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Sun Y, Xiao Z, Chen B, Zhao Y, Dai J. Advances in Material-Assisted Electromagnetic Neural Stimulation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2400346. [PMID: 38594598 DOI: 10.1002/adma.202400346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 03/26/2024] [Indexed: 04/11/2024]
Abstract
Bioelectricity plays a crucial role in organisms, being closely connected to neural activity and physiological processes. Disruptions in the nervous system can lead to chaotic ionic currents at the injured site, causing disturbances in the local cellular microenvironment, impairing biological pathways, and resulting in a loss of neural functions. Electromagnetic stimulation has the ability to generate internal currents, which can be utilized to counter tissue damage and aid in the restoration of movement in paralyzed limbs. By incorporating implanted materials, electromagnetic stimulation can be targeted more accurately, thereby significantly improving the effectiveness and safety of such interventions. Currently, there have been significant advancements in the development of numerous promising electromagnetic stimulation strategies with diverse materials. This review provides a comprehensive summary of the fundamental theories, neural stimulation modulating materials, material application strategies, and pre-clinical therapeutic effects associated with electromagnetic stimulation for neural repair. It offers a thorough analysis of current techniques that employ materials to enhance electromagnetic stimulation, as well as potential therapeutic strategies for future applications.
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Affiliation(s)
- Yuting Sun
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhifeng Xiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Bing Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yannan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jianwu Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Tianjin Key Laboratory of Biomedical Materials, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
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2
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Akhtar N, Wani AK, Sharma NR, Sanami S, Kaleem S, Machfud M, Purbiati T, Sugiono S, Djumali D, Retnaning Prahardini PE, Purwati RD, Supriadi K, Rahayu F. Microbial exopolysaccharides: Unveiling the pharmacological aspects for therapeutic advancements. Carbohydr Res 2024; 539:109118. [PMID: 38643705 DOI: 10.1016/j.carres.2024.109118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 04/23/2024]
Abstract
Microbial exopolysaccharides (EPSs) have emerged as a fascinating area of research in the field of pharmacology due to their diverse and potent biological activities. This review paper aims to provide a comprehensive overview of the pharmacological properties exhibited by EPSs, shedding light on their potential applications in various therapeutic areas. The review begins by introducing EPSs, exploring their various sources, significance in microbial growth and survival, and their applications across different industries. Subsequently, a thorough examination of the pharmaceutical properties of microbial EPSs unveils their antioxidant, immunomodulatory, antimicrobial, antidepressant, antidiabetic, antiviral, antihyperlipidemic, hepatoprotective, anti-inflammatory, and anticancer activities. Mechanistic insights into how different EPSs exert these therapeutic effects have also been discussed in this review. The review also provides comprehensive information about the monosaccharide composition, backbone, branches, glycosidic bonds, and molecular weight of pharmacologically active EPSs from various microbial sources. Furthermore, the factors that can affect the pharmacological activities of EPSs and approaches to improve the EPSs' pharmacological activity have also been discussed. In conclusion, this review illuminates the immense pharmaceutical promise of microbial EPS as versatile bioactive compounds with wide-ranging therapeutic applications. By elucidating their structural features, biological activities, and potential applications, this review aims to catalyze further research and development efforts in leveraging the pharmaceutical potential of microbial EPS for the advancement of human health and well-being, while also contributing to sustainable and environmentally friendly practices in the pharmaceutical industry.
