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Rahman M, Mahady Dip T, Padhye R, Houshyar S. Review on electrically conductive smart nerve guide conduit for peripheral nerve regeneration. J Biomed Mater Res A 2023; 111:1916-1950. [PMID: 37555548 DOI: 10.1002/jbm.a.37595] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 01/29/2023] [Accepted: 07/26/2023] [Indexed: 08/10/2023]
Abstract
At present, peripheral nerve injuries (PNIs) are one of the leading causes of substantial impairment around the globe. Complete recovery of nerve function after an injury is challenging. Currently, autologous nerve grafts are being used as a treatment; however, this has several downsides, for example, donor site morbidity, shortage of donor sites, loss of sensation, inflammation, and neuroma development. The most promising alternative is the development of a nerve guide conduit (NGC) to direct the restoration and renewal of neuronal axons from the proximal to the distal end to facilitate nerve regeneration and maximize sensory and functional recovery. Alternatively, the response of nerve cells to electrical stimulation (ES) has a substantial regenerative effect. The incorporation of electrically conductive biomaterials in the fabrication of smart NGCs facilitates the function of ES throughout the active proliferation state. This article overviews the potency of the various categories of electroactive smart biomaterials, including conductive and piezoelectric nanomaterials, piezoelectric polymers, and organic conductive polymers that researchers have employed latterly to fabricate smart NGCs and their potentiality in future clinical application. It also summarizes a comprehensive analysis of the recent research and advancements in the application of ES in the field of NGC.
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Affiliation(s)
- Mustafijur Rahman
- Center for Materials Innovation and Future Fashion (CMIFF), School of Fashion and Textiles, RMIT University, Brunswick, Australia
- Department of Dyes and Chemical Engineering, Bangladesh University of Textiles, Dhaka, Bangladesh
| | - Tanvir Mahady Dip
- Department of Materials, University of Manchester, Manchester, UK
- Department of Yarn Engineering, Bangladesh University of Textiles, Dhaka, Bangladesh
| | - Rajiv Padhye
- Center for Materials Innovation and Future Fashion (CMIFF), School of Fashion and Textiles, RMIT University, Brunswick, Australia
| | - Shadi Houshyar
- School of Engineering, RMIT University, Melbourne, Victoria, Australia
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Hrncirik F, Roberts I, Sevgili I, Swords C, Bance M. Models of Cochlea Used in Cochlear Implant Research: A Review. Ann Biomed Eng 2023; 51:1390-1407. [PMID: 37087541 PMCID: PMC10264527 DOI: 10.1007/s10439-023-03192-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 03/20/2023] [Indexed: 04/24/2023]
Abstract
As the first clinically translated machine-neural interface, cochlear implants (CI) have demonstrated much success in providing hearing to those with severe to profound hearing loss. Despite their clinical effectiveness, key drawbacks such as hearing damage, partly from insertion forces that arise during implantation, and current spread, which limits focussing ability, prevent wider CI eligibility. In this review, we provide an overview of the anatomical and physical properties of the cochlea as a resource to aid the development of accurate models to improve future CI treatments. We highlight the advancements in the development of various physical, animal, tissue engineering, and computational models of the cochlea and the need for such models, challenges in their use, and a perspective on their future directions.
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Affiliation(s)
- Filip Hrncirik
- Cambridge Hearing Group, Cambridge, UK.
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK.
| | - Iwan Roberts
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Ilkem Sevgili
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Chloe Swords
- Cambridge Hearing Group, Cambridge, UK
- Department of Physiology, Development and Neurosciences, University of Cambridge, Cambridge, CB2 3DY, UK
| | - Manohar Bance
- Cambridge Hearing Group, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
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Yamazaki H, Kohno Y, Kawano S. Oscillation Characteristics of an Artificial Cochlear Sensory Epithelium Optimized for a Micrometer-Scale Curved Structure. MICROMACHINES 2022; 13:mi13050768. [PMID: 35630235 PMCID: PMC9147464 DOI: 10.3390/mi13050768] [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: 04/18/2022] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 02/01/2023]
Abstract
Based on the modern microelectromechanical systems technology, we present a revolutionary miniaturized artificial cochlear sensory epithelium for future implantation tests on guinea pigs. The device was curved to fit the spiral structure of the cochlea and miniaturized to a maximum dimension of <1 mm to be implanted in the cochlea. First, the effect of the curved configuration on the oscillation characteristics of a trapezoidal membrane was evaluated using the relatively larger devices, which had a trapezoidal and a comparable curved shape designed for high-precision in vitro measurements. Both experimental and numerical analyses were used to determine the resonance frequencies and positions, and multiple oscillation modes were clearly observed. Because the maximum oscillation amplitude positions, i.e., the resonance positions, differed depending on the resonance frequencies in both trapezoidal and curved membrane devices, the sound frequency was determined based on the resonance position, thus reproducing the frequency selectivity of the basilar membrane in the organ of Corti. Furthermore, the resonance frequencies and positions of these two devices with different configurations were determined to be quantitatively consistent and similar in terms of mechanical dynamics. This result shows that despite a curved angle of 50−60°, the effect of the curved shape on oscillation characteristics was negligible. Second, the nanometer-scale oscillation of the miniaturized device was successfully measured, and the local resonance frequency in air was varied from 157 to 277 kHz using an experimental system that could measure the amplitude distribution in a two-dimensional (2D) plane with a high accuracy and reproducibility at a high speed. The miniaturized device developed in this study was shown to have frequency selectivity, and when the device was implanted in the cochlea, it was expected to discriminate frequencies in the same manner as the basilar membrane in the biological system. This study established methods for fabricating and evaluating the miniaturized device, and the proposed miniaturized device in a curved shape demonstrated the feasibility of next-generation cochlear implants.
