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Zhang T, Dou Y, Li Y, Luo R, Yang L, Zhang W, Wang Y, Zhang X. Design and performance of double-layered artificial chordae. Regen Biomater 2024; 11:rbae076. [PMID: 39055301 PMCID: PMC11269677 DOI: 10.1093/rb/rbae076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/24/2024] [Accepted: 06/08/2024] [Indexed: 07/27/2024] Open
Abstract
Surgical repair with artificial chordae replacement has emerged as a standard treatment for mitral regurgitation. Expanded polytetrafluoroethylene (ePTFE) sutures are commonly employed as artificial chordae; however, they have certain limitations, such as potential long-term rupture and undesired material/tissue response. This study introduces a novel approach to artificial chordae design, termed the New Artificial Chordae (NAC), which incorporates a double-layered structure. The NAC comprises a multi-strand braided core composed of ultra-high molecular weight polyethylene (UHMWPE) fibers as the inner core, and an outer tube made of hydrophobic porous ePTFE. Compared to traditional ePTFE sutures, NAC exhibits increased flexibility, enhanced tensile strength, longer elongation and improved fatigue resistance. Moreover, NAC exhibits a more hydrophobic surface, which contributes to enhanced hemocompatibility. The study also includes in vivo investigations conducted on animal models to evaluate the biocompatibility and functional efficacy of the artificial chordae. These experiments demonstrate the enhanced durability and biocompatibility of the NAC, characterized by improved mechanical strength, minimal tissue response and reduced thrombus formation. These findings suggest the potential application of NAC as a prosthetic chordae replacement, offering promising prospects to address the limitations associated with current artificial chordae materials and providing novel ideas and approaches for the development of sustainable and biocompatible regenerative biomaterials.
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Affiliation(s)
- Tingchao Zhang
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
- Hangzhou Valgen Medtech Co, Ltd, Hangzhou, 310052, China
| | - Yichen Dou
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
| | - Yang Li
- Hangzhou Valgen Medtech Co, Ltd, Hangzhou, 310052, China
| | - Rifang Luo
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
| | - Li Yang
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
| | - Weiwei Zhang
- Hangzhou Valgen Medtech Co, Ltd, Hangzhou, 310052, China
| | - Yunbing Wang
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
| | - Xingdong Zhang
- National Engineering Research Center for Biomaterials and College of Biomedical Engineering, Sichuan University, Chengdu, 610065, China
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2
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Zhang H, Li X, Qu Z, Zhang W, Wang Q, Cao D, Wang Y, Wang X, Wang Y, Yu L, Ding J. Effects of serum proteins on corrosion rates and product bioabsorbability of biodegradable metals. Regen Biomater 2023; 11:rbad112. [PMID: 38173765 PMCID: PMC10761199 DOI: 10.1093/rb/rbad112] [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: 10/26/2023] [Revised: 12/03/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Corrodible metals are the newest kind of biodegradable materials and raise a new problem of the corrosion products. However, the removal of the precipitated products has been unclear and even largely ignored in publications. Herein, we find that albumin, an abundant macromolecule in serum, enhances the solubility of corrosion products of iron in blood mimetic Hank's solution significantly. This is universal for other main biodegradable metals such as magnesium, zinc and polyester-coated iron. Albumin also influences corrosion rates in diverse trends in Hank's solution and normal saline. Based on quantitative study theoretically and experimentally, both the effects on corrosion rates and soluble fractions are interpreted by a unified mechanism, and the key factor leading to different corrosion behaviors in corrosion media is the interference of albumin to the Ca/P passivation layer on the metal surface. This work has illustrated that the interactions between metals and media macromolecules should be taken into consideration in the design of the next-generation metal-based biodegradable medical devices in the formulism of precision medicine. The improved Hank's solution in the presence of albumin and with a higher content of initial calcium salt is suggested to access biodegradable metals potentially for cardiovascular medical devices, where the content of calcium salt is calculated after consideration of chelating of calcium ions by albumin, resulting in the physiological concentration of free calcium ions.
