1
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Teong YW, Mustapha KB, Ibitoye MO. Finite element analysis and surrogate-optimized design of a nature-inspired auxetic stent. Comput Methods Biomech Biomed Engin 2024:1-17. [PMID: 39256915 DOI: 10.1080/10255842.2024.2399018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/06/2024] [Accepted: 08/21/2024] [Indexed: 09/12/2024]
Abstract
Prior studies have revealed that the structural design of stents is critical to reducing some of the alarming post-operative complications associated with stent-related intervention. However, the technical search for stents that guarantee robustness against stent-induced post-intervention complications remains an open problem. Along this objective, this study investigates a re-entrant auxetic stent's structural response and performance optimizations. In pursuit of the goal, a nonlinear finite element analysis (FEA) is employed to uncover metrics characterizing the auxetic stent's mechanical behavior. Subsequently, the non-dominated sorting genetic algorithm (NSGA-II) is implemented to simultaneously minimize the stent's von Mises stress and the elastic radial recoil (ERR). Results from the FEA revealed a tight connection between the stent's response and the features of the base auxetic building block (the rib length, strut width, and the re-entrant angle). It is observed that the auxetic stent exhibits a much lower ERR. Besides, larger values of its rib length and re-entrant angle are noticed to favor smaller von Mises stress. The Pareto-optimal front from the NSGA-II-based optimization scheme revealed a sharp trade-off in the simultaneous minimization of the von Mises stress and the ERR. Moreover, an optimal combination of the auxetic unit cell's geometric parameters is found to yield a much lower maximum von Mises stress of ≈ 403 MPa and ERR of ≈ 0.4 % .
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Affiliation(s)
- Y W Teong
- Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham (Malaysia Campus), Semenyih, Malaysia
| | - K B Mustapha
- Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham (Malaysia Campus), Semenyih, Malaysia
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2
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Wang Y, Guo Y, Yang H. Mechanical Properties of Re-Entrant Hybrid Honeycomb Structures for Morphing Wings. Biomimetics (Basel) 2024; 9:521. [PMID: 39329543 DOI: 10.3390/biomimetics9090521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/25/2024] [Accepted: 08/26/2024] [Indexed: 09/28/2024] Open
Abstract
The exceptional energy absorption, deformability, and tuneable Poisson's ratio properties of negative Poisson's ratio (NPR) honeycomb biomimetic structures make them highly suitable for applications in aerospace, medical, and acoustic stealth industries. The present study proposes a re-entrant hybrid honeycomb (REHH) structure comprising a re-entrant octagonal unit cell and a re-entrant hexagonal unit cell. Theoretical models of the in-plane elastic modulus and Poisson's ratio are established based on beam theory, and these models are validated through finite element (FE) simulations and tensile experiments conducted on the REHH samples. The influence of the cell geometry parameters on the in-plane elastic behaviours is investigated. The results indicate that the NPR performance of the REHH structure exhibits superior deformation capability compared with the four-point star hybrid honeycomb (FSHH) structure. The experimental REHH structure samples exhibit significant tensile displacement capabilities in the x-direction.
