87 research outputs found
Wireless tools for neuromodulation
Epilepsy is a spectrum of diseases characterized by recurrent seizures. It is estimated that 50 million individuals worldwide are affected and 30% of cases are medically refractory or drug resistant. Vagus nerve stimulation (VNS) and deep brain stimulation (DBS) are the only FDA approved device based therapies. Neither therapy offers complete seizure freedom in a majority of users. Novel methodologies are needed to better understand mechanisms and chronic nature of epilepsy. Most tools for neuromodulation in rodents are tethered. The few wireless devices use batteries or are inductively powered. The tether restricts movement, limits behavioral tests, and increases the risk of infection. Batteries are large and heavy with a limited lifetime. Inductive powering suffers from rapid efficiency drops due to alignment mismatches and increased distances. Miniature wireless tools that offer behavioral freedom, data acquisition, and stimulation are needed. This dissertation presents a platform of electrical, optical and radiofrequency (RF) technologies for device based neuromodulation. The platform can be configured with features including: two channels differential recording, one channel electrical stimulation, and one channel optical stimulation. Typical device operation consumes less than 4 mW. The analog front end has a bandwidth of 0.7 Hz - 1 kHz and a gain of 60 dB, and the constant current driver provides biphasic electrical stimulation. For use with optogenetics, the deep brain optical stimulation module provides 27 mW/mm2 of blue light (473 nm) with 21.01 mA. Pairing of stimulating and recording technologies allows closed-loop operation. A wireless powering cage is designed using the resonantly coupled filter energy transfer (RCFET) methodology. RF energy is coupled through magnetic resonance. The cage has a PTE ranging from 1.8-6.28% for a volume of 11 x 11 x 11 in3. This is sufficient to chronically house subjects. The technologies are validated through various in vivo preparations. The tools are designed to study epilepsy, SUDEP, and urinary incontinence but can be configured for other studies. The broad application of these technologies can enable the scientific community to better study chronic diseases and closed-loop therapies
Technology applications
A summary of NASA Technology Utilization programs for the period of 1 December 1971 through 31 May 1972 is presented. An abbreviated description of the overall Technology Utilization Applications Program is provided as a background for the specific applications examples. Subjects discussed are in the broad headings of: (1) cancer, (2) cardiovascular disease, (2) medical instrumentation, (4) urinary system disorders, (5) rehabilitation medicine, (6) air and water pollution, (7) housing and urban construction, (8) fire safety, (9) law enforcement and criminalistics, (10) transportation, and (11) mine safety
μνλλ¬Όμ λμ κ²½ μκ·Ήμ μν μμ μ΄μν μ κ²½μκ·ΉκΈ°
νμλ
Όλ¬Έ(λ°μ¬)--μμΈλνκ΅ λνμ :곡과λν μ κΈ°Β·μ 보곡νλΆ,2020. 2. κΉμ±μ€.In this study, a fully implantable neural stimulator that is designed to stimulate the brain in the small animal is described. Electrical stimulation of the small animal is applicable to pre-clinical study, and behavior study for neuroscience research, etc. Especially, behavior study of the freely moving animal is useful to observe the modulation of sensory and motor functions by the stimulation. It involves conditioning animal's movement response through directional neural stimulation on the region of interest. The main technique that enables such applications is the development of an implantable neural stimulator. Implantable neural stimulator is used to modulate the behavior of the animal, while it ensures the free movement of the animals. Therefore, stable operation in vivo and device size are important issues in the design of implantable neural stimulators. Conventional neural stimulators for brain stimulation of small animal are comprised of electrodes implanted in the brain and a pulse generation circuit mounted on the back of the animal. The electrical stimulation generated from the circuit is conveyed to the target region by the electrodes wire-connected with the circuit. The devices are powered by a large battery, and controlled by a microcontroller unit. While it represents a simple approach, it is subject to various potential risks including short operation time, infection at the wound, mechanical failure of the device, and animals being hindered to move naturally, etc. A neural stimulator that is miniaturized, fully implantable, low-powered, and capable of wireless communication is required.