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Yamazaki H, Tsuji T, Doi K, Kawano S. Mathematical model of the auditory nerve response to stimulation by a micro-machined cochlea. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3430. [PMID: 33336933 DOI: 10.1002/cnm.3430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 11/20/2020] [Accepted: 12/13/2020] [Indexed: 06/12/2023]
Abstract
We report a novel mathematical model of an artificial auditory system consisting of a micro-machined cochlea and the auditory nerve response it evokes. The modeled micro-machined cochlea is one previously realized experimentally by mimicking functions of the cochlea [Shintaku et al, Sens. Actuat. 158 (2010) 183-192; Inaoka et al, Proc. Natl. Acad. Sci. USA 108 (2011) 18390-18395]. First, from the viewpoint of mechanical engineering, the frequency characteristics of a model device were experimentally investigated to develop an artificial basilar membrane based on a spring-mass-damper system. In addition, a nonlinear feedback controller mimicking the function of the outer hair cells was incorporated in this experimental system. That is, the developed device reproduces the proportional relationship between the oscillation amplitude of the basilar membrane and the cube root of the sound pressure observed in the mammalian auditory system, which is what enables it to have a wide dynamic range, and the characteristics of the control performance were evaluated numerically and experimentally. Furthermore, the stimulation of the auditory nerve by the micro-machined cochlea was investigated using the present mathematical model, and the simulation results were compared with our previous experimental results from animal testing [Shintaku et al, J. Biomech. Sci. Eng. 8 (2013) 198-208]. The simulation results were found to be in reasonably good agreement with those from the previous animal test; namely, there exists a threshold at which the excitation of the nerve starts and a saturation value for the firing rate under a large input. The proposed numerical model was able to qualitatively reproduce the results of the animal test with the micro-machined cochlea and is thus expected to guide the evaluation of micro-machined cochleae for future animal experiments.
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Affiliation(s)
- Hiroki Yamazaki
- Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Tetsuro Tsuji
- Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Kentaro Doi
- Graduate School of Engineering Science, Osaka University, Osaka, Japan
| | - Satoyuki Kawano
- Graduate School of Engineering Science, Osaka University, Osaka, Japan
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Chung J, Jung Y, Hur S, Kim JH, Kim SJ, Kim WD, Choung YH, Oh SH. Development and Characterization of a Biomimetic Totally Implantable Artificial Basilar Membrane System. Front Bioeng Biotechnol 2021; 9:693849. [PMID: 34336805 PMCID: PMC8324085 DOI: 10.3389/fbioe.2021.693849] [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: 04/12/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
Cochlear implants (CIs) have become the standard treatment for severe-to-profound sensorineural hearing loss. Conventional CIs have some challenges, such as the use of extracorporeal devices, and high power consumption for frequency analysis. To overcome these, artificial basilar membranes (ABMs) made of piezoelectric materials have been studied. This study aimed to verify the conceptual idea of a totally implantable ABM system. A prototype of the totally implantable system composed of the ABM developed in previous research, an electronic module (EM) for the amplification of electrical output from the ABM, and electrode was developed. We investigated the feasibility of the ABM system and obtained meaningful auditory brainstem responses of deafened guinea pigs by implanting the electrode of the ABM system. Also, an optimal method of coupling the ABM system to the human ossicle for transducing sound waves into electrical signals using the middle ear vibration was studied and the electrical signal output according to the sound stimuli was measured successfully. Although the overall power output from the ABM system is still less than the conventional CIs and further improvements to the ABM system are needed, we found a possibility of the developed ABM system as a totally implantable CIs in the future.
