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Hiendlmeier L, Zurita F, Vogel J, Del Duca F, Al Boustani G, Peng H, Kopic I, Nikić M, F Teshima T, Wolfrum B. 4D-Printed Soft and Stretchable Self-Folding Cuff Electrodes for Small-Nerve Interfacing. Adv Mater 2023; 35:e2210206. [PMID: 36594106 DOI: 10.1002/adma.202210206] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Peripheral nerve interfacing (PNI) has a high clinical potential for treating various diseases, such as obesity or diabetes. However, currently existing electrodes present challenges to the interfacing procedure, which limit their clinical application, in particular, when targeting small peripheral nerves (<200 µm). To improve the electrode handling and implantation, a nerve interface that can fold itself to a cuff around a small nerve, triggered by the body moisture during insertion, is fabricated. This folding is achieved by printing a bilayer of a flexible polyurethane printing resin and a highly swelling sodium acrylate hydrogel using photopolymerization. When immersed in an aqueous liquid, the hydrogel swells and folds the electrode softly around the nerve. Furthermore, the electrodes are robust, can be stretched (>20%), and bent to facilitate the implantation due to the use of soft and stretchable printing resins as substrates and a microcracked gold film as conductive layer. The straightforward implantation and extraction of the electrode as well as stimulation and recording capabilities on a small peripheral nerve in vivo are demonstrated. It is believed that such simple and robust to use self-folding electrodes will pave the way for bringing PNI to a broader clinical application.
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Affiliation(s)
- Lukas Hiendlmeier
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
| | - Francisco Zurita
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
| | - Jonas Vogel
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
| | - Fulvia Del Duca
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
| | - George Al Boustani
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
| | - Hu Peng
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
| | - Inola Kopic
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
| | - Marta Nikić
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
| | - Tetsuhiko F Teshima
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
| | - Bernhard Wolfrum
- Neuroelectronics, Munich Institute of Biomedical Engineering, School of Computation, Informatics and Technology, Technical University of Munich, Hans-Piloty-Str. 1, 85748, Garching, Germany
- Medical & Health Informatics Laboratories, NTT Research Incorporated, 940 Stewart Dr, Sunnyvale, CA, 94085, USA
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2
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Han L, Wang Y, Wu L, Wu Z, He Y, Mao H, Gu Z. Effects of Chemical Composition on the Shape Memory Property of Poly(dl-lactide- co-trimethylene carbonate) as Self-Morphing Small-Diameter Vascular Scaffolds. ACS Biomater Sci Eng 2023; 9:520-530. [PMID: 36459430 DOI: 10.1021/acsbiomaterials.2c01345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Smart materials have great potential in many biomedical applications, in which biodegradable shape memory polymers (SMPs) can be used as surgical sutures, implants, and stents. Poly(dl-lactide-co-trimethylene carbonate) (PDLLTC) represents one of the promising SMPs and is widely used in biomedical applications. However, the relationship between its shape memory property and chemical structure has not been fully studied and needs further elaboration. In this work, PDLLTC copolymers in different compositions have been synthesized, and their shape memory properties have been investigated. It has been found that the shape memory property is related to the chemical composition and polymeric chain segments. The copolymer with a DLLA/TMC ratio of 75:25 (PDLLTC7525) has been demonstrated with great shape fixation and recovery ratio at human body temperature. Furthermore, PDLLTC7525-based self-morphing small-diameter vascular scaffolds adhered with inner electrospun aligned gelatin/hyaluronic acid (Gel/HA) nanofibers have been constructed, as a merit of its shape memory property. The scaffolds have been demonstrated to facilitate the proliferation and adhesion of endothelial cells on the inner layer. Therefore, PDLLTC with tailorable shape memory properties represents a promising candidate for the development of SMPs, as well as for small-diameter vascular scaffolds construction.
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Affiliation(s)
- Lu Han
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China
| | - Yuqi Wang
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China
| | - Lihuang Wu
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China
| | - Zixiang Wu
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China
| | - Yiyan He
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China.,NJTech-BARTY Joint Research Center for Innovative Medical Technology, Nanjing Tech University, Nanjing210000, P. R. China
| | - Hongli Mao
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China.,NJTech-BARTY Joint Research Center for Innovative Medical Technology, Nanjing Tech University, Nanjing210000, P. R. China
| | - Zhongwei Gu
- Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing211816, P. R. China.,NJTech-BARTY Joint Research Center for Innovative Medical Technology, Nanjing Tech University, Nanjing210000, P. R. China
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3
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Wei J, Qu R, Wang Y, Liu L, Yang J, Xu H, Hu X, Song X. A medicated shape memory composite of grafting tannin/poly(l-lactide). Int J Biol Macromol 2022; 209:1586-1592. [PMID: 35427641 DOI: 10.1016/j.ijbiomac.2022.04.074] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/04/2022] [Accepted: 04/10/2022] [Indexed: 11/05/2022]
Abstract
Establishing drug release from shape memory polymers (SMPs) for biomedical applications will broaden the horizon of SMP applications from commercial medical device to scientific drug delivery system. Therefore, a strategy combining degradable SMP with drug release is put forward. However, there are few reports about the relevance between them so far. In the work, incorporations of three grafting tannins (TA) as switching phase into poly (l-lactide)(PLLA) construct different thermoresponsive SM composites. TA-PCL-COOH/PLLA exhibites good shape fixation (Rf) and recovery rate (Rr) at 55 °C, and its recovery time is 75 s. After loading lipophilic drug, SM capability of medicated TA-PCL-COOH/PLLA enhances, the Rf and Rr are 97.8% and 97.2%, in particular, its recovery time decreases to 32 s. The effect of SM on drug release is explored. After the first round of SM, the drug release accelerates obviously at body temperature; for example, the release amount of drug increases from 46.5% to 66.1% at initial 12 h due to change of microstructure and improvement of wettability. The drug release rate climbs only slightly as the SM round increases.
