Stacked Piezoelectric Composites for Battery-Free Bone Stimulation
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Solution Overview
Problem
Current spinal fusion therapies face limitations, including the need for battery packs and user compliance issues with external devices, and risks associated with synthetic bone morphogenic protein (BMP) treatments, such as ectopic bone formation and potential carcinogenic effects.
Innovation Solution
Development of stacked piezoelectric composites comprising a polymer matrix with piezoelectric structures, which generate direct current stimulation without a battery pack, utilizing a thermoset or thermoplastic polymer matrix with piezoelectric fibers or particles, and an electrically insulating encapsulation coating, connected in a series and parallel configuration to provide electrical stimulation for tissue stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery-operated DC electrical internal stimulators are used, then electrical stimulation can be provided for bone healing, but a second surgery site is required for the battery and the device has limited lifetime
Solution Approach 1:
The patent extracts and removes the battery pack from the electrical stimulation system. Instead of using a battery-operated DC stimulator that requires a second surgery site, the invention uses piezoelectric materials that generate electrical charge directly from mechanical stress applied to the implant, eliminating the need for a separate power source and reducing surgical complexity.
Solution Approach 2:
The piezoelectric implant serves itself by generating electrical stimulation from the mechanical loading that naturally occurs during patient movement and rehabilitation. The mechanical stress applied to the piezoelectric material during normal use automatically generates the electrical charge needed for bone healing, making the device self-powered and eliminating battery replacement or removal surgeries.
2Device complexity
If piezoelectric materials are used to generate electrical stimulation, then no battery pack is needed, but the materials tend to be stiff and brittle
Solution Approach 1:
The patent employs composite materials that combine piezoelectric ceramics or polymers with more ductile matrix materials. This composite structure maintains the piezoelectric effect for electrical charge generation while the matrix material provides toughness and flexibility, reducing the brittleness inherent in pure piezoelectric ceramics and enabling the implant to withstand mechanical loading without fracture.
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 solution enables effective bone growth stimulation without the need for external power sources, reducing complications associated with BMP treatments and improving user compliance, while providing a safer and more efficient method for spinal fusion.
Implementation Method 1
Piezoelectric materials respond to stress with the generation of a net surface charge
Data Source
AI summary
The present application relates to stacked piezoelectric composites comprising piezoelectric structures. Suitably, the composites are useful as tissue-stimulating implants, including spinal fusion implants. The present application also relates to methods of making stacked piezoelectric composites.