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McGlumphy S, Damai A, Salameh L, Corbin GB, Wang Q, Markiewicz J, Mosher JJ, Spitzer N, Quiñones R. Biocompatible antibiotic-coupled nickel-titanium nanoparticles as a potential coating material for biomedical devices. Heliyon 2024; 10:e31434. [PMID: 38831845 PMCID: PMC11145499 DOI: 10.1016/j.heliyon.2024.e31434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/04/2024] [Accepted: 05/15/2024] [Indexed: 06/05/2024] Open
Abstract
The challenges facing metallic implants for reconstructive surgery include the leaching of toxic metal ions, a mismatch in elastic modulus between the implant and the treated tissue, and the risk of infection. These problems can be addressed by passivating the metal surface with an organic substrate and incorporating antibiotic molecules. Nitinol (NiTi), a nickel-titanium alloy, is used in devices for biomedical applications due to its shape memory and superelasticity. However, unmodified NiTi carries a risk of localized nickel toxicity and inadequately supports angiogenesis or neuroregeneration due to limited cell adhesion, poor biomineralization, and little antibacterial activity. To address these challenges, NiTi nanoparticles were modified using self-assembled phosphonic acid monolayers and functionalized with the antibiotics ceftriaxone and vancomycin via the formation of an amide. Surface modifications were monitored to confirm that phosphonic acid modifications were present on NiTi nanoparticles and 100% of the samples formed ordered films. Modifications were stable for more than a year. Elemental composition showed the presence of nickel, titanium, and phosphorus (1.9% for each sample) after surface modifications. Dynamic light scattering analysis suggested some agglomeration in solution. However, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed a particle size distribution of <100 nm, the even distribution of nanoparticles on coverslips, and elemental composition before and after cell culture. B35 neuroblastoma cells exhibited no inhibition of survival and extended neurites of approximately 100 μm in total length when cultured on coverslips coated with only poly-l-lysine or with phosphonic acid-modified NiTi, indicating high biocompatibility. The ability to support neural cell growth and differentiation makes modified NiTi nanoparticles a promising coating for surfaces in metallic bone and nerve implants. NiTi nanoparticles functionalized with ceftriaxone inhibited Escherichia coli and Serratia marcescens (SM6) at doses of 375 and 750 μg whereas the growth of Bacillus subtilis was inhibited by a dose of only 37.5 μg. NiTi-vancomycin was effective against B. subtilis at all doses even after mammalian cell culture. These are common bacteria associated with infected implants, further supporting the potential use of functionalized NiTi in coating reconstructive implants.
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Affiliation(s)
- Sarah McGlumphy
- Department of Chemistry, Marshall University, Huntington, WV, 25755, USA
- Department of Biological Sciences, Marshall University, Huntington, WV, 25755, USA
| | - Aakriti Damai
- Department of Chemistry, Marshall University, Huntington, WV, 25755, USA
- Department of Biological Sciences, Marshall University, Huntington, WV, 25755, USA
| | - Lena Salameh
- Department of Chemistry, Marshall University, Huntington, WV, 25755, USA
| | - Gabriell B. Corbin
- Department of Biological Sciences, Marshall University, Huntington, WV, 25755, USA
| | - Qiang Wang
- Shared Research Facilities, West Virginia University, Morgantown, WV, 25606, USA
| | - John Markiewicz
- Department of Chemistry, Marshall University, Huntington, WV, 25755, USA
| | - Jennifer J. Mosher
- Department of Biological Sciences, Marshall University, Huntington, WV, 25755, USA
| | - Nadja Spitzer
- Department of Biological Sciences, Marshall University, Huntington, WV, 25755, USA
| | - Rosalynn Quiñones
- Department of Chemistry, Marshall University, Huntington, WV, 25755, USA
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Stoyanova-Ivanova A, Georgieva M, Petrov V, Andreeva L, Petkov A, Georgiev V. Effects of Clinical Use on the Mechanical Properties of Bio-Active ® (BA) and TriTanium ® (TR) Multiforce Nickel-Titanium Orthodontic Archwires. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16020483. [PMID: 36676221 PMCID: PMC9865704 DOI: 10.3390/ma16020483] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/28/2022] [Accepted: 12/31/2022] [Indexed: 06/01/2023]
Abstract
Multiforce orthodontic archwires are thermodynamic wires made of nickel-titanium alloy (Ni-Ti). They release biologically tolerable forces along their length, progressively increasing from front to back. The frontal archwires' segments distribute the weakest force: the premolar, the greater, and the molar, the greatest. The aim of the present study was to determine the influence of clinical use on the mechanical properties of two types of multi-force orthodontic archwires (TriTanium®, American orthodontics; Bio-Active®, GC) with dimensions of 0.016 × 0.022 inches for periods of up to 8 weeks and over 8 weeks of in-vivo use. A three-point bending test was used, and the data gained is statistically analyzed through a multi-variance comparison Mann-Whitney test. We found that after uses of up to 8 weeks and over 8 weeks, the shape memory effect and superelasticity are preserved, as well as the tendency for differential force release along the length of the archwires is kept.