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Affiliation(s)
- Junge Wei
- School of Chemical Engineering, Changchun University of Technology, China
| | - Rui Qu
- School of Chemical Engineering, Changchun University of Technology, China
| | - Yanhe Wang
- Jiangxi Center of Modern Apparel Engineering and Technology, Jiangxi Institute of Fashion Technology, China
| | - Lei Liu
- School of Chemical Engineering, Changchun University of Technology, China
| | - Jie Yang
- School of Chemical Engineering, Changchun University of Technology, China
| | - Huidi Xu
- School of Chemical Engineering, Changchun University of Technology, China
| | - Xiaohong Hu
- School of Chemical Engineering, Changchun University of Technology, China
| | - Xiaofeng Song
- School of Chemical Engineering, Changchun University of Technology, China.
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Jang D, Thompson CB, Chatterjee S, Korley LT. Engineering bio-inspired peptide-polyurea hybrids with thermo-responsive shape memory behaviour. Mol Syst Des Eng 2021; 6:1003-1015. [PMID: 35096418 PMCID: PMC8797660 DOI: 10.1039/d1me00043h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Inspired by Nature's tunability driven by the modulation of structural organization, we utilize peptide motifs as an approach to tailor not only hierarchical structure, but also thermo-responsive shape memory properties of conventional polymeric materials. Specifically, poly(β-benzyl-L-aspartate)-b-poly(dimethylsiloxane)-b-poly(β-benzyl-L-aspartate) was incorporated as the soft segment in peptide-polyurea hybrids to manipulate hierarchical ordering through peptide secondary structure and a balance of inter- and intra-molecular hydrogen bonding. Employing these bioinspired peptidic polyureas, we investigated the influence of secondary structure on microphase-separated morphology, and shape fixity and recovery via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), small-angle X-ray scattering (SAXS) and dynamic mechanical analysis (DMA). The β-sheet motifs promoted phase mixing through extensive inter-molecular hydrogen bonding between the hard block and peptide segments and provided an increased chain elasticity, resulting in decreased shape fixity compared to a non-peptidic control. In contrast, intra-molecular hydrogen bonding driven by the α-helical arrangements yielded a microphase-separated and hierarchically ordered morphology, leading to an increase in the shape fixing ratio. These results indicate that peptide secondary structure provides a convenient handle for tuning shape memory properties by regulating hydrogen bonding with the surrounding polyurea hard segment, wherein extent of hydrogen bonding and phase mixing between the peptidic block and hard segment dictate the resulting shape memory behaviour. Furthermore, the ability to shift secondary structure as a function of temperature was also demonstrated as a pathway to influence shape memory response. This research highlights that peptide secondary conformation influences the hierarchical ordering and modulates the shape memory response of peptide-polymer hybrids. We anticipate that these findings will enable the design of smart bio-inspired materials with responsive and tailored function via a balance of hydrogen bonding character, structural organization, and mechanics.
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Affiliation(s)
- Daseul Jang
- Department of Materials Science and Engineering, University of Delaware, 127 The Green, 201 Dupont Hall, Newark, DE. USA. 19716
| | - Chase B. Thompson
- Department of Materials Science and Engineering, University of Delaware, 127 The Green, 201 Dupont Hall, Newark, DE. USA. 19716
| | - Sourav Chatterjee
- Department of Materials Science and Engineering, University of Delaware, 127 The Green, 201 Dupont Hall, Newark, DE. USA. 19716
| | - LaShanda T.J. Korley
- Department of Materials Science and Engineering, University of Delaware, 127 The Green, 201 Dupont Hall, Newark, DE. USA. 19716
- Department of Chemical and Biomolecular Engineering, University of Delaware, 151 Academy St. Newark, DE, 19716
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5
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Ouchi S, Niiyama E, Sugo K, Uto K, Takenaka S, Kikuchi A, Ebara M. Shape-memory balloon offering simultaneous thermo/chemotherapies to improve anti-osteosarcoma efficacy. Biomater Sci 2021; 9:6957-6965. [PMID: 34546257 DOI: 10.1039/d1bm00780g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper proposes a shape-memory balloon (SMB) to improve bone cement injection efficiency and postoperative thermo/chemotherapy for bone tumors. The SMB consists of biodegradable poly(ε-caprolactone) (PCL), an anticancer drug (doxorubicin, DOX), and heat-generating magnetic nanoparticles (MNPs). The balloon shape is fabricated in a mold by crosslinking PCL macromonomers with DOX and MNPs. The mechanical properties and shape-transition temperature (approximately 40 °C) of the SMB are modulated by adjusting the molecular weight of PCL and the crosslinking density. This allows safe inflation at the affected site with a 400% expansion rate by simple blow molding. The expanded shape is temporarily memorized at 37 °C, and the computed tomography image shows that the bone cement is successfully injected without extra pressure or leakage. The SMB releases DOX for over 4 weeks, allowing a prolonged effect at the local site. The local dosing is constant as the medication is continuously released, demonstrating an ON-OFF switchable heating/cooling response to alternating magnetic field irradiation. In vitro cytotoxic studies have demonstrated that heat generation/drug release and only drug release from the balloon kill approximately 99% and 60% of human osteosarcoma cells, respectively. The proposed SMB is promising in postoperative local thermo/chemotherapy for bone tumors.
