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Sharafkhani N, Long JM, Adams SD, Kouzani AZ. A self-stiffening compliant intracortical microprobe. Biomed Microdevices 2024; 26:17. [PMID: 38345721 PMCID: PMC10861748 DOI: 10.1007/s10544-024-00700-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2024] [Indexed: 02/15/2024]
Abstract
Utilising a flexible intracortical microprobe to record/stimulate neurons minimises the incompatibility between the implanted microprobe and the brain, reducing tissue damage due to the brain micromotion. Applying bio-dissolvable coating materials temporarily makes a flexible microprobe stiff to tolerate the penetration force during insertion. However, the inability to adjust the dissolving time after the microprobe contact with the cerebrospinal fluid may lead to inaccuracy in the microprobe positioning. Furthermore, since the dissolving process is irreversible, any subsequent positioning error cannot be corrected by re-stiffening the microprobe. The purpose of this study is to propose an intracortical microprobe that incorporates two compressible structures to make the microprobe both adaptive to the brain during operation and stiff during insertion. Applying a compressive force by an inserter compresses the two compressible structures completely, resulting in increasing the equivalent elastic modulus. Thus, instant switching between stiff and soft modes can be accomplished as many times as necessary to ensure high-accuracy positioning while causing minimal tissue damage. The equivalent elastic modulus of the microprobe during operation is ≈ 23 kPa, which is ≈ 42% less than the existing counterpart, resulting in ≈ 46% less maximum strain generated on the surrounding tissue under brain longitudinal motion. The self-stiffening microprobe and surrounding neural tissue are simulated during insertion and operation to confirm the efficiency of the design. Two-photon polymerisation technology is utilised to 3D print the proposed microprobe, which is experimentally validated and inserted into a lamb's brain without buckling.
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Affiliation(s)
- Naser Sharafkhani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - John M Long
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Scott D Adams
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - Abbas Z Kouzani
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia.
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Duan Y, Wang S, Yuan Q, Shi Y, Jiang N, Jiang D, Song J, Wang P, Zhuang L. Long-Term Flexible Neural Interface for Synchronous Recording of Cross-Regional Sensory Processing along the Olfactory Pathway. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2205768. [PMID: 37035943 DOI: 10.1002/smll.202205768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 02/04/2023] [Indexed: 06/19/2023]
Abstract
Humans perceive the world through five senses, of which olfaction is the oldest evolutionary sense that enables the detection of chemicals in the external environment. Recent progress in bioinspired electronics has boosted the development of artificial sensory systems. Here, a biohybrid olfactory system is proposed by integrating living mammals with implantable flexible neural electrodes, to employ the outstanding properties of mammalian olfactory system. In olfactory perception, the peripheral organ-olfactory epithelium (OE) projects axons into the olfactory relay station-olfactory bulb (OB). The olfactory information encoded in the neural activity is recorded from both OE and OB simultaneously using flexible neural electrodes. Results reveal that spontaneous slow oscillations (<12 Hz) in both OE and OB closely follow respiration. This respiration-locked rhythm modulates the amplitude of fast oscillations (>20 Hz), which are associated with odor perception. Further, by extracting the characteristics of odor-evoked oscillatory signals, responses of different odors are identified and classified with 80% accuracy. This study demonstrates for the first time that the flexible electrode enables chronic stable electrophysiological recordings of the peripheral and central olfactory system in vivo. Overall, the method provides a novel neural interface for olfactory biosensing and cognitive processing.
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Affiliation(s)
- Yan Duan
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
- The MOE Frontier Science Center for Brain Science and Brain-Machine Integration, Zhejiang University, Hangzhou, 310027, China
| | - Suhao Wang
- Department of Engineering Mechanics, Soft Matter Research Center, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, 310027, China
| | - Qunchen Yuan
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
- Innovation Center for Smart Medical Technologies & Devices, Binjiang Institute of Zhejiang University, Hangzhou, 310027, China
| | - Yingqian Shi
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Nan Jiang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Deming Jiang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
- Innovation Center for Smart Medical Technologies & Devices, Binjiang Institute of Zhejiang University, Hangzhou, 310027, China
| | - Jizhou Song
- Department of Engineering Mechanics, Soft Matter Research Center, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, 310027, China
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, 310027, China
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310012, China
| | - Ping Wang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
- The MOE Frontier Science Center for Brain Science and Brain-Machine Integration, Zhejiang University, Hangzhou, 310027, China
- Innovation Center for Smart Medical Technologies & Devices, Binjiang Institute of Zhejiang University, Hangzhou, 310027, China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050, China
| | - Liujing Zhuang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Education Ministry, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China
- The MOE Frontier Science Center for Brain Science and Brain-Machine Integration, Zhejiang University, Hangzhou, 310027, China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai, 200050, 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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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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Vandekerckhove B, Missinne J, Vonck K, Bauwens P, Verplancke R, Boon P, Raedt R, Vanfleteren J. Technological Challenges in the Development of Optogenetic Closed-Loop Therapy Approaches in Epilepsy and Related Network Disorders of the Brain. MICROMACHINES 2020; 12:38. [PMID: 33396287 PMCID: PMC7824489 DOI: 10.3390/mi12010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 12/25/2022]
Abstract
Epilepsy is a chronic, neurological disorder affecting millions of people every year. The current available pharmacological and surgical treatments are lacking in overall efficacy and cause side-effects like cognitive impairment, depression, tremor, abnormal liver and kidney function. In recent years, the application of optogenetic implants have shown promise to target aberrant neuronal circuits in epilepsy with the advantage of both high spatial and temporal resolution and high cell-specificity, a feature that could tackle both the efficacy and side-effect problems in epilepsy treatment. Optrodes consist of electrodes to record local field potentials and an optical component to modulate neurons via activation of opsin expressed by these neurons. The goal of optogenetics in epilepsy is to interrupt seizure activity in its earliest state, providing a so-called closed-loop therapeutic intervention. The chronic implantation in vivo poses specific demands for the engineering of therapeutic optrodes. Enzymatic degradation and glial encapsulation of implants may compromise long-term recording and sufficient illumination of the opsin-expressing neural tissue. Engineering efforts for optimal optrode design have to be directed towards limitation of the foreign body reaction by reducing the implant's elastic modulus and overall size, while still providing stable long-term recording and large-area illumination, and guaranteeing successful intracerebral implantation. This paper presents an overview of the challenges and recent advances in the field of electrode design, neural-tissue illumination, and neural-probe implantation, with the goal of identifying a suitable candidate to be incorporated in a therapeutic approach for long-term treatment of epilepsy patients.
