Hematite Nanoparticle Stents for Coronary Spasm
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Solution Overview
Problem
Current coronary artery stents face issues such as neointimal hyperplasia, in-stent restenosis, and late stent thrombosis due to their material properties, and there is a need for stents with improved biocompatibility and mechanical strength that can be fabricated rapidly and precisely for patient-specific use.
Innovation Solution
The development of patient-specific stimuli-responsive cardiovascular stents using 3D printed polymer nanocomposites doped with hematite (α-Fe2O3) nanoparticles, which exhibit shape memory effects and can be actuated remotely with a magnetic field, providing improved mechanical strength and biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic stents are used to provide structural strength and reduce strut thickness, then mechanical strength is improved, but neointimalhyperplasia and in-stent restenosis occur
Solution Approach 1:
The patent employs composite materials consisting of biodegradable polymer matrix combined with magnetic nanoparticles (Fe3O4). This composite structure provides the necessary mechanical strength while the biodegradable nature eliminates the harmful effects of permanent metallic stents, including neointimalhyperplasia and restenosis. The composite material degrades over time, allowing tissue regeneration without the long-term complications associated with metallic implants.
Solution Approach 2:
The patent utilizes parameter changes in the form of magnetic field application to control the physical state and mechanical properties of the stent. By applying external magnetic fields, the stent can transition between different structural states, providing strength when needed and becoming more compliant as it degrades, thereby avoiding the fixed harmful interactions of traditional metallic stents with blood vessels.
2Reliability
If drug coating is applied to prevent restenosis, then biocompatibility is improved, but drug coating depletes over time causing late stent thrombosis
Solution Approach 1:
The magnetic nanoparticle-enhanced biodegradable stent provides self-service functionality through magnetic field-responsive behavior. The stent can actively adjust its structural properties in response to magnetic stimulation, providing ongoing therapeutic effect without relying on depleting drug coatings. This eliminates the problem of late stent thrombosis caused by drug depletion while maintaining improved biocompatibility throughout the stent's lifecycle.
Solution Approach 2:
The patent replaces the chemical drug delivery mechanism with a magnetic field-responsive mechanical system. Instead of relying on drug coating that depletes over time, the stent uses magnetic nanoparticles to respond to external magnetic fields, providing controlled structural adjustment and therapeutic effects that persist without the limitations of drug coating duration.
3Manufacturing precision
If 3D printing is used to fabricate patient-specific stents, then manufacturing precision is improved, but fabrication time must be minimized for rapid deployment
Solution Approach 1:
The patent implements preliminary action by pre-programming the magnetic nanoparticle distribution and stent structural parameters during the 3D printing fabrication process. Patient-specific geometries are precisely fabricated with embedded magnetic nanoparticles in predetermined patterns, allowing the stent to be ready for immediate magnetic field activation upon implantation. This preliminary configuration enables both high manufacturing precision and rapid deployment without requiring post-fabrication adjustments.
Solution Approach 2:
The 3D printing process creates a universal platform that can fabricate various patient-specific stent designs using the same biodegradable polymer and magnetic nanoparticle composite material. The multi-functionality of the 3D printing system allows it to produce customized geometries, structural features, and nanoparticle distributions all in a single fabrication process, achieving both precision and efficiency.
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
These stents eliminate the need for post-surgical interventions by allowing for precise adjustment and adaptation to varying conditions, enhancing patient-specific treatment outcomes and reducing complications like thrombosis and restenosis.
Implementation Method 1
3D printed polymer nanocomposites doped with hematite (α-Fe2O3) nanoparticles, which exhibit shape memory effects and can be actuated remotely with a magnetic field
Implementation Method 2
can be actuated remotely with a magnetic field
Data Source
AI summary
Example systems, methods, and apparatus are disclosed herein for a design and fabrication of patient-specific stimuli-responsive cardiovascular stents for coronary artery spasm treatment to eliminate post-surgical interventions. The stimuli-responsive material may be a magnetically-induced shape memory nanoparticle such as Hematite dispersed in PLA. Such Hematite may be at a concentration of 10 wt % to 20 wt %.