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Affiliation(s)
- Yan Wang
- Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao 066004, China
| | - Yingjie Guo
- Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao 066004, China
| | - Hui Yang
- Parallel Robot and Mechatronic System Laboratory of Hebei Province, Yanshan University, Qinhuangdao 066004, China
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3
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Sun M, Hu X, Tian L, Yang X, Min L. Auxetic Biomedical Metamaterials for Orthopedic Surgery Applications: A Comprehensive Review. Orthop Surg 2024; 16:1801-1815. [PMID: 38961661 PMCID: PMC11293933 DOI: 10.1111/os.14142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 07/05/2024] Open
Abstract
Poisson's ratio in auxetic materials shifts from typically positive to negative, causing lateral expansion during axial tension. This scale-independent characteristic, originating from tailored architectures, exhibits specific physical properties, including energy adsorption, shear resistance, and fracture resistance. These metamaterials demonstrate exotic mechanical properties with potential applications in several engineering fields, but biomedical applications seem to be one of the most relevant, with an increasing number of articles published in recent years, which present opportunities ranging from cellular repair to organ reconstruction with outstanding mechanical performance, mechanical conduction, and biological activity compared with traditional biomedical metamaterials. Therefore, focusing on understanding the potential of these structures and promoting theoretical and experimental investigations into the benefits of their unique mechanical properties is necessary for achieving high-performance biomedical applications. Considering the demand for advanced biomaterial implants in surgical technology and the profound advancement of additive manufacturing technology that are particularly relevant to fabricating complex and customizable auxetic mechanical metamaterials, this review focuses on the fundamental geometric configuration and unique physical properties of negative Poisson's ratio materials, then categorizes and summarizes auxetic material applications across some surgical departments, revealing efficacy in joint surgery, spinal surgery, trauma surgery, and sports medicine contexts. Additionally, it emphasizes the substantial potential of auxetic materials as innovative biomedical solutions in orthopedics and demonstrates the significant potential for comprehensive surgical application in the future.
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Affiliation(s)
- Minghao Sun
- Department of Orthopedic Surgery and Orthopedic Research InstituteWest China Hospital, Sichuan UniversityChengduChina
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan ProvinceChengduChina
| | - Xin Hu
- Department of Orthopedic Surgery and Orthopedic Research InstituteWest China Hospital, Sichuan UniversityChengduChina
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan ProvinceChengduChina
| | - Leilei Tian
- Department of AnesthesiologyWest China Hospital, Sichuan University/West China School of Nursing, Sichuan UniversityChengduChina
| | - Xiao Yang
- National Engineering Research Center for BiomaterialsSichuan UniversityChengduChina
- Provincial Engineering Research Center for Biomaterials Genome of SichuanSichuan UniversityChengduChina
| | - Li Min
- Department of Orthopedic Surgery and Orthopedic Research InstituteWest China Hospital, Sichuan UniversityChengduChina
- Model Worker and Craftsman Talent Innovation Workshop of Sichuan ProvinceChengduChina
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4
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Blankenship B, Meier T, Arvin SL, Li J, Seymour N, De La Torre N, Hsu B, Zhao N, Mavrikos S, Li R, Grigoropoulos CP. Nondestructive Imaging of Manufacturing Defects in Microarchitected Materials. ACS APPLIED ENGINEERING MATERIALS 2024; 2:1737-1742. [PMID: 39086613 PMCID: PMC11287491 DOI: 10.1021/acsaenm.4c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 08/02/2024]
Abstract
Defects in microarchitected materials exhibit a dual nature, capable of both unlocking innovative functionalities and degrading their performance. Specifically, while intentional defects are strategically introduced to customize and enhance mechanical responses, inadvertent defects stemming from manufacturing errors can disrupt the symmetries and intricate interactions within these materials. In this study, we demonstrate a nondestructive optical imaging technique that can precisely locate defects inside microscale metamaterials, as well as provide detailed insights on the specific type of defect.
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Affiliation(s)
- Brian
W. Blankenship
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Timon Meier
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Sophia Lafia Arvin
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Jingang Li
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Nathan Seymour
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Natalia De La Torre
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Brian Hsu
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Naichen Zhao
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Stefanos Mavrikos
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Runxuan Li
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
| | - Costas P. Grigoropoulos
- Laser
Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, California 94720, United States
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5
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Wang L, Wang W, Jiang Y, Yuan Y. Optimizing the compression resistance of low-nickel stainless steel coronary stents using finite element and response surface methodology. J Biomech 2024; 172:112227. [PMID: 39004042 DOI: 10.1016/j.jbiomech.2024.112227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 06/13/2024] [Accepted: 07/09/2024] [Indexed: 07/16/2024]
Abstract
Considering the high strength and excellent biocompatibility of low-nickel stainless steel, this paper focused on optimizing the design of a vascular stent made from this material using finite element analysis (FEA) combined with the response surface methodology (RSM). The aim is to achieve the desired compressive resistance for the stent while maintaining a thin stent wall thickness. The parameters of the stent's support unit width (H), strut width (W), and thickness (T) were selected as input parameters, while the output parameters obtained from FEA included the compressive load, the equivalent plastic strain (PEEQ), axial shortening rate, radial recoil rate, and metal coverage rate. The mathematical models of input parameters and output parameters were established by using the Box Behnken design (BBD) of RSM. The model equations were solved under constrained conditions, and the optimal structural parameters, namely H, W, and T, were finally determined as 0.770 mm, 0.100 mm, and 0.075 mm respectively. In this situation, the compression load of the stent reached the target value of 0.38 N/mm; the PEEQ resulting from the stent expansion was small; the axial shortening, radial recoil, and metal coverage index were all minimized within the required range.
