Magneto-Hydrodynamic Interstitial Fluid Sampling Device
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Solution Overview
Problem
Current non-invasive devices for sampling analytes from skin, such as glucose, have limited extraction volume and rate due to localized extraction at the electrode-skin interface, requiring sensitive detection techniques and are not efficient in extracting a substantial volume of interstitial fluid.
Innovation Solution
A magneto-hydrodynamic (MHD) device that uses a pair of electrodes and a magnetic field to drive interstitial fluid from the dermis towards the skin surface, increasing the extraction rate by applying a Lorentz force perpendicular to the skin surface, allowing for extraction between electrodes as well as under the negative electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If reverse iontophoresis is used for noninvasive IF sampling, then analytes can be extracted through skin, but the extraction volume is limited and extraction rate is low
Solution Approach 1:
The device divides the extraction area into multiple zones by using a first electrode and a second electrode separated by a distance, enabling extraction to occur at multiple locations (between electrodes and under the negative electrode) rather than at a single point, thereby increasing total extraction volume and rate
Solution Approach 2:
The invention introduces a spatial dimension to the extraction process by positioning electrodes at a distance from each other, creating a three-dimensional extraction zone between and around the electrodes, which expands the effective extraction volume compared to traditional single-point extraction
2Quantity of substance
If extraction occurs locally at the electrode-skin interface, then the device structure is simple, but the extraction volume is limited
Solution Approach 1:
The extraction process is segmented into multiple zones by using separated electrodes, with extraction occurring both between the electrodes and under the negative electrode, thereby expanding the total extraction volume without requiring complex multi-component device structures
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 MHD device effectively increases the extraction volume and rate of interstitial fluid, enabling more efficient sampling and analysis of analytes like glucose, with no pain or skin reactions, and correlates with blood glucose levels.
Implementation Method 1
direction of the magnetic field produced by the one or more magnets, and direction of the electric current produced by the power source is adapted to be such that Lorentz force produced by the magnetic field and the electric current is adapted to drive the interstitial fluid from the dermis substantially towards the skin surface
Implementation Method 2
The present invention is based on the observation that at least some of the state-of-the-art problems related to sampling of one or more analytes from skin can be solved or at least alleviated by exploiting the magneto-hydrodynamic (MHD) phenomenon
Implementation Method 3
WO 2010/001122 A2 discloses a patch for sampling one or more analytes through the skin of a patient. The patch comprises an electrode layer that is positioned adjacent to the skin of a patient, and means for actuating an electrode layer to induce the withdrawal of analyte through the skin by reverse iontophoresis
Data Source
AI summary
The application relates to a device (100) for non-invasively sampling interstitial fluid comprising one or more analytes from dermis (101a) to skin surface (101b) by using the magneto-hydrodynamic effect. The device comprises a first electrode (102a) and a second electrode (102b) adapted to be positioned adjacent to the skin surface, the first electrode separated from the second electrode by a distance (103), a power source (104) adapted to induce an electric current through the first electrode, the interstitial fluid and the second electrode, and also a magnet (105) adapted to produce a magnetic field to the interstitial fluid. Direction of the magnetic field and direction of the electric current produced by the magnet and the power source, respectively, is such that Lorentz force drives the fluid from the dermis towards the skin surface.