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Sander MY, Zhu X. Infrared neuromodulation-a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:066701. [PMID: 38701769 DOI: 10.1088/1361-6633/ad4729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 05/03/2024] [Indexed: 05/05/2024]
Abstract
Infrared (IR) neuromodulation (INM) is an emerging light-based neuromodulation approach that can reversibly control neuronal and muscular activities through the transient and localized deposition of pulsed IR light without requiring any chemical or genetic pre-treatment of the target cells. Though the efficacy and short-term safety of INM have been widely demonstrated in both peripheral and central nervous systems, the investigations of the detailed cellular and biological processes and the underlying biophysical mechanisms are still ongoing. In this review, we discuss the current research progress in the INM field with a focus on the more recently discovered IR nerve inhibition. Major biophysical mechanisms associated with IR nerve stimulation are summarized. As the INM effects are primarily attributed to the spatiotemporal thermal transients induced by water and tissue absorption of pulsed IR light, temperature monitoring techniques and simulation models adopted in INM studies are discussed. Potential translational applications, current limitations, and challenges of the field are elucidated to provide guidance for future INM research and advancement.
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Affiliation(s)
- Michelle Y Sander
- Department of Electrical and Computer Engineering, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America
- Division of Materials Science and Engineering, Boston University, 15 Saint Mary's Street, Brookline, MA 02446, United States of America
- Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, United States of America
| | - Xuedong Zhu
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, United States of America
- Photonics Center, Boston University, 8 Saint Mary's Street, Boston, MA 02215, United States of America
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, United States of America
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Stoddart PR, Begeng JM, Tong W, Ibbotson MR, Kameneva T. Nanoparticle-based optical interfaces for retinal neuromodulation: a review. Front Cell Neurosci 2024; 18:1360870. [PMID: 38572073 PMCID: PMC10987880 DOI: 10.3389/fncel.2024.1360870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Degeneration of photoreceptors in the retina is a leading cause of blindness, but commonly leaves the retinal ganglion cells (RGCs) and/or bipolar cells extant. Consequently, these cells are an attractive target for the invasive electrical implants colloquially known as "bionic eyes." However, after more than two decades of concerted effort, interfaces based on conventional electrical stimulation approaches have delivered limited efficacy, primarily due to the current spread in retinal tissue, which precludes high-acuity vision. The ideal prosthetic solution would be less invasive, provide single-cell resolution and an ability to differentiate between different cell types. Nanoparticle-mediated approaches can address some of these requirements, with particular attention being directed at light-sensitive nanoparticles that can be accessed via the intrinsic optics of the eye. Here we survey the available known nanoparticle-based optical transduction mechanisms that can be exploited for neuromodulation. We review the rapid progress in the field, together with outstanding challenges that must be addressed to translate these techniques to clinical practice. In particular, successful translation will likely require efficient delivery of nanoparticles to stable and precisely defined locations in the retinal tissues. Therefore, we also emphasize the current literature relating to the pharmacokinetics of nanoparticles in the eye. While considerable challenges remain to be overcome, progress to date shows great potential for nanoparticle-based interfaces to revolutionize the field of visual prostheses.
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Affiliation(s)
- Paul R. Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - James M. Begeng
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Wei Tong
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
- School of Physics, The University of Melbourne, Melbourne, VIC, Australia
| | - Michael R. Ibbotson
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Tatiana Kameneva
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
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Song L, Wang H, Peng R. Advances in the Regulation of Neural Function by Infrared Light. Int J Mol Sci 2024; 25:928. [PMID: 38256001 PMCID: PMC10815576 DOI: 10.3390/ijms25020928] [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] [Received: 12/19/2023] [Revised: 01/02/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
In recent years, with the rapid development of optical technology, infrared light has been increasingly used in biomedical fields. Research has shown that infrared light could play roles in light stimulation and biological regulation. Infrared light has been used to regulate neural function due to its high spatial resolution, safety and neural sensitivity and has been considered a useful method to replace traditional neural regulation approaches. Infrared neuromodulation methods have been used for neural activation, central nervous system disorder treatment and cognitive enhancement. Research on the regulation of neural function by infrared light stimulation began only recently, and the underlying mechanism remains unclear. This article reviews the characteristics of infrared light, the advantages and disadvantages of infrared neuromodulation, its effects on improving individual health, and its mechanism. This article aims to provide a reference for future research on the use of infrared neural regulation to treat neuropsychological disorders.
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Affiliation(s)
| | - Hui Wang
- Beijing Institute of Radiation Medicine, Beijing 100850, China
| | - Ruiyun Peng
- Beijing Institute of Radiation Medicine, Beijing 100850, China
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Almasri RM, Ladouceur F, Mawad D, Esrafilzadeh D, Firth J, Lehmann T, Poole-Warren LA, Lovell NH, Al Abed A. Emerging trends in the development of flexible optrode arrays for electrophysiology. APL Bioeng 2023; 7:031503. [PMID: 37692375 PMCID: PMC10491464 DOI: 10.1063/5.0153753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/08/2023] [Indexed: 09/12/2023] Open
Abstract
Optical-electrode (optrode) arrays use light to modulate excitable biological tissues and/or transduce bioelectrical signals into the optical domain. Light offers several advantages over electrical wiring, including the ability to encode multiple data channels within a single beam. This approach is at the forefront of innovation aimed at increasing spatial resolution and channel count in multichannel electrophysiology systems. This review presents an overview of devices and material systems that utilize light for electrophysiology recording and stimulation. The work focuses on the current and emerging methods and their applications, and provides a detailed discussion of the design and fabrication of flexible arrayed devices. Optrode arrays feature components non-existent in conventional multi-electrode arrays, such as waveguides, optical circuitry, light-emitting diodes, and optoelectronic and light-sensitive functional materials, packaged in planar, penetrating, or endoscopic forms. Often these are combined with dielectric and conductive structures and, less frequently, with multi-functional sensors. While creating flexible optrode arrays is feasible and necessary to minimize tissue-device mechanical mismatch, key factors must be considered for regulatory approval and clinical use. These include the biocompatibility of optical and photonic components. Additionally, material selection should match the operating wavelength of the specific electrophysiology application, minimizing light scattering and optical losses under physiologically induced stresses and strains. Flexible and soft variants of traditionally rigid photonic circuitry for passive optical multiplexing should be developed to advance the field. We evaluate fabrication techniques against these requirements. We foresee a future whereby established telecommunications techniques are engineered into flexible optrode arrays to enable unprecedented large-scale high-resolution electrophysiology systems.
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Affiliation(s)
- Reem M. Almasri
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | | | - Damia Mawad
- School of Materials Science and Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Dorna Esrafilzadeh
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
| | - Josiah Firth
- Australian National Fabrication Facility, UNSW, Sydney, NSW 2052, Australia
| | - Torsten Lehmann
- School of Electrical Engineering and Telecommunications, UNSW, Sydney, NSW 2052, Australia
| | | | | | - Amr Al Abed
- Graduate School of Biomedical Engineering, UNSW, Sydney, NSW 2052, Australia
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Lewis THJ, Zhuo J, McClellan JX, Getsy PM, Ryan RM, Jenkins MJ, Lewis SJ. Infrared light elicits endothelium-dependent vasodilation in isolated occipital arteries of the rat via soluble guanylyl cyclase-dependent mechanisms. Front Physiol 2023; 14:1219998. [PMID: 37664436 PMCID: PMC10471192 DOI: 10.3389/fphys.2023.1219998] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023] Open
Abstract
The left and right occipital arteries provide blood supply to afferent cell bodies in the ipsilateral nodose and petrosal ganglia. This supply is free of an effective blood-ganglion barrier, so changes in occipital artery blood flow directly affect the access of circulating factors to the afferent cell bodies. The application of infrared (IR) light to modulate neural and other cell processes has yielded information about basic biological processes within tissues and is gaining traction as a potential therapy for a variety of disease processes. To address whether IR can directly modulate vascular function, we performed wire myography studies to determine the actions of IR on occipital arteries isolated from male Sprague-Dawley rats. Based on our previous research that functionally-important differences exist between occipital artery segments close to their origin at the external carotid artery (ECA) and those closer to the nodose ganglion, the occipital arteries were dissected into two segments, one closer to the ECA and the other closer to the nodose ganglion. Segments were constricted with 5-hydroxytryptamine to a level equal to 50% of the maximal response generated by the application of a high (80 mM) concentration of K+ ions. The direct application of pulsed IR (1,460 nm) for 5 s produced a rapid vasodilation in occipital arteries that was significantly more pronounced in segments closest to the ECA, although the ECA itself was minimally responsive. The vasodilation remained for a substantial time (at least 120 s) after cessation of IR application. The vasodilation during and following cessation of the IR application was markedly diminished in occipital arteries denuded of the endothelium. In addition, the vasodilation elicited by IR in endothelium-intact occipital arteries was substantially reduced in the presence of a selective inhibitor of the nitric oxide-sensitive guanylate cyclase, 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ). It appears that IR causes endothelium-dependent, nitric-oxide-mediated vasodilation in the occipital arteries of the rat. The ability of IR to generate rapid and sustained vasodilation may provide new therapeutic approaches for restoring or improving blood flow to targeted tissues.
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Affiliation(s)
- Tristan H. J. Lewis
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Junqi Zhuo
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Jacob X. McClellan
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Paulina M. Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Rita M. Ryan
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Michael. J. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J. Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
- Departments of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
- Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, OH, United States
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Makaroff SN, Nummenmaa AR, Noetscher GM, Qi Z, McIntyre CC, Bingham CS. Influence of charges deposited on membranes of human hyperdirect pathway axons on depolarization during subthalamic deep brain stimulation. J Neural Eng 2023; 20:10.1088/1741-2552/ace5de. [PMID: 37429285 PMCID: PMC10542971 DOI: 10.1088/1741-2552/ace5de] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Objective.The motor hyperdirect pathway (HDP) is a key target in the treatment of Parkinson's disease with deep brain stimulation (DBS). Biophysical models of HDP DBS have been used to explore the mechanisms of stimulation. Built upon finite element method volume conductor solutions, such models are limited by a resolution mismatch, where the volume conductor is modeled at the macro scale, while the neural elements are at the micro scale. New techniques are needed to better integrate volume conductor models with neuron models.Approach.We simulated subthalamic DBS of the human HDP using finely meshed axon models to calculate surface charge deposition on insulting membranes of nonmyelinated axons. We converted the corresponding double layer extracellular problem to a single layer problem and applied the well-conditioned charge-based boundary element fast multipole method (BEM-FMM) with unconstrained numerical spatial resolution. Commonly used simplified estimations of membrane depolarization were compared with more realistic solutions.Main result.Neither centerline potential nor estimates of axon recruitment were impacted by the estimation method used except at axon bifurcations and hemispherical terminations. Local estimates of axon polarization were often much higher at bifurcations and terminations than at any other place along the axon and terminal arbor. Local average estimates of terminal electric field are higher by 10%-20%.Significance. Biophysical models of action potential initiation in the HDP suggest that axon terminations are often the lowest threshold elements for activation. The results of this study reinforce that hypothesis and suggest that this phenomenon is even more pronounced than previously realized.