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Affiliation(s)
- Lingling Wang
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
| | - Weiqiang Wang
- School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China.
| | - Yi Jiang
- Dalian Hanzheng Medical Instrument Inspection Co., Ltd, Dalian 116100, China
| | - Yonghui Yuan
- Clinical Research Center for Malignant Tumor of Liaoning Province, Cancer Hospital of Dalian University of Technology, Shenyang 110042, China.
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6
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Vellaparambil R, Han WS, Di Giovanni P, Avril S. Experimental validation of auxetic stent designs: three-point bending of 3D printed Titanium prototypes. FRONTIERS IN MEDICAL TECHNOLOGY 2024; 6:1388207. [PMID: 38770028 PMCID: PMC11102953 DOI: 10.3389/fmedt.2024.1388207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/22/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction Numerical simulations have demonstrated the superior bending flexibility of auxetic stents compared to conventional stent designs for endovascular procedures. However, conventional stent manufacturing techniques struggle to produce complex auxetic stent designs, fueling the adoption of additive manufacturing techniques. Methods In this study, we employed DMLS additive manufacturing to create Titanium Ti64 alloy stent prototypes based on auxetic stent designs investigated in a previous study. These prototypes were then subjected to experimental three-point bending tests. Result The experimental results were replicated using a finite element model, which showed remarkable accuracy in predicting the bending flexibility of four auxetic stents and two conventional stents. Discussion Although this validation study demonstrates the promising potential of DMLS and other additive manufacturing methods for fabricating auxetic stents, further optimization of current stent design limitations and the incorporation of post-processing techniques are essential to enhance the reliability of these additive manufacturing processes.
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Affiliation(s)
- Rahul Vellaparambil
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, Saint-Etienne, France
- Research and Development Department, HSL S.R.L, Trento, Italy
| | - Woo-Suck Han
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, Saint-Etienne, France
| | | | - Stéphane Avril
- Mines Saint-Etienne, Université Jean Monnet Saint-Etienne, INSERM, SAINBIOSE U1059, Saint-Etienne, France
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7
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Chansoria P, Rütsche D, Wang A, Liu H, D'Angella D, Rizzo R, Hasenauer A, Weber P, Qiu W, Ibrahim NBM, Korshunova N, Qin X, Zenobi‐Wong M. Synergizing Algorithmic Design, Photoclick Chemistry and Multi-Material Volumetric Printing for Accelerating Complex Shape Engineering. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300912. [PMID: 37400372 PMCID: PMC10502818 DOI: 10.1002/advs.202300912] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/12/2023] [Indexed: 07/05/2023]
Abstract
The field of biomedical design and manufacturing has been rapidly evolving, with implants and grafts featuring complex 3D design constraints and materials distributions. By combining a new coding-based design and modeling approach with high-throughput volumetric printing, a new approach is demonstrated to transform the way complex shapes are designed and fabricated for biomedical applications. Here, an algorithmic voxel-based approach is used that can rapidly generate a large design library of porous structures, auxetic meshes and cylinders, or perfusable constructs. By deploying finite cell modeling within the algorithmic design framework, large arrays of selected auxetic designs can be computationally modeled. Finally, the design schemes are used in conjunction with new approaches for multi-material volumetric printing based on thiol-ene photoclick chemistry to rapidly fabricate complex heterogeneous shapes. Collectively, the new design, modeling and fabrication techniques can be used toward a wide spectrum of products such as actuators, biomedical implants and grafts, or tissue and disease models.