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Affiliation(s)
- Nahid Akhtar
- School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, (144411), Punjab, India
| | - Atif Khurshid Wani
- School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, (144411), Punjab, India.
| | - Neeta Raj Sharma
- School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, (144411), Punjab, India
| | - Samira Sanami
- Health Promotion Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shaikh Kaleem
- School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, (144411), Punjab, India
| | - Moch Machfud
- Research Center for Estate Crops, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | - Titiek Purbiati
- Research Center for Horticulture, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | - Sugiono Sugiono
- Research Center for Horticulture, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | - Djumali Djumali
- Research Center for Estate Crops, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | | | - Rully Dyah Purwati
- Research Center for Estate Crops, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | - Khojin Supriadi
- Research Center for Food Crops, National Research and Innovation Agency, Bogor, (16911), Indonesia
| | - Farida Rahayu
- Research Center for Genetic Engineering, National Research and Innovation Agency, Bogor, (16911), Indonesia
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3
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Kiran NS, Yashaswini C, Singh S, Prajapati BG. Revisiting microbial exopolysaccharides: a biocompatible and sustainable polymeric material for multifaceted biomedical applications. 3 Biotech 2024; 14:95. [PMID: 38449708 PMCID: PMC10912413 DOI: 10.1007/s13205-024-03946-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 01/28/2024] [Indexed: 03/08/2024] Open
Abstract
Microbial exopolysaccharides (EPS) have gained significant attention as versatile biomolecules with multifarious applications across various sectors. This review explores the valorisation of EPS and its potential impact on diverse sectors, including food, pharmaceuticals, cosmetics, and biotechnology. EPS, secreted by microorganisms, possess unique physicochemical properties, such as high molecular weight, water solubility, and biocompatibility, making them attractive for numerous functional roles. Additionally, EPS exhibit significant bioactivity, contributing to their potential use in pharmaceuticals for drug delivery and tissue engineering applications. Moreover, the eco-friendly and sustainable nature of microbial EPS production aligns with the growing demand for environmentally conscious processes. However, challenges still exist in large-scale production, purification, and regulatory approval for commercial use. Advances in bioprocessing and microbial engineering offer promising solutions to overcome these hurdles. Stringent investigations have concluded EPS as novel sources for sustainable applications that are likely to emerge and develop, further reinforcing the significance of these biopolymers in addressing contemporary societal needs and driving innovation in various industrial sectors. Overall, the microbial EPS represents a thriving field with immense potential for meeting diverse industrial demands and advancing sustainable technologies.
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Affiliation(s)
| | - Chandrashekar Yashaswini
- Department of Biotechnology, School of Applied Sciences, REVA University, Bengaluru, Karnataka India
| | - Sudarshan Singh
- Office of Research Administration, Chiang Mai University, Chiang Mai, Thailand
- Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand
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Wang Y, Yang X, Zhang X, Wang Y, Pei W. Implantable intracortical microelectrodes: reviewing the present with a focus on the future. MICROSYSTEMS & NANOENGINEERING 2023; 9:7. [PMID: 36620394 PMCID: PMC9814492 DOI: 10.1038/s41378-022-00451-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/08/2022] [Accepted: 08/22/2022] [Indexed: 06/17/2023]
Abstract
Implantable intracortical microelectrodes can record a neuron's rapidly changing action potentials (spikes). In vivo neural activity recording methods often have either high temporal or spatial resolution, but not both. There is an increasing need to record more neurons over a longer duration in vivo. However, there remain many challenges to overcome before achieving long-term, stable, high-quality recordings and realizing comprehensive, accurate brain activity analysis. Based on the vision of an idealized implantable microelectrode device, the performance requirements for microelectrodes are divided into four aspects, including recording quality, recording stability, recording throughput, and multifunctionality, which are presented in order of importance. The challenges and current possible solutions for implantable microelectrodes are given from the perspective of each aspect. The current developments in microelectrode technology are analyzed and summarized.