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Affiliation(s)
- Angelina Stoyanova-Ivanova
- G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria
| | - Mirela Georgieva
- Faculty of Dental Medicine, Medical University of Sofia, St. G. Sofiiski Blvd., 1431 Sofia, Bulgaria
| | - Valeri Petrov
- Faculty of Dental Medicine, Medical University of Sofia, St. G. Sofiiski Blvd., 1431 Sofia, Bulgaria
| | - Laura Andreeva
- Faculty of Dental Medicine, Medical University of Sofia, St. G. Sofiiski Blvd., 1431 Sofia, Bulgaria
| | - Alexander Petkov
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
| | - Velizar Georgiev
- G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee, 1784 Sofia, Bulgaria
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Passias BJ, Verre JJ, McGrath K, DeGenova DT, Taylor BC. The Use of Shape-Memory Alloy Staples (Nitinol) in the Treatment of Pubic Symphyseal Disruptions: Clinical Results and Radiographic Outcomes. J Long Term Eff Med Implants 2022; 33:67-74. [PMID: 36382706 DOI: 10.1615/jlongtermeffmedimplants.2022043658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Nitinol is a shape-memory alloy that has many diverse applications in the field of orthopedics. There have been no previous investigations reporting clinical or radiographic outcomes of the use of nitinol staples in the definitive stabilization of the pubic symphysis. A retrospective chart review was completed on 42 patients who underwent operative stabilization of pubic symphyseal disruption at an urban level-1 trauma center. Patients treated with pelvic staples alone, or in conjunction with traditional plates and screws, were compared with those treated without the use of a shape memory alloys. Thirty-four patients were included for final analysis (8 staples and 26 controls) in this investigation. Three of eight patients in the pelvic staple group had implant failures, with two having a loss of reduction (25%); this was not significantly different from the seven hardware failures (P = 0.61) seen in the control group without any loss of reduction (P = 0.17). Failures in the nitinol staple group occurred earlier at 17.3 days compared with the control group at 101.7 days (P = 0.003). There were no significant differences between groups with regards to any of the other pre- or postoperative variables investigated. The use of nitinol staples vs. traditional plate and screw constructs for stabilizing the pubic symphysis did not result in more clinical failures. The hardware failures identified in the nitinol staple group occurred significantly earlier in the postoperative period, and were associated with a loss of reduction of the pubic symphysis.
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Affiliation(s)
- Braden J Passias
- Department of Orthopedic Surgery, Doctors Hospital OhioHealth, Columbus, OH 43228, USA; Department of Orthopedic Surgery, OhioHealth Grant Medical Center, Columbus, OH 43215, USA
| | - John J Verre
- Department of Orthopedic Surgery, OhioHealth Grant Medical Center, Columbus, OH 43215, USA
| | - Kyle McGrath
- Ohio University Heritage College of Osteopathic Medicine, Athens, OH 45701
| | - Daniel T DeGenova
- Department of Orthopedic Surgery, Doctors Hospital OhioHealth, Columbus, OH 43228, USA
| | - Benjamin C Taylor
- Department of Orthopedic Surgery, OhioHealth Grant Medical Center, Columbus, OH 43215, USA
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A Nonlinear Probabilistic Pitting Corrosion Model of Ni–Ti Alloy Immersed in Shallow Seawater. MICROMACHINES 2022; 13:mi13071031. [PMID: 35888848 PMCID: PMC9323705 DOI: 10.3390/mi13071031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 02/01/2023]
Abstract
The degradation of metal materials in a marine environment represents the consequence of the electrochemical corrosion of metals under the influence of the environment. The application of new materials in the maritime industry requires experimental, real-world research on the form of corrosive damage and the intensity of the corrosion. This paper analyses the pitting corrosion of a rod-shaped nickel–titanium (Ni–Ti) alloy that was produced by means of the continuous casting method. In total, three samples were posted in a real seawater environment and analysed after 6, 12, and 18 months. Pits were detected on the Ni–Ti alloy after 18 months of exposure to the marine environment. The database on pitting corrosion was created by measuring depth in mm, which was performed by means of a nonlinear method, and by the generation of an artificial database of a total of 120, gauged in critical pit areas. The data were obtained by the application of a nonlinear model, and under the assumption that corrosion starts after 12 months of exposure in the corrosive marine environment. The EDX analysis of the Ni–Ti alloy composition inside the pits and on the edges of the pits indicated that the corrosion process in the hole of the pit occurs due to the degradation of the Ni.
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Safavi MS, Bordbar-Khiabani A, Khalil-Allafi J, Mozafari M, Visai L. Additive Manufacturing: An Opportunity for the Fabrication of Near-Net-Shape NiTi Implants. JOURNAL OF MANUFACTURING AND MATERIALS PROCESSING 2022; 6:65. [DOI: 10.3390/jmmp6030065] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Nickel–titanium (NiTi) is a shape-memory alloy, a type of material whose name is derived from its ability to recover its original shape upon heating to a certain temperature. NiTi falls under the umbrella of metallic materials, offering high superelasticity, acceptable corrosion resistance, a relatively low elastic modulus, and desirable biocompatibility. There are several challenges regarding the processing and machinability of NiTi, originating from its high ductility and reactivity. Additive manufacturing (AM), commonly known as 3D printing, is a promising candidate for solving problems in the fabrication of near-net-shape NiTi biomaterials with controlled porosity. Powder-bed fusion and directed energy deposition are AM approaches employed to produce synthetic NiTi implants. A short summary of the principles and the pros and cons of these approaches is provided. The influence of the operating parameters, which can change the microstructural features, including the porosity content and orientation of the crystals, on the mechanical properties is addressed. Surface-modification techniques are recommended for suppressing the Ni ion leaching from the surface of AM-fabricated NiTi, which is a technical challenge faced by the long-term in vivo application of NiTi.