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Affiliation(s)
- Sosuke Ouchi
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), Ibaraki 305-0044, Japan. .,Department of Materials Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Eri Niiyama
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), Ibaraki 305-0044, Japan. .,Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Ken Sugo
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), Ibaraki 305-0044, Japan. .,Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Koichiro Uto
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), Ibaraki 305-0044, Japan.
| | - Satoshi Takenaka
- Department of Orthopaedic Surgery, Osaka International Cancer Institute, Osaka 541-8567, Japan
| | - Akihiko Kikuchi
- Department of Materials Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan
| | - Mitsuhiro Ebara
- Research Center for Functional Materials, National Institute for Materials Science (NIMS), Ibaraki 305-0044, Japan. .,Department of Materials Science and Technology, Tokyo University of Science, Tokyo 125-8585, Japan.,Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
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6
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Sarvari R, Keyhanvar P, Agbolaghi S, Gholami Farashah MS, Sadrhaghighi A, Nouri M, Roshangar L. Shape-memory materials and their clinical applications. INT J POLYM MATER PO 2020. [DOI: 10.1080/00914037.2020.1833010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Raana Sarvari
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Stem Cell And Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Peyman Keyhanvar
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Medical Nanotechnology, School of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
- Convergence of Knowledge, Technology and Society Network (CKTSN), Universal Scientific Education and Research Network (USERN), Tabriz, Iran
- ARTAN110 Startup Accelerator, Tabriz, Iran
| | - Samira Agbolaghi
- Chemical Engineering Department, Faculty of Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
| | | | - Amirhouman Sadrhaghighi
- Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Nouri
- Department of Reproductive Biology, Faculty of Advanced Medical Sciences, University of Medical Sciences, Tabriz, Iran
| | - Laila Roshangar
- Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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7
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Xiao R, Huang WM. Heating/Solvent Responsive Shape-Memory Polymers for Implant Biomedical Devices in Minimally Invasive Surgery: Current Status and Challenge. Macromol Biosci 2020; 20:e2000108. [PMID: 32567193 DOI: 10.1002/mabi.202000108] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/03/2020] [Indexed: 12/16/2022]
Abstract
This review is about the fundamentals and practical issues in applying both heating and solvent responsive shape memory polymers (SMPs) for implant biomedical devices via minimally invasive surgery. After revealing the general requirements in the design of biomedical devices based on SMPs and the fundamentals for the shape-memory effect in SMPs, the underlying mechanisms, characterization methods, and several representative biomedical applications, including vascular stents, tissue scaffolds, occlusion devices, drug delivery systems, and the current R&D status of them, are discussed. The new opportunities arising from emerging technologies, such as 3D printing, and new materials, such as vitrimer, are also highlighted. Finally, the major challenge that limits the practical clinical applications of SMPs at present is addressed.
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Affiliation(s)
- Rui Xiao
- Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China
| | - Wei Min Huang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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Ahn SH, Jeong J, Kim SJ. Emerging Encapsulation Technologies for Long-Term Reliability of Microfabricated Implantable Devices. Micromachines (Basel) 2019; 10:E508. [PMID: 31370259 PMCID: PMC6723304 DOI: 10.3390/mi10080508] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/20/2019] [Accepted: 07/29/2019] [Indexed: 01/11/2023]
Abstract
The development of reliable long-term encapsulation technologies for implantable biomedical devices is of paramount importance for the safe and stable operation of implants in the body over a period of several decades. Conventional technologies based on titanium or ceramic packaging, however, are not suitable for encapsulating microfabricated devices due to their limited scalability, incompatibility with microfabrication processes, and difficulties with miniaturization. A variety of emerging materials have been proposed for encapsulation of microfabricated implants, including thin-film inorganic coatings of Al2O3, HfO2, SiO2, SiC, and diamond, as well as organic polymers of polyimide, parylene, liquid crystal polymer, silicone elastomer, SU-8, and cyclic olefin copolymer. While none of these materials have yet been proven to be as hermetic as conventional metal packages nor widely used in regulatory approved devices for chronic implantation, a number of studies have demonstrated promising outcomes on their long-term encapsulation performance through a multitude of fabrication and testing methodologies. The present review article aims to provide a comprehensive, up-to-date overview of the long-term encapsulation performance of these emerging materials with a specific focus on publications that have quantitatively estimated the lifetime of encapsulation technologies in aqueous environments.
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Affiliation(s)
- Seung-Hee Ahn
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea
| | - Joonsoo Jeong
- Department of Biomedical Engineering, School of Medicine, Pusan National University, Yangsan 50612, Korea.
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
- Institute of Aging, College of Medicine, Seoul National University, Seoul 08826, Korea.
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Kim C, Jeong J, Kim SJ. Recent Progress on Non-Conventional Microfabricated Probes for the Chronic Recording of Cortical Neural Activity. Sensors (Basel) 2019; 19:E1069. [PMID: 30832357 PMCID: PMC6427797 DOI: 10.3390/s19051069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 02/06/2023]
Abstract
Microfabrication technology for cortical interfaces has advanced rapidly over the past few decades for electrophysiological studies and neuroprosthetic devices offering the precise recording and stimulation of neural activity in the cortex. While various cortical microelectrode arrays have been extensively and successfully demonstrated in animal and clinical studies, there remains room for further improvement of the probe structure, materials, and fabrication technology, particularly for high-fidelity recording in chronic implantation. A variety of non-conventional probes featuring unique characteristics in their designs, materials and fabrication methods have been proposed to address the limitations of the conventional standard shank-type ("Utah-" or "Michigan-" type) devices. Such non-conventional probes include multi-sided arrays to avoid shielding and increase recording volumes, mesh- or thread-like arrays for minimized glial scarring and immune response, tube-type or cylindrical probes for three-dimensional (3D) recording and multi-modality, folded arrays for high conformability and 3D recording, self-softening or self-deployable probes for minimized tissue damage and extensions of the recording sites beyond gliosis, nanostructured probes to reduce the immune response, and cone-shaped electrodes for promoting tissue ingrowth and long-term recording stability. Herein, the recent progress with reference to the many different types of non-conventional arrays is reviewed while highlighting the challenges to be addressed and the microfabrication techniques necessary to implement such features.