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Affiliation(s)
- Yang Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xinze Yang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiwen Zhang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yijun Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- Chinese Institute for Brain Research, 102206 Beijing, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
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5
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Merken L, Schelles M, Ceyssens F, Kraft M, Janssen P. Thin flexible arrays for long-term multi-electrode recordings in macaque primary visual cortex. J Neural Eng 2022; 19. [PMID: 36215972 DOI: 10.1088/1741-2552/ac98e2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/10/2022] [Indexed: 01/11/2023]
Abstract
Objective.Basic, translational and clinical neuroscience are increasingly focusing on large-scale invasive recordings of neuronal activity. However, in large animals such as nonhuman primates and humans-in which the larger brain size with sulci and gyri imposes additional challenges compared to rodents, there is a huge unmet need to record from hundreds of neurons simultaneously anywhere in the brain for long periods of time. Here, we tested the electrical and mechanical properties of thin, flexible multi-electrode arrays (MEAs) inserted into the primary visual cortex of two macaque monkeys, and assessed their magnetic resonance imaging (MRI) compatibility and their capacity to record extracellular activity over a period of 1 year.Approach.To allow insertion of the floating arrays into the visual cortex, the 20 by 100µm2shafts were temporarily strengthened by means of a resorbable poly(lactic-co-glycolic acid) coating.Main results. After manual insertion of the arrays, theex vivoandin vivoMRI compatibility of the arrays proved to be excellent. We recorded clear single-unit activity from up to 50% of the electrodes, and multi-unit activity (MUA) on 60%-100% of the electrodes, which allowed detailed measurements of the receptive fields and the orientation selectivity of the neurons. Even 1 year after insertion, we obtained significant MUA responses on 70%-100% of the electrodes, while the receptive fields remained remarkably stable over the entire recording period.Significance.Thus, the thin and flexible MEAs we tested offer several crucial advantages compared to existing arrays, most notably in terms of brain tissue compliance, scalability, and brain coverage. Future brain-machine interface applications in humans may strongly benefit from this new generation of chronically implanted MEAs.
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Affiliation(s)
- Lara Merken
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Maarten Schelles
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,ReVision Implant NV, Haasrode 3053, Belgium
| | | | - Michael Kraft
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,Leuven Institute for Micro- and Nanotechnology (LIMNI), Leuven 3000, Belgium
| | - Peter Janssen
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
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Luo J, Xue N, Chen J. A Review: Research Progress of Neural Probes for Brain Research and Brain-Computer Interface. BIOSENSORS 2022; 12:bios12121167. [PMID: 36551135 PMCID: PMC9775442 DOI: 10.3390/bios12121167] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 06/01/2023]
Abstract
Neural probes, as an invasive physiological tool at the mesoscopic scale, can decipher the code of brain connections and communications from the cellular or even molecular level, and realize information fusion between the human body and external machines. In addition to traditional electrodes, two new types of neural probes have been developed in recent years: optoprobes based on optogenetics and magnetrodes that record neural magnetic signals. In this review, we give a comprehensive overview of these three kinds of neural probes. We firstly discuss the development of microelectrodes and strategies for their flexibility, which is mainly represented by the selection of flexible substrates and new electrode materials. Subsequently, the concept of optogenetics is introduced, followed by the review of several novel structures of optoprobes, which are divided into multifunctional optoprobes integrated with microfluidic channels, artifact-free optoprobes, three-dimensional drivable optoprobes, and flexible optoprobes. At last, we introduce the fundamental perspectives of magnetoresistive (MR) sensors and then review the research progress of magnetrodes based on it.