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Affiliation(s)
- Parth Chansoria
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | - Dominic Rütsche
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
- Department of SurgeryUniversity Children's HospitalBasel4056Switzerland
| | - Anny Wang
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
- Hyperganic Group GmbH80799MunichGermany
| | - Hao Liu
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | | | - Riccardo Rizzo
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | - Amelia Hasenauer
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | - Patrick Weber
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | - Wanwan Qiu
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | | | | | - Xiao‐Hua Qin
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
| | - Marcy Zenobi‐Wong
- Department of Health Sciences and TechnologyETH Zürich UniversityZürich8092Switzerland
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8
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Munyensanga P, El Mabrouk K. Elemental and experimental analysis of modified stent's structure under uniaxial compression load. J Mech Behav Biomed Mater 2023; 143:105903. [PMID: 37182368 DOI: 10.1016/j.jmbbm.2023.105903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/04/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Abstract
Additive manufacturing has enabled the fabrication of lightweight complex metamaterials that possess high energy absorption and impact resistance properties. Stents, a typical 3D auxetic material, have significant self-expanding behavior, and their mechanical properties can be finely tuned over a wide range. In this study, we systematically analyzed three distinctive elastic-plastic regions using experimental, numerical simulations, and theoretical analysis, focusing on investigating the energy absorption capability of a designed structure by varying tessellated unit cell numbers in two section views in X- and Y-direction. Two batches of 5 specimens each were 3D printed using FDM techniques. The results showed that designing a self-expanding stent with innovative capabilities was possible, with the yield stress ranging between 1.5 MPa and 2.0 MPa and extended effective elastic moduli derived from the deformation mode of tessellated unit cells. The maximum energy absorption for all structures ranged between 7.1J and 18J, with similar capabilities observed for the designed stents. However, increasing unit cells along the X-direction resulted in a significant increase in SEA, while the Y-direction remained unchanged. Therefore, these structures have a significant influence on areas requiring energy absorption. In addition, they are the ideal class of energy absorbers for cushioning applications. Furthermore, their energy-absorption capacity can be easily tailored to meet specific end-use requirements by varying their structural parameters using unit cell tessellation.
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Affiliation(s)
- Patrick Munyensanga
- Euromed Research Center, Euromed Polytechnic School, Euromed University of Fes, Eco-Campus, Meknes Road, 30 030, Fes, Morocco
| | - Khalil El Mabrouk
- Euromed Research Center, Euromed Polytechnic School, Euromed University of Fes, Eco-Campus, Meknes Road, 30 030, Fes, Morocco.
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9
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Vellaparambil R, Han WS, Di Giovanni P, Avril S. Potential of auxetic designs in endovascular aortic repair: A computational study of their mechanical performance. J Mech Behav Biomed Mater 2023; 138:105644. [PMID: 36608533 DOI: 10.1016/j.jmbbm.2022.105644] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/01/2022] [Accepted: 12/25/2022] [Indexed: 12/27/2022]
Abstract
With the rising popularity of endovascular aortic repair (EVAR) for aortic aneurysms and dissections, there is a crucial need for investigating the delayed appearance of post-EVAR complications such as stent-graft kinking, fracture and migration respectively. These complications have been noted to be influenced by the radial stiffness and bending flexibility attributes of stent-grafts. Auxetic designs with negative Poisson's ratio offer interesting advantages such as enhanced fracture toughness, superior indentation resistance and adaptive stiffness in response to intricate morphology for stenting applications over conventional stent designs. The objective of this study is to propose different auxetic stent candidates and to compare their mechanical performance with two conventional stent candidates for endovascular applications using numerical simulation through crimp/crushing tests for their radial stiffness and three-point bending/kinking tests for their flexibility, respectively. The results demonstrate that the novel hybrid auxetic designs (CRE and CSTAR) possess the best trade-off between radial stiffness and bending flexibility characteristics among all candidates for stent-graft applications.