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Affiliation(s)
- Sergey N Makaroff
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Aapo R Nummenmaa
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States of America
| | - Gregory M Noetscher
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
- ARMY DEVCOM-SC, General Greene Ave, Natick, MA 01760, United States of America
| | - Zhen Qi
- Electrical and Computer Engineering Department, Worcester Polytechnic Institution, Worcester, MA 01609, United States of America
| | - Cameron C McIntyre
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Neurosurgery, Duke University, Durham, NC 27710, United States of America
| | - Clayton S Bingham
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
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Barrett JN, Barrett EF, Rajguru SM. Mitochondrial responses to intracellular Ca 2+ release following infrared stimulation. J Neurophysiol 2023; 129:700-716. [PMID: 36752512 PMCID: PMC10026987 DOI: 10.1152/jn.00293.2022] [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] [Received: 07/11/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Many studies of Ca2+ effects on mitochondrial respiration in intact cells have used electrical and/or chemical stimulation to elevate intracellular [Ca2+], and have reported increases in [NADH] and increased ADP/ATP ratios as dominant controllers of respiration. This study tested a different form of stimulation: brief temperature increases produced by pulses of infrared light (IR, 1,863 nm, 8-10°C for ∼5 s). Fluorescence imaging techniques applied to single PC-12 cells in low µM extracellular [Ca2+] revealed IR stimulation-induced increases in both cytosolic (fluo5F) and mitochondrial (rhod2) [Ca2+]. IR stimulation increased O2 consumption (porphyrin fluorescence), and produced an alkaline shift in mitochondrial matrix pH (Snarf1), indicating activation of the electron transport chain (ETC). The increase in O2 consumption persisted in oligomycin, and began during a decrease in NADH, suggesting that the initial increase in ETC activity was not driven by increased ATP synthase activity or an increased fuel supply to ETC complex I. Imaging with two potentiometric dyes [tetramethyl rhodamine methyl ester (TMRM) and R123] indicated a depolarizing shift in ΔΨm that persisted in high [K+] medium. High-resolution fluorescence imaging disclosed large, reversible mitochondrial depolarizations that were inhibited by cyclosporin A (CSA), consistent with the opening of transient mitochondrial permeability transition pores. IR stimulation also produced a Ca2+-dependent increase in superoxide production (MitoSox) that was not inhibited by CSA, indicating that the increase in superoxide did not require transition pore opening. Thus, the intracellular Ca2+ release that follows pulses of infrared light offers new insights into Ca2+-dependent processes controlling respiration and reactive oxygen species in intact cells.NEW & NOTEWORTHY Pulses of infrared light (IR) provide a novel method for rapidly transferring Ca2+ from the endoplasmic reticulum to mitochondria in intact cells. In PC12 cells the resulting ETC activation was not driven by increased ATP synthase activity or NADH. IR stimulation produced a Ca2+-dependent, reversible depolarization of ΔΨm that was partially blocked by cyclosporin A, and a Ca2+-dependent increase in superoxide that did not require transition pore opening.
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Affiliation(s)
- John N Barrett
- Department of Physiology and Biophysics, University of Miami, Florida, United States
- Neuroscience Program, University of Miami, Florida, United States
| | - Ellen F Barrett
- Department of Physiology and Biophysics, University of Miami, Florida, United States
- Neuroscience Program, University of Miami, Florida, United States
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Florida, United States
- Department of Otolaryngology, University of Miami, Florida, United States
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Kim T, Kadji H, Whalen AJ, Ashourvan A, Freeman E, Fried SI, Tadigadapa S, Schiff SJ. Thermal effects on neurons during stimulation of the brain. J Neural Eng 2022; 19:056029. [PMID: 36126646 PMCID: PMC9855718 DOI: 10.1088/1741-2552/ac9339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/13/2022] [Accepted: 09/20/2022] [Indexed: 01/25/2023]
Abstract
All electric and magnetic stimulation of the brain deposits thermal energy in the brain. This occurs through either Joule heating of the conductors carrying current through electrodes and magnetic coils, or through dissipation of energy in the conductive brain.Objective.Although electrical interaction with brain tissue is inseparable from thermal effects when electrodes are used, magnetic induction enables us to separate Joule heating from induction effects by contrasting AC and DC driving of magnetic coils using the same energy deposition within the conductors. Since mammalian cortical neurons have no known sensitivity to static magnetic fields, and if there is no evidence of effect on spike timing to oscillating magnetic fields, we can presume that the induced electrical currents within the brain are below the molecular shot noise where any interaction with tissue is purely thermal.Approach.In this study, we examined a range of frequencies produced from micromagnetic coils operating below the molecular shot noise threshold for electrical interaction with single neurons.Main results.We found that small temperature increases and decreases of 1∘C caused consistent transient suppression and excitation of neurons during temperature change. Numerical modeling of the biophysics demonstrated that the Na-K pump, and to a lesser extent the Nernst potential, could account for these transient effects. Such effects are dependent upon compartmental ion fluxes and the rate of temperature change.Significance.A new bifurcation is described in the model dynamics that accounts for the transient suppression and excitation; in addition, we note the remarkable similarity of this bifurcation's rate dependency with other thermal rate-dependent tipping points in planetary warming dynamics. These experimental and theoretical findings demonstrate that stimulation of the brain must take into account small thermal effects that are ubiquitously present in electrical and magnetic stimulation. More sophisticated models of electrical current interaction with neurons combined with thermal effects will lead to more accurate modulation of neuronal activity.
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Affiliation(s)
- TaeKen Kim
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
| | - Herve Kadji
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Radiation Oncology, Hackensack Meridian Health Mountainside Medical Center, Montclair, NJ, United States of America
| | - Andrew J Whalen
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
| | - Arian Ashourvan
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
| | - Eugene Freeman
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Honeywell International Aerospace Advanced Technology, Plymouth, MN, United States of America
| | - Shelley I Fried
- Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States of America
- Boston VA Healthcare System, Boston 02130, United States of America
| | - Srinivas Tadigadapa
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, United States of America
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA, United States of America
| | - Steven J Schiff
- Department of Physics, The Pennsylvania State University, University Park, PA, United States of America
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States of America
- Department of Neurosurgery, Penn State College of Medicine, Hershey, PA 17033, United States of America
- Department of Neurosurgery, Yale University, 333 Cedar Street, TMP 410, New Haven, CT 06510, United States of America
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Zhu X, Lin JW, Sander MY. Bidirectional modulation of evoked synaptic transmission by pulsed infrared light. Sci Rep 2022; 12:14196. [PMID: 35987765 PMCID: PMC9392733 DOI: 10.1038/s41598-022-18139-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/05/2022] [Indexed: 12/05/2022] Open
Abstract
Infrared (IR) neuromodulation (INM) has been demonstrated as a novel modulation modality of neuronal excitability. However, the effects of pulsed IR light on synaptic transmission have not been investigated systematically. In this report, the IR light (2 μm) is used to directly modulate evoked synaptic transmission at the crayfish opener neuromuscular junction. The extracellularly recorded terminal action potentials (tAPs) and evoked excitatory postsynaptic currents (EPSCs) modulated by localized IR light illumination (500 ms, 3–13 mW) aimed at the synapses are analyzed. The impact of a single IR light pulse on the presynaptic Ca2+ influx is monitored with Ca2+ indicators. The EPSC amplitude is enhanced, and its rising phase is accelerated under relatively low IR light power levels and localized temperature rises. Increasing the IR light power reversibly suppresses and eventually blocks the EPSCs. Meanwhile, the synaptic delay, tAP amplitude, and presynaptic Ca2+ influx decrease monotonously with higher IR light power. It is demonstrated for the first time that IR light illumination has bidirectional effects on evoked synaptic transmission. These results highlight the efficacy and flexibility of using pulsed IR light to directly control synaptic transmission and advance our understanding of INM of neural networks.
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Fang J, Liu D, Xu D, Wu Q, Li H, Li Y, Hu N. Integrated Au-Nanoroded Biosensing and Regulating Platform for Photothermal Therapy of Bradyarrhythmia. Research (Wash D C) 2022; 2022:9854342. [PMID: 35233537 PMCID: PMC8848336 DOI: 10.34133/2022/9854342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/18/2022] [Indexed: 12/02/2022] Open
Abstract
Bradyarrhythmia is a kind of cardiovascular disease caused by dysregulation of cardiomyocytes, which seriously threatens human life. Currently, treatment strategies of bradyarrhythmia mainly include drug therapy, surgery, or implantable cardioverter defibrillators, but these strategies are limited by drug side effect, surgical trauma, and instability of implanted devices. Here, we developed an integrated Au-nanoroded biosensing and regulating platform to investigate the photothermal therapy of cardiac bradyarrhythmia in vitro. Au-nanoroded electrode array can simultaneously accumulate energy from the photothermal regulation and monitor the electrophsiological state to restore normal rhythm of cardiomyocytes in real time. To treat the cardiomyocytes cultured on Au-nanoroded device by near-infrared (NIR) laser irradiation, cardiomyocytes return to normal for long term after irradiation of suitable NIR energy and maintenance. Compared with the conventional strategies, the photothermal strategy is more effective and convenient to regulate the cardiomyocytes. Furthermore, mRNA sequencing shows that the differential expression genes in cardiomyocytes are significantly increased after photothermal strategy, which are involved in the regulation of the heart rate, cardiac conduction, and ion transport. This work establishes a promising integrated biosensing and regulating platform for photothermal therapy of bradyarrhythmia in vitro and provides reliable evidence of photothermal regulation on cardiomyocytes for cardiological clinical studies.
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Affiliation(s)
- Jiaru Fang
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China.,Stoddart Institute of Molecular Science, Department of Chemistry, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China
| | - Dong Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China
| | - Dongxin Xu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China
| | - Qianni Wu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China
| | - Hongbo Li
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China
| | - Ying Li
- Molecular Cancer Research Center, School of Medicine, Sun Yat-sen University, Shenzhen 518107, China
| | - Ning Hu
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-sen University, Guangzhou 510006, China.,Stoddart Institute of Molecular Science, Department of Chemistry, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310058, China.,State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, China
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11
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Zhu X, Lin JW, Turnali A, Sander MY. Single infrared light pulses induce excitatory and inhibitory neuromodulation. BIOMEDICAL OPTICS EXPRESS 2022; 13:374-388. [PMID: 35154878 PMCID: PMC8803021 DOI: 10.1364/boe.444577] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
The excitatory and inhibitory effects of single and brief infrared (IR) light pulses (2 µm) with millisecond durations and various power levels are investigated with a custom-built fiber amplification system. Intracellular recordings from motor axons of the crayfish opener neuromuscular junction are performed ex vivo. Single IR light pulses induce a membrane depolarization during the light pulses, which is followed by a hyperpolarization that can last up to 100 ms. The depolarization amplitude is dependent on the optical pulse duration, total energy deposition and membrane potential, but is insensitive to tetrodotoxin. The hyperpolarization reverses its polarity near the potassium equilibrium potential and is barium-sensitive. The membrane depolarization activates an action potential (AP) when the axon is near firing threshold, while the hyperpolarization reversibly inhibits rhythmically firing APs. In summary, we demonstrate for the first time that single and brief IR light pulses can evoke initial depolarization followed by hyperpolarization on individual motor axons. The corresponding mechanisms and functional outcomes of the dual effects are investigated.