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Affiliation(s)
- Jiahui Luo
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ning Xue
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiamin Chen
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Walton F, Cerezo-Sanchez M, McGlynn E, Das R, Heidari H. Cleanroom strategies for micro- and nano-fabricating flexible implantable neural electronics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20210009. [PMID: 35658678 PMCID: PMC9168450 DOI: 10.1098/rsta.2021.0009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Implantable electronic neural interfaces typically take the form of probes and are made with rigid materials such as silicon and metals. These have advantages such as compatibility with integrated microchips, simple implantation and high-density nanofabrication but tend to be lacking in terms of biointegration, biocompatibility and durability due to their mechanical rigidity. This leads to damage to the device or, more importantly, the brain tissue surrounding the implant. Flexible polymer-based probes offer superior biocompatibility in terms of surface biochemistry and better matched mechanical properties. Research which aims to bring the fabrication of electronics on flexible polymer substrates to the nano-regime is remarkably sparse, despite the push for flexible consumer electronics in the last decade or so. Cleanroom-based nanofabrication techniques such as photolithography have been used as pattern transfer methods by the semiconductor industry to produce single nanometre scale devices and are now also used for making flexible circuit boards. There is still much scope for miniaturizing flexible electronics further using photolithography, bringing the possibility of nanoscale, non-invasive, high-density flexible neural interfacing. This work explores the fabrication challenges of using photolithography and complementary techniques in a cleanroom for producing flexible electronic neural probes with nanometre-scale features. This article is part of the theme issue 'Advanced neurotechnologies: translating innovation for health and well-being'.
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Affiliation(s)
- Finlay Walton
- Microelectronics Lab, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Maria Cerezo-Sanchez
- Microelectronics Lab, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Eve McGlynn
- Microelectronics Lab, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Rupam Das
- Microelectronics Lab, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Hadi Heidari
- Microelectronics Lab, James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
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Wei C, Wang Y, Pei W, Han X, Lin L, Liu Z, Ming G, Chen R, Wu P, Yang X, Zheng L, Wang Y. Distributed implantation of a flexible microelectrode array for neural recording. MICROSYSTEMS & NANOENGINEERING 2022; 8:50. [PMID: 35572780 PMCID: PMC9098495 DOI: 10.1038/s41378-022-00366-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/14/2022] [Accepted: 02/02/2022] [Indexed: 06/15/2023]
Abstract
Flexible multichannel electrode arrays (fMEAs) with multiple filaments can be flexibly implanted in various patterns. It is necessary to develop a method for implanting the fMEA in different locations and at various depths based on the recording demands. This study proposed a strategy for reducing the microelectrode volume with integrated packaging. An implantation system was developed specifically for semiautomatic distributed implantation. The feasibility and convenience of the fMEA and implantation platform were verified in rodents. The acute and chronic recording results provied the effectiveness of the packaging and implantation methods. These methods could provide a novel strategy for developing fMEAs with more filaments and recording sites to measure functional interactions across multiple brain regions.
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Affiliation(s)
- Chunrong Wei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- School of Future Technologies, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yang Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- School of Microelectronics, University of Sciences and Technology of China, 230000 Hefei, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xinyong Han
- Institute of Automation, Chinese Academy of Sciences, 100190 Beijing, China
| | - Longnian Lin
- Key Laboratory of Brain Functional Genomics, East China Normal University, 200062 Shanghai, China
| | - Zhiduo Liu
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Gege Ming
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- School of Future Technologies, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Ruru Chen
- Brain Machine Fusion Intelligence Institute, 215131 Suzhou, China
| | - Pingping Wu
- University of Chinese Academy of Sciences, 100049 Beijing, China
- School of Future Technologies, University of Chinese Academy of Sciences, 100049 Beijing, China
- Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 100190 Beijing, China
| | - Xiaowei Yang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
| | - Li Zheng
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- School of Future Technologies, University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Yijun Wang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, 100083 Beijing, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- Chinese Institute for Brain Research, 102206 Beijing, China
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Research Progress on the Flexibility of an Implantable Neural Microelectrode. MICROMACHINES 2022; 13:mi13030386. [PMID: 35334680 PMCID: PMC8954487 DOI: 10.3390/mi13030386] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/25/2021] [Accepted: 01/16/2022] [Indexed: 12/22/2022]
Abstract
Neural microelectrode is the important bridge of information exchange between the human body and machines. By recording and transmitting nerve signals with electrodes, people can control the external machines. At the same time, using electrodes to electrically stimulate nerve tissue, people with long-term brain diseases will be safely and reliably treated. Young’s modulus of the traditional rigid electrode probe is not matched well with that of biological tissue, and tissue immune rejection is easy to generate, resulting in the electrode not being able to achieve long-term safety and reliable working. In recent years, the choice of flexible materials and design of electrode structures can achieve modulus matching between electrode and biological tissue, and tissue damage is decreased. This review discusses nerve microelectrodes based on flexible electrode materials and substrate materials. Simultaneously, different structural designs of neural microelectrodes are reviewed. However, flexible electrode probes are difficult to implant into the brain. Only with the aid of certain auxiliary devices, can the implant be safe and reliable. The implantation method of the nerve microelectrode is also reviewed.