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Affiliation(s)
- Rahul Vellaparambil
- Mines Saint-Etienne, Univ Lyon, Univ Jean Monnet, Etablissement Francais du Sang, INSERM, U 1059 Sainbiose, Centre CIS, F - 42023, Saint-Etienne, France; R&D Department, HSL S.R.L, Trento, Italy
| | - Woo-Suck Han
- Mines Saint-Etienne, Univ Lyon, Univ Jean Monnet, Etablissement Francais du Sang, INSERM, U 1059 Sainbiose, Centre CIS, F - 42023, Saint-Etienne, France
| | | | - Stéphane Avril
- Mines Saint-Etienne, Univ Lyon, Univ Jean Monnet, Etablissement Francais du Sang, INSERM, U 1059 Sainbiose, Centre CIS, F - 42023, Saint-Etienne, France.
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10
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Ahadi F, Azadi M, Biglari M, Bodaghi M, Khaleghian A. Evaluation of coronary stents: A review of types, materials, processing techniques, design, and problems. Heliyon 2023; 9:e13575. [PMID: 36846695 PMCID: PMC9950843 DOI: 10.1016/j.heliyon.2023.e13575] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 01/22/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023] Open
Abstract
In the world, one of the leading causes of death is coronary artery disease (CAD). There are several ways to treat this disease, and stenting is currently the most appropriate way in many cases. Nowadays, the use of stents has rapidly increased, and they have been introduced in various models, with different geometries and materials. To select the most appropriate stent required, it is necessary to have an analysis of the mechanical behavior of various types of stents. The purpose of this article is to provide a complete overview of advanced research in the field of stents and to discuss and conclude important studies on different topics in the field of stents. In this review, we introduce the types of coronary stents, materials, stent processing technique, stent design, classification of stents based on the mechanism of expansion, and problems and complications of stents. In this article, by reviewing the biomechanical studies conducted in this field and collecting and classifying their results, a useful set of information has been presented to continue research in the direction of designing and manufacturing more efficient stents, although the clinical-engineering field still needs to continue research to optimize the design and construction. The optimum design of stents in the future is possible by simulation and using numerical methods and adequate knowledge of stent and artery biomechanics.
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Affiliation(s)
- Fatemeh Ahadi
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mohammad Azadi
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mojtaba Biglari
- Faculty of Mechanical Engineering, Semnan University, Semnan, Iran
| | - Mahdi Bodaghi
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Ali Khaleghian
- Department of Biochemistry, Semnan University of Medical Sciences, Semnan, Iran
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Wang Y, Wu H, Fan S, Wu J, Yang S. Structure design and mechanical performance analysis of three kinds of bioresorbable poly-lactic acid (PLA) stents. Comput Methods Biomech Biomed Engin 2023; 26:25-37. [PMID: 35341394 DOI: 10.1080/10255842.2022.2045485] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular stent implantation has become an important choice for the treatment of severe cardiovascular and cerebrovascular blockage. Rational design is vital to ensure the mechanical properties of the vascular stents, which are important both to the implantation and service as for clinical treatment of coronary heart disease. Therefore we proposed a wholly new non-uniform honeycomb stent E and compared with an inverted honeycomb-like shaped stent F and a honeycomb-like shaped stent G. To evaluate their properties, a finite element method (FEM) was used to simulate the implantation process (crimp, crimp recoil, expand, and expand recoil) of these three different kinds of stents. Results showed that the stent E exhibits better mechanical behaviour than the other two stents F and G as far as radial strength and axial shortening performances and that the distribution of equivalent stress among the stent E is more uniform than that among the other two stents F and G. After that, a three-point bending method was used to study the bending flexibility of these three vascular stents. Stent E shows high bending stiffness compared with stents F and G due to the existence of additional support bridges in its structure. This study can be helpful to the rational design of optimizable PLA stents for its practical clinical performance and therefore possibly improve the prognosis of patients.
