Wireless Bone Graft Strain Sensor with Inductive Powering
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Solution Overview
Problem
Existing strain sensors lack the ability to effectively measure strain on biological substrates like bone grafts and predict healing potential, as they require batteries and attachment hardware, which can interfere with the biological environment and reduce sensitivity.
Innovation Solution
A wireless, inductively-powered strain sensor device with a strain sensing circuit composed of dielectric and conductive layers, directly deposited on a bone graft substrate using a biocompatible bonding interface, eliminating the need for batteries and attachment hardware, and utilizing MEMS techniques for fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional strain sensors with batteries and attachment hardware are used, then the sensor can function as a strain gauge, but the biological environment is interfered with and sensitivity is reduced
Solution Approach 1:
The patent removes the battery and attachment hardware from the sensor system, extracting the harmful components that interfere with the biological environment. The strain sensing circuit is directly deposited on the bone graft substrate, eliminating the need for separate attachment mechanisms and power sources that would otherwise compromise sensor reliability in the biological setting.
Solution Approach 2:
The patent merges the strain sensing circuit with the bone graft substrate by directly depositing the sensor layers onto the substrate. This integration eliminates the need for separate attachment hardware and creates a unified structure that maintains sensor functionality while avoiding interference with the biological environment.
2Stability of the object's composition
If attachment hardware is used to secure the sensor, then the sensor can be fixed to the bone graft, but the sensitivity of the sensor is reduced
Solution Approach 1:
The strain sensing circuit is directly deposited on the bone graft substrate, merging the sensor and substrate into a single integrated structure. This eliminates the need for attachment hardware that would compromise sensitivity, while the direct integration ensures stable fixation without introducing harmful interfaces.
Solution Approach 2:
The patent uses a bonding interface layer composed of silicon nitride and PDMS as an intermediary between the bone graft substrate and the strain sensing circuit. This intermediate layer provides secure attachment while maintaining strain propagation properties, avoiding the need for rigid attachment hardware that would reduce sensitivity.
3Ease of manufacture
If silicon-based sensors are used, then the sensor can be manufactured with standard materials, but the strain propagation properties are inferior compared to direct bone graft attachment
Solution Approach 1:
The patent changes the material parameters of the sensor substrate from conventional silicon-based materials to bone graft substrate materials with matching mechanical properties. This parameter change enables direct attachment without attachment hardware, improving strain propagation properties while maintaining manufacturability through standard deposition techniques.
Solution Approach 2:
The patent employs composite material structures, combining bone graft substrate with dielectric and conductive layers in a multi-layer composite configuration. This composite approach allows the sensor to be directly integrated with the biological substrate, improving strain propagation while maintaining ease of manufacture through sequential deposition processes.
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 sensor provides enhanced sensitivity and accurate strain measurement, predicting healing potential without the interference of external hardware, with improved strain propagation properties due to the direct attachment on the bone graft, offering better performance than silicon-based sensors.
Implementation Method 1
The sensor can be an inductively-powered telemetric wireless sensor (i.e., no battery source)
Implementation Method 2
a strain sensing circuit (strain sensing elements), which is composed of a first dielectric layer and a first conductive layer, that functions as a strain gauge
Implementation Method 3
A bonding interface can be disposed between the biological substrate and the first dielectric layer
Data Source
AI summary
A strain sensor device having a biological substrate composed of a standalone bone graft or an isolated piece of bone that can be incorporated directly into, or attached to another piece of bone that is then implantable, in a biological subject, and a method thereof. The strain sensor device can includes a strain sensing circuit, which is composed of at least a first dielectric layer and a first conductive layer, that functions as a strain gauge. The first dielectric layer can be composed of dielectric material disposed over the biological substrate. The first conductive layer, which has a pattern, can be disposed over the first dielectric material. A bonding interface is disposed between the biological substrate and the first dielectric layer. The bonding interface can be composed of an underlayer of polydimethylsiloxane and a first interface layer. The underlayer can be disposed on the bone graft substrate.