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Otte E, Vlachos A, Asplund M. Engineering strategies towards overcoming bleeding and glial scar formation around neural probes. Cell Tissue Res 2022; 387:461-477. [PMID: 35029757 PMCID: PMC8975777 DOI: 10.1007/s00441-021-03567-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022]
Abstract
Neural probes are sophisticated electrophysiological tools used for intra-cortical recording and stimulation. These microelectrode arrays, designed to penetrate and interface the brain from within, contribute at the forefront of basic and clinical neuroscience. However, one of the challenges and currently most significant limitations is their ‘seamless’ long-term integration into the surrounding brain tissue. Following implantation, which is typically accompanied by bleeding, the tissue responds with a scarring process, resulting in a gliotic region closest to the probe. This glial scarring is often associated with neuroinflammation, neurodegeneration, and a leaky blood–brain interface (BBI). The engineering progress on minimizing this reaction in the form of improved materials, microfabrication, and surgical techniques is summarized in this review. As research over the past decade has progressed towards a more detailed understanding of the nature of this biological response, it is time to pose the question: Are penetrating probes completely free from glial scarring at all possible?
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11
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Thielen B, Meng E. A comparison of insertion methods for surgical placement of penetrating neural interfaces. J Neural Eng 2021; 18:10.1088/1741-2552/abf6f2. [PMID: 33845469 PMCID: PMC8600966 DOI: 10.1088/1741-2552/abf6f2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/12/2021] [Indexed: 02/07/2023]
Abstract
Many implantable electrode arrays exist for the purpose of stimulating or recording electrical activity in brain, spinal, or peripheral nerve tissue, however most of these devices are constructed from materials that are mechanically rigid. A growing body of evidence suggests that the chronic presence of these rigid probes in the neural tissue causes a significant immune response and glial encapsulation of the probes, which in turn leads to gradual increase in distance between the electrodes and surrounding neurons. In recording electrodes, the consequence is the loss of signal quality and, therefore, the inability to collect electrophysiological recordings long term. In stimulation electrodes, higher current injection is required to achieve a comparable response which can lead to tissue and electrode damage. To minimize the impact of the immune response, flexible neural probes constructed with softer materials have been developed. These flexible probes, however, are often not strong enough to be inserted on their own into the tissue, and instead fail via mechanical buckling of the shank under the force of insertion. Several strategies have been developed to allow the insertion of flexible probes while minimizing tissue damage. It is critical to keep these strategies in mind during probe design in order to ensure successful surgical placement. In this review, existing insertion strategies will be presented and evaluated with respect to surgical difficulty, immune response, ability to reach the target tissue, and overall limitations of the technique. Overall, the majority of these insertion techniques have only been evaluated for the insertion of a single probe and do not quantify the accuracy of probe placement. More work needs to be performed to evaluate and optimize insertion methods for accurate placement of devices and for devices with multiple probes.