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Affiliation(s)
- Bram Vandekerckhove
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Jeroen Missinne
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Kristl Vonck
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Pieter Bauwens
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Rik Verplancke
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
| | - Paul Boon
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Robrecht Raedt
- 4Brain Team, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (K.V.); (P.B.); (R.R.)
| | - Jan Vanfleteren
- Center for Microsystems Technology, Imec and Ghent University, 9000 Ghent, Belgium; (B.V.); (J.M.); (P.B.); (R.V.)
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Apollo NV, Murphy B, Prezelski K, Driscoll N, Richardson AG, Lucas TH, Vitale F. Gels, jets, mosquitoes, and magnets: a review of implantation strategies for soft neural probes. J Neural Eng 2020; 17:041002. [PMID: 32759476 PMCID: PMC8152109 DOI: 10.1088/1741-2552/abacd7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Implantable neuroelectronic interfaces have enabled breakthrough advances in the clinical diagnosis and treatment of neurological disorders, as well as in fundamental studies of brain function, behavior, and disease. Intracranial electroencephalography (EEG) mapping with stereo-EEG (sEEG) depth electrodes is routinely adopted for precise epilepsy diagnostics and surgical treatment, while deep brain stimulation has become the standard of care for managing movement disorders. Intracortical microelectrode arrays for high-fidelity recordings of neural spiking activity have led to impressive demonstrations of the power of brain-machine interfaces for motor and sensory functional recovery. Yet, despite the rapid pace of technology development, the issue of establishing a safe, long-term, stable, and functional interface between neuroelectronic devices and the host brain tissue still remains largely unresolved. A body of work spanning at least the last 15 years suggests that safe, chronic integration between invasive electrodes and the brain requires a close match between the mechanical properties of man-made components and the neural tissue. In other words, the next generation of invasive electrodes should be soft and compliant, without sacrificing biological and chemical stability. Soft neuroelectronic interfaces, however, pose a new and significant surgical challenge: bending and buckling during implantation that can preclude accurate and safe device placement. In this topical review, we describe the next generation of soft electrodes and the surgical implantation methods for safe and precise insertion into brain structures. We provide an overview of the most recent innovations in the field of insertion strategies for flexible neural electrodes such as dissolvable or biodegradable carriers, microactuators, biologically-inspired support structures, and electromagnetic drives. In our analysis, we also highlight approaches developed in different fields, such as robotic surgery, which could be potentially adapted and translated to the insertion of flexible neural probes.
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Affiliation(s)
- Nicholas V Apollo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Brendan Murphy
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Kayla Prezelski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
| | - Nicolette Driscoll
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
| | - Andrew G Richardson
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Timothy H Lucas
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
| | - Flavia Vitale
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Center for Neurotrauma, Neurodegeneration, and Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, 19104, United States of America
- These authors contributed equally
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States of America
- Department of Physical Medicine & Rehabilitation, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, United States of America
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Jefferys JGR, Arafat MA, Irazoqui PP, Lovick TA. Brainstem activity, apnea, and death during seizures induced by intrahippocampal kainic acid in anaesthetized rats. Epilepsia 2019; 60:2346-2358. [PMID: 31705531 DOI: 10.1111/epi.16374] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/25/2019] [Accepted: 10/04/2019] [Indexed: 11/30/2022]
Affiliation(s)
- John G. R. Jefferys
- Weldon School of Biomedical Engineering Purdue University West Lafayette IN USA
- Department of Pharmacology Oxford University Oxford UK
| | - Muhammad A. Arafat
- Weldon School of Biomedical Engineering Purdue University West Lafayette IN USA
- Department of Electrical and Computer Engineering Purdue University West Lafayette IN USA
| | - Pedro P. Irazoqui
- Weldon School of Biomedical Engineering Purdue University West Lafayette IN USA
- Department of Electrical and Computer Engineering Purdue University West Lafayette IN USA
| | - Thelma A. Lovick
- Weldon School of Biomedical Engineering Purdue University West Lafayette IN USA
- School of Physiology, Pharmacology and Neuroscience University of Bristol Bristol UK
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