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Affiliation(s)
- Xuedong Zhu
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
| | - Jen-Wei Lin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Ahmet Turnali
- Department of Electrical and Computer Engineering, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
| | - Michelle Y. Sander
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, USA
- Department of Electrical and Computer Engineering, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
- Division of Materials Science and Engineering, Boston University, 15 Saint Mary’s Street, Brookline, MA 02446, USA
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12
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Niehoff J, Matzkies M, Nguemo F, Hescheler J, Reppel M. The influence of light on the beat rate variability of murine embryonic stem cell derived cardiomyocytes. Biomed Pharmacother 2021; 146:112589. [PMID: 34968926 DOI: 10.1016/j.biopha.2021.112589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The human heart rhythm can be quantified by analyzing the heart rate variability (HRV). A major influencing factor of the HRV is the circadian rhythm. The ocular light and the hormone melatonin play decisive roles in the circadian rhythm. The beat rate variability (BRV) is considered to be the in vitro equivalent of the HRV. Previous studies have demonstrated the influence of melatonin on cardiomyocytes. Also, the influence of light on cardiomyocytes has been described before. Nevertheless, the effect of light on the BRV of cardiomyocytes has not yet been examined. MATERIAL AND METHODS The BRV of spontaneously beating cardiomyocytes was measured with microelectrode arrays over a time period of 30 min. The experiments were either performed with light exposure (with and without an infrared filter) or in complete darkness. RESULTS The BRV was higher and the beating frequency was lower when the cardiomyocytes were exposed to the full spectrum of light, compared to the measurements in darkness as well as to the measurements with an infrared filter. In contrast, the differences of BRV between the measurements in darkness and the measurements with an infrared filter were not as distinct. CONCLUSIONS This is the first study demonstrating the influence of light on the beating rhythm of heart tissue in vitro. The results indicate that especially the infrared spectrum of light alters the BRV. These findings could be of interest for clinical applications such as the field of optical pacing as well as in neonatal patient care.
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Affiliation(s)
- Julius Niehoff
- Institute for Neurophysiology, Faculty of Medicine, University of Cologne, Cologne, Germany; Department of Radiology, Neuroradiology and Nuclear Medicine, Johannes Wesling University Hospital, Ruhr University Bochum, Bochum, Germany.
| | - Matthias Matzkies
- Institute for Neurophysiology, Faculty of Medicine, University of Cologne, Cologne, Germany.
| | - Filomain Nguemo
- Institute for Neurophysiology, Faculty of Medicine, University of Cologne, Cologne, Germany.
| | - Jürgen Hescheler
- Institute for Neurophysiology, Faculty of Medicine, University of Cologne, Cologne, Germany.
| | - Michael Reppel
- Institute for Neurophysiology, Faculty of Medicine, University of Cologne, Cologne, Germany; Praxis für Kardiologie und Angiologie, Landsberg am Lech, Germany; Medical Clinic II, University Clinic of Schleswig-Holstein/Campus Luebeck, Luebeck, Germany.
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13
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Opto-thermal technologies for microscopic analysis of cellular temperature-sensing systems. Biophys Rev 2021; 14:41-54. [PMID: 35340595 PMCID: PMC8921355 DOI: 10.1007/s12551-021-00854-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/12/2021] [Indexed: 12/15/2022] Open
Abstract
AbstractCould enzymatic activities and their cooperative functions act as cellular temperature-sensing systems? This review introduces recent opto-thermal technologies for microscopic analyses of various types of cellular temperature-sensing system. Optical microheating technologies have been developed for local and rapid temperature manipulations at the cellular level. Advanced luminescent thermometers visualize the dynamics of cellular local temperature in space and time during microheating. An optical heater and thermometer can be combined into one smart nanomaterial that demonstrates hybrid function. These technologies have revealed a variety of cellular responses to spatial and temporal changes in temperature. Spatial temperature gradients cause asymmetric deformations during mitosis and neurite outgrowth. Rapid changes in temperature causes imbalance of intracellular Ca2+ homeostasis and membrane potential. Among those responses, heat-induced muscle contractions are highlighted. It is also demonstrated that the short-term heating hyperactivates molecular motors to exceed their maximal activities at optimal temperatures. We discuss future prospects for opto-thermal manipulation of cellular functions and contributions to obtain a deeper understanding of the mechanisms of cellular temperature-sensing systems.
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14
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Tajarenejad H, Ansari MA, Akbari S, Yazdanfar H, Hamidi SM. Optical neural stimulation using the thermoplasmonic effect of gold nano-hexagon. BIOMEDICAL OPTICS EXPRESS 2021; 12:6013-6023. [PMID: 34745718 PMCID: PMC8548018 DOI: 10.1364/boe.438593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
The use of nanoparticle photothermal effect as adjuvants in neuromodulation has recently received much attention, with many open questions about new nanostructures' effect on the action potential. The photothermal properties of hexagonal gold nanoparticles are investigated in this work, including the absorption peak wavelength and light-heat conversion rate, using both experimental and simulation methods. Furthermore, the ability to use these nanostructures in axonal neural stimulation and cardiac stimulation by measuring temperature changes of gold nano-hexagons under 532 nm laser irradiation is studied. In addition, their thermal effect on neural responses is investigated by modeling small-diameter unmyelinated axons and heart pacemaker cells. The results show that the increase in temperature caused by these nano-hexagons can successfully stimulate the small diameter axon and produce an action potential. Experiments have also demonstrated that the heat created by gold nano-hexagons affects toad cardiac rhythm and increases T wave amplitude. An increase in T wave amplitude on toad heart rhythm shows the thermal effect of nano hexagons heat on heart pacemaker cells and intracellular ion flows. This work demonstrates the feasibility of utilizing these nanostructures to create portable and compact medical devices, such as optical pacemakers or cardiac stimulation.
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15
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Rice D, Martinelli GP, Jiang W, Holstein GR, Rajguru SM. Pulsed Infrared Stimulation of Vertical Semicircular Canals Evokes Cardiovascular Changes in the Rat. Front Neurol 2021; 12:680044. [PMID: 34122320 PMCID: PMC8193737 DOI: 10.3389/fneur.2021.680044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 04/20/2021] [Indexed: 11/28/2022] Open
Abstract
A variety of stimuli activating vestibular end organs, including sinusoidal galvanic vestibular stimulation, whole body rotation and tilt, and head flexion have been shown to evoke significant changes in blood pressure (BP) and heart rate (HR). While a role for the vertical semicircular canals in altering autonomic activity has been hypothesized, studies to-date attribute the evoked BP and HR responses to the otolith organs. The present study determined whether unilateral activation of the posterior (PC) or anterior (AC) semicircular canal is sufficient to elicit changes in BP and/or HR. The study employed frequency-modulated pulsed infrared radiation (IR: 1,863 nm) directed via optical fibers to PC or AC of adult male Long-Evans rats. BP and HR changes were detected using a small-animal single pressure telemetry device implanted in the femoral artery. Eye movements evoked during IR of the vestibular endorgans were used to confirm the stimulation site. We found that sinusoidal IR delivered to either PC or AC elicited a rapid decrease in BP and HR followed by a stimulation frequency-matched modulation. The magnitude of the initial decrements in HR and BP did not correlate with the energy of the suprathreshold stimulus. This response pattern was consistent across multiple trials within an experimental session, replicable, and in most animals showed no evidence of habituation or an additive effect. Frequency modulated electrical current delivered to the PC and IR stimulation of the AC, caused decrements in HR and BP that resembled those evoked by IR of the PC. Frequency domain heart rate variability assessment revealed that, in most subjects, IR stimulation increased the low frequency (LF) component and decreased the high frequency (HF) component, resulting in an increase in the LF/HF ratio. This ratio estimates the relative contributions of sympathetic nervous system (SNS) and parasympathetic nervous system (PNS) activities. An injection of atropine, a muscarinic cholinergic receptor antagonist, diminished the IR evoked changes in HR, while the non-selective beta blocker propranolol eliminated changes in both HR and BP. This study provides direct evidence that activation of a single vertical semicircular canal is sufficient to activate and modulate central pathways that control HR and BP.
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Affiliation(s)
- Darrian Rice
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Giorgio P Martinelli
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Weitao Jiang
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States
| | - Gay R Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami, Miami, FL, United States.,Department of Otolaryngology, University of Miami, Miami, FL, United States
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16
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Brown WGA, Needham K, Begeng JM, Thompson AC, Nayagam BA, Kameneva T, Stoddart PR. Response of primary auditory neurons to stimulation with infrared light in vitro. J Neural Eng 2021; 18:046003. [PMID: 33724234 DOI: 10.1088/1741-2552/abe7b8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. APPROACH Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2-5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. MAIN RESULTS The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. SIGNIFICANCE This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.
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Affiliation(s)
- William G A Brown
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, John Street, Hawthorn VIC 3122, Australia
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Li J, Li H, Rao P, Luo J, Wang X, Wang L. Shining light on cardiac electrophysiology: From detection to intervention, from basic research to translational applications. Life Sci 2021; 274:119357. [PMID: 33737082 DOI: 10.1016/j.lfs.2021.119357] [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: 12/05/2020] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Cardiac arrhythmias are an important group of cardiovascular diseases, which can occur alone or in association with other cardiovascular diseases. The development of cardiac arrhythmias cannot be separated from changes in cardiac electrophysiology, and the investigation and clarification of cardiac electrophysiological changes are beneficial for the treatment of cardiac arrhythmias. However, electrical energy-based pacemakers and defibrillators, which are widely used to treat arrhythmias, still have certain disadvantages. Thereby, optics promises to be used for optical manipulation and its use in biomedicine is increasing. Since visible light is readily absorbed and scattered in living tissues and tissue penetration is shallow, optical modulation for cells and tissues requires conversion media that convert light energy into bioelectrical activity. In this regard, fluorescent dyes, light-sensitive ion channels, and optical nanomaterials can assume this role, the corresponding optical mapping technology, optogenetics technology, and optical systems based on luminescent nanomaterials have been introduced into the research in cardiovascular field and are expected to be new tools for the study and treatment of cardiac arrhythmias. In addition, infrared and near-infrared light has strong tissue penetration, which is one of the excellent options of external trigger for achieving optical modulation, and is also widely used in the study of optical modulation of biological activities. Here, the advantages of optical applications are summarized, the research progresses and emerging applications of optical-based technologies as detection and intervention tools for cardiac electrophysiological are highlighted. Moreover, the prospects for future applications of optics in clinical diagnosis and treatment are discussed.
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Affiliation(s)
- Jianyi Li
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Haitao Li
- Department of Cardiology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou 570311, PR China
| | - Panpan Rao
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Junmiao Luo
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China
| | - Xi Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China; Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China.
| | - Long Wang
- Cardiovascular Research Institute, Wuhan University, Wuhan 430060, PR China; Hubei Key Laboratory of Cardiology, Wuhan 430060, PR China; Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan 430060, PR China.
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18
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Xu Y, Magnuson M, Agarwal A, Tan X, Richter CP. Infrared neural stimulation at different wavelengths and pulse shapes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:89-100. [PMID: 33359901 DOI: 10.1016/j.pbiomolbio.2020.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 11/26/2020] [Accepted: 12/18/2020] [Indexed: 11/30/2022]
Abstract
Neural stimulation with infrared radiation has been explored for brain tissue, peripheral nerves, and cranial nerves including the auditory nerve. Initial experiments were conducted at wavelengths between λ = 1850 and λ = 2140 nm and the radiant energy was delivered with square pulses. Water absorption of the infrared radiation at λ = 1860 nm is similar to absorption at wavelengths between λ = 1310 and λ = 1600 nm, which are in the radiation wavelength range used for the communication industry. Technology for those wavelengths has already been developed and miniaturized and is readily available. The possibility of the infrared light to evoke compound action potentials (CAP) in the cochlea at λ = 1,375, λ = 1,460, and λ = 1550 nm was explored and compared to that of λ = 1860 nm in guinea pigs. Furthermore, rise and fall times of the 100 μs long pulses were changed and four basic pulse shapes (square, triangular, ramp-up, and ramp-down) were explored in their ability to evoke a CAP. In animals with pure tone threshold averages (PTAs) above 70 dB SPL, the results show that the favorable wavelength is λ = 1460 nm to reach threshold for stimulation and λ = 1375 nm or λ = 1460 nm for obtaining maximum amplitude. The most favorable pulse shape is either ramp-up or triangular.
