minimal sample volume
Solution Approach 2:
The invention creates a fixed geometric template (capillary cavity extending beyond the separation interface) that replicates the optimal collection position across all devices, eliminating the need to adapt to variations in separation interface position due to molding or individual differences
2Quantity of substance
If the capillary cavity is positioned close to the separation interface to minimize sample volume, then less sample is required, but variations in molding and individual differences cause the separation interface to shift, leading to blood cell contamination
Solution Approach 1:
The capillary cavity is pre-positioned to extend beyond the separation interface before centrifugal separation. This ensures that when separation occurs, the plasma component is drawn from a position that accounts for potential interface shifts, preventing blood cell contamination while maintaining minimal sample volume
Solution Approach 2:
The invention creates a specific local geometry where the capillary cavity extends beyond the separation interface, providing a dedicated plasma collection zone that is optimized for both minimal sample volume and high separation purity
3Productivity
If the analyzing device is rotated at high speed to quickly separate and transfer plasma, then the analysis time is reduced, but the optical path length varies during rotation, affecting measurement precision
Solution Approach 1:
The invention uses periodic rotation of the analyzing device, alternating between high-speed rotation for rapid plasma separation and transfer, and stationary positions for precise optical measurement. This periodic action enables both fast analysis and accurate measurement by separating these functions in time
Solution Approach 2:
The invention dynamically adjusts the rotation state of the analyzing device, using high-speed rotation when plasma separation and transfer are needed, and stopping rotation when optical path length measurement is required, thereby optimizing both analysis speed and measurement precision at different stages
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 approach allows for accurate and efficient collection of the required plasma component from a minimal sample volume, reducing patient load, minimizing blood cell contamination, and achieving precise measurements by correcting for optical path length errors.
Implementation Method 1
the plasma component 59a in the separating cavity 58 is drawn into a cavity 62 through a capillary cavity 61 connected to one end of a capillary channel 60
Implementation Method 2
the sample liquid in the first cavity 56 is transferred to a separating cavity 58 by rotating an analyzing device 54 about an axis 57. After that, as shown in FIG. 59B, the sample liquid is centrifugally separated into a plasma component 59a and a blood cell component 59b
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A solution component 18a separated in a separating cavity 23 is connected to a measuring cavity through a connecting channel 37 and a measurement channel 38, and a first capillary cavity 33 is provided on one side of the separating cavity 23 so as to communicate with the connecting channel 37. The first capillary cavity 33 is formed to extend to the outside of a separation interface 18c of a sample liquid separated in the separating cavity 23.