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Affiliation(s)
- Mir Saman Safavi
- Research Center for Advanced Materials, Faculty of Materials Engineering, Sahand University of Technology, Tabriz 51335-1996, Iran
- Molecular Medicine Department (DMM), Center for Health Technologies (CHT), UdR INSTM, University of Pavia, Via Taramelli 3/B, 27100 Pavia, Italy
| | - Aydin Bordbar-Khiabani
- Department of Tissue Engineering and Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 144961-4535, Iran
| | - Jafar Khalil-Allafi
- Research Center for Advanced Materials, Faculty of Materials Engineering, Sahand University of Technology, Tabriz 51335-1996, Iran
| | - Masoud Mozafari
- Department of Tissue Engineering and Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 144961-4535, Iran
| | - Livia Visai
- Molecular Medicine Department (DMM), Center for Health Technologies (CHT), UdR INSTM, University of Pavia, Via Taramelli 3/B, 27100 Pavia, Italy
- Medicina Clinica-Specialistica, UOR5 Laboratorio di Nanotecnologie, ICS Maugeri, IRCCS, 27100 Pavia, Italy
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6
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Pješčić-Šćepanović J, Vastag G, Ivošević Š, Kovač N, Rudolf R. Corrosion of NiTiDiscs in Different Seawater Environments. MATERIALS 2022; 15:ma15082841. [PMID: 35454534 PMCID: PMC9024834 DOI: 10.3390/ma15082841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 03/28/2022] [Accepted: 04/02/2022] [Indexed: 11/21/2022]
Abstract
This paper gives an approach to the corrosion resistance analysis and changes in the chemical composition of anNiTi alloy in the shape of a disc, depending on different real seawater environments. The NiTi discs were analysed after 6 months of exposure in real seawater environments: the atmosphere, a tidal zone, and seawater. The corrosion tests showed that the highest corrosion rate for the discs is in seawater because this had the highest value of current density, and the initial disc had the most negative potential. Measuring the chemical composition of the discs using inductively coupled plasma and X-ray fluorescence before the experiment and semiquantitative analysis after the experiment showed the chemical composition after 6 months of exposure. Furthermore, the applied principal component analysis and cluster analysis revealed the influence of the different environments on the changes in the chemical composition of the discs. Cluster analysis detected small differences between the similar corrosive influences of the analysed types of environments during the period of exposure. The obtained results confirm that PCA can detect subtle quantitative differences among the corrosive influences of the types of marine environments, although the examined corrosive influences are quite similar. The applied chemometric methods (CA and PCA) are, therefore, sensitive enough to register the existence of slight differences among corrosive environmental influences on the analysed NiTi SMA.
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Affiliation(s)
- Jelena Pješčić-Šćepanović
- Faculty of Metallurgy and Technology, University of Montenegro, Dzordza Vasingtona bb, 81000 Podgorica, Montenegro
- Correspondence:
| | - Gyöngyi Vastag
- Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovića 3, 21 000 Novi Sad, Serbia;
| | - Špiro Ivošević
- Faculty of Maritime Studies Kotor, University of Montenegro, Put I Bokeljske Brigade 44, 85330 Kotor, Montenegro;
| | - Nataša Kovač
- Faculty of Applied Sciences, University of Donja Gorica, Oktoih 1, Donja Gorica, 81000 Podgorica, Montenegro;
| | - Rebeka Rudolf
- Faculty of Mechanical Engineering, University of Maribor, Smetanova ul. 17, 2000 Maribor, Slovenia;
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7
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Two-Step Geometry Design Method, Numerical Simulations and Experimental Studies of Bioresorbable Stents. MATERIALS 2022; 15:ma15072385. [PMID: 35407718 PMCID: PMC8999420 DOI: 10.3390/ma15072385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 11/16/2022]
Abstract
The stent-implantation process during angioplasty procedures usually involves clamping the stent onto a catheter to a size that allows delivery to the place inside the artery. Finding the right geometrical form of the stent to ensure good functionality in the open form and to enable the clamping process is one of the key elements in the stent-design process. In the first part of the work, an original two-step procedure for stent-geometry design was proposed. This was due to the necessary selection of a geometry that would provide adequate support to the blood-vessel wall without causing damage to the vessel. Numerical simulations of the crimping and deployment processes were performed to verify the method. At the end of this stage, the optimal stent was selected for further testing. In addition, numerical simulations of selected experimental tests (catheter-crimping process, compression process) were used to verify the obtained geometrical forms. The results of experimental tests on stents produced by the microinjection method are presented. The digital image correlation (DIC) method was used to compare the results of numerical simulation and experimental tests. The two-step modeling approach was found to help select the appropriate geometry of the expanded stent, which is an extremely important step in the design of the crimping process. In the part of the paper where the results obtained by numerical simulation were compared with those gained by experiment and using the DIC method, a good compatibility of the displacement results can be observed. For both longitudinal and transverse (pinch) stent compression, the results practically coincide. The paper presents also the application of the DIC method which significantly expands the research possibilities, allowing for a detailed inspection of the deformation state and, above all, verification of local dangerous areas. This approach significantly increases the possibility of assessing the quality of the stents.
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Kumari G, Abhishek K, Singh S, Hussain A, Altamimi MA, Madhyastha H, Webster TJ, Dev A. A voyage from 3D to 4D printing in nanomedicine and healthcare: part II. Nanomedicine (Lond) 2022; 17:255-270. [PMID: 35109687 DOI: 10.2217/nnm-2021-0454] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Recent advancements in biomedical tissue engineering are gaining wide interest. Implementing biology of living cells and organisms using technological solutions such as incorporating 4D printing and bioprinting for tissue regeneration/tissue repair, organ regeneration, early diagnosis of deadly diseases (particularly cancer, cardiac disorders and tuberculosis) has successfully opened a new generation of biomedical research. The present review primarily addresses the clinical application of 4D printing and bioprinting techniques for applications such as early detection of diseases and drug delivery. Notably, this review continues the discussion from part I regarding published informative data, in vitro and in vivo findings, commercial biosensors for early disease diagnosis, drug delivery and current challenges in 4D printing/bioprinting.