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Affiliation(s)
- Chaebin Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
| | - Joonsoo Jeong
- Department of Biomedical Engineering, School of Medicine, Pusan National University, Yangsan 50612, Korea.
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
- Institute on Aging, College of Medicine, Seoul National University, Seoul 08826, Korea.
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10
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Chen K, Dreger NZ, Peng F, Vogt BD, Becker ML, Cakmak M. Nonlinear Mechano-Optical Behavior and Strain-Induced Structural Changes of l-Valine-Based Poly(ester urea)s. Macromolecules 2018. [DOI: 10.1021/acs.macromol.8b01176] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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11
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Abstract
Probe techniques for monitoring in vivo chemistry (e.g., electrochemical sensors and microdialysis sampling probes) have significantly contributed to a better understanding of neurotransmission in correlation to behaviors and neurological disorders. Microfabrication allows construction of neural probes with high reproducibility, scalability, design flexibility, and multiplexed features. This technology has translated well into fabricating miniaturized neurochemical probes for electrochemical detection and sampling. Microfabricated electrochemical probes provide a better control of spatial resolution with multisite detection on a single compact platform. This development allows the observation of heterogeneity of neurochemical activity precisely within the brain region. Microfabricated sampling probes are starting to emerge that enable chemical measurements at high spatial resolution and potential for reducing tissue damage. Recent advancement in analytical methods also facilitates neurochemical monitoring at high temporal resolution. Furthermore, a positive feature of microfabricated probes is that they can be feasibly built with other sensing and stimulating platforms including optogenetics. Such integrated probes will empower researchers to precisely elucidate brain function and develop novel treatments for neurological disorders.
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Affiliation(s)
| | - Thomas S. White
- Macromolecular Science and Engineering, University of Michigan, 3003E, NCRC Building 28, 2800 Plymouth Rd., Ann Arbor, MI 48109
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, 930 N. University Ave, Ann Arbor, MI 48109
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109
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Wellman SM, Eles JR, Ludwig KA, Seymour JP, Michelson NJ, McFadden WE, Vazquez AL, Kozai TDY. A Materials Roadmap to Functional Neural Interface Design. Adv Funct Mater 2018; 28:1701269. [PMID: 29805350 PMCID: PMC5963731 DOI: 10.1002/adfm.201701269] [Citation(s) in RCA: 169] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Advancement in neurotechnologies for electrophysiology, neurochemical sensing, neuromodulation, and optogenetics are revolutionizing scientific understanding of the brain while enabling treatments, cures, and preventative measures for a variety of neurological disorders. The grand challenge in neural interface engineering is to seamlessly integrate the interface between neurobiology and engineered technology, to record from and modulate neurons over chronic timescales. However, the biological inflammatory response to implants, neural degeneration, and long-term material stability diminish the quality of interface overtime. Recent advances in functional materials have been aimed at engineering solutions for chronic neural interfaces. Yet, the development and deployment of neural interfaces designed from novel materials have introduced new challenges that have largely avoided being addressed. Many engineering efforts that solely focus on optimizing individual probe design parameters, such as softness or flexibility, downplay critical multi-dimensional interactions between different physical properties of the device that contribute to overall performance and biocompatibility. Moreover, the use of these new materials present substantial new difficulties that must be addressed before regulatory approval for use in human patients will be achievable. In this review, the interdependence of different electrode components are highlighted to demonstrate the current materials-based challenges facing the field of neural interface engineering.
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Affiliation(s)
- Steven M Wellman
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - James R Eles
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Kip A Ludwig
- Department of Neurologic Surgery, 200 First St. SW, Rochester, MN 55905
| | - John P Seymour
- Electrical & Computer Engineering, 1301 Beal Ave., 2227 EECS, Ann Arbor, MI 48109
| | - Nicholas J Michelson
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - William E McFadden
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Alberto L Vazquez
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
| | - Takashi D Y Kozai
- Department of Bioengineering, Center for the Basis of Neural Cognition, McGowan Institute of Regenerative Medicine, NeuroTech Center, University of Pittsburgh Brain Institute, Center for Neuroscience at the University of Pittsburgh, University of Pittsburgh, 208 Center for Biotechnology, 300 Technology Dr., Pittsburgh, PA 15219, United States
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Shoffstall A, Capadona JR. Prospects for a Robust Cortical Recording Interface. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
Shape memory materials have emerged as an important class of materials in medicine due to their ability to change shape in response to a specific stimulus, enabling the simplification of medical procedures, use of minimally invasive techniques, and access to new treatment modalities. Shape memory polymers, in particular, are well suited for such applications given their excellent shape memory performance, tunable materials properties, minimal toxicity, and potential for biodegradation and resorption. This review provides an overview of biodegradable shape memory polymers that have been used in medical applications. The majority of biodegradable shape memory polymers are based on thermally responsive polyesters or polymers that contain hydrolyzable ester linkages. These materials have been targeted for use in applications pertaining to embolization, drug delivery, stents, tissue engineering, and wound closure. The development of biodegradable shape memory polymers with unique properties or responsiveness to novel stimuli has the potential to facilitate the optimization and development of new medical applications.