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Affiliation(s)
- Hongjie Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Xin Li
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Zehua Qu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Wanqian Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Qunsong Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Dinglingge Cao
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yaoben Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Xin Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yang Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Lin Yu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Jiandong Ding
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
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Wang G, Feng Y, Gao C, Zhang X, Wang Q, Zhang J, Zhang H, Wu Y, Li X, Wang L, Fu Y, Yu X, Zhang D, Liu J, Ding J. Biaxial stretching of polytetrafluoroethylene in industrial scale to fabricate medical ePTFE membrane with node-fibril microstructure. Regen Biomater 2023; 10:rbad056. [PMID: 37397871 PMCID: PMC10310521 DOI: 10.1093/rb/rbad056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Expanded polytetrafluoroethylene (ePTFE) is promising in biomedical fields such as covered stents and plastic surgery owing to its excellent biocompatibility and mechanical properties. However, ePTFE material prepared by the traditional biaxial stretching process is with thicker middle and thinner sides due to the bowing effect, which poses a major problem in industrial-scale fabrication. To solve this problem, we design an olive-shaped winding roller to provide the middle part of the ePTFE tape with a greater longitudinal stretching amplitude than the two sides, so as to make up for the excessive longitudinal retraction tendency of the middle part when it is transversely stretched. The as-fabricated ePTFE membrane has, as designed, uniform thickness and node-fibril microstructure. In addition, we examine the effects of mass ratio of lubricant to PTFE powder, biaxial stretching ratio and sintering temperature on the performance of the resultant ePTFE membranes. Particularly, the relation between the internal microstructure of the ePTFE membrane and its mechanical properties is revealed. Besides stable mechanical properties, the sintered ePTFE membrane exhibits satisfactory biological properties. We make a series of biological assessments including in vitro hemolysis, coagulation, bacterial reverse mutation and in vivo thrombosis, intracutaneous reactivity test, pyrogen test and subchronic systemic toxicity test; all of the results meet the relevant international standards. The muscle implantation of the sintered ePTFE membrane into rabbits indicates acceptable inflammatory reactions of our sintered ePTFE membrane fabricated on industrial scale. Such a medical-grade raw material with the unique physical form and condensed-state microstructure is expected to afford an inert biomaterial potentially for stent-graft membrane.
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Affiliation(s)
- Gang Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
- R&D Center, Lifevalve Medical Scientific Co., Ltd., Shenzhen 518057, China
| | - Yusheng Feng
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
| | - Caiyun Gao
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Xu Zhang
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
- R&D Center, Lifevalve Medical Scientific Co., Ltd., Shenzhen 518057, China
| | - Qunsong Wang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Jie Zhang
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
- R&D Center, Lifevalve Medical Scientific Co., Ltd., Shenzhen 518057, China
| | - Hongjie Zhang
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Yongqiang Wu
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
- R&D Center, Lifevalve Medical Scientific Co., Ltd., Shenzhen 518057, China
| | - Xin Li
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Lin Wang
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
- R&D Center, Lifevalve Medical Scientific Co., Ltd., Shenzhen 518057, China
| | - Ye Fu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Xiaoye Yu
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
| | - Deyuan Zhang
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
| | - Jianxiong Liu
- R&D Center, Lifetech Scientific (Shenzhen) Co., Ltd., Shenzhen 518057, China
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Huang C, Shen Y, Zhao Y, Zhang Z, Gao S, Hong J, Xu J, Meng Q, Sun X, Sun J. Sustained release of brimonidine from polydimethylsiloxane-coating silicone rubber implant to reduce intraocular pressure in glaucoma. Regen Biomater 2023; 10:rbad041. [PMID: 37303848 PMCID: PMC10247868 DOI: 10.1093/rb/rbad041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/16/2023] [Accepted: 04/03/2023] [Indexed: 06/13/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness, affecting 111 million people by 2040 worldwide. Intraocular pressure (IOP) is the only controllable risk factor for the disease and current treatment options seek to reduce IOP via daily taking eye drops. However, shortcomings of eye drops, such as poor bioavailability and unsatisfied therapeutic effects, may lead to inadequate patient compliance. In this study, an effective brimonidine (BRI)-loaded silicone rubber (SR) implant coated with polydimethylsiloxane (BRI@SR@PDMS) is designed and fully investigated for IOP reduction treatment. The in vitro BRI release from BRI@SR@PDMS implant reveals a more sustainable trend lasting over 1 month, with a gradually declined immediate drug concentration. The carrier materials show no cytotoxicity on human corneal epithelial cells and mice corneal epithelial cells in vitro. After administrated into rabbit's conjunctival sac, the BRI@SR@PDMS implant releases BRI in a sustained fashion and effectively reduces IOP for 18 days with great biosafety. In contrast, BRI eye drops only maintain IOP-lowering effect for 6 h. Therefore, as a substitute of eye drops, the BRI@SR@PDMS implant can be applied as a promising non-invasive platform to achieve long-term IOP-lowering in patients suffering from ocular hypertension or glaucoma.
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Affiliation(s)
| | | | | | - Zhutian Zhang
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai 200031, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai 200031, China
| | - Shunxiang Gao
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai 200031, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai 200031, China
| | - Jiaxu Hong
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai 200031, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai 200031, China
| | - Jianjiang Xu
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai 200031, China
- Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai 200031, China
| | | | | | - Jianguo Sun
- Correspondence address. (J.S.); (X.S.); (Q.M.)