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Affiliation(s)
- Gourvi Kumari
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Kumar Abhishek
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Sneha Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Afzal Hussain
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh, 11451, Saudi Arabia
| | - Mohammad A Altamimi
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh, 11451, Saudi Arabia
| | - Harishkumar Madhyastha
- Department of Cardiovascular Physiology, School of Medicine, University of Miyazaki, Miyazaki, 889 1692, Japan
| | - Thomas J Webster
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| | - Abhimanyu Dev
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
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9
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Kumari G, Abhishek K, Singh S, Hussain A, Altamimi MA, Madhyastha H, Webster TJ, Dev A. A voyage from 3D to 4D printing in nanomedicine and healthcare: part I. Nanomedicine (Lond) 2022; 17:237-253. [PMID: 35109704 DOI: 10.2217/nnm-2021-0285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The transition from 3D to 4D printing has revolutionized various domains of healthcare, pharmaceuticals, design and architecture, and coating processes. The evolution from 3D printing to 4D printing (4DP) has added a fourth dimension as a time-dependent response. This review discusses the significance, demands, various types of smart materials/biomaterials, as well as bioinks and printers used in 4DP technology. This review also provides insights into the limitations of the bioprinting process and bioinks used in various bioprinting technologies and the challenges that come with these limitations. A brief discussion on the future potential of the fundamentals and capabilities of 4D printing is also discussed.
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Affiliation(s)
- Gourvi Kumari
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Kumar Abhishek
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Sneha Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Afzal Hussain
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh, 11451, Saudi Arabia
| | - Mohammad A Altamimi
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh, 11451, Saudi Arabia
| | - Harishkumar Madhyastha
- Department of Cardiovascular Physiology, School of Medicine, University of Miyazaki, Miyazaki, 889 1692, Japan
| | - Thomas J Webster
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA
| | - Abhimanyu Dev
- Department of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
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10
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Multivariate Regression Analysis of the NiTi Alloys’ Surface Corrosion Depending on the Measured Oxygen Value: Tests in Three Different Marine Environments. CRYSTALS 2022. [DOI: 10.3390/cryst12020183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Actual corrosion experiments are based mainly on methodologies that measure the corrosion rate of alloys as a function of the parameters that characterise different external influences and the specific environment in which the alloys are placed. Corrosive processes are viewed as complex stochastic processes described by linear and nonlinear probabilistic models. In contrast to these common ways of analysing corrosive processes, this paper investigates the corrosion process in terms of chemical changes in the alloys’ surface compositions. For this purpose, two NiTi Shape Memory Alloys obtained by different technological production processes were tested, followed by an analysis of the empirical data obtained in a real experiment that included monitoring the corrosion behaviour. Both the analysed alloys were exposed to three different types of marine environment: air, tide, and sea. Data were collected continuously after 6, 12 and 18 months of samples’ exposure to the marine environmental influences. A total of six empirical databases were formed, one for each of the observed NiTi alloys in each of the three observed environments. The empirical databases systematised the data related to the measurements of the surface chemical composition obtained using Energy Dispersive X-Ray (EDX) and Focused Ion Beam (FIB) analyses. Statistical analysis was performed to determine the correlation between the corrosion depth and the percentage of oxygen in the sample surfaces as well as to determine the similarities and differences in the corrosive behaviour of the two observed alloys in different marine environments.
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11
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Medranda GA, Forrestal BJ, Case BC, Waksman R, Bernardo NL. Exploiting the Transformation Temperature to Reform an Infolded Nitinol Self-Expanding Peripheral Stent. J Endovasc Ther 2022; 29:971-974. [PMID: 35018852 DOI: 10.1177/15266028211068758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Nickel-titanium (nitinol) alloys possess a special set of properties that allow for a wide range of applications. Specifically, the transformation temperature for self-expanding nitinol peripheral stents allows for easy crimping at or below room temperature and reformation at body temperature becoming superelastic. CASE REPORT We report the case of an elderly man with iliac stenting 1 month prior, who presented several weeks after recovering from coronavirus disease 2019 with recurrent anterior-wall ST-elevation myocardial infarction. This was complicated by deformation and infolding of the previously implanted nitinol self-expanding stent in his right common iliac artery (CIA). Understanding nitinol's specific properties, we proceeded with rapid injections of iced saline to cool the nitinol stent to its transformation temperature while nudging the distal end of the stent with a partially inflated balloon. This maneuver softened the nitinol stent, allowing us to "unfold" and reappose it against the wall of the right CIA, resulting in successful restoration of the original shape of the nitinol self-expanding stent. CONCLUSION This represents the first reported case describing treatment of an infolded nitinol self-expanding peripheral stent by exploiting the transformation temperature of nitinol using iced cold saline to successfully restore the stent's original shape and structure.
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Affiliation(s)
- Giorgio A Medranda
- Section of Interventional Cardiology, MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC, USA
| | - Brian J Forrestal
- Section of Interventional Cardiology, MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC, USA
| | - Brian C Case
- Section of Interventional Cardiology, MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC, USA
| | - Ron Waksman
- Section of Interventional Cardiology, MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC, USA.,Georgetown University, Washington, DC, USA
| | - Nelson L Bernardo
- Section of Interventional Cardiology, MedStar Heart and Vascular Institute, MedStar Washington Hospital Center, Washington, DC, USA
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Abstract
A very extensive literature review presents the possibilities and needs of using, in endodontics, the alloys commonly known as nitinol. Nitinol, as the most modern group of engineering materials used to develop root canals, is equilibrium nickel and titanium alloys in terms of the elements’ atomic concentration, or very similar. The main audience of this paper is engineers, tool designers and manufacturers, PhD students, and students of materials and manufacturing engineering but this article can also certainly be used by dentists. The paper aims to present a full material science characterization of the structure and properties of nitinol alloys and to discuss all structural phenomena that determine the performance properties of these alloys, including those applied to manufacture the endodontic tools. The paper presents the selection of these alloys’ chemical composition and processing conditions and their importance in the endodontic treatment of teeth. The results of laboratory studies on the analysis of changes during the sterilization of endodontic instruments made of nitinol alloys are also included. The summary of all the literature analyses is an SWOT analysis of strengths, weaknesses, opportunities, and threats, and is a forecast of the development strategy of this material in a specific application such as endodontics.
