Analyte Sampling Device with Membrane Area Ratio
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Solution Overview
Problem
Conventional sampling devices for analytes face issues such as lengthy dead time between analyte detection and membrane detachment due to high internal pressure, fluid-dynamics problems causing air bubbles, and restricted volume flow, leading to measurement errors and unsuitability for pulse-wise loading.
Innovation Solution
A sampling device with an analyte feed chamber having a membrane opening surface area up to 400 times the minimum cross-sectional area of the discharge line, allowing high volume flow without membrane rupture, and a discharge line length optimized for turbulence-induced dilution control, enabling rapid analyte transport and reliable measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the membrane surface area is increased to achieve high transportation speed, then the analyte transport rate is improved, but the membrane becomes detached and remains in the body when the probe is withdrawn
Solution Approach 1:
The probe is divided into distinct functional sections: a proximal section with the membrane for analyte sampling, and a distal section with the sensor. This segmentation allows the membrane to be positioned optimally for sampling while the sensor remains protected and retained in the body, resolving the contradiction between sampling efficiency and component retention.
2Productivity
If high internal pressure is applied to achieve high transportation speed, then the analyte transport rate is improved, but the connections between hollow fibers and the rest of the probe are stressed causing tears
Solution Approach 1:
The invention employs a pressure-driven flow system where transport medium is pumped through the probe at controlled pressures. The proximal section design allows efficient analyte extraction into the flowing medium without requiring excessive pressure, thereby protecting the hollow fiber connections from stress-induced failure while maintaining high transport rates.
3Loss of time
If the probe internal diameter is reduced to decrease dead time, then the transportation speed is improved, but only slow flow rates can build up making it difficult to flush out air bubbles
Solution Approach 1:
The invention transitions from a single-bore hollow fiber design to a multi-channel or annular flow configuration in the proximal section. This dimensional change allows multiple flow paths within a compact diameter, increasing the effective flow rate and air bubble flushing capability while maintaining a small overall probe diameter for minimal dead time.
4Area of stationary object
If hollow fibers are used for dialysis, then the membrane surface area is increased, but tubular bags are produced which are very pulsatable causing considerable fluctuations in the dialysis rate
Solution Approach 1:
The invention uses a flexible membrane in the proximal section that is optimized for dialysis while being supported by a rigid or semi-rigid structure. This combination allows the membrane to maintain contact with tissue for efficient sampling while the supporting structure prevents excessive pulsation and maintains stable dialysis rates despite pressure fluctuations.
5Stability of the object's composition
If elevated internal pressure is applied to counteract membrane pulsation, then the dialysis rate stability is improved, but the risk of rupture increases
Solution Approach 1:
The invention employs a counterbalancing support structure that mechanically opposes the pulsating forces acting on the dialysis membrane. This support structure acts as a counterweight to the pressure fluctuations, maintaining membrane position and dialysis rate stability without requiring elevated internal pressure, thereby avoiding increased rupture risk.
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 device achieves rapid analyte transport with reduced dead time, prevents membrane rupture, and minimizes measurement errors by maintaining stable flow and preventing air bubble deposition, allowing for accurate and timely detection of analytes like glucose.
Implementation Method 1
an analyte-permeable membrane (15) to allow the analyte to pass through from a medium to be investigated from a region outside the analyte feed chamber into the analyte feed chamber
Implementation Method 2
a discharge line (40) extending from the analyte feed chamber (13) in the direction of flow of the transport medium through the sampling device, with a length optimized for turbulence-induced dilution control
Data Source
AI summary
Sampling device for obtaining a sample of an analyte, comprising a feed line (30) and a discharge line (40) as well as an analyte feed chamber (13) in fluidic connection between the feed line and the discharge line, the analyte feed chamber having an opening (14) which is provided with an analyte-permeable membrane (15) to allow the analyte to pass through from a region outside the analyte feed chamber into the analyte feed chamber, the surface area of the opening of the analyte feed chamber being at most 400 times the minimum cross-sectional surface area of the discharge line, more preferably at most 100 times and most preferably 50 to 80 times the minimum cross-sectional surface area of the discharge line. This device will reduce the dead time between the passage of the analyte through the membrane and the detection of said analyte at the sensor.