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Affiliation(s)
- Gregory I. Peterson
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
| | - Andrey V. Dobrynin
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
| | - Matthew L. Becker
- The University of Akron Department of Polymer Science Akron OH 44325‐3909 USA
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Abstract
Emerging neural prosthetics require precise positional tuning and stable interfaces with single neurons for optimal function over a lifetime. In this study, we report an autonomous control to precisely navigate microscale electrodes in soft, viscoelastic brain tissue without visual feedback. The autonomous control optimizes signal-to-noise ratio (SNR) of single neuronal recordings in viscoelastic brain tissue while maintaining quasi-static mechanical stress conditions to improve stability of the implant-tissue interface. Force-displacement curves from microelectrodes in in vivo rodent experiments are used to estimate viscoelastic parameters of the brain. Using a combination of computational models and experiments, we determined an optimal movement for the microelectrodes with bidirectional displacements of 3:2 ratio between forward and backward displacements and a inter-movement interval of 40 s for minimizing mechanical stress in the surrounding brain tissue. A regulator with the above optimal bidirectional motion for the microelectrodes in in vivo experiments resulted in significant reduction in the number of microelectrode movements (0.23 movements/min) and longer periods of stable SNR (53 % of the time) compared to a regulator using a conventional linear, unidirectional microelectrode movement (with 1.48 movements/min and stable SNR 23 % of the time).
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Affiliation(s)
- Sindhu Anand
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA
| | - Swathy Sampath Kumar
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA
| | - Jit Muthuswamy
- Biomedical Engineering, School of Biological and Health Systems Engineering, Arizona State University, ECG 334, P. O. Box 879709, Tempe, AZ, 85287-9709, USA.
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Lee WL, Low HY. Geometry- and Length Scale-Dependent Deformation and Recovery on Micro- and Nanopatterned Shape Memory Polymer Surfaces. Sci Rep 2016; 6:23686. [PMID: 27026290 PMCID: PMC4812242 DOI: 10.1038/srep23686] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/11/2016] [Indexed: 11/09/2022] Open
Abstract
Micro- and nanoscale surface textures, when optimally designed, present a unique approach to improve surface functionalities. Coupling surface texture with shape memory polymers may generate reversibly tuneable surface properties. A shape memory polyetherurethane is used to prepare various surface textures including 2 μm- and 200 nm-gratings, 250 nm-pillars and 200 nm-holes. The mechanical deformation via stretching and recovery of the surface texture are investigated as a function of length scales and shapes. Results show the 200 nm-grating exhibiting more deformation than 2 μm-grating. Grating imparts anisotropic and surface area-to-volume effects, causing different degree of deformation between gratings and pillars under the same applied macroscopic strain. Full distribution of stress within the film causes the holes to deform more substantially than the pillars. In the recovery study, unlike a nearly complete recovery for the gratings after 10 transformation cycles, the high contribution of surface energy impedes the recovery of holes and pillars. The surface textures are shown to perform a switchable wetting function. This study provides insights into how geometric features of shape memory surface patterns can be designed to modulate the shape programming and recovery, and how the control of reversibly deformable surface textures can be applied to transfer microdroplets.
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Affiliation(s)
- Wei Li Lee
- Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Hong Yee Low
- Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
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Lee JH, Kim H, Kim JH, Lee SH. Soft implantable microelectrodes for future medicine: prosthetics, neural signal recording and neuromodulation. Lab Chip 2016; 16:959-76. [PMID: 26891410 DOI: 10.1039/c5lc00842e] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Implantable devices have provided various potential diagnostic options and therapeutic methods in diverse medical fields. A variety of hard-material-based implantable electrodes have been developed. However, several limitations for their chronic implantation remain, including mechanical mismatches at the interface between the electrode and the soft tissue, and biocompatibility. Soft-material-based implantable devices are suitable candidates for complementing the limitations of hard electrodes. Advances in microtechnology and materials science have largely solved many challenges, such as optimization of shape, minimization of infection, enhancement of biocompatibility and integration with components for diverse functions. Significant strides have also been made in mechanical matching of electrodes to soft tissue. In this review, we provide an overview of recent advances in soft-material-based implantable electrodes for medical applications, categorized according to their implantation site and material composition. We then review specific applications in three categories: neuroprosthetics, neural signal recording, and neuromodulation. Finally, we describe various strategies for the future development and application of implantable, soft-material-based devices.
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Affiliation(s)
- Joong Hoon Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea
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Nagaraj V, Lee S, Krook-Magnuson E, Soltesz I, Benquet P, Irazoqui P, Netoff T. Future of seizure prediction and intervention: closing the loop. J Clin Neurophysiol 2015; 32:194-206. [PMID: 26035672 PMCID: PMC4455045 DOI: 10.1097/wnp.0000000000000139] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The ultimate goal of epilepsy therapies is to provide seizure control for all patients while eliminating side effects. Improved specificity of intervention through on-demand approaches may overcome many of the limitations of current intervention strategies. This article reviews the progress in seizure prediction and detection, potential new therapies to provide improved specificity, and devices to achieve these ends. Specifically, we discuss (1) potential signal modalities and algorithms for seizure detection and prediction, (2) closed-loop intervention approaches, and (3) hardware for implementing these algorithms and interventions. Seizure prediction and therapies maximize efficacy, whereas minimizing side effects through improved specificity may represent the future of epilepsy treatments.