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13
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A Critical Appraisal of the Use and Properties of Nickel-Titanium Dental Alloys. MATERIALS 2021; 14:ma14247859. [PMID: 34947453 PMCID: PMC8703947 DOI: 10.3390/ma14247859] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/02/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022]
Abstract
Nickel-titanium (NiTi) archwires are used in dentistry for orthodontic treatment. NiTi alloys have favourable mechanical characteristics, such as superelasticity and shape memory, and are also known as a corrosion-resistant alloy. In specific cases, an archwire could be attacked by certain types of corrosion or wear degradation, which can cause the leaching of metal ions and a hypersensitive response due to increased concentrations of Ni in the human body. A systematic search of the literature retrieved 102 relevant studies. The review paper focuses on three main fields: (i) electrochemical properties of NiTi wires and the effect of different environments on the properties of NiTi wires (fluoride and low pH); (ii) tribocorrosion, a combination of chemical and mechanical wear of the material, and (iii) the biocompatibility of NiTi alloy and its subsequent effect on the human body. The review showed that corrosion properties are affected by microstructure, pH of saliva and the presence of fluorides. A high variation in published results should be, therefore, interpreted with care. The release of nickel ions was assessed using the same unit, showing that the vast majority of metal ions were released in the first few days of exposure, then a stable, steady state was reached. In tribocorrosion studies, the increased concentrations of Ni ions were reported.
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Zanza A, D’Angelo M, Reda R, Gambarini G, Testarelli L, Di Nardo D. An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective-An Overview. Bioengineering (Basel) 2021; 8:bioengineering8120218. [PMID: 34940371 PMCID: PMC8698980 DOI: 10.3390/bioengineering8120218] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 12/21/2022] Open
Abstract
Since the introduction of Nickel-Titanium alloy as the material of choice for the manufacturing of endodontic rotary instruments, the success rate of the root canal therapies has been significantly increased. This success mainly arises from the properties of the Nickel-Titanium alloy: the biocompatibility, the superelasticity and the shape memory effect. Those characteristics have led to a reduction in time of endodontic treatments, a simplification of instrumentation procedures and an increase of predictability and effectiveness of endodontic treatments. Nevertheless, the intracanal separation of Nickel-Titanium rotary instruments is still a major concern of endodontists, with a consequent possible reduction in the outcome rate. As thoroughly demonstrated, the two main causes of intracanal separation of endodontic instruments are the cyclic fatigue and the torsional loads. As results, in order to reduce the percentage of intracanal separation research and manufacturers have been focused on the parameters that directly or indirectly influence mechanical properties of endodontic rotary instruments. This review describes the current state of the art regarding the Nickel-Titanium alloy in endodontics, the mechanical behavior of endodontic rotary instruments and the relative stresses acting on them during intracanal instrumentation, highlighting the limitation of the current literature.
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15
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Navickaitė K, Ianniciello L, Tušek J, Engelbrecht K, Bahl CRH, Penzel M, Nestler K, Böttger-Hiller F, Zeidler H. Plasma Electrolytic Polishing of Nitinol: Investigation of Functional Properties. MATERIALS 2021; 14:ma14216450. [PMID: 34771978 PMCID: PMC8585380 DOI: 10.3390/ma14216450] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 11/30/2022]
Abstract
A novel, environmentally friendly, fast, and flexible polishing process for Nitinol parts is presented in this study. Nitinol samples with both superelastic and shape memory properties at room temperature were investigated. The chemical contamination and surface roughness of superelastic Nitinol plates were examined before and after plasma electrolytic polishing. The shift in phase transformation temperature and tensile strength before and after the polishing process were analysed using Nitinol wire with shape memory properties. The obtained experimental results were compared to the data obtained on reference samples examined in the as-received condition. It was found that plasma electrolytic polishing, when the right process parameters are applied, is capable of delivering Nitinol parts with extremely high surface quality. Moreover, it was experimentally proven that plasma electrolytic polishing does not have a negative impact on functionality or mechanical properties of polished parts.
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Affiliation(s)
- Kristina Navickaitė
- Institute for Machine Elements, Engineering Design and Manufacturing, Technical University Bergakademie Freiberg, Chair for Additive Manufacturing, Agricolastrasse 1, 09599 Freiberg, Germany; (M.P.); (H.Z.)
- Beckmann-Institut für Technologieentwicklung e.V., Annaberger Str. 73, 09111 Chemnitz, Germany; (K.N.); (F.B.-H.)
- Correspondence:
| | - Lucia Ianniciello
- Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej, 2800 Kongens Lyngby, Denmark; (L.I.); (K.E.); (C.R.H.B.)
| | - Jaka Tušek
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerceva 6, SI-1000 Ljubljana, Slovenia;
| | - Kurt Engelbrecht
- Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej, 2800 Kongens Lyngby, Denmark; (L.I.); (K.E.); (C.R.H.B.)
| | - Christian R. H. Bahl
- Department of Energy Conversion and Storage, Technical University of Denmark, Anker Engelunds Vej, 2800 Kongens Lyngby, Denmark; (L.I.); (K.E.); (C.R.H.B.)
| | - Michael Penzel
- Institute for Machine Elements, Engineering Design and Manufacturing, Technical University Bergakademie Freiberg, Chair for Additive Manufacturing, Agricolastrasse 1, 09599 Freiberg, Germany; (M.P.); (H.Z.)