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Affiliation(s)
- Brianna Thielen
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
| | - Ellis Meng
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States of America
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12
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Zhang W, Zhou X, He Y, Xu L, Xie J. Implanting mechanics of PEG/DEX coated flexible neural probe: impacts of fabricating methods. Biomed Microdevices 2021; 23:17. [PMID: 33730217 DOI: 10.1007/s10544-021-00552-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2021] [Indexed: 12/15/2022]
Abstract
Resorbable coatings are processed on flexible implants to facilitate penetrations. However, impacts of fabricating methods on implantation damage of coated probes are unclear. Herein, photosensitive polyimide (PSPI) based flexible neural implants are fabricated through clean-room technology. Polyethyleneglycol (PEG) - dexamethasone (DEX) coatings are processed through an improved micro moulding protocol in micro channels, fabricated by computer-numerical-controlled (CNC) micro milling, laser machining, and deep reactive ion etching (DRIE), respectively. An in vitro testing system is developed, using maximum insertion force [Formula: see text] and mean region-of-interest strain [Formula: see text] to accurately evaluate effects of the three fabricating methods on implantation damage at different insertion speed. Rat cerebrum, agarose gel, and silicone rubber are used as brain phantoms for tests. Results show that lower insertion speed, and micro channels fabricated by CNC micro milling or DRIE can minimize implantation damage. The decrease of insertion speed from 2.0 mm/s to 0.5 mm/s reduces [Formula: see text] by 76.2% ~85.1% and [Formula: see text] by 11.6% ~14.7%, respectively. Compared with laser machining, CNC micro milling and DRIE ensure dimensional accuracy of the PEG/DEX coating, reducing [Formula: see text] by 20.2% ~51.4% and [Formula: see text] by 8.0% ~11.6%, respectively. Compared with biological rat cerebrum, [Formula: see text] reduces by 5.8% ~25.1% in agarose gel phantom and increases by 7.7% ~21.0% in silicone rubber phantom, respectively. This study improves processing methods of polymer coatings and reveals mechanical difference between current used abiotic brain phantoms and biological brain tissues. Implantation tests establish quantitative relationship among insertion speed, fabricating methods, and implantation damage.
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Affiliation(s)
- Wenguang Zhang
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Xuhui Zhou
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yuxin He
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Liyue Xu
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Xie
- School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
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Mohd Nadzir M, Nurhayati RW, Idris FN, Nguyen MH. Biomedical Applications of Bacterial Exopolysaccharides: A Review. Polymers (Basel) 2021; 13:530. [PMID: 33578978 PMCID: PMC7916691 DOI: 10.3390/polym13040530] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 01/28/2021] [Accepted: 02/02/2021] [Indexed: 12/11/2022] Open
Abstract
Bacterial exopolysaccharides (EPSs) are an essential group of compounds secreted by bacteria. These versatile EPSs are utilized individually or in combination with different materials for a broad range of biomedical field functions. The various applications can be explained by the vast number of derivatives with useful properties that can be controlled. This review offers insight on the current research trend of nine commonly used EPSs, their biosynthesis pathways, their characteristics, and the biomedical applications of these relevant bioproducts.
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Affiliation(s)
- Masrina Mohd Nadzir
- School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal 14300, Malaysia;
| | - Retno Wahyu Nurhayati
- Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424, Indonesia;
- Stem Cell and Tissue Engineering Research Cluster, Indonesian Medical Education and Research Institute, Faculty of Medicine, Universitas Indonesia, Jl. Salemba Raya No. 6, Jakarta 10430, Indonesia
| | - Farhana Nazira Idris
- School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Nibong Tebal 14300, Malaysia;
| | - Minh Hong Nguyen
- Faculty of Biotechnology, Chemistry and Environmental Engineering, Phenikaa University, Hanoi 12116, Vietnam;
- Bioresource Research Center, Phenikaa University, Hanoi 12116, Vietnam
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14
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Wang X, Weltman Hirschberg A, Xu H, Slingsby-Smith Z, Lecomte A, Scholten K, Song D, Meng E. A Parylene Neural Probe Array for Multi-Region Deep Brain Recordings. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2020; 29:499-513. [PMID: 35663261 PMCID: PMC9164222 DOI: 10.1109/jmems.2020.3000235] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A Parylene C polymer neural probe array with 64 electrodes purposefully positioned across 8 individual shanks to anatomically match specific regions of the hippocampus was designed, fabricated, characterized, and implemented in vivo for enabling recording in deep brain regions in freely moving rats. Thin film polymer arrays were fabricated using surface micromachining techniques and mechanically braced to prevent buckling during surgical implantation. Importantly, the mechanical bracing technique developed in this work involves a novel biodegradable polymer brace that temporarily reduces shank length and consequently, increases its stiffness during implantation, therefore enabling access to deeper brain regions while preserving a low original cross-sectional area of the shanks. The resulting mechanical properties of braced shanks were evaluated at the benchtop. Arrays were then implemented in vivo in freely moving rats, achieving both acute and chronic recordings from the pyramidal cells in the cornu ammonis (CA) 1 and CA3 regions of the hippocampus which are responsible for memory encoding. This work demonstrated the potential for minimally invasive polymer-based neural probe arrays for multi-region recording in deep brain structures.