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Affiliation(s)
- Yangyang Wang
- Department of Chemistry and Chemistry Engineering, University of South China, Hengyang, China
| | - Hongmei Wu
- Department of Chemistry and Chemistry Engineering, University of South China, Hengyang, China
| | - Shiyi Fan
- Department of Chemistry and Chemistry Engineering, University of South China, Hengyang, China
| | - Jingzhi Wu
- Department of Chemistry and Chemistry Engineering, University of South China, Hengyang, China
| | - Sisi Yang
- Department of Chemistry and Chemistry Engineering, University of South China, Hengyang, China
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12
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Auxetic Metamaterials for Biomedical Devices: Current Situation, Main Challenges, and Research Trends. MATERIALS 2022; 15:ma15041439. [PMID: 35207976 PMCID: PMC8874587 DOI: 10.3390/ma15041439] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/05/2022] [Accepted: 02/08/2022] [Indexed: 01/23/2023]
Abstract
Auxetic metamaterials are characterized by a negative Poisson ratio (NPR) and display an unexpected property of lateral expansion when stretched and densification when compressed. Auxetic properties can be achieved by designing special microstructures, hence their classification as metamaterials, and can be manufactured with varied raw materials and methods. Since work in this field began, auxetics have been considered for different biomedical applications, as some biological tissues have auxetic-like behaviour due to their lightweight structure and morphing properties, which makes auxetics ideal for interacting with the human body. This research study is developed with the aim of presenting an updated overview of auxetic metamaterials for biomedical devices. It stands out for providing a comprehensive view of medical applications for auxetics, including a focus on prosthetics, orthotics, ergonomic appliances, performance enhancement devices, in vitro medical devices for interacting with cells, and advanced medicinal clinical products, especially tissue engineering scaffolds with living cells. Innovative design and simulation approaches for the engineering of auxetic-based products are covered, and the relevant manufacturing technologies for prototyping and producing auxetics are analysed, taking into consideration those capable of processing biomaterials and enabling multi-scale and multi-material auxetics. An engineering design rational for auxetics-based medical devices is presented with integrative purposes. Finally, key research, development and expected technological breakthroughs are discussed.
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13
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Xue H, Saha SC, Beier S, Jepson N, Luo Z. Topological Optimization of Auxetic Coronary Stents Considering Hemodynamics. Front Bioeng Biotechnol 2021; 9:728914. [PMID: 34589473 PMCID: PMC8473832 DOI: 10.3389/fbioe.2021.728914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/27/2021] [Indexed: 12/05/2022] Open
Abstract
This paper is to design a new type of auxetic metamaterial-inspired structural architectures to innovate coronary stents under hemodynamics via a topological optimization method. The new architectures will low the occurrence of stent thrombosis (ST) and in-stent restenosis (ISR) associated with the mechanical factors and the adverse hemodynamics. A multiscale level-set approach with the numerical homogenization method and computational fluid dynamics is applied to implement auxetic microarchitectures and stenting structure. A homogenized effective modified fluid permeability (MFP) is proposed to efficiently connect design variables with motions of blood flow around the stent, and a Darcy-Stokes system is used to describe the coupling behavior of the stent structure and fluid. The optimization is formulated to include three objectives from different scales: MFP and auxetic property in the microscale and stenting stiffness in the macroscale. The design is numerically validated in the commercial software MATLAB and ANSYS, respectively. The simulation results show that the new design can not only supply desired auxetic behavior to benefit the deliverability and reduce incidence of the mechanical failure but also improve wall shear stress distribution to low the induced adverse hemodynamic changes. Hence, the proposed stenting architectures can help improve safety in stent implantation, to facilitate design of new generation of stents.
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Affiliation(s)
- Huipeng Xue
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
| | - Suvash C Saha
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
| | - Susann Beier
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Kensington, NSW, Australia
| | - Nigel Jepson
- Department Cardiology, Prince of Wales Hospital, Randwick, NSW, Australia
| | - Zhen Luo
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Sydney, NSW, Australia
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Wolf AT. Auxetische Materialien. CHEM UNSERER ZEIT 2021. [DOI: 10.1002/ciuz.202000067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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