DESIGNING PROGRAMMABLE FERROMAGNETIC SOFT METASTRUCTURES FOR MINIMALLY INVASIVE ENDOVASCULAR THERAPY.

Area of Science:

• Biomedical Engineering
• Materials Science
• Mechanical Engineering

Background:

• Minimally invasive endovascular therapy (MIET) faces limitations with current devices, causing issues like aneurysm recanalization and valve leaks.
• Existing devices struggle with incomplete treatment and suboptimal sealing, necessitating improved therapeutic solutions.

Purpose of the Study:

• To introduce a novel metastructure design for MIET devices using re-entrant honeycomb structures with negative Poisson's ratio (NPR).
• To develop magnetically activated structures (MAS) from ferromagnetic soft materials for adjustable mechanical properties and remote control.
• To evaluate the performance and potential of these MAS-NPR metastructures for enhanced vascular interventions.

Main Methods:

• Topology optimization and cylindrical mapping were used to design NPR metastructures.
• Ferromagnetic soft materials were employed to create magnetically activated structures (MAS).
• Magneto-mechanical simulations and experimental tests on prototype beams were conducted to validate the model and analyze deformation behaviors.

Main Results:

• The validated model demonstrated that plane matrix NPR metamaterials expand vertically and horizontally under magnetic fields.
• Cylindrical NPR structures showed simultaneous axial and radial expansion when subjected to magnetic fields.
• The study confirmed the accuracy of magneto-mechanical simulations for ferromagnetic soft materials.

Conclusions:

• The proposed methodology shows significant potential for developing advanced magnetically activated MIET devices.
• These devices offer improved biocompatibility, reduced adverse reactions, and enhanced therapeutic outcomes in vascular treatments.
• Integrating ferromagnetic soft materials into metastructures enables the design of stents with tunable mechanical properties for sophisticated endovascular interventions.