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Affiliation(s)
- Vivek Nagaraj
- Graduate Program in Neuroscience, University of Minnesota
| | - Steven Lee
- Weldon School of Biomedical Engineering, Purdue University
| | | | - Ivan Soltesz
- Department of Anatomy & Neurobiology, University of California, Irvine
| | | | - Pedro Irazoqui
- Weldon School of Biomedical Engineering, Purdue University
| | - Theoden Netoff
- Graduate Program in Neuroscience, University of Minnesota
- Department of Biomedical Engineering, University of Minnesota
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Abstract
OBJECTIVE The objective of this research is to characterize the mechanical interactions of (1) soft, compliant and (2) non-compliant implants with the surrounding brain tissue in a rodent brain. Understanding such interactions will enable the engineering of novel materials that will improve stability and reliability of brain implants. APPROACH Acute force measurements were made using a load cell in n = 3 live rats, each with 4 craniotomies. Using an indentation method, brain tissue was tested for changes in force using established protocols. A total of 4 non-compliant, bare silicon microshanks, 3 non-compliant polyvinyl acetate (PVAc)-coated silicon microshanks, and 6 compliant, nanocomposite microshanks were tested. Stress values were calculated by dividing the force by surface area and strain was estimated using a linear stress-strain relationship. Micromotion effects from breathing and vascular pulsatility on tissue stress were estimated from a 5 s interval of steady-state measurements. Viscoelastic properties were estimated using a second-order Prony series expansion of stress-displacement curves for each shank. MAIN RESULTS The distribution of strain values imposed on brain tissue for both compliant nanocomposite microshanks and PVAc-coated, non-compliant silicon microshanks were significantly lower compared to non-compliant bare silicon shanks. Interestingly, step-indentation experiments also showed that compliant, nanocomposite materials significantly decreased stress relaxation rates in the brain tissue at the interface (p < 0.05) compared to non-compliant silicon and PVAc-coated silicon materials. Furthermore, both PVAc-coated non-compliant silicon and compliant nanocomposite shanks showed significantly reduced (by 4-5 fold) stresses due to tissue micromotion at the interface. SIGNIFICANCE The results of this study showed that soft, adaptive materials reduce strains and strain rates and micromotion induced stresses in the surrounding brain tissue. Understanding the material behavior at the site of tissue contact will help to improve neural implant design.
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Affiliation(s)
- Arati Sridharan
- School of Biological & Health Systems Engineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, AZ 85287, USA
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Abstract
Shape-memory polymers (SMPs) are a new class of smart materials, which have the capability to change from a temporary shape 'A' to a memorized permanent shape 'B' upon application of an external stimulus. In recent years, SMPs have attracted much attention from basic and fundamental research to industrial and practical applications due to the cheap and efficient alternative to well-known metallic shape-memory alloys. Since the shape-memory effect in SMPs is not related to a specific material property of single polymers, the control of nanoarchitecture of polymer networks is particularly important for the smart functions of SMPs. Such nanoarchitectonic approaches have enabled us to further create shape-memory surfaces (SMSs) with tunable surface topography at nano scale. The present review aims to bring together the exciting design of SMSs and the ever-expanding range of their uses as tools to control cell functions. The goal for these endeavors is to mimic the surrounding mechanical cues of extracellular environments which have been considered as critical parameters in cell fate determination. The untapped potential of SMSs makes them one of the most exciting interfaces of materials science and cell mechanobiology.
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Affiliation(s)
- Mitsuhiro Ebara
- Biomaterials Unit, International Center for Materials Nanoarchitectonics (WPI-MANA), Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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Abstract
To ensure long-term consistent neural recordings, next-generation intracortical microelectrodes are being developed with an increased emphasis on reducing the neuro-inflammatory response. The increased emphasis stems from the improved understanding of the multifaceted role that inflammation may play in disrupting both biologic and abiologic components of the overall neural interface circuit. To combat neuro-inflammation and improve recording quality, the field is actively progressing from traditional inorganic materials towards approaches that either minimizes the microelectrode footprint or that incorporate compliant materials, bioactive molecules, conducting polymers or nanomaterials. However, the immune-privileged cortical tissue introduces an added complexity compared to other biomedical applications that remains to be fully understood. This review provides a comprehensive reflection on the current understanding of the key failure modes that may impact intracortical microelectrode performance. In addition, a detailed overview of the current status of various materials-based approaches that have gained interest for neural interfacing applications is presented, and key challenges that remain to be overcome are discussed. Finally, we present our vision on the future directions of materials-based treatments to improve intracortical microelectrodes for neural interfacing.
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Affiliation(s)
- Mehdi Jorfi
- Adolphe Merkle Institute, University of Fribourg, Rte de l'Ancienne Papeterie, CH-1723 Marly, Switzerland
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Abstract
The miniaturization and retained full shape-memory functionality with particle switching to different predefined shapes is reported for semi-crystalline multiblock copolymer matrices with all dimensions in the low micrometer-range. A matrix size-induced reduction of crystallinity suggests limitations of functionality in the low nanometer range. Applications as actuators in microdevices or as microcarriers with switchable shapes for modulated biorecognition are suggested.