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Affiliation(s)
- Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA; Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA
| | - Mario Magnuson
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Aditi Agarwal
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Ave, Searle 12-561, Chicago, IL, 60611, USA; Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA; The Hugh Knowles Center, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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19
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Fekete Z, Horváth ÁC, Zátonyi A. Infrared neuromodulation:a neuroengineering perspective. J Neural Eng 2020; 17:051003. [PMID: 33055373 DOI: 10.1088/1741-2552/abb3b2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Infrared neuromodulation (INM) is a branch of photobiomodulation that offers direct or indirect control of cellular activity through elevation of temperature in a spatially confined region of the target tissue. Research on INM started about 15 ago and is gradually attracting the attention of the neuroscience community, as numerous experimental studies have provided firm evidence on the safe and reproducible excitation and inhibition of neuronal firing in both in vitro and in vivo conditions. However, its biophysical mechanism is not fully understood and several engineered interfaces have been created to investigate infrared stimulation in both the peripheral and central nervous system. In this review, recent applications and present knowledge on the effects of INM on cellular activity are summarized, and an overview of the technical approaches to deliver infrared light to cells and to interrogate the optically evoked response is provided. The micro- and nanoengineered interfaces used to investigate the influence of INM are described in detail.
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Affiliation(s)
- Z Fekete
- Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest 1083, Hungary. Author to whom any correspondence should be addressed
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20
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Lo PA, Huang K, Zhou Q, Humayun MS, Yue L. Ultrasonic Retinal Neuromodulation and Acoustic Retinal Prosthesis. MICROMACHINES 2020; 11:mi11100929. [PMID: 33066085 PMCID: PMC7600354 DOI: 10.3390/mi11100929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/11/2020] [Accepted: 10/11/2020] [Indexed: 12/16/2022]
Abstract
Ultrasound is an emerging method for non-invasive neuromodulation. Studies in the past have demonstrated that ultrasound can reversibly activate and inhibit neural activities in the brain. Recent research shows the possibility of using ultrasound ranging from 0.5 to 43 MHz in acoustic frequency to activate the retinal neurons without causing detectable damages to the cells. This review recapitulates pilot studies that explored retinal responses to the ultrasound exposure, discusses the advantages and limitations of the ultrasonic stimulation, and offers an overview of engineering perspectives in developing an acoustic retinal prosthesis. For comparison, this article also presents studies in the ultrasonic stimulation of the visual cortex. Despite that, the summarized research is still in an early stage; ultrasonic retinal stimulation appears to be a viable technology that exhibits enormous therapeutic potential for non-invasive vision restoration.
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Affiliation(s)
- Pei-An Lo
- Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA; (P.-A.L.); (K.H.); (Q.Z.); (M.S.H.)
- Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA 90033, USA
| | - Kyana Huang
- Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA; (P.-A.L.); (K.H.); (Q.Z.); (M.S.H.)
| | - Qifa Zhou
- Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA; (P.-A.L.); (K.H.); (Q.Z.); (M.S.H.)
- Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA 90033, USA
| | - Mark S. Humayun
- Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA; (P.-A.L.); (K.H.); (Q.Z.); (M.S.H.)
- Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA 90033, USA
| | - Lan Yue
- Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA; (P.-A.L.); (K.H.); (Q.Z.); (M.S.H.)
- Ginsburg Institute for Biomedical Therapeutics, University of Southern California, Los Angeles, CA 90033, USA
- Correspondence:
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21
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Zhu X, Lin JW, Sander MY. Infrared inhibition impacts on locally initiated and propagating action potentials and the downstream synaptic transmission. NEUROPHOTONICS 2020; 7:045003. [PMID: 33094124 PMCID: PMC7554448 DOI: 10.1117/1.nph.7.4.045003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/28/2020] [Indexed: 05/15/2023]
Abstract
Significance: Systematic studies of the physiological outputs induced by infrared (IR)-mediated inhibition of motor nerves can provide guidance for therapeutic applications and offer critical insights into IR light modulation of complex neural networks. Aim: We explore the IR-mediated inhibition of action potentials (APs) that either propagate along single axons or are initiated locally and their downstream synaptic transmission responses. Approach: APs were evoked locally by two-electrode current clamp or at a distance for propagating APs. The neuromuscular transmission was recorded with intracellular electrodes in muscle cells or macro-patch pipettes on terminal bouton clusters. Results: IR light pulses completely and reversibly terminate the locally initiated APs firing at low frequencies, which leads to blocking of the synaptic transmission. However, IR light pulses only suppress but do not block the amplitude and duration of propagating APs nor locally initiated APs firing at high frequencies. Such suppressed APs do not influence the postsynaptic responses at a distance. While the suppression of AP amplitude and duration is similar for propagating and locally evoked APs, only the former exhibits a 7% to 21% increase in the maximum time derivative of the AP rising phase. Conclusions: The suppressed APs of motor axons can resume their waveforms after passing the localized IR light illumination site, leaving the muscular and synaptic responses unchanged. IR-mediated modulation on propagating and locally evoked APs should be considered as two separate models for axonal and somatic modulations.
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Affiliation(s)
- Xuedong Zhu
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
- Boston University, Photonics Center, Boston, Massachusetts, United States
| | - Jen-Wei Lin
- Boston University, Department of Biology, Boston, Massachusetts, United States
| | - Michelle Y. Sander
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
- Boston University, Photonics Center, Boston, Massachusetts, United States
- Boston University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
- Boston University, Division of Materials Science and Engineering, Brookline, Massachusetts, United States
- Address all correspondence to Michelle Y. Sander,
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Coventry BS, Sick JT, Talavage TM, Stantz KM, Bartlett EL. Short-wave Infrared Neural Stimulation Drives Graded Sciatic Nerve Activation Across A Continuum of Wavelengths. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:3581-3585. [PMID: 33018777 DOI: 10.1109/embc44109.2020.9176177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Infrared neural stimulation (INS) is an optical stimulation technique which uses coherent light to stimulate nerves and neurons and which shows increased spatial selectivity compared to electrical stimulation. This could improve deep brain, high channel count, or vagus nerve stimulation. In this study, we seek to understand the wavelength dependence of INS in the near-infrared optical window. Rat sciatic nerves were excised ex vivo and stimulated with wavelengths between 700 and 900 nm. Recorded compound nerve action potentials (CNAPs) showed that stimulation was maximized in the 700 nm window despite comparable laser power levels across wavelengths. Computational models demonstrated that wavelength-based activation dependencies were not a result of passive optical properties. This data demonstrates that INS is both wavelength and power level dependent, which inform stimulation systems to actively target neural microcircuits in humans.
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Xia QL, Wang MQ, Jiang B, Hu N, Wu XY, Hou WS, Nyberg T. Infrared Laser Pulses Excite Action Potentials in Primary Cortex Neurons In Vitro .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:5184-5187. [PMID: 31947026 DOI: 10.1109/embc.2019.8856712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Infrared neural modulation (INM) has been well studied in the peripheral nervous system (PNS) for potential clinical applications. However, limited research has been conducted on the central nervous systems (CNS). In this study, we aimed at investigating the feasibility of using pulsed infrared (IR) laser with a wavelength of 1940 nm to excite network activity of cultivated rat cortex neurons.We cultured rat cortex neurons, forming neural networks with spontaneous neural activity, on glass multi-electrode arrays (MEAs). Laser at a power of 600 mW and a pulse rate of 10 Hz were used to stimulate the neural networks using the optics of an inverted microscope. Pulse durations were varied from 200 μs to 1 ms. The spike rate was calculated to evaluate the change of the neural network activity during the IR stimuli and the corresponding frequency components of neural response were calculated to examine whether recorded spikes were evoked by the IR pulse or not. A temperature model was adapted from a previous study to estimate the temperature rise during laser pulsing.We observed that the IR irradiation with a pulse duration of 800 μs and 1 ms could excite neuronal action potentials. The temperature rose 18.5 and 23.9 °C, for pulse durations of 800 μs and 1 ms, respectively. Thus, in addition to previously shown inhibition of IR irradiation with a wavelength of 1550 nm, we demonstrate an optical method that can modulate neural network activity in vitro. The preliminary results from this paper also suggested that MEA recording technology coupled with a laser and microscope systems can be exploited as a new approach for future studies to understand mechanisms and characterize laser parameters of INM for CNS neurons.
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Zhu X, Lin JW, Sander MY. Infrared inhibition and waveform modulation of action potentials in the crayfish motor axon. BIOMEDICAL OPTICS EXPRESS 2019; 10:6580-6594. [PMID: 31853418 PMCID: PMC6913409 DOI: 10.1364/boe.10.006580] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/12/2019] [Accepted: 11/19/2019] [Indexed: 05/02/2023]
Abstract
The infrared (IR) inhibition of axonal activities in the crayfish neuromuscular preparation is studied using 2 µm IR light pulses with varying durations. The intracellular neuronal activities are monitored with two-electrode current clamp, while the IR-induced temperature changes are measured by the open patch technique simultaneously. It is demonstrated that the IR pulses can reversibly shape or block locally initiated action potentials. Suppression of the AP amplitude and duration and decrease in axonal excitability by IR pulses are quantitatively analyzed. While the AP amplitude and duration decrease similarly during IR illumination, it is discovered that the recovery of the AP duration after the IR pulses is slower than that of the AP amplitude. An IR-induced decrease in the input resistance (8.8%) is detected and discussed together with the temperature dependent changes in channel kinetics as contributing factors for the inhibition reported here.
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Affiliation(s)
- Xuedong Zhu
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
| | - Jen-Wei Lin
- Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02215, USA
| | - Michelle Y. Sander
- Neurophotonics Center, Boston University, 24 Cummington Mall, Boston, MA 02215, USA
- Department of Electrical and Computer Engineering, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
- Division of Materials Science and Engineering, Boston University, 15 Saint Mary’s Street, Brookline, MA 02446, USA
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25
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Optical stimulation of cardiac cells with a polymer-supported silicon nanowire matrix. Proc Natl Acad Sci U S A 2018; 116:413-421. [PMID: 30538202 DOI: 10.1073/pnas.1816428115] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electronic pacemakers can treat electrical conduction disorders in hearts; however, they are invasive, bulky, and linked to increased incidence of infection at the tissue-device interface. Thus, researchers have looked to other more biocompatible methods for cardiac pacing or resynchronization, such as femtosecond infrared light pulsing, optogenetics, and polymer-based cardiac patches integrated with metal electrodes. Here we develop a biocompatible nongenetic approach for the optical modulation of cardiac cells and tissues. We demonstrate that a polymer-silicon nanowire composite mesh can be used to convert fast moving, low-radiance optical inputs into stimulatory signals in target cardiac cells. Our method allows for the stimulation of the cultured cardiomyocytes or ex vivo heart to beat at a higher target frequency.