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Affiliation(s)
- Xuechun Wang
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Huijing Xu
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | | | - Aziliz Lecomte
- Fondazione Istituto Italiano di Technologia, 16163 Genova, Italy
| | - Kee Scholten
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Dong Song
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
| | - Ellis Meng
- Biomedical Engineering and Electrical and Computer Engineering Department, University of Southern California, Los Angeles, CA 90089 USA
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15
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van Daal RJJ, Sun JJ, Ceyssens F, Michon F, Kraft M, Puers R, Kloosterman F. System for recording from multiple flexible polyimide neural probes in freely behaving animals. J Neural Eng 2020; 17:016046. [DOI: 10.1088/1741-2552/ab5e19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Ferguson M, Sharma D, Ross D, Zhao F. A Critical Review of Microelectrode Arrays and Strategies for Improving Neural Interfaces. Adv Healthc Mater 2019; 8:e1900558. [PMID: 31464094 PMCID: PMC6786932 DOI: 10.1002/adhm.201900558] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/25/2019] [Indexed: 12/19/2022]
Abstract
Though neural interface systems (NISs) can provide a potential solution for mitigating the effects of limb loss and central nervous system damage, the microelectrode array (MEA) component of NISs remains a significant limiting factor to their widespread clinical applications. Several strategies can be applied to MEA designs to increase their biocompatibility. Herein, an overview of NISs and their applications is provided, along with a detailed discussion of strategies for alleviating the foreign body response (FBR) and abnormalities seen at the interface of MEAs and the brain tissue following MEA implantation. Various surface modifications, including natural/synthetic surface coatings, hydrogels, and topography alterations, have shown to be highly successful in improving neural cell adhesion, reducing gliosis, and increasing MEA longevity. Different MEA surface geometries, such as those seen in the Utah and Michigan arrays, can help alleviate the resultant FBR by reducing insertion damage, while providing new avenues for improving MEA recording performance and resolution. Increasing overall flexibility of MEAs as well as reducing their stiffness is also shown to reduce MEA induced micromotion along with FBR severity. By combining multiple different properties into a single MEA, the severity and duration of an FBR postimplantation can be reduced substantially.
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Affiliation(s)
- Morgan Ferguson
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Dhavan Sharma
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - David Ross
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
| | - Feng Zhao
- Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931
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Pancrazio JJ, Cogan SF. Editorial for the Special Issue on Neural Electrodes: Design and Applications. MICROMACHINES 2019; 10:E466. [PMID: 31336980 PMCID: PMC6680485 DOI: 10.3390/mi10070466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 07/09/2019] [Indexed: 12/14/2022]
Abstract
Neural electrodes enable the recording and stimulation of bioelectrical activity from the nervous system [...].
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Affiliation(s)
- Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, BSB 13.633, Richardson, TX 75080, USA.
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas, 800 W. Campbell Road, BSB 13.633, Richardson, TX 75080, USA.
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