- Beckmann-Institut für Technologieentwicklung e.V., Annaberger Str. 73, 09111 Chemnitz, Germany; (K.N.); (F.B.-H.)
| | - Klaus Nestler
- Beckmann-Institut für Technologieentwicklung e.V., Annaberger Str. 73, 09111 Chemnitz, Germany; (K.N.); (F.B.-H.)
| | - Falko Böttger-Hiller
- Beckmann-Institut für Technologieentwicklung e.V., Annaberger Str. 73, 09111 Chemnitz, Germany; (K.N.); (F.B.-H.)
| | - Henning Zeidler
- Institute for Machine Elements, Engineering Design and Manufacturing, Technical University Bergakademie Freiberg, Chair for Additive Manufacturing, Agricolastrasse 1, 09599 Freiberg, Germany; (M.P.); (H.Z.)
- Beckmann-Institut für Technologieentwicklung e.V., Annaberger Str. 73, 09111 Chemnitz, Germany; (K.N.); (F.B.-H.)
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16
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Is Gutta-Percha Still the “Gold Standard” among Filling Materials in Endodontic Treatment? Processes (Basel) 2021. [DOI: 10.3390/pr9081467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The paper is an extensive monographic review of the literature, and also uses the results of the authors’ own experimental research illustrating the noticed developmental tendencies of the filling material based on gutta-percha. The whole body of literature proves the correctness of the research thesis that this material is the best currently that can be used in endodontics. Caries is one of the most common global infectious diseases. Since the dawn of humankind, the consequence of the disease has been the loss of dentition over time through dental extractions. Both tooth caries and tooth loss cause numerous complications and systemic diseases, which have a serious impact on insurance systems and on the well-being, quality, and length of human life. Endodontic treatment, which has been developing since 1836, is an alternative to tooth extraction. Based on an extensive literature review, the methodology of qualifying patients for endodontic treatment was analyzed. The importance of selecting filling material and techniques for the development and obturation of the root canal during endodontic treatment was described. Particular attention was paid to the materials science aspects and the sequence of phase transformations and precipitation processes, as well as the need to ensure the stoichiometric chemical composition of Ni–Ti alloys, and the vacuum metallurgical processes and material processing technologies for the effects of shape memory and superelasticity, which determine the suitability of tools made of this alloy for endodontic purposes. The phenomena accompanying the sterilization of such tools, limiting the relatively small number of times of their use, play an important role. The methods of root canal preparation and obturation methods through cold side condensation and thermoplastic methods, including the most modern of them, the thermo-hydraulic condensation (THC) technique, were analyzed. An important element of the research hypothesis was to prove the assumption that to optimize the technology of development and obturation of root canals, tests of filling effectiveness are identified by the density and size of the gaps between the root canal wall, and the filling methods used and devices appropriate for material research, using mainly microscopy such as light stereoscopic (LSM) and scanning electron (SEM). The most beneficial preparations were obtained by making a longitudinal breakthrough of 48 natural human teeth, extracted for medical reasons, different from caries, with compliance with all ethical principles in this field. The teeth were prepared using various methods and filled with multiple obturation techniques, using a virtual selection of experimental variants. The breakthroughs were made in liquid nitrogen after a one-sided incision with a narrow gap created by a diamond disc using a materialographic cutter. The best effectiveness of the root canal filling was ensured by the technology of preparing the root canals with K3 rotary nitinol tools and filling the teeth with the THC thermoplastic method using the System B and Obtura III devices with studs and pellets of filling material based on gutta-percha after covering the root canal walls with a thin layer of AH Plus sealant. In this way, the research thesis was confirmed.
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17
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Efficiency Analysis of SMA-Based Actuators: Possibilities of Configuration According to the Application. ACTUATORS 2021. [DOI: 10.3390/act10030063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Shape memory alloy (SMA) actuators have recently demonstrated their potential for various applications in fields such as robotics, medicine, aerospace, and automotive. Its features, such as low weight and high force, simplicity, noiseless operation, and low cost compared with other conventional actuator, are only a few advantages of this actuator, which is receiving increasing interest among researchers. However, the use of these actuators is still limited by some of their characteristics: high position error in the cooling stage when the actuator works at frequencies that exceed the necessary cooling time and high electrical energy consumption. Different actuator configurations can help minimize these disadvantages through modifying the length, the number of cables, or the sheath used in the actuator, which modify the characteristics of the complete system. In this work, we developed different configurations of SMA actuators and tested their performance in terms of efficiency and the position error in the cooling stage. The findings demonstrate that over-dimensioned actuators are more energetically efficient and present a faster initial form recovery. The multi-wires actuator configuration produce a better response in terms of position but are less energy efficient. These conclusions allow for the selection of the most appropriate configuration based on the requirements of each particular application.
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18
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A Probabilistic Method for Estimating the Influence of Corrosion on the CuAlNi Shape Memory Alloy in Different Marine Environments. CRYSTALS 2021. [DOI: 10.3390/cryst11030274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper gives an approach to the probabilistic percent corrosion depth estimation model for the CuAlNi Shape Memory Alloy (SMA) in different marine environments. Real testing was performed for validation of the theoretical model, where CuAlNi SMAs were exposed to 6 and 12 months in different seawater environments. Focus Ion Beam (FIB) analysis was used to measure the real corrosion depth on the surfaces of tested samples. A statistical approach to the investigation of the corrosion rate of CuAlNi SMA is given, where the corrosion rate is observed as a continuous random variable described by a linear corrosion model, with the assumption that corrosion starts immediately upon alloy surfaces being exposed to the influences of the marine environment. The three best-fitted two-parameter distributions for estimating the cumulative density function and the probability density function of the random variable were obtained by applying adequate statistical tests. Furthermore, using EDX analyses, we identified the chemical composition of the corroded materials, and with the help of Principal Component Analyses, we determined which corrosion environment had the most dominant influence on the corrosion process. The research results indicated that the changeable environment in the tides had a more heterogenic chemical content, which accelerated the corrosion rate.