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26
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Urban P, Pritzl SD, Konrad DB, Frank JA, Pernpeintner C, Roeske CR, Trauner D, Lohmüller T. Light-Controlled Lipid Interaction and Membrane Organization in Photolipid Bilayer Vesicles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13368-13374. [PMID: 30346771 DOI: 10.1021/acs.langmuir.8b03241] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Controlling lateral interactions between lipid molecules in a bilayer membrane to guide membrane organization and domain formation is a key factor for studying and emulating membrane functionality in synthetic biological systems. Here, we demonstrate an approach to reversibly control lipid organization, domain formation, and membrane stiffness of phospholipid bilayer membranes using the photoswitchable phospholipid azo-PC. azo-PC contains an azobenzene group in the sn2 acyl chain that undergoes reversible photoisomerization on illumination with UV-A and visible light. We demonstrate that the concentration of the photolipid molecules and also the assembly and disassembly of photolipids into lipid domains can be monitored by UV-vis spectroscopy because of a blue shift induced by photolipid aggregation.
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Affiliation(s)
- Patrick Urban
- Photonics and Optoelectronics Group, Department of Physics and CeNS , Ludwig-Maximilians-Universität München , Amalienstraße 54 , 80799 Munich , Germany
| | - Stefanie D Pritzl
- Photonics and Optoelectronics Group, Department of Physics and CeNS , Ludwig-Maximilians-Universität München , Amalienstraße 54 , 80799 Munich , Germany
| | - David B Konrad
- Department of Chemistry and Center for Integrated Protein Science , Ludwig-Maximilians-Universität München , Butenandtstraße 5-13 , 81377 Munich , Germany
| | - James A Frank
- Department of Chemistry and Center for Integrated Protein Science , Ludwig-Maximilians-Universität München , Butenandtstraße 5-13 , 81377 Munich , Germany
| | - Carla Pernpeintner
- Photonics and Optoelectronics Group, Department of Physics and CeNS , Ludwig-Maximilians-Universität München , Amalienstraße 54 , 80799 Munich , Germany
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 Munich , Germany
| | - Christian R Roeske
- Photonics and Optoelectronics Group, Department of Physics and CeNS , Ludwig-Maximilians-Universität München , Amalienstraße 54 , 80799 Munich , Germany
| | - Dirk Trauner
- Department of Chemistry and Center for Integrated Protein Science , Ludwig-Maximilians-Universität München , Butenandtstraße 5-13 , 81377 Munich , Germany
- Department of Chemistry , New York University , Silver Center, 100 Washington Square East, Room 712 , New York 10003 , United States
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 Munich , Germany
| | - Theobald Lohmüller
- Photonics and Optoelectronics Group, Department of Physics and CeNS , Ludwig-Maximilians-Universität München , Amalienstraße 54 , 80799 Munich , Germany
- Nanosystems Initiative Munich , Schellingstraße 4 , 80799 Munich , Germany
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27
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Xu Y, Xia N, Lim M, Tan X, Tran MH, Boulger E, Peng F, Young H, Rau C, Rack A, Richter CP. Multichannel optrodes for photonic stimulation. NEUROPHOTONICS 2018; 5:045002. [PMID: 30397630 PMCID: PMC6197865 DOI: 10.1117/1.nph.5.4.045002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/24/2018] [Indexed: 05/27/2023]
Abstract
An emerging method in the field of neural stimulation is the use of photons to activate neurons. The possible advantage of optical stimulation over electrical is attributable to its spatially selective activation of small neuron populations, which is promising in generating superior spatial resolution in neural interfaces. Two principal methods are explored for cochlear prostheses: direct stimulation of nerves with infrared light and optogenetics. This paper discusses basic requirements for developing a light delivery system (LDS) for the cochlea and provides examples for building such devices. The proposed device relies on small optical sources, which are assembled in an array to be inserted into the cochlea. The mechanical properties, the biocompatibility, and the efficacy of optrodes have been tested in animal models. The force required to insert optrodes into a model of the human scala tympani was comparable to insertion forces obtained for contemporary cochlear implant electrodes. Side-emitting diodes are powerful enough to evoke auditory responses in guinea pigs. Chronic implantation of the LDS did not elevate auditory brainstem responses over 26 weeks.
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Affiliation(s)
- Yingyue Xu
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
| | - Nan Xia
- Qingdao University, Institute for Digital Medicine and Computer-assisted Surgery, Qingdao, China
| | - Michelle Lim
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Xiaodong Tan
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Minh Ha Tran
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Erin Boulger
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Fei Peng
- Chongqing University, Bioengineering College, Chongqing, China
| | - Hunter Young
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
| | - Christoph Rau
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, United Kingdom
| | - Alexander Rack
- Structure of Materials Group-ID19, European Synchrotron Radiation Facility, Cedex 9, France
| | - Claus-Peter Richter
- Northwestern University Feinberg School of Medicine, Department of Otolaryngology, Chicago, Illinois, United States
- Northwestern University, Department of Communication Sciences and Disorders, Evanston, Illinois, United States
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Hugh Knowles Center for Clinical and Basic Sciences in Hearing, Evanston, Illinois, United States
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28
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Eom K, Byun KM, Jun SB, Kim SJ, Lee J. Theoretical Study on Gold-Nanorod-Enhanced Near-Infrared Neural Stimulation. Biophys J 2018; 115:1481-1497. [PMID: 30266321 DOI: 10.1016/j.bpj.2018.09.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 12/30/2022] Open
Abstract
Over the past decade, optical methods have emerged for modulating brain functions as an alternative to electrical stimulation. Among various optical techniques, infrared neural stimulation has been effective via a thermal mechanism enabling focused and noninvasive stimulation without any genetic manipulation, but it results in bulk heating of neural tissue. Recently, it has been shown that neural cells can be activated more efficiently by pulsed near-infrared (NIR) light delivered to gold nanorods (GNRs) near the neural cells. Despite its potential, however, the biophysical mechanism underlying this GNR-enhanced NIR stimulation has not been clearly explained yet. Here, we propose an integrative and quantitative model to elucidate the mechanism by modeling heat generated from interaction between NIR light and GNRs, the temperature-dependent ion channels (transient receptor potential vanilloid 1; TRPV1) in the neuronal membrane, and a heat-induced capacitive current through the membrane. Our results show that NIR pulses induce abrupt temperature elevation near the neuronal membrane and lead to both the TRPV1-channel and capacitive currents. Both current sources synergistically increase the membrane potential and elicit an action potential, and which mechanism is dominant depends on conditions such as the laser pulse duration and TRPV1 channel density. Although the TRPV1 mechanism dominates in most cases we tested, the capacitive current makes a larger contribution when a very short laser pulse is illuminated on neural cells with relatively low TRPV1 channel densities.
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Affiliation(s)
- Kyungsik Eom
- School of Engineering, Brown University, Providence, Rhode Island
| | - Kyung Min Byun
- Department of Biomedical Engineering, Kyung Hee University, Yongin, South Korea
| | - Sang Beom Jun
- Department of Electronics Engineering, Ewha Womans University, Seoul, South Korea; Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, South Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, South Korea
| | - Jonghwan Lee
- School of Engineering, Brown University, Providence, Rhode Island; Carney Institute for Brain Science, Brown University, Providence, Rhode Island.
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29
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Barrett JN, Rincon S, Singh J, Matthewman C, Pasos J, Barrett EF, Rajguru SM. Pulsed infrared releases Ca 2+ from the endoplasmic reticulum of cultured spiral ganglion neurons. J Neurophysiol 2018; 120:509-524. [PMID: 29668377 DOI: 10.1152/jn.00740.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Inner ear spiral ganglion neurons were cultured from day 4 postnatal mice and loaded with a fluorescent Ca2+ indicator (fluo-4, -5F, or -5N). Pulses of infrared radiation (IR; 1,863 nm, 200 µs, 200-250 Hz for 2-5 s, delivered via an optical fiber) produced a rapid, transient temperature increase of 6-12°C (above a baseline of 24-30°C). These IR pulse trains evoked transient increases in both nuclear and cytosolic Ca2+ concentration ([Ca2+]) of 0.20-1.4 µM, with a simultaneous reduction of [Ca2+] in regions containing endoplasmic reticulum (ER). IR-induced increases in cytosolic [Ca2+] continued in medium containing no added Ca2+ (±Ca2+ buffers) and low [Na+], indicating that the [Ca2+] increase was mediated by release from intracellular stores. Consistent with this hypothesis, the IR-induced [Ca2+] response was prolonged and eventually blocked by inhibition of ER Ca2+-ATPase with cyclopiazonic acid, and was also inhibited by a high concentration of ryanodine and by inhibitors of inositol (1,4,5)-trisphosphate (IP3)-mediated Ca2+ release (xestospongin C and 2-aminoethoxydiphenyl borate). The thermal sensitivity of the response suggested involvement of warmth-sensitive transient receptor potential (TRP) channels. The IR-induced [Ca2+] increase was inhibited by TRPV4 inhibitors (HC-067047 and GSK-2193874), and immunostaining of spiral ganglion cultures demonstrated the presence of TRPV4 and TRPM2 that colocalized with ER marker GRP78. These results suggest that the temperature sensitivity of IR-induced [Ca2+] elevations is conferred by TRP channels on ER membranes, which facilitate Ca2+ efflux into the cytosol and thereby contribute to Ca2+-induced Ca2+-release via IP3 and ryanodine receptors. NEW & NOTEWORTHY Infrared radiation-induced photothermal effects release Ca2+ from the endoplasmic reticulum of primary spiral ganglion neurons. This Ca2+ release is mediated by activation of transient receptor potential (TRPV4) channels and involves amplification by Ca2+-induced Ca2+-release. The neurons immunostained for warmth-sensitive channels, TRPV4 and TRPM2, which colocalize with endoplasmic reticulum. Pulsed infrared radiation provides a novel experimental tool for releasing intracellular Ca2+, studying Ca2+ regulatory mechanisms, and influencing neuronal excitability.
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Affiliation(s)
- John N Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Samantha Rincon
- Department of Biomedical Engineering, University of Miami , Miami, Florida
| | - Jayanti Singh
- Department of Otolaryngology, University of Miami , Miami, Florida
| | | | - Julio Pasos
- Department of Otolaryngology, University of Miami , Miami, Florida
| | - Ellen F Barrett
- Department of Physiology and Biophysics, University of Miami , Miami, Florida.,Neuroscience Program, University of Miami , Miami, Florida
| | - Suhrud M Rajguru
- Department of Biomedical Engineering, University of Miami , Miami, Florida.,Department of Otolaryngology, University of Miami , Miami, Florida
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30
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Azimzadeh JB, Fabella BA, Kastan NR, Hudspeth AJ. Thermal Excitation of the Mechanotransduction Apparatus of Hair Cells. Neuron 2018; 97:586-595.e4. [PMID: 29395911 PMCID: PMC5805653 DOI: 10.1016/j.neuron.2018.01.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/13/2017] [Accepted: 01/03/2018] [Indexed: 12/21/2022]
Abstract
Although a hair bundle is normally deflected by mechanical stimuli, we found that irradiation of a hair cell from the bullfrog's sacculus with ultraviolet light causes rapid motion of the hair bundle toward its tall edge. This movement is associated with opening of mechanotransduction channels and disappears when tip links are disrupted. We localized the absorptive element responsible for the motion to the region directly below the hair bundle and measured an action spectrum similar to the absorption spectra of mitochondrial constituents. Temperature measurements revealed heating around the site of absorption; direct heating of the hair bundle confirmed that the response to light is mediated through heat. Although mechanical offsets of the hair bundle revealed that heat softens gating springs, it also acts directly to open transduction channels. This study identifies an unconventional method of hair-cell stimulation and clarifies the previously unexplained sensitivity of auditory organs to thermal stimulation.
