Capillary Structure for Reliable Body Fluid Transport
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing self-contained test units for body fluids face challenges in reliably guiding small volumes of fluid from the body part receiving surface to the test member, particularly when the volume of body fluid is very small, leading to uncontrolled or undesired flow.
Innovation Solution
A self-contained test unit with a capillary member featuring a first recess for the lancet and a second recess with a larger surface area to volume ratio, designed to guide the body fluid from the body part receiving surface to the test member, utilizing capillary forces to ensure accurate and reproducible fluid transport, even for small volumes less than 500 nl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional capillary structure is used to guide body fluid, then the structure is simple, but the fluid flow becomes uncontrolled or unreliable when the volume is very small
Solution Approach 1:
The capillary member is divided into two distinct recesses: a first recess with smaller surface area to volume ratio and a second recess with larger surface area to volume ratio. This segmentation allows each recess to perform a specific function in controlling fluid flow, with the second recess specifically designed to guide small volumes of body fluid reliably to the test member through enhanced capillary forces.
Solution Approach 2:
Different regions of the capillary member are given different geometric properties. The second recess has a specifically designed larger surface area to volume ratio compared to the first recess, creating local variations in capillary forces that optimize fluid guidance in the critical region where small volumes of body fluid need to be transported reliably.
2Quantity of substance
If the volume of body fluid is very small, then the test unit is less invasive, but the fluid transport becomes difficult to control
Solution Approach 1:
The invention changes the geometric parameters of the capillary recesses, specifically the surface area to volume ratio, to optimize capillary forces. The second recess is designed with a larger surface area to volume ratio, which enhances capillary action and enables reliable transport of very small volumes of body fluid (less than 500 nl) to the test member.
3Reliability
If the second recess has a larger surface area to volume ratio, then capillary forces are enhanced for small fluid volumes, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies optimal ranges for the surface area to volume ratio parameters of the two recesses. By defining these parameter ranges, the design balances the need for enhanced capillary forces in the second recess with practical manufacturing capabilities, ensuring that the geometric precision required is achievable while still obtaining reliable fluid transport for small volumes.
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 design ensures successful and reproducible testing by capillary forces, preventing uncontrolled fluid flow and effectively transporting small volumes of body fluid to the test member, making it convenient and reliable for use by both skilled and unskilled users.
Implementation Method 1
A self contained test unit for testing body fluid... a capillary member (110) having a first recess (112) configured for receiving the lancet and having a second recess (114) configured for guiding the body fluid from the body part receiving surface (102) to a test member (108)... the second recess (114) has a larger surface area to volume ratio than the first recess (112)
Data Source
Figure 1~4
Figure 5
Figure 6A~7
AI summary
A device 100 for testing body fluid (blood) comprising a body part receiving surface 102 for receiving a patient's body part, a movably mounted lancet including a lancet tip configured for piercing the skin of the patient to produce flow of body fluid, and a capillary member 110 having a first recess 112 configured for receiving the lancet and having a second recess 114 configured to channel the body fluid from the body part receiving surface 102 to a test member for interacting with the body fluid to aid in the determination of information about body fluid components, wherein the second recess 114 has a larger surface area to volume ratio than the first recess 112. The second recess 114 may be separate from or integral with the first recess 112.