Auxetic 3D printed metastructure stents for enhanced mechanical and structural performance and biocompatibility in coronary artery treatments

Research into next-generation materials is crucial for addressing complex mechanical challenges, leading scientists to explore auxetic structures that expand laterally when stretched, unlike traditional materials. This study aims to address the gap in the design and performance evaluation of hybrid auxetic stents for vascular applications, focusing on their mechanical properties and potential advantages over conventional stents. A new auxetic unit cell was designed, integrating arrowhead and missing rib geometries. The structure was fabricated using fused filament fabrication 3D printing, a cost-effective method suitable for rapid prototyping. The mechanical properties of the stents were examined through finite element analysis and experimental tests, evaluating parameters such as foreshortening, expansion, recoil, dog-boning, and normalized surface area. The results revealed significant improvements in the performance of the newly designed stents compared to the non-auxetic stents. Notably, the optimum stent exhibited a foreshortening value of 3.27 %, an expansion of 9.03 %, a recoil of 2.43 %, a dog-boning value of 5.77 %, and a normalized surface area of 1.65 mm, indicating balanced and enhanced mechanical properties. The findings highlight the auxetic stent's ability to maintain structural integrity under physiological conditions, reduce shortcomings associated with traditional stents, and provide better adaptability to dynamic anatomical structures. This study demonstrates the feasibility and potential of auxetic designs in stent applications, offering valuable insights into optimizing stent performance. The proposed auxetic structures present a promising avenue for future research and development in medical implants, contributing to improved patient outcomes and expanding the applications of auxetic materials in the biomedical field. STATEMENT OF SIGNIFICANCE: This study introduces a hybrid auxetic stents designed for vascular applications, a significant advancement over traditional stent materials. By exploring auxetic structures-materials that expand when stretched-we address the limitations of conventional stents. The designed stents, fabricated using 3D printing, demonstrate enhanced mechanical properties such as reduced recoil and improved adaptability to dynamic anatomical conditions. Our results show that these stents can minimize complications and improve patient outcomes, representing a promising direction for future research in medical implants. This work contributes valuable insights into the optimization of stent performance and expands the potential applications of auxetic materials in the biomedical field, engaging both researchers and medical professionals interested in innovative solutions for vascular health.