Implantable Biosensor Using SAW Sensors for Continuous Glucose Monitoring
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Solution Overview
Problem
Current methods for monitoring analyte concentrations in body fluids, such as glucose, are limited by the need for discrete sampling and laborious analysis, lacking continuous measurement capabilities, which is particularly problematic for managing diseases like diabetes mellitus that require frequent and timely insulin dosage adjustments.
Innovation Solution
An implantable, wireless, and battery-free biosensor using a hydrogel-filled measuring chamber with a semi-permeable membrane and microacoustic SAW sensors to detect changes in analyte concentrations through physical property changes, allowing for continuous, passive monitoring without the need for energy storage or active telemetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sampling and laboratory analysis methods are used, then measurement precision can be achieved, but continuous monitoring is impossible and time loss occurs between sample collection and result availability
Solution Approach 1:
The patent implements continuous monitoring by placing a biosensor directly in the body fluid environment, enabling real-time detection of analyte concentration changes without discrete sampling. The sensor continuously measures physical property changes caused by analyte binding, providing ongoing data streams rather than periodic measurements, thus eliminating time loss between sampling and result availability.
Solution Approach 2:
The patent replaces mechanical sampling and laboratory analysis systems with a wireless biosensor that directly detects analyte concentration through physical property changes in body fluids. The sensor uses piezoelectric materials and acoustic wave detection to measure changes in fluid properties caused by analyte binding, substituting complex mechanical sampling procedures with direct physical measurement.
2Productivity
If implantable biosensors with active telemetry are used, then continuous monitoring is enabled, but battery life limits the duration of action
Solution Approach 1:
The patent implements a passive biosensor system that harvests energy from the body fluid environment itself rather than requiring an external battery. The sensor detects analyte concentration changes through physical property modifications in the fluid, using the fluid's own properties as the energy source for wireless signal transmission, thereby eliminating battery life limitations.
Solution Approach 2:
The patent replaces active telemetry systems with a passive wireless detection system. Instead of using batteries to power active signal transmission, the system uses the body fluid's physical properties (such as conductivity or acoustic characteristics) as the transmission medium, substituting mechanical energy storage with environmental energy harvesting.
3Measurement precision
If hydrogels are used to detect analyte concentration changes, then selective conversion of analyte concentration into physical quantity changes is achieved, but the device complexity increases due to additional components needed for signal processing and power supply
Solution Approach 1:
The patent extracts and eliminates the most complex components from traditional implantable biosensors, specifically removing batteries, active signal processing circuits, and complex power supply systems. The sensor core remains, utilizing hydrogel-based analyte detection, but all energy-intensive components are removed, replacing them with passive wireless detection and environmental energy harvesting.
Solution Approach 2:
The patent makes the biosensor system self-sufficient by using the body fluid environment to provide both the analyte for detection and the energy for signal transmission. The hydrogel sensor detects analyte concentration changes while the same fluid environment provides the energy source for wireless communication, eliminating the need for separate power supply components.
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
Enables continuous, efficient monitoring of analyte concentrations, such as glucose, without the limitations of battery life or energy transmission, facilitating optimized insulin dosing and improved disease management.
Implementation Method 1
Hydrogels can be designed, for example, to react to changes in the concentration of certain ions (e.g., pH) or certain substances (e.g., glucose or hormones) with relatively large changes in their volume.
Implementation Method 2
Hydrogels are special polymers capable of absorbing a solvent, such as water, in quantities many times their own volume.
Implementation Method 3
SAW sensors consist of a piezoelectric substrate on whose surface so-called interdigital electrodes (IDTs) are located. When an alternating voltage is applied to an IDT, acoustic surface waves are generated via the inverse piezoelectric effect and propagate across the substrate's surface.
Implementation Method 4
When an alternating voltage is applied to an IDT, acoustic surface waves are generated via the inverse piezoelectric effect and propagate across the substrate's surface. These surface waves can be reflected by one or more acoustic reflectors (e.g., another IDT) and then generate an alternating voltage in the input IDT via the piezoelectric effect.
Data Source
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AI summary
The application relates to an implantable biosensor (2) comprising a measuring chamber (102) filled with a test fluid (104) that is capable of converting a change in the concentration of a predetermined analyte or ion species into a change in a physical quantity. The measuring chamber is closed by at least one membrane (103) that is permeable to the analyte or ion species and impermeable to the test fluid. Furthermore, the biosensor is equipped with at least one microacoustic sensor (105) that is operatively connected to the test fluid in such a way that it can detect the physical quantity changing with the concentration of the analyte or ion species. The application also extends to a sensor arrangement comprising at least one such implantable biosensor, which includes a sensing device wirelessly coupled to the biosensor.