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Affiliation(s)
- Christian Wischke
- Institute of Biomaterial Science and Berlin-Brandenburg Center for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, 14513 Teltow, Germany
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Lendlein A, Behl M, Hiebl B, Wischke C. Shape-memory polymers as a technology platform for biomedical applications. Expert Rev Med Devices 2014; 7:357-79. [DOI: 10.1586/erd.10.8] [Citation(s) in RCA: 317] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Affiliation(s)
- Hemjyoti Kalita
- Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences; Tezpur University; Tezpur 784028 Assam India
| | - Niranjan Karak
- Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences; Tezpur University; Tezpur 784028 Assam India
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Huang WM, Song CL, Fu YQ, Wang CC, Zhao Y, Purnawali H, Lu HB, Tang C, Ding Z, Zhang JL. Shaping tissue with shape memory materials. Adv Drug Deliv Rev 2013; 65:515-35. [PMID: 22727746 DOI: 10.1016/j.addr.2012.06.004] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 03/30/2012] [Accepted: 06/13/2012] [Indexed: 01/11/2023]
Abstract
After being severely and quasi-plastically deformed, shape memory materials are able to return to their original shape at the presence of the right stimulus. After a brief presentation about the fundamentals, including various shape memory effects, working mechanisms, and typical shape memory materials for biomedical applications, we summarize some major applications in shaping tissue with shape memory materials. The focus is on some most recent development. Outlook is also discussed at the end of this paper.
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Affiliation(s)
- Sarah M. Brosnan
- Department of Chemistry, University of North Carolina at Chapel Hill, 131 South Road, Chapel
Hill, North Carolina 27510-3290, United States
| | - Andrew H. Brown
- Department of Chemistry, University of North Carolina at Chapel Hill, 131 South Road, Chapel
Hill, North Carolina 27510-3290, United States
| | - Valerie Sheares Ashby
- Department of Chemistry, University of North Carolina at Chapel Hill, 131 South Road, Chapel
Hill, North Carolina 27510-3290, United States
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Azra C, Ding Y, Plummer CJ, Månson JAE. Influence of molecular architecture on the isothermal time-dependent response of amorphous shape memory polyurethanes. Eur Polym J 2013. [DOI: 10.1016/j.eurpolymj.2012.10.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Hu J, Zhu Y, Huang H, Lu J. Recent advances in shape–memory polymers: Structure, mechanism, functionality, modeling and applications. Prog Polym Sci 2012; 37:1720-63. [DOI: 10.1016/j.progpolymsci.2012.06.001] [Citation(s) in RCA: 919] [Impact Index Per Article: 76.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Fernandes R, Gracias DH. Self-folding polymeric containers for encapsulation and delivery of drugs. Adv Drug Deliv Rev 2012; 64:1579-89. [PMID: 22425612 DOI: 10.1016/j.addr.2012.02.012] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 02/21/2012] [Accepted: 02/29/2012] [Indexed: 11/29/2022]
Abstract
Self-folding broadly refers to self-assembly processes wherein thin films or interconnected planar templates curve, roll-up or fold into three dimensional (3D) structures such as cylindrical tubes, spirals, corrugated sheets or polyhedra. The process has been demonstrated with metallic, semiconducting and polymeric films and has been used to curve tubes with diameters as small as 2nm and fold polyhedra as small as 100nm, with a surface patterning resolution of 15nm. Self-folding methods are important for drug delivery applications since they provide a means to realize 3D, biocompatible, all-polymeric containers with well-tailored composition, size, shape, wall thickness, porosity, surface patterns and chemistry. Self-folding is also a highly parallel process, and it is possible to encapsulate or self-load therapeutic cargo during assembly. A variety of therapeutic cargos such as small molecules, peptides, proteins, bacteria, fungi and mammalian cells have been encapsulated in self-folded polymeric containers. In this review, we focus on self-folding of all-polymeric containers. We discuss the mechanistic aspects of self-folding of polymeric containers driven by differential stresses or surface tension forces, the applications of self-folding polymers in drug delivery and we outline future challenges.
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Affiliation(s)
- Rohan Fernandes
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
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Lakhera N, Laursen CM, Safranski DL, Frick CP. Biodegradable thermoset shape-memory polymer developed from poly(β-amino ester) networks. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/polb.23059] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Andrei A, Welkenhuysen M, Ameye L, Nuttin B, Eberle W. Chronic behavior evaluation of a micro-machined neural implant with optimized design based on an experimentally derived model. Annu Int Conf IEEE Eng Med Biol Soc 2012; 2011:2292-5. [PMID: 22254799 DOI: 10.1109/iembs.2011.6090577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Understanding the mechanical interactions between implants and the surrounding tissue is known to have an important role for improving the bio-compatibility of such devices. Using a recently developed model, a particular micro-machined neural implant design aiming the reduction of insertion forces dependence on the insertion speed was optimized. Implantations with 10 and 100 μm/s insertion speeds showed excellent agreement with the predicted behavior. Lesion size, gliosis (GFAP), inflammation (ED1) and neuronal cells density (NeuN) was evaluated after 6 week of chronic implantation showing no insertion speed dependence.
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Andrei A, Welkenhuysen M, Nuttin B, Eberle W. A response surface model predicting thein vivoinsertion behavior of micromachined neural implants. J Neural Eng 2011; 9:016005. [DOI: 10.1088/1741-2560/9/1/016005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Welkenhuysen M, Andrei A, Ameye L, Eberle W, Nuttin B. Effect of Insertion Speed on Tissue Response and Insertion Mechanics of a Chronically Implanted Silicon-Based Neural Probe. IEEE Trans Biomed Eng 2011; 58:3250-9. [DOI: 10.1109/tbme.2011.2166963] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wischke C, Neffe AT, Steuer S, Lendlein A. Amorphous Polymer Networks Combining Three Functionalities–Shape-memory, Biodegradability, and Drug Release. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-1190-nn11-34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractShape-memory polymers are of high scientific and technological interest in the biomedical field, e.g., as matrix for self-anchoring implantable devices. In this study, two different star-shaped copolyester tetroles, semi-crystalline oligo[(-caprolactone)-co-glycolide]tetrol (oCG) and amorphous oligo[(rac-lactide)-co-glycolide]tetrol (oLG), were synthesized and subsequently crosslinked by a low molecular weight diisocyanate resulting in copolyester urethane networks (N-CG, N-LG). Both networks could be loaded with model drugs and a diffusion controlled release of the drugs was observed without any effect on the mass loss as measure of hydrolytic degradation. However, the N-CG network’s capability of shape programming was disturbed as the crystallinity of the precursors got lost in the complex three dimensional architecture after crosslinking. By contrast, amorphous N-LG network showed an excellent shape-memory capability with a switching temperature around 36 °C corresponding to their glass transition temperature. This led to triple-functional materials combining biodegradability, shape-memory, and controlled drug release.
