Minimally invasive endovascular therapy (MIET) revolutionizes vascular disease treatment through percutaneous access and transcatheter implantation of medical devices. Conventional devices encounter challenges such as incomplete treatment, leading to issues like recanalization in brain aneurysms, endoleaks in aortic aneurysms, and paravalvular leaks in cardiac valves. This study introduces a novel metastructure design for MIET, employing re-entrant honeycomb structures with negative Poisson’s ratio (NPR), created through topology optimization and mapped onto a cylindrical surface.
Utilizing soft ferromagnetic materials, we developed magnetically activated structures (MAS) with adjustable mechanical properties. These structures can change shape under noninvasive magnetic fields, enabling them to conform to blood vessel walls and address leaks or movement issues. The remote control of the stent design using external magnetic fields provides precise control over placement and positioning inside blood vessels.
We performed magneto-mechanical simulations to evaluate the performance of the proposed design. Experimental tests were conducted on prototype beams to assess their bending and torsional responses to external magnetic fields. The simulation results were compared with experimental data to determine the accuracy of the magneto-mechanical simulation model for ferromagnetic soft materials. Then, the simulation model is applied to a cylindrical structure with Negative Poisson’s Ratio (NPR) metamaterial. Due to the complicity of the cylindrical structure, the hexahedron mesh is generated using conformal mapping and sweeping methods. The simulation results indicate that the cylindrical structure demonstrates simultaneous axial and radial expansion when subjected to an external magnetic field. Our future designs will leverage topology optimization for patient-specific geometries, aiming for enhanced compatibility with individual patient models.
2025-04-09 09:00:00