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19
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Georgieva M, Stoyanova-Ivanova A, Cherneva S, Petrov V, Petrova V, Andreeva L, Mihailov V, Petkov A, Mikli V. Characterization and comparison of as received and clinically retrieved Bio-active™ orthodontic archwires. BIOTECHNOL BIOTEC EQ 2021. [DOI: 10.1080/13102818.2021.1964381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Affiliation(s)
- Mirela Georgieva
- Department of Orthodontics, Faculty of Dental Medicine, Medical University Sofia, Sofia, Bulgaria
| | - Angelina Stoyanova-Ivanova
- Department of Liquid Crystals and Biomolecular Layers, G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Sabina Cherneva
- Department of Solid Mechanics, Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Valeri Petrov
- Department of Orthodontics, Faculty of Dental Medicine, Medical University Sofia, Sofia, Bulgaria
| | - Violeta Petrova
- Department of Liquid Crystals and Biomolecular Layers, G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Laura Andreeva
- Department of Orthodontics, Faculty of Dental Medicine, Medical University Sofia, Sofia, Bulgaria
| | - Valentin Mihailov
- Department of Liquid Crystals and Biomolecular Layers, G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
- Department of Laser, Atomic, Molecular and Plasma Physics, G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Alexander Petkov
- H. H. Wills Physics Laboratory, Department of Physics, University of Bristol, Bristol, UK
| | - Valdek Mikli
- Department of Material and Environmental Technology, Institute of Materials and Environmental Technology, Tallinn University of Technology, Tallinn, Estonia
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20
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Naumov P, Karothu DP, Ahmed E, Catalano L, Commins P, Mahmoud Halabi J, Al-Handawi MB, Li L. The Rise of the Dynamic Crystals. J Am Chem Soc 2020; 142:13256-13272. [DOI: 10.1021/jacs.0c05440] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Panče Naumov
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
- Radcliffe Institute for Advanced Study, Harvard University, 10 Garden Street, Cambridge, Massachusetts 02138, United States
| | | | - Ejaz Ahmed
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Luca Catalano
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Patrick Commins
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Jad Mahmoud Halabi
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | | | - Liang Li
- New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
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21
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Study on the Mechanical Properties of Bionic Protection and Self-Recovery Structures. MATERIALS 2020; 13:ma13020389. [PMID: 31952129 PMCID: PMC7013465 DOI: 10.3390/ma13020389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 11/19/2022]
Abstract
A novel protective structure, based on shrimp chela structure and the shape of odontodactylus scyllarus, has been shown to improve impact resistance and energy absorption. A finite element model of NiTi alloy with shape memory was constructed based on the basic principles of structural bionics. The protective structure utilizes NiTi alloy as the matrix, a material with many advantages including excellent compression energy absorption, reusability after unloading, and long life. The mechanical properties of the single-layer model were obtained by static crushing experiments and numerical simulations. Building upon the idea of the monolayer bionic structure design, a two-layer structure is also conceived. Both single-layer and double-layer structures have excellent compression energy absorption and self-recovery capabilities. Compared with the single-layer structure, the double-layer structure showed larger compression deformation and exhibited better energy absorption capacity. These results have important academic and practical significance for improving the impact resistance of protective armor. Our study makes it possible to repair automatic rebounds under the action of pressure load and improves the endurance and material utilization rate of other protective structures.
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22
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Experimental validation of adaptive pedicle screws—a novel implant concept using shape memory alloys. Med Biol Eng Comput 2019; 58:55-65. [DOI: 10.1007/s11517-019-02059-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 11/02/2019] [Indexed: 12/28/2022]
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23
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Sensitivity and Uncertainty Analysis of One-Dimensional Tanaka and Liang-Rogers Shape Memory Alloy Constitutive Models. MATERIALS 2019; 12:ma12101687. [PMID: 31137640 PMCID: PMC6566620 DOI: 10.3390/ma12101687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 11/21/2022]
Abstract
A shape memory alloy (SMA) can remember its original shape and recover from strain due to loading once it is exposed to heat (shape memory effect). SMAs also exhibit elastic response to applied stress above the characteristic temperature at which transformation to austenite is completed (pseudoelasticity or superelasticity). Shape memory effect and pseudoelasticity of SMAs have been addressed by several microscopic thermodynamic and macroscopic phenomenological models using different modeling approaches. The Tanaka and Liang-Rogers models are two of the most widely used macroscopic phenomenological constitutive models for describing SMA behavior. In this paper, we performed sensitivity and uncertainty analysis using Sobol and extended Fourier Amplitude Sensitivity Testing (eFAST) methods for the Tanaka and Liang-Rogers models at different operating temperatures and loading conditions. The stress-dependent and average sensitivity indices have been analyzed and are presented for determining the most influential parameters for these models. The results show that variability is primarily caused by a change in operating temperature and loading conditions. Both models appear to be influenced by the uncertainty in elastic modulus of the material significantly. The analyses presented in this paper aim to provide a better insight for designing applications using SMAs by increasing the understanding of these models’ sensitivity to the input parameters and the cause of output variability due to uncertainty in the same input parameters.