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Affiliation(s)
- Juyong Chung
- Department of Otolaryngology, Wonkwang University School of Medicine, Iksan, South Korea
| | - Youngdo Jung
- Department of Nature-Inspired System and Application, Korea Institute of Machinery and Materials, Daejeon, South Korea
| | - Shin Hur
- Department of Nature-Inspired System and Application, Korea Institute of Machinery and Materials, Daejeon, South Korea
| | - Jin Ho Kim
- Nano-Bioelectronics & Systems Laboratory, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Sung June Kim
- Nano-Bioelectronics & Systems Laboratory, Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Wan Doo Kim
- Department of Nature-Inspired System and Application, Korea Institute of Machinery and Materials, Daejeon, South Korea
| | - Yun-Hoon Choung
- Department of Otolaryngology, Ajou University School of Medicine, Suwon, South Korea
| | - Seung-Ha Oh
- Department of Otorhinolaryngology, Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul National University College of Medicine, Seoul, South Korea
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Tong W, An Q, Wang Z, Li Y, Tong Q, Li H, Zhang Y, Zhang Y. Enhanced Electricity Generation and Tunable Preservation in Porous Polymeric Materials via Coupled Piezoelectric and Dielectric Processes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2003087. [PMID: 32844463 DOI: 10.1002/adma.202003087] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/07/2020] [Indexed: 06/11/2023]
Abstract
Biological systems and artificial devices convert omnipresent low-frequency and weak mechanical stimulation into electricity for important functions. However, in-depth understanding of the energy conversion, boosting, and preservation processes of the coupled piezo-dielectric phenomenon in polymeric artificial materials is still lacking. In this study, combined experimental and simulation methods are employed to rationalize the process of energy conversion and preservation via a coupled piezo-dielectric phenomena in composite polymeric films. Both the intensity of the transmembrane electric voltages and the kinetic aspects of the energy generation and preservation process are elucidated. The study indicates that composite films consisting of a conductive filler fraction below the percolation threshold, effectively convert low-frequency mechanical stimulation to preserved electrical energy. Interestingly, film structure engineered into porous film has the ability to break the intertwined high-voltage and exhibits a low-preservation-period relationship; it can simultaneously provide high electric field intensity, high induction velocity, and a long preservation period. The model is not only supported by the experiments but is also consistent with the electricity generation and preservation features of other reported piezo-dielectric films. The systematic understanding can facilitate and inspire new device designs to better address the energy, environmental, and biomedical challenges faced by modern societies.
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Affiliation(s)
- Wangshu Tong
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Qi An
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Zhihao Wang
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Yanan Li
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Qingwei Tong
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Haitao Li
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Yi Zhang
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
| | - Yihe Zhang
- Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral Materials, School of Materials Science and Technology, China University of Geosciences, Beijing, 100083, China
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Yamazaki H, Yamanaka D, Kawano S. A Preliminary Prototype High-Speed Feedback Control of an Artificial Cochlear Sensory Epithelium Mimicking Function of Outer Hair Cells. MICROMACHINES 2020; 11:mi11070644. [PMID: 32610696 PMCID: PMC7407979 DOI: 10.3390/mi11070644] [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: 05/28/2020] [Revised: 06/22/2020] [Accepted: 06/26/2020] [Indexed: 12/20/2022]
Abstract
A novel feedback control technique for the local oscillation amplitude in an artificial cochlear sensory epithelium that mimics the functions of the outer hair cells in the cochlea is successfully developed and can be implemented with a control time on the order of hundreds of milliseconds. The prototype artificial cochlear sensory epithelium was improved from that developed in our previous study to enable the instantaneous determination of the local resonance position based on the electrical output from a bimorph piezoelectric membrane. The device contains local patterned electrodes deposited with micro electro mechanical system (MEMS) technology that is used to detect the electrical output and oscillate the device by applying local electrical stimuli. The main feature of the present feedback control system is the principle that the resonance position is recognized by simultaneously measuring the local electrical outputs of all of the electrodes and comparing their magnitudes, which drastically reduces the feedback control time. In this way, it takes 0.8 s to control the local oscillation of the device, representing the speed of control with the order of one hundred times relative to that in the previous study using the mechanical automatic stage to scan the oscillation amplitude at each electrode. Furthermore, the intrinsic difficulties in the experiment such as the electrical measurement against the electromagnetic noise, adhesion of materials, and fatigue failure mechanism of the oscillation system are also shown and discussed in detail based on the many scientific aspects. The basic knowledge of the MEMS fabrication and the experimental measurement would provide useful suggestions for future research. The proposed preliminary prototype high-speed feedback control can aid in the future development of fully implantable cochlear implants with a wider dynamic range.
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Miki N, Miyazaki K, Morimoto Y. Editorial for the Special Issue of Selected Papers from the 8th Symposium on Micro⁻Nano Science and Technology on Micromachines. MICROMACHINES 2018; 9:E627. [PMID: 30486485 PMCID: PMC6316716 DOI: 10.3390/mi9120627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 11/25/2018] [Indexed: 11/17/2022]
Abstract
The Micro⁻Nano Science and Technology Division of JSME (Japan Society of Mechanical Engineers) promotes academic activities to pioneer novel research topics on microscopic mechanics. [...].
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Affiliation(s)
- Norihisa Miki
- Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan.
| | - Koji Miyazaki
- Department of Mechanical and Control Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu, Fukuoka 804-8550, Japan.
| | - Yuya Morimoto
- Institute of Industrial Science (IIS), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan.
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