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Wischke C, Neffe AT, Steuer S, Lendlein A. Comparing techniques for drug loading of shape-memory polymer networks – effect on their functionalities. Eur J Pharm Sci 2010; 41:136-47. [DOI: 10.1016/j.ejps.2010.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 06/02/2010] [Indexed: 10/19/2022]
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Wischke C, Neffe AT, Steuer S, Engelhardt E, Lendlein A. AB-polymer Networks with Cooligoester and Poly(n
-butyl acrylate) Segments as a Multifunctional Matrix for Controlled Drug Release. Macromol Biosci 2010; 10:1063-72. [DOI: 10.1002/mabi.201000089] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Shape memory polymers (SMPs) are smart materials that can remember a primary shape and can return to this primary shape from a deformed secondary shape when given an appropriate stimulus. This property allows them to be delivered in a compact form via minimally invasive surgeries in humans, and deployed to achieve complex final shapes. Here we review the various biomedical applications of SMPs and the challenges they face with respect to actuation and biocompatibility. While shape memory behavior has been demonstrated with heat, light and chemical environment, here we focus our discussion on thermally stimulated SMPs.
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Affiliation(s)
- Ward Small
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Pooja Singhal
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
| | - Thomas S. Wilson
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Duncan J. Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
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Jaroch DB, Ward MP, Chow EY, Rickus JL, Irazoqui PP. Magnetic insertion system for flexible electrode implantation. J Neurosci Methods 2009; 183:213-22. [DOI: 10.1016/j.jneumeth.2009.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Revised: 06/29/2009] [Accepted: 07/01/2009] [Indexed: 11/18/2022]
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Sharp AA, Ortega AM, Restrepo D, Curran-Everett D, Gall K. In vivo penetration mechanics and mechanical properties of mouse brain tissue at micrometer scales. IEEE Trans Biomed Eng 2009; 56:45-53. [PMID: 19224718 DOI: 10.1109/tbme.2008.2003261] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Substantial advancement in the understanding of the neuronal basis of behavior and the treatment of neurological disorders has been achieved via the implantation of various devices into the brain. To design and optimize the next generation of neuronal implants while striving to minimize tissue damage, it is necessary to understand the mechanics of probe insertion at relevant length scales. Unfortunately, a broad-based understanding of brain-implant interactions at the necessary micrometer scales is largely missing. This paper presents a generalizable description of the micrometer-scale penetration mechanics and material properties of mouse brain tissue in vivo. Cylindrical stainless steel probes were inserted into the cerebral cortex and olfactory bulb of mice. The effects of probe size, probe geometry, insertion rate, insertion location, animal age, and the presence of the dura and pia on the resulting forces were measured continuously throughout probe insertion and removal. Material properties (modulus, cutting force, and frictional force) were extracted using mechanical analysis. The use of rigid, incompressible, cylindrical probes allows for a general understanding of how probe design and insertion methods influence the penetration mechanics of brain tissue in vivo that can be applied to the quantitative design of most future implantable devices.
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Affiliation(s)
- Andrew A Sharp
- Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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Wischke C, Neffe AT, Steuer S, Lendlein A. Evaluation of a degradable shape-memory polymer network as matrix for controlled drug release. J Control Release 2009; 138:243-50. [DOI: 10.1016/j.jconrel.2009.05.027] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 05/11/2009] [Accepted: 05/21/2009] [Indexed: 11/15/2022]
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Murday JS, Siegel RW, Stein J, Wright JF. Translational nanomedicine: status assessment and opportunities. Nanomedicine 2009; 5:251-73. [PMID: 19540359 DOI: 10.1016/j.nano.2009.06.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 06/07/2009] [Indexed: 10/20/2022]
Abstract
UNLABELLED Nano-enabled technologies hold great promise for medicine and health. The rapid progress by the physical sciences/engineering communities in synthesizing nanostructures and characterizing their properties must be rapidly exploited in medicine and health toward reducing mortality rate, morbidity an illness imposes on a patient, disease prevalence, and general societal burden. A National Science Foundation-funded workshop, "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience," was held 16-19 March 2008 at the University of Southern California. Based on that workshop and literature review, this article briefly explores scientific, economic, and societal drivers for nanomedicine initiatives; examines the science, engineering, and medical research needs; succinctly reviews the US federal investment directly germane to medicine and health, with brief mention of the European Union (EU) effort; and presents recommendations to accelerate the translation of nano-enabled technologies from laboratory discovery into clinical practice. FROM THE CLINICAL EDITOR An excellent review paper based on the NSF funded workshop "Re-Engineering Basic and Clinical Research to Catalyze Translational Nanoscience" (16-19 March 2008) and extensive literature search, this paper briefly explores the current state and future perspectives of nanomedicine.
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Affiliation(s)
- James S Murday
- University of Southern California, Washington, DC 20004 USA.
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Safranski DL, Gall K. Effect of chemical structure and crosslinking density on the thermo-mechanical properties and toughness of (meth)acrylate shape memory polymer networks. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.07.060] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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