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24
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Maleckis K, Anttila E, Aylward P, Poulson W, Desyatova A, MacTaggart J, Kamenskiy A. Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material, Design, and Performance. Ann Biomed Eng 2018; 46:684-704. [PMID: 29470746 DOI: 10.1007/s10439-018-1990-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/31/2018] [Indexed: 12/12/2022]
Abstract
Endovascular stenting has matured into a commonly used treatment for peripheral arterial disease (PAD) due to its minimally invasive nature and associated reductions in short-term morbidity and mortality. The mechanical properties of the superelastic Nitinol alloy have played a major role in the explosion of peripheral artery stenting, with modern stents demonstrating reasonable resilience and durability. Yet in the superficial femoral and popliteal arteries, even the newest generation Nitinol stents continue to demonstrate clinical outcomes that leave significant room for improvement. Restenosis and progression of native arterial disease often lead to recurrence of symptoms and reinterventions that increase morbidity and health care expenditures. One of the main factors thought to be associated with stent failure in the femoropopliteal artery (FPA) is the unique and highly dynamic mechanical environment of the lower limb. Clinical and experimental data demonstrate that the FPA undergoes significant deformations with limb flexion. It is hypothesized that the inability of many existing stent designs to conform to these deformations likely plays a role in reconstruction failure, as repetitive movements of the leg and thigh combine with mechanical mismatch between the artery and the stent and result in mechanical damage to both the artery and the stent. In this review we will identify challenges and provide a mechanical perspective of FPA stenting, and then discuss current research directions with promise to provide a better understanding of Nitinol, specific features of stent design, and improved characterization of the biomechanical environment of the FPA to facilitate development of better stents for patients with PAD.
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Affiliation(s)
- Kaspars Maleckis
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
| | - Eric Anttila
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
| | - Paul Aylward
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
| | - William Poulson
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
| | - Anastasia Desyatova
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA
| | - Jason MacTaggart
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA.
| | - Alexey Kamenskiy
- Department of Surgery, 987690 Nebraska Medical Center, University of Nebraska Medical Center, Omaha, NE, 68198-7690, USA.
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25
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Abstract
Shape memory alloy (SMA) actuators have drawn much attention and interest due to their unique and superior properties, and are expected to be equipped in many modern vehicles at competitive market prices. The key advantage is that SMA actuators do not require bulky and complicated mechanical design to function, where the active element (e.g. SMA wire or spring) can be deformed by applying minimal external force and will retain to their previous form when subjected to certain stimuli such as thermomechanical or magnetic changes. This paper describes the SMA attributes that make them ideally suited as actuators in automotive applications and to address their limitations, feasibilities and prospects.
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26
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Khara HS, Diehl DL, Gross SA. Esophageal stent fracture: case report and review of the literature. World J Gastroenterol 2014; 20:2715-2720. [PMID: 24627608 PMCID: PMC3949281 DOI: 10.3748/wjg.v20.i10.2715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 09/13/2013] [Accepted: 09/29/2013] [Indexed: 02/06/2023] Open
Abstract
Endoscopic esophageal stent placement is widely used in the treatment of a variety of benign and malignant esophageal conditions. Self expanding metal stents (SEMS) are associated with significantly reduced stent related mortality and morbidity compared to plastic stents for treatment of esophageal conditions; however they have known complications of stent migration, stent occlusion, tumor ingrowth, stricture formation, reflux, bleeding and perforation amongst others. A rare and infrequently reported complication of SEMS is stent fracture and subsequent migration of the broken pieces. There have only been a handful of published case reports describing this problem. In this report we describe a case of a spontaneously fractured nitinol esophageal SEMS, and review the available literature on the unusual occurrence of SEMS fracture placed for benign or malignant obstruction in the esophagus. SEMS fracture could be a potentially dangerous event and should be considered in a patient having recurrent dysphagia despite successful placement of an esophageal SEMS. It usually requires endoscopic therapy and may unfortunately require surgery for retrieval of a distally migrated fragment. Early recognition and prompt management may be able to prevent further problems.
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27
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Abstract
Internal fixation has become a pillar of surgical specialties, yet the evolution of these devices has been relatively short. The first known description of medical management of a fracture was found in the Edwin Smith Papyrus of Ancient Egypt (circa 2600 bc). The first description of internal fixation in the medical literature was in the 18th century. The advancement of techniques and technology over the last 150 years has helped to preserve both life and function. The pace of advancement continues to accelerate as surgeons continue to seek new technology for osseous fixation. The authors present a thorough review of the history of internal fixation and the transformation into a multibillion dollar industry.
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28
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Abstract
This review describes recent progresses in the development and applications of smart polymeric gels, especially in the context of biomedical devices. The review has been organized into three separate sections: defining the basis of smart properties in polymeric gels; describing representative stimuli to which these gels respond; and illustrating a sample application area, namely, microfluidics. One of the major limitations in the use of hydrogels in stimuli-responsive applications is the diffusion rate limited transduction of signals. This can be obviated by engineering interconnected pores in the polymer structure to form capillary networks in the matrix and by downscaling the size of hydrogels to significantly decrease diffusion paths. Reducing the lag time in the induction of smart responses can be highly useful in biomedical devices, such as sensors and actuators. This review also describes molecular imprinting techniques to fabricate hydrogels for specific molecular recognition of target analytes. Additionally, it describes the significant advances in bottom-up nanofabrication strategies, involving supramolecular chemistry. Learning to assemble supramolecular structures from nature has led to the rapid prototyping of functional supramolecular devices. In essence, the barriers in the current performance potential of biomedical devices can be lowered or removed by the rapid convergence of interdisciplinary technologies.
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Affiliation(s)
- Somali Chaterji
- Weldon School of Biomedical Engineering Purdue University, 206 S. Intramural Drive, West Lafayette, IN 47907
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