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Affiliation(s)
- Julien B Azimzadeh
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Brian A Fabella
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Nathaniel R Kastan
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - A J Hudspeth
- Howard Hughes Medical Institute, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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31
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Abstract
Optical pacing (OP) uses pulsed infrared light to initiate heartbeats in electrically excitable cardiac tissues without employing exogenous agents. OP is an alternative approach to electrical pacing that may overcome some its disadvantages for some applications. In this review, we discuss the initial demonstrations, mechanisms, safety, advantages and applications of OP.
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Affiliation(s)
- S M Ford
- Rainbow Babies and Children's Hospital Divisions of Neonatology and Pediatric Cardiology, 11100 Euclid Ave, MS 6010, Cleveland, OH 44106, United States of America
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32
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Tan X, Jahan I, Xu Y, Stock S, Kwan CC, Soriano C, Xiao X, García-Añoveros J, Fritzsch B, Richter CP. Auditory Neural Activity in Congenitally Deaf Mice Induced by Infrared Neural Stimulation. Sci Rep 2018; 8:388. [PMID: 29321651 PMCID: PMC5762820 DOI: 10.1038/s41598-017-18814-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/11/2017] [Indexed: 11/16/2022] Open
Abstract
To determine whether responses during infrared neural stimulation (INS) result from the direct interaction with spiral ganglion neurons (SGNs), we tested three genetically modified deaf mouse models: Atoh1-cre; Atoh1f/f (Atoh1 conditional knockout, CKO), Atoh1-cre; Atoh1f/kiNeurog1 (Neurog1 knockin, KI), and the Vglut3 knockout (Vglut3−/−) mice. All animals were exposed to tone bursts and clicks up to 107 dB (re 20 µPa) and to INS, delivered with a 200 µm optical fiber. The wavelength (λ) was 1860 nm, the radiant energy (Q) 0-800 µJ/pulse, and the pulse width (PW) 100–500 µs. No auditory responses to acoustic stimuli could be evoked in any of these animals. INS could not evoke auditory brainstem responses in Atoh1 CKO mice but could in Neurog1 KI and Vglut3−/− mice. X-ray micro-computed tomography of the cochleae showed that responses correlated with the presence of SGNs and hair cells. Results in Neurog1 KI mice do not support a mechanical stimulation through the vibration of the basilar membrane, but cannot rule out the direct activation of the inner hair cells. Results in Vglut3−/− mice, which have no synaptic transmission between inner hair cells and SGNs, suggested that hair cells are not required.
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Affiliation(s)
- Xiaodong Tan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Israt Jahan
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Yingyue Xu
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Stuart Stock
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL, 60611, USA
| | - Changyow Claire Kwan
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA
| | - Carmen Soriano
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA
| | - Jaime García-Añoveros
- Departments of Anesthesiology, Physiology, and Neurology, Northwestern University Institute for Neuroscience, Ward 10-070, 303 East Chicago Avenue, Chicago, IL, 60611, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, 129 E. Jefferson Street, Iowa City, IA, 52242, USA
| | - Claus-Peter Richter
- Department of Otolaryngology, Northwestern University Feinberg School of Medicine, 320 E. Chicago Avenue, Searle 12-561, Chicago, IL, 60611, USA. .,Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Tech E310, Evanston, IL, 60208, USA. .,The Hugh Knowles Center, Department of Communication Sciences and Disorders, Northwestern University, Frances Searle Building, 2240 Campus Drive, Evanston, IL, 60208, USA.
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33
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Greenberg JM, Lumbreras V, Pelaez D, Rajguru SM, Cheung HS. Neural Crest Stem Cells Can Differentiate to a Cardiomyogenic Lineage with an Ability to Contract in Response to Pulsed Infrared Stimulation. Tissue Eng Part C Methods 2017; 22:982-990. [PMID: 28192031 DOI: 10.1089/ten.tec.2016.0232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION Cellular cardiomyoplasty has rapidly risen to prominence in the clinic following a myocardial infarction; however, low engraftment of transplanted cells limits the therapeutic benefit to these procedures. Recently, lineage-specific stem cells differentiated into cardiomyocytes have gained much attention to assist in the repair of an injured heart tissue; however, questions regarding the ideal cell source remain. In the present study, we have identified a source that is easy to extract stem cells from and show that the cells present have a high plasticity toward the cardiomyogenic lineage. We focused on the recently discovered neural crest stem cells residing in the periodontal ligament that can be easily obtained through dental procedures. MATERIALS AND METHODS Neural crest stem cells were obtained from human excised third molars and differentiated in culture using a protocol for directed differentiation into cardiomyocytes. Differentiation of cells was assessed through gene expression and immunostaining studies. Optical stimulation using pulsed infrared radiation (IR) (λ = 1863 nm) was delivered to cell aggregates to study their contractile ability. RESULTS We show that neural crest stem cells can be differentiated to a cardiomyogenic lineage, which was verified through immunostaining and gene expression. We observed a significant increase in cardiomyocyte-specific markers, NK2 homeobox 5 (NKX2.5) and troponin T type 2 (TNNT2), with positive changes in tropomyosin I (TPM1), gap junction protein alpha 1/Cx43 (GJA1/Cx43), and myocyte enhancement factor 2C (MEF2C). Furthermore, we were able to elicit and maintain pulse-by-pulse contractile responses in the derived cells, including in cardiospheres, with pulsed IR delivered at various radiant energies. The contractility in responses to IR could be maintained at different frequencies (0.25-2 Hz) and up to 10-min durations. While these cells did not maintain their contractility following cessation of IR, these cells demonstrated responses to the optical stimuli that are consistent with previous reports. We also found no evidence for irreversible mitochondrial depolarization in these cells following the long duration of infrared stimulation, suggesting the robustness of these cells. CONCLUSIONS Overall, these results suggest the merit of neural crest-derived stem cells for cardiomyogenic applications and a potential cell source for repair that should contribute to efforts to translate cell-based strategies to the clinic.
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Affiliation(s)
- Jordan M Greenberg
- 1 Department of Biomedical Engineering, College of Engineering, University of Miami , Coral Gables, Florida
| | - Vicente Lumbreras
- 1 Department of Biomedical Engineering, College of Engineering, University of Miami , Coral Gables, Florida
| | - Daniel Pelaez
- 2 Geriatric Research, Education and Clinical Center (GRECC), Miami Veterans Affairs Medical Center , Miami, Florida
| | - Suhrud M Rajguru
- 1 Department of Biomedical Engineering, College of Engineering, University of Miami , Coral Gables, Florida.,3 Department of Otolaryngology, Miller School of Medicine, University of Miami , Miami, Florida
| | - Herman S Cheung
- 1 Department of Biomedical Engineering, College of Engineering, University of Miami , Coral Gables, Florida.,2 Geriatric Research, Education and Clinical Center (GRECC), Miami Veterans Affairs Medical Center , Miami, Florida
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34
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Correspondence: Revisiting the theoretical cell membrane thermal capacitance response. Nat Commun 2017; 8:1431. [PMID: 29127422 PMCID: PMC5820289 DOI: 10.1038/s41467-017-00435-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 06/28/2017] [Indexed: 12/14/2022] Open
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35
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Paris L, Marc I, Charlot B, Dumas M, Valmier J, Bardin F. Millisecond infrared laser pulses depolarize and elicit action potentials on in-vitro dorsal root ganglion neurons. BIOMEDICAL OPTICS EXPRESS 2017; 8:4568-4578. [PMID: 29082085 PMCID: PMC5654800 DOI: 10.1364/boe.8.004568] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/25/2017] [Accepted: 07/26/2017] [Indexed: 05/27/2023]
Abstract
This work focuses on the optical stimulation of dorsal root ganglion (DRG) neurons through infrared laser light stimulation. We show that a few millisecond laser pulse at 1875 nm induces a membrane depolarization, which was observed by the patch-clamp technique. This stimulation led to action potentials firing on a minority of neurons beyond an energy threshold. A depolarization without action potential was observed for the majority of DRG neurons, even beyond the action potential energy threshold. The use of ruthenium red, a thermal channel blocker, stops the action potential generation, but has no effects on membrane depolarization. Local temperature measurements reveal that the depolarization amplitude is sensitive to the amplitude of the temperature rise as well as to the time rate of change of temperature, but in a way which may not fully follow a photothermal capacitive mechanism, suggesting that more complex mechanisms are involved.
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Affiliation(s)
- Lambert Paris
- Institut d’Electronique et des Systèmes, CNRS UMR5214, Université de Montpellier, Montpellier, France
- Institut des Neurosciences de Montpellier, INSERM U1051, Montpellier, France
| | | | - Benoit Charlot
- Institut d’Electronique et des Systèmes, CNRS UMR5214, Université de Montpellier, Montpellier, France
| | | | - Jean Valmier
- Institut des Neurosciences de Montpellier, INSERM U1051, Montpellier, France
| | - Fabrice Bardin
- Institut d’Electronique et des Systèmes, CNRS UMR5214, Université de Montpellier, Montpellier, France
- MIPA, Université de Nîmes, Place Gabriel Péri, 30000, Nîmes, France
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36
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McPheeters MT, Wang YT, Werdich AA, Jenkins MW, Laurita KR. An infrared optical pacing system for screening cardiac electrophysiology in human cardiomyocytes. PLoS One 2017; 12:e0183761. [PMID: 28837652 PMCID: PMC5570338 DOI: 10.1371/journal.pone.0183761] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 08/10/2017] [Indexed: 01/05/2023] Open
Abstract
Human cardiac myocytes derived from pluripotent stem cells (hCM) have invigorated interest in genetic disease mechanisms and cardiac safety testing; however, the technology to fully assess electrophysiological function in an assay that is amenable to high throughput screening has lagged. We describe a fully contactless system using optical pacing with an infrared (IR) laser and multi-site high fidelity fluorescence imaging to assess multiple electrophysiological parameters from hCM monolayers in a standard 96-well plate. Simultaneous multi-site action potentials (FluoVolt) or Ca2+ transients (Fluo4-AM) were measured, from which high resolution maps of conduction velocity and action potential duration (APD) were obtained in a single well. Energy thresholds for optical pacing were determined for cell plating density, laser spot size, pulse width, and wavelength and found to be within ranges reported previously for reliable pacing. Action potentials measured using FluoVolt and a microelectrode exhibited the same morphology and rate of depolarization. Importantly, we show that this can be achieved accurately with minimal damage to hCM due to optical pacing or fluorescence excitation. Finally, using this assay we demonstrate that hCM exhibit reproducible changes in repolarization and impulse conduction velocity for Flecainide and Quinidine, two well described reference compounds. In conclusion, we demonstrate a high fidelity electrophysiological screening assay that incorporates optical pacing with IR light to control beating rate of hCM monolayers.