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Davis R, Singh A, Debnath K, Keshri AK, Soares P, Sopchenski L, Terryn HA, Prakash V. Surface modification of biodegradable Mg alloy by adapting µEDM capabilities with cryogenically-treated tool electrodes. THE INTERNATIONAL JOURNAL, ADVANCED MANUFACTURING TECHNOLOGY 2023; 126:4617-4636. [PMID: 37197058 PMCID: PMC10122982 DOI: 10.1007/s00170-023-11395-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/29/2023] [Indexed: 05/19/2023]
Abstract
Biomaterials are engineered to develop an interaction with living cells for therapeutic and diagnostic purposes. The last decade reported a tremendously rising shift in the requirement for miniaturized biomedical implants exhibiting high precision and comprising various biomaterials such as non-biodegradable titanium (Ti) alloys and biodegradable magnesium (Mg) alloys. The excellent mechanical properties and lightweight characteristics of Mg AZ91D alloy make it an emerging material for biomedical applications. In this regard, micro-electric discharge machining (µEDM) is an excellent method that can be used to make micro-components with high dimensional accuracy. In the present research, attempts were made to improve the µEDM capabilities by using cryogenically-treated copper (CTCTE) and brass tool electrodes (CTBTE) amid machining of biodegradable Mg AZ91D alloy, followed by their comparison with a pair of untreated copper (UCTE) and brass tool electrodes (UBTE) in terms of minimum machining-time and dimensional-irregularity. To investigate the possible modification on the surfaces achieved with minimum machining-time and dimensional-irregularity, the morphology, chemistry, micro-hardness, corrosion resistance, topography, and wettability of these surfaces were further examined. The surface produced by CTCTE exhibited the minimum surface micro-cracks and craters, acceptable recast layer thickness (2.6 µm), 17.45% improved micro-hardness, satisfactory corrosion resistance, adequate surface roughness (Ra: 1.08 µm), and suitable hydrophobic behavior (contact angle: 119°), confirming improved biodegradation rate. Additionally, a comparative analysis among the tool electrodes revealed that cryogenically-treated tool electrodes outperformed the untreated ones. CTCTE-induced modification on the Mg AZ91D alloy surface suggests its suitability in biodegradable medical implant applications.
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Affiliation(s)
- Rahul Davis
- Department of Mechanical Engineering, Vaugh Institute of Agricultural Engineering and Technology, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, 211007 India
| | - Abhishek Singh
- Department of Mechanical Engineering, National Institute of Technology Patna, Patna, 800005 India
| | - Kishore Debnath
- Department of Mechanical Engineering, National Institute of Technology Meghalaya, Shillong, 793003 India
| | - Anup Kumar Keshri
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Patna, Patna, 801106 India
| | - Paulo Soares
- Department of Mechanical Engineering, Pontifícia Universidade Católica Do Paraná, Curitiba, PR 80215-901 Brazil
| | - Luciane Sopchenski
- Department of Materials and Chemistry, Research Group Electrochemical and Surface Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Herman A. Terryn
- Department of Materials and Chemistry, Research Group Electrochemical and Surface Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ved Prakash
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology Patna, Patna, 801106 India
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Li X, Ding J. Establishment of coverage-mass equation to quantify the corrosion inhomogeneity and examination of medium effects on iron corrosion. Regen Biomater 2023; 10:rbad007. [PMID: 36817974 PMCID: PMC9933843 DOI: 10.1093/rb/rbad007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/19/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
Metal corrosion is important in the fields of biomedicine as well as construction and transportation etc. While most corrosion occurs inhomogeneously, there is so far no satisfactory parameter to characterize corrosion inhomogeneity. Herein, we employ the Poisson raindrop question to model the corrosion process and derive an equation to relate corrosion coverage and corrosion mass. The resultant equation is named coverage-mass equation, abbreviated as C-M equation. We also suggest corrosion mass at 50% coverage, termed as half-coverage mass M corro50%, as an inhomogeneity parameter to quantify corrosion inhomogeneity. The equation is confirmed and the half-coverage mass M corro50% is justified in our experiments of iron corrosion in five aqueous media, normal saline, phosphate-buffered saline, Hank's solution, deionized water and artificial seawater, where the former three ones are biomimetic and very important in studies of biomedical materials. The half-coverage mass M corro50% is proved to be more comprehensive and mathematically convergent than the traditional pitting factor. Iron corrosion is detected using visual observation, scanning electron microscopy with a build-in energy dispersive spectrometer, inductive coupled plasma emission spectrometry and electrochemical measurements. Both rates and inhomogeneity extents of iron corrosion are compared among the five aqueous media. The factors underlying the medium effects on corrosion rate and inhomogeneity are discussed and interpreted. Corrosion rates of iron in the five media differ about 7-fold, and half-coverage mass values differ about 300 000-fold. The fastest corrosion and the most significant inhomogeneity occur both in biomimetic media, but not the same one. The new equation (C-M equation) and the new quantity (half-coverage mass) are stimulating for dealing with a dynamic and stochastic process with global inhomogeneity including but not limited to metal corrosion. The findings are particularly meaningful for research and development of next-generation biodegradable materials.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China
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