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Cai L, Wang Y, Luo Z, Wang J, Ren H, Zhao Y. Designing self-triggered micro/milli devices for gastrointestinal tract drug delivery. Expert Opin Drug Deliv 2023; 20:1415-1425. [PMID: 37817636 DOI: 10.1080/17425247.2023.2269092] [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: 07/13/2023] [Accepted: 10/06/2023] [Indexed: 10/12/2023]
Abstract
INTRODUCTION Self-triggered micro-/milli-devices (STMDs), which are artificial devices capable of responding to the surrounding environment and transferring external energy into kinetic energy, thus realizing autonomous movement, have come to the forefront as a powerful tool in cargo delivery via gastrointestinal tract. Urgent needs have been raised to overview the development of this area. AREAS COVERED We summarize the advancement of designing STMDs for delivery via gastrointestinal tract. We first give a brief overview on the opportunities and challenges of delivery via gastrointestinal tract involving gastric barriers and intestinal barriers. Then, emphasis is laid on the design and applications of STMDs for delivery via gastrointestinal tract. We focus on their morphological characteristics and function design, expounding their working mechanisms in the complex gastrointestinal tract. EXPERT OPINION Although with much progress in STMDs, there is still a huge gap between laboratory researches and clinical applications due to some limitations including latent digestive burden, sophisticated fabrication, unstable delivery, and so on. We give a discussion on the potential, challenges, and prospects of developing STMDs for delivery via gastrointestinal tract.
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Affiliation(s)
- Lijun Cai
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | | | - Zhiqiang Luo
- Department of Rheumatology and Immunology, Nanjing Drum Tower Hospital, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
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Hoddy B, Ahmed N, Al-Lamee K, Bullett N, Curzen N, Bressloff NW. Investigating the Equivalent Plastic Strain in a Variable Ring Length and Strut Width Thin-Strut Bioresorbable Scaffold. Cardiovasc Eng Technol 2022; 13:899-914. [PMID: 35819580 PMCID: PMC9750924 DOI: 10.1007/s13239-022-00625-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 04/18/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE The ArterioSorb[Formula: see text] bioresorbable scaffold (BRS) developed by Arterius Ltd is about to enter first in man clinical trials. Previous generations of BRS have been vulnerable to brittle fracture, when expanded via balloon inflation in-vivo, which can be extremely detrimental to patient outcome. Therefore, this study explores the effect of variable ring length and strut width (as facilitated by the ArterioSorb[Formula: see text] design) on fracture resistance via analysis of the distribution of equivalent plastic strain in the scaffold struts post expansion. Scaffold performance is also assessed with respect to side branch access, radial strength, final deployed diameter and percentage recoil. METHODS Finite element analysis was conducted of the crimping, expansion and radial crushing of five scaffold designs comprising different variations in ring length and strut width. The Abaqus/Explicit (DS SIMULIA) solution method was used for all simulations. Direct comparison between in-silico predictions and in-vitro measurements of the performance of the open cell variant of the ArterioSorb[Formula: see text] were made. Paths across the width of the crown apex and around the scaffold rings were defined along which the plastic strain distribution was analysed. RESULTS The in-silico results demonstrated good predictions of final shape for the baseline scaffold design. Percentage recoil and radial strength were predicted to be, respectively, 2.8 and 1.7 times higher than the experimentally measured values, predominantly due to the limitations of the anisotropic elasto-plastic material property model used for the scaffold. Average maximum values of equivalent plastic strain were up to 2.4 times higher in the wide strut designs relative to the narrow strut scaffolds. As well as the concomitant risk of strut fracture, the wide strut designs also exhibited twisting and splaying behaviour at the crowns located on the scaffold end rings. Not only are these phenomena detrimental to the radial strength and risk of strut fracture but they also increase the likelihood of damage to the vessel wall. However, the baseline scaffold design was observed to tolerate significant over expansion without inducing excessive plastic strains, a result which is particularly encouraging, due to post-dilatation being commonplace in clinical practice. CONCLUSION Therefore, the narrow strut designs investigated herein, are likely to offer optimal performance and potentially better patient outcomes. Further work should address the material modelling of next generation polymeric BRS to more accurately capture their mechanical behaviour. Observation of the in-vitro testing indicates that the ArterioSorb[Formula: see text] BRS can tolerate greater levels of over expansion than anticipated.
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Affiliation(s)
- Ben Hoddy
- grid.5491.90000 0004 1936 9297Computational Engineering and Design Research Group, University of Southampton, Southampton, UK
| | - Naveed Ahmed
- grid.498018.c0000 0004 0581 8370Arterius Ltd, Leeds, UK
| | | | - Nial Bullett
- grid.498018.c0000 0004 0581 8370Arterius Ltd, Leeds, UK
| | - Nick Curzen
- grid.430506.40000 0004 0465 4079Coronary Research Group, Southampton University Hospitals NHS Trust, Southampton, UK ,grid.5491.90000 0004 1936 9297Faculty of Medicine, University of Southampton, Southampton, UK
| | - Neil W. Bressloff
- grid.5491.90000 0004 1936 9297Computational Engineering and Design Research Group, University of Southampton, Southampton, UK
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Wu X, Wu S, Kawashima H, Hara H, Ono M, Gao C, Wang R, Lunardi M, Sharif F, Wijns W, Serruys PW, Onuma Y. Current perspectives on bioresorbable scaffolds in coronary intervention and other fields. Expert Rev Med Devices 2021; 18:351-365. [PMID: 33739213 DOI: 10.1080/17434440.2021.1904894] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: The first-generation bioresorbable scaffolds (BRSs) had a large strut profile to compensate for the insufficient radial strength of bioresorbable polymer materials, resulting in higher scaffold thrombosis rates than conventional drug-eluting stents. To improve the clinical safety and efficacy, the new generation BRSs have been improved by optimal structure design, post-processing of bioresorbable polymer materials, or altering bioresorbable metallic alloys.Areas covered: This review summarizes the lessons learned from the first-generation BRS, updates the clinical outcomes of trials evaluating ABSORB bioresorbable vascular scaffold at long-term and bioresorbable metallic alloy-based devices, and examines recent outcomes of BRS treated in STEMI patients. This review also provides an overview of the current clinical data of seven BRSs manufactured in Asia, and of the BRSs extended application in other clinical arenas.Expert opinion: Drawbacks of the first-generation BRSs need to be addressed by the next generation of these stents with novel materials and technologies. Clinical research, including randomized controlled trials, are required to further evaluate BRSs application in coronary artery disease. The encouraging results of BRSs innovation applied in the peripheral arteries and gastrointestinal tracts support other potential clinical applications of BRS technology.
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Affiliation(s)
- Xinlei Wu
- Institute of Cardiovascular Development and Translational Medicine, the Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.,Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Sijing Wu
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland.,Department of Cardiology, Beijing Anzhen Hospital, Beijing, China
| | - Hideyuki Kawashima
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Hironori Hara
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Masafumi Ono
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Chao Gao
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland.,Department of Cardiology, Xijing Hospital, Xi'an, China
| | - Rutao Wang
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland.,Department of Cardiology, Xijing Hospital, Xi'an, China
| | - Mattia Lunardi
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Faisal Sharif
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - William Wijns
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
| | - Patrick W Serruys
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland.,National Heart & Lung Institute, Imperial College London, London, UK
| | - Yoshinobu Onuma
- Department of Cardiology, National University of Ireland Galway (NUIG), Galway, Ireland
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