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Affiliation(s)
- Matthew T. McPheeters
- Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Yves T. Wang
- Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Andreas A. Werdich
- Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, Boston, Massachusetts, United States of America
| | - Michael W. Jenkins
- Pediatrics, Case Western Reserve University, Cleveland, Ohio, United States of America
- Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kenneth R. Laurita
- Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, Boston, Massachusetts, United States of America
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, United States of America
- Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Weissler Y, Farah N, Shoham S. Simulation of morphologically structured photo-thermal neural stimulation. J Neural Eng 2017; 14:055001. [PMID: 28820744 DOI: 10.1088/1741-2552/aa7805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Rational design of next-generation techniques for photo-thermal excitation requires the development of tools capable of modeling the effects of spatially- and temporally-dependent temperature distribution on cellular neuronal structures. APPROACH We present a new computer simulation tool for predicting the effects of arbitrary spatiotemporally-structured photo-thermal stimulation on 3D, morphologically realistic neurons. The new simulation tool is based on interfacing two generic platforms, NEURON and MATLAB and is therefore suited for capturing different kinds of stimuli and neural models. MAIN RESULTS Simulation results are validated using photo-absorber induced neuro-thermal stimulation (PAINTS) empirical results, and advanced features are explored. SIGNIFICANCE The new simulation tool could have an important role in understanding and investigating complex optical stimulation at the single-cell and network levels.
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Affiliation(s)
- Y Weissler
- The Faculty of Biomedical Engineering and Russel-Berrie Nanoscience and Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel
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38
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Gold Nanoparticles for Modulating Neuronal Behavior. NANOMATERIALS 2017; 7:nano7040092. [PMID: 28441776 PMCID: PMC5408184 DOI: 10.3390/nano7040092] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 11/30/2022]
Abstract
Understanding the detailed functioning and pathophysiology of the brain and the nervous system continues to challenge the scientific community, particularly in terms of scaling up techniques for monitoring and interfacing with complex 3D networks. Nanotechnology has the potential to support this scaling up, where the eventual goal would be to address individual nerve cells within functional units of both the central and peripheral nervous system. Gold nanoparticles provide a variety of physical and chemical properties that have attracted attention as a light-activated nanoscale neuronal interface. This review provides a critical overview of the photothermal and photomechanical properties of chemically functionalized gold nanoparticles that have been exploited to trigger a range of biological responses in neuronal tissues, including modulation of electrical activity and nerve regeneration. The prospects and challenges for further development are also discussed.
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Tolstykh GP, Olsovsky CA, Ibey BL, Beier HT. Ryanodine and IP 3 receptor-mediated calcium signaling play a pivotal role in neurological infrared laser modulation. NEUROPHOTONICS 2017; 4:025001. [PMID: 28413806 PMCID: PMC5381754 DOI: 10.1117/1.nph.4.2.025001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/20/2017] [Indexed: 05/13/2023]
Abstract
Pulsed infrared (IR) laser energy has been shown to modulate neurological activity through both stimulation and inhibition of action potentials. While the mechanism(s) behind this phenomenon is (are) not completely understood, certain hypotheses suggest that the rise in temperature from IR exposure could activate temperature- or pressure-sensitive ion channels or create pores in the cellular outer membrane, allowing an influx of typically plasma-membrane-impermeant ions. Studies using fluorescent intensity-based calcium ion ([Formula: see text]) sensitive dyes show changes in [Formula: see text] levels after various IR stimulation parameters, which suggests that [Formula: see text] may originate from the external solution. However, activation of intracellular signaling pathways has also been demonstrated, indicating a more complex mechanism of increasing intracellular [Formula: see text] concentration. We quantified the [Formula: see text] mobilization in terms of influx from the external solution and efflux from intracellular organelles using Fura-2 and a high-speed ratiometric imaging system that rapidly alternates the dye excitation wavelengths. Using nonexcitable Chinese hamster ovarian ([Formula: see text]) cells and neuroblastoma-glioma (NG108) cells, we demonstrate that intracellular [Formula: see text] receptors play an important role in the IR-induced [Formula: see text], with the [Formula: see text] response augmented by ryanodine receptors in excitable cells.
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Affiliation(s)
- Gleb P. Tolstykh
- General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, Texas, United States
- Address all correspondence to: Gleb P. Tolstykh, E-mail:
| | - Cory A. Olsovsky
- Texas A&M University, Department of Biomedical Engineering, College Station, Texas, United States
| | - Bennett L. Ibey
- Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
| | - Hope T. Beier
- Air Force Research Laboratory, 711th Human Performance Wing, Airman System Directorate, Bioeffects Division, Optical Radiation Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, Texas, United States
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40
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Eom K, Hwang S, Yun S, Byun KM, Jun SB, Kim SJ. Photothermal activation of astrocyte cells using localized surface plasmon resonance of gold nanorods. JOURNAL OF BIOPHOTONICS 2017; 10:486-493. [PMID: 28164459 DOI: 10.1002/jbio.201600280] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/30/2016] [Accepted: 01/12/2016] [Indexed: 06/06/2023]
Abstract
Although it has been revealed that astrocytes, generally known as star-shaped glial cells, play critical roles in the functions of central nervous system, there have been few efforts to directly modulate their activities and responses. In this study, an optical stimulation strategy for producing intracellular Ca2+ transients of astrocytes is demonstrated using near-infrared (NIR) light and localized surface plasmon resonance. It is presented that NIR stimulation of micro-second duration combined with gold nanorods (GNRs) efficiently produces stronger Ca2+ transients of astrocytes, which seems to be associated with a local heat generation by photothermal effects of GNRs. Since the proposed scheme can directly activate astrocytes with a high reliability, it is expected that GNR-mediated NIR stimulation could be utilized to facilitate minimally invasive physiological studies on the astrocyte functions. Photos of intracellular Ca2+ transient of astrocytes with membrane-bound GNRs after optical stimulation at 30 s.
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Affiliation(s)
- Kyungsik Eom
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Seoyoung Hwang
- Department of Electronics Engineering, Ewha Womans University, Seoul, 03760, South Korea
| | - Seunghyeon Yun
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Kyung Min Byun
- Department of Biomedical Engineering, Kyung Hee University, Yongin, 17104, South Korea
| | - Sang Beom Jun
- Department of Electronics Engineering, Ewha Womans University, Seoul, 03760, South Korea
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, 03760, South Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, South Korea
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BODIPY-Conjugated Xyloside Primes Fluorescent Glycosaminoglycans in the Inner Ear of Opsanus tau. J Assoc Res Otolaryngol 2016; 17:525-540. [PMID: 27619213 DOI: 10.1007/s10162-016-0585-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/23/2016] [Indexed: 12/22/2022] Open
Abstract
We report on a new xyloside conjugated to BODIPY, BX and its utility to prime fluorescent glycosaminoglycans (BX-GAGs) within the inner ear in vivo. When BX is administered directly into the endolymphatic space of the oyster toadfish (Opsanus tau) inner ear, fluorescent BX-GAGs are primed and become visible in the sensory epithelia of the semicircular canals, utricle, and saccule. Confocal and 2-photon microscopy of vestibular organs fixed 4 h following BX treatment, reveal BX-GAGs constituting glycocalyces that envelop hair cell kinocilium, nerve fibers, and capillaries. In the presence of GAG-specific enzymes, the BX-GAG signals are diminished, suggesting that chondroitin sulfates are the primary GAGs primed by BX. Results are consistent with similar click-xylosides in CHO cell lines, where the xyloside enters the Golgi and preferentially initiates chondroitin sulfate B production. Introduction of BX produces a temporary block of hair cell mechanoelectrical transduction (MET) currents in the crista, reduction in background discharge rate of afferent neurons, and a reduction in sensitivity to physiological stimulation. A six-degree-of-freedom pharmacokinetic mathematical model has been applied to interpret the time course and spatial distribution of BX and BX-GAGs. Results demonstrate a new optical approach to study GAG biology in the inner ear, for tracking synthesis and localization in real time.
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Entwisle B, McMullan S, Bokiniec P, Gross S, Chung R, Withford M. In vitro neuronal depolarization and increased synaptic activity induced by infrared neural stimulation. BIOMEDICAL OPTICS EXPRESS 2016; 7:3211-3219. [PMID: 27699093 PMCID: PMC5030005 DOI: 10.1364/boe.7.003211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/07/2016] [Accepted: 07/14/2016] [Indexed: 05/11/2023]
Abstract
Neuronal responses to infrared neural stimulation (INS) are explored at the single cell level using patch-clamp electrophysiology. We examined membrane and synaptic responses of solitary tract neurons recorded in acute slices prepared from the Sprague-Dawley rat. Neurons were stimulated using a compact 1890 nm waveguide laser with light delivered to a small target area, comparable to the size of a single cell, via a single-mode fiber. We show that infrared radiation increased spontaneous synaptic event frequency, and evoked steady-state currents and neuronal depolarization. The magnitude of the responses was proportional to laser output.
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Affiliation(s)
- Blake Entwisle
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
| | - Simon McMullan
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Phillip Bokiniec
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Simon Gross
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
| | - Roger Chung
- Australian School of Advanced Medicine, Faculty of Human Sciences, Macquarie University,
Australia
| | - Michael Withford
- Department of Physics and Astronomy, Faculty of Science and Engineering, Macquarie University, Australia Centre for Ultrahigh bandwidth Devices for Optical Systems,
Australia
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43
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Optoacoustic effect is responsible for laser-induced cochlear responses. Sci Rep 2016; 6:28141. [PMID: 27301846 PMCID: PMC4908384 DOI: 10.1038/srep28141] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/27/2016] [Indexed: 12/17/2022] Open
Abstract
Optical stimulation of the cochlea with laser light has been suggested as an alternative to conventional treatment of sensorineural hearing loss with cochlear implants. The underlying mechanisms are controversially discussed: The stimulation can either be based on a direct excitation of neurons, or it is a result of an optoacoustic pressure wave acting on the basilar membrane. Animal studies comparing the intra-cochlear optical stimulation of hearing and deafened guinea pigs have indicated that the stimulation requires intact hair cells. Therefore, optoacoustic stimulation seems to be the underlying mechanism. The present study investigates optoacoustic characteristics using pulsed laser stimulation for in vivo experiments on hearing guinea pigs and pressure measurements in water. As a result, in vivo as well as pressure measurements showed corresponding signal shapes. The amplitude of the signal for both measurements depended on the absorption coefficient and on the maximum of the first time-derivative of laser pulse power (velocity of heat deposition). In conclusion, the pressure measurements directly demonstrated that laser light generates acoustic waves, with amplitudes suitable for stimulating the (partially) intact cochlea. These findings corroborate optoacoustic as the basic mechanism of optical intra-cochlear stimulation.
