Diagnostic Test Strip With Depending Portion for Blood Sample Transport
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Solution Overview
Problem
Existing test strips face challenges in ensuring sufficient fluid samples, such as blood, are directed to measurement sites without user intervention, especially for sub-microliter samples, and in maintaining sample integrity during transport.
Innovation Solution
A diagnostic test strip with a capillary channel and a depending portion that uses surface tension and adhesion to guide fluid samples from a lancet hole to the capillary channel, featuring a hydrophobic fluid transport path and slits to direct the droplet toward the center, ensuring efficient transport to the measurement site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a test strip is designed to collect and test smaller fluid samples (sub-microliter samples), then the sample volume requirement is reduced, but it becomes difficult to ensure sufficient sample reaches the measurement site without user intervention
Solution Approach 1:
The test strip incorporates a depending portion that automatically directs fluid sample droplets from the collection site to the measurement site through capillary action, eliminating the need for user manipulation. The strip self-regulates sample transport using its structural design and surface tension properties.
Solution Approach 2:
The depending portion acts as an intermediary structure between the fluid sample collection area and the measurement site. It mediates the transport process by providing a controlled path that guides the droplet through capillary forces, ensuring reliable sample delivery without direct user involvement.
2Ease of manufacture
If the strip structure is simplified to reduce manufacturing complexity, then production cost decreases, but the ability to direct fluid sample to measurement site without user involvement is compromised
Solution Approach 1:
The test strip is segmented into distinct functional zones: a depending portion for droplet capture and direction, a fluid transport path for controlled sample flow, and a measurement site for analysis. This segmentation allows each component to perform its specific function while maintaining overall manufacturing simplicity.
Solution Approach 2:
The depending portion extends in a third dimension (vertically downward) from the planar strip structure. This dimensional addition provides automatic droplet direction capability without complicating the overall strip manufacturing process, as the depending portion can be formed through simple molding or cutting techniques.
3Ease of operation
If the depending portion is designed to extend away from the strip to direct droplets, then sample direction control is improved, but the risk of sample loss during transport increases
Solution Approach 1:
The fluid transport path utilizes capillary action (a hydraulic principle) to move the sample droplet along the strip. The capillary channels and hydrophobic/hydrophilic surface patterns create controlled fluid flow that prevents sample loss by maintaining continuous contact between the droplet and the transport path.
Solution Approach 2:
The surface properties of the fluid transport path are modified with hydrophobic and hydrophilic regions to control droplet movement. By changing the surface energy parameters, the system ensures the droplet follows the intended path without detaching or being lost, while still achieving effective direction control.
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
The solution effectively directs and retains fluid samples on the test strip, ensuring sufficient sample volume reaches the measurement site, reducing sample loss and facilitating accurate testing without user involvement.
Implementation Method 1
A capillary channel having a mouth at one end and containing a measurement site toward the opposite end is positioned on the major side, such that fluid sample contacting the strip moves from the mouth through the capillary channel to the measurement site
Implementation Method 2
The strip is provided with a hydrophobic fluid transport path which causes a droplet of fluid sample contacting the depending portion to be directed from the depending portion, along the fluid transport path
Implementation Method 3
A depending portion extends away from the strip on the side facing the fluid sample, such that a droplet of fluid sample contacting the depending portion is directed from the depending portion
Data Source
AI summary
A test strip for testing a blood sample is provided with a fluid transport feature to facilitate transport of a blood sample obtained from a lancing operation through a capillary channel to a measurement site. A fluid transport path is defined on the major face of the strip terminating at the mouth of the capillary channel. The fluid transport path includes a depending portion at one end opposite the mouth of the channel. The depending portion extends away from the strip on the side facing the fluid sample, such that a droplet of fluid sample contacting the depending portion is directed toward the mouth of the capillary channel. Thereafter the sample moves by capillary action to the measurement site.