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44
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Rabbitt RD, Brichta AM, Tabatabaee H, Boutros PJ, Ahn J, Della Santina CC, Poppi LA, Lim R. Heat pulse excitability of vestibular hair cells and afferent neurons. J Neurophysiol 2016; 116:825-43. [PMID: 27226448 DOI: 10.1152/jn.00110.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022] Open
Abstract
In the present study we combined electrophysiology with optical heat pulse stimuli to examine thermodynamics of membrane electrical excitability in mammalian vestibular hair cells and afferent neurons. We recorded whole cell currents in mammalian type II vestibular hair cells using an excised preparation (mouse) and action potentials (APs) in afferent neurons in vivo (chinchilla) in response to optical heat pulses applied to the crista (ΔT ≈ 0.25°C per pulse). Afferent spike trains evoked by heat pulse stimuli were diverse and included asynchronous inhibition, asynchronous excitation, and/or phase-locked APs synchronized to each infrared heat pulse. Thermal responses of membrane currents responsible for APs in ganglion neurons were strictly excitatory, with Q10 ≈ 2. In contrast, hair cells responded with a mix of excitatory and inhibitory currents. Excitatory hair cell membrane currents included a thermoelectric capacitive current proportional to the rate of temperature rise (dT/dt) and an inward conduction current driven by ΔT An iberiotoxin-sensitive inhibitory conduction current was also evoked by ΔT, rising in <3 ms and decaying with a time constant of ∼24 ms. The inhibitory component dominated whole cell currents in 50% of hair cells at -68 mV and in 67% of hair cells at -60 mV. Responses were quantified and described on the basis of first principles of thermodynamics. Results identify key molecular targets underlying heat pulse excitability in vestibular sensory organs and provide quantitative methods for rational application of optical heat pulses to examine protein biophysics and manipulate cellular excitability.
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Affiliation(s)
- Richard D Rabbitt
- Departments of Bioengineering and Otolaryngology, University of Utah, Salt Lake City, Utah;
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Hessam Tabatabaee
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Peter J Boutros
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - JoongHo Ahn
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Charles C Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Lauren A Poppi
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
| | - Rebecca Lim
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, New South Wales, Australia; and
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45
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Oyama K, Arai T, Isaka A, Sekiguchi T, Itoh H, Seto Y, Miyazaki M, Itabashi T, Ohki T, Suzuki M, Ishiwata S. Directional bleb formation in spherical cells under temperature gradient. Biophys J 2016. [PMID: 26200871 DOI: 10.1016/j.bpj.2015.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Living cells sense absolute temperature and temporal changes in temperature using biological thermosensors such as ion channels. Here, we reveal, to our knowledge, a novel mechanism of sensing spatial temperature gradients within single cells. Spherical mitotic cells form directional membrane extensions (polar blebs) under sharp temperature gradients (≥∼0.065°C μm(-1); 1.3°C temperature difference within a cell), which are created by local heating with a focused 1455-nm laser beam under an optical microscope. On the other hand, multiple nondirectional blebs are formed under gradual temperature gradients or uniform heating. During heating, the distribution of actomyosin complexes becomes inhomogeneous due to a break in the symmetry of its contractile force, highlighting the role of the actomyosin complex as a sensor of local temperature gradients.
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Affiliation(s)
- Kotaro Oyama
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
| | - Tomomi Arai
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Akira Isaka
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Taku Sekiguchi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Hideki Itoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; Institute of Medical Biology, Agency for Science, Technology and Research (A(∗)STAR), Singapore, Singapore
| | - Yusuke Seto
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Makito Miyazaki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takeshi Itabashi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Takashi Ohki
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
| | - Shin'ichi Ishiwata
- Department of Physics, School of Advanced Science and Engineering, Waseda University, Tokyo, Japan; WASEDA Bioscience Research Institute in Singapore (WABIOS), Singapore, Singapore; Organization for University Research Initiatives, Waseda University, Tokyo, Japan.
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46
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Oyama K, Zeeb V, Kawamura Y, Arai T, Gotoh M, Itoh H, Itabashi T, Suzuki M, Ishiwata S. Triggering of high-speed neurite outgrowth using an optical microheater. Sci Rep 2015; 5:16611. [PMID: 26568288 PMCID: PMC4645119 DOI: 10.1038/srep16611] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 10/16/2015] [Indexed: 12/12/2022] Open
Abstract
Optical microheating is a powerful non-invasive method for manipulating biological functions such as gene expression, muscle contraction, and cell excitation. Here, we demonstrate its potential usage for regulating neurite outgrowth. We found that optical microheating with a water-absorbable 1,455-nm laser beam triggers directional and explosive neurite outgrowth and branching in rat hippocampal neurons. The focused laser beam under a microscope rapidly increases the local temperature from 36 °C to 41 °C (stabilized within 2 s), resulting in the elongation of neurites by more than 10 μm within 1 min. This high-speed, persistent elongation of neurites was suppressed by inhibitors of both microtubule and actin polymerization, indicating that the thermosensitive dynamics of these cytoskeletons play crucial roles in this heat-induced neurite outgrowth. Furthermore, we showed that microheating induced the regrowth of injured neurites and the interconnection of neurites. These results demonstrate the efficacy of optical microheating methods for the construction of arbitrary neural networks.
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Affiliation(s)
- Kotaro Oyama
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Vadim Zeeb
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region 142292, Russia
| | - Yuki Kawamura
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Tomomi Arai
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Department of Cell Physiology, The Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Mizuho Gotoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Hideki Itoh
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), 8A Biomedical Grove, #06-06 Immunos, Singapore 138648, Singapore
| | - Takeshi Itabashi
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Madoka Suzuki
- WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore.,Organization for University Research Initiatives, Waseda University, #304, Block 120-4, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041 Japan
| | - Shin'ichi Ishiwata
- Department of Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.,WASEDA Bioscience Research Institute in Singapore (WABIOS), 11 Biopolis Way, #05-02 Helios, Singapore 138667, Singapore.,Organization for University Research Initiatives, Waseda University, #304, Block 120-4, 513 Wasedatsurumaki-cho, Shinjuku-ku, Tokyo, 162-0041 Japan
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47
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Radiant energy required for infrared neural stimulation. Sci Rep 2015; 5:13273. [PMID: 26305106 PMCID: PMC4548241 DOI: 10.1038/srep13273] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 07/06/2015] [Indexed: 12/15/2022] Open
Abstract
Infrared neural stimulation (INS) has been proposed as an alternative method to electrical stimulation because of its spatial selective stimulation. Independent of the mechanism for INS, to translate the method into a device it is important to determine the energy for stimulation required at the target structure. Custom-designed, flat and angle polished fibers, were used to deliver the photons. By rotating the angle polished fibers, the orientation of the radiation beam in the cochlea could be changed. INS-evoked compound action potentials and single unit responses in the central nucleus of the inferior colliculus (ICC) were recorded. X-ray computed tomography was used to determine the orientation of the optical fiber. Maximum responses were observed when the radiation beam was directed towards the spiral ganglion neurons (SGNs), whereas little responses were seen when the beam was directed towards the basilar membrane. The radiant exposure required at the SGNs to evoke compound action potentials (CAPs) or ICC responses was on average 18.9 ± 12.2 or 10.3 ± 4.9 mJ/cm(2), respectively. For cochlear INS it has been debated whether the radiation directly stimulates the SGNs or evokes a photoacoustic effect. The results support the view that a direct interaction between neurons and radiation dominates the response to INS.
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48
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Young HK, Tan X, Xia N, Richter CP. Target structures for cochlear infrared neural stimulation. NEUROPHOTONICS 2015; 2:025002. [PMID: 26158006 PMCID: PMC4478722 DOI: 10.1117/1.nph.2.2.025002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 04/21/2015] [Indexed: 05/13/2023]
Abstract
Infrared neural stimulation (INS) is a method to depolarize neurons with infrared light. While consensus exists that heating of the target structure is essential, subsequent steps that result in the generation of an action potential are controversially discussed in the literature. The question of whether cochlear INS is an acoustic event has not been clarified. Results have been published that could be explained solely by an acoustic event. However, data exist that do not support an acoustical stimulus as the dominant factor in cochlear INS. We review the different findings that have been suggested for the mechanism of INS. Furthermore, we present the data that clarify the role of an acoustical event in cochlear INS. Masking experiments have been performed in hearing, hearing impaired, and severely hearing impaired animals. In normal hearing animals, the laser response could be masked by the acoustic stimulus. Once thresholds to acoustic stimuli were elevated, the ability to acoustically mask the INS response gradually disappeared. Thresholds for acoustic stimuli were significantly elevated in animals with compromised cochlear function, while the thresholds for optical stimulation remained largely unchanged. The results suggest that the direct interaction between the radiation and the target structure dominates cochlear INS.
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Affiliation(s)
- Hunter K. Young
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Xiaodong Tan
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
| | - Nan Xia
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Chongqing University, Key Laboratory of Biorheological Science and Technology, Ministry of Education, 174 Shazheng Street, Chongqing 400044, China
| | - Claus-Peter Richter
- Northwestern University, Department of Otolaryngology, 303 East Chicago Avenue, Searle 12-561, Chicago, Illinois 60611, United States
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Tech E310, Evanston, Illinois 60208, United States
- Northwestern University, The Hugh Knowles Center, Department of Communication Sciences and Disorders, 2240 Campus Drive, Evanston, Illinois 60208, United States
- Address all correspondence to: Claus-Peter Richter, E-mail:
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Infrared neural stimulation fails to evoke neural activity in the deaf guinea pig cochlea. Hear Res 2015; 324:46-53. [PMID: 25796297 DOI: 10.1016/j.heares.2015.03.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 03/02/2015] [Accepted: 03/09/2015] [Indexed: 11/23/2022]
Abstract
At present there is some debate as to the processes by which infrared neural stimulation (INS) activates neurons in the cochlea, as the lasers used for INS can potentially generate a range of secondary stimuli e.g. an acoustic stimulus is produced when the light is absorbed by water. To clarify whether INS in the cochlea requires functioning hair cells and to explore the potential relevance to cochlear implants, experiments using INS were performed in the cochleae of both normal hearing and profoundly deaf guinea pigs. A response to laser stimulation was readily evoked in normal hearing cochlea. However, no response was evoked in any profoundly deaf cochleae, for either acute or chronic deafening, contrary to previous work where a response was observed after acute deafening with ototoxic drugs. A neural response to electrical stimulation was readily evoked in all cochleae after deafening. The absence of a response from optical stimuli in profoundly deaf cochleae suggests that the response from INS in the cochlea is hair cell mediated.
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Thompson AC, Stoddart PR, Jansen ED. Optical Stimulation of Neurons. ACTA ACUST UNITED AC 2015; 3:162-177. [PMID: 26322269 PMCID: PMC4541079 DOI: 10.2174/2211555203666141117220611] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/26/2014] [Accepted: 10/20/2014] [Indexed: 01/01/2023]
Abstract
Our capacity to interface with the nervous system remains overwhelmingly reliant on electrical stimulation devices, such as electrode arrays and cuff electrodes that can stimulate both central and peripheral nervous systems. However, electrical stimulation has to deal with multiple challenges, including selectivity, spatial resolution, mechanical stability, implant-induced injury and the subsequent inflammatory response. Optical stimulation techniques may avoid some of these challenges by providing more selective stimulation, higher spatial resolution and reduced invasiveness of the device, while also avoiding the electrical artefacts that complicate recordings of electrically stimulated neuronal activity. This review explores the current status of optical stimulation techniques, including optogenetic methods, photoactive molecule approaches and infrared neural stimulation, together with emerging techniques such as hybrid optical-electrical stimulation, nanoparticle enhanced stimulation and optoelectric methods. Infrared neural stimulation is particularly emphasised, due to the potential for direct activation of neural tissue by infrared light, as opposed to techniques that rely on the introduction of exogenous light responsive materials. However, infrared neural stimulation remains imperfectly understood, and techniques for accurately delivering light are still under development. While the various techniques reviewed here confirm the overall feasibility of optical stimulation, a number of challenges remain to be overcome before they can deliver their full potential.
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Affiliation(s)
- Alexander C Thompson
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - Paul R Stoddart
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Australia
| | - E Duco Jansen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
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