In this dissertation, a fully implantable stimulator with remote controllability, compact size, and minimal power consumption is suggested for freely moving animal application. The stimulator consists of modular units of surface-type and depth-type arrays for accessing target brain area, package for accommodating the stimulating electronics all of which are assembled after independent fabrication and implantation using customized flat cables and connectors. The electronics in the package contains ZigBee telemetry for low-power wireless communication, inductive link for recharging lithium battery, and an ASIC that generates biphasic pulse for neural stimulation. A dual-mode power-saving scheme with a duty cycling was applied to minimize the power consumption. All modules were packaged using liquid crystal polymer (LCP) to avoid any chemical reaction after implantation.
To evaluate the fabricated stimulator, wireless operation test was conducted. Signal-to-Noise Ratio (SNR) of the ZigBee telemetry were measured, and its communication range and data streaming capacity were tested. The amount of power delivered during the charging session depending on the coil distance was measured. After the evaluation of the device functionality, the stimulator was implanted into rats to train the animals to turn to the left (or right) following a directional cue applied to the barrel cortex. Functionality of the device was also demonstrated in a three-dimensional maze structure, by guiding the rats to navigate better in the maze. Finally, several aspects of the fabricated device were discussed further.λ³Έ μ°κ΅¬μμλ μν λλ¬Όμ λλλ₯Ό μκ·ΉνκΈ° μν μμ μ΄μν μ κ²½μκ·ΉκΈ°κ° κ°λ°λμλ€. μν λλ¬Όμ μ κΈ°μκ·Ήμ μ μμ μ°κ΅¬, μ κ²½κ³Όν μ°κ΅¬λ₯Ό μν νλμ°κ΅¬ λ±μ νμ©λλ€. νΉν, μμ λ‘κ² μμ§μ΄λ λλ¬Όμ λμμΌλ‘ ν νλ μ°κ΅¬λ μκ·Ήμ μν κ°κ° λ° μ΄λ κΈ°λ₯μ μ‘°μ μ κ΄μ°°νλ λ° μ μ©νκ² νμ©λλ€. νλ μ°κ΅¬λ λλμ νΉμ κ΄μ¬ μμμ μ§μ μ μΌλ‘ μκ·Ήνμ¬ λλ¬Όμ νλλ°μμ 쑰건ννλ λ°©μμΌλ‘ μνλλ€. μ΄λ¬ν μ μ©μ κ°λ₯μΌ νλ ν΅μ¬κΈ°μ μ μ΄μν μ κ²½μκ·ΉκΈ°μ κ°λ°μ΄λ€. μ΄μν μ κ²½μκ·ΉκΈ°λ λλ¬Όμ μμ§μμ λ°©ν΄νμ§ μμΌλ©΄μλ κ·Έ νλμ μ‘°μ νκΈ° μν΄ μ¬μ©λλ€. λ°λΌμ λλ¬Ό λ΄μμμ μμ μ μΈ λμκ³Ό μ₯μΉμ ν¬κΈ°κ° μ΄μν μ κ²½μκ·ΉκΈ°λ₯Ό μ€κ³ν¨μ μμ΄ μ€μν λ¬Έμ μ΄λ€. κΈ°μ‘΄μ μ κ²½μκ·ΉκΈ°λ λλμ μ΄μλλ μ κ·Ή λΆλΆκ³Ό, λλ¬Όμ λ± λΆλΆμ μμΉν νλ‘λΆλΆμΌλ‘ ꡬμ±λλ€. νλ‘μμ μμ°λ μ κΈ°μκ·Ήμ νλ‘μ μ μ μΌλ‘ μ°κ²°λ μ κ·Ήμ ν΅ν΄ λͺ©ν μ§μ μΌλ‘ μ λ¬λλ€. μ₯μΉλ λ°°ν°λ¦¬μ μν΄ κ΅¬λλλ©°, λ΄μ₯λ λ§μ΄ν¬λ‘ 컨νΈλ‘€λ¬μ μν΄ μ μ΄λλ€. μ΄λ μ½κ³ κ°λ¨ν μ κ·Όλ°©μμ΄μ§λ§, 짧μ λμμκ°, μ΄μλΆμμ κ°μΌμ΄λ μ₯μΉμ κΈ°κ³μ κ²°ν¨, κ·Έλ¦¬κ³ λλ¬Όμ μμ°μ€λ¬μ΄ μμ§μ λ°©ν΄ λ± μ¬λ¬ λ¬Έμ μ μ μΌκΈ°ν μ μλ€. μ΄λ¬ν λ¬Έμ μ κ°μ μ μν΄ λ¬΄μ ν΅μ μ΄ κ°λ₯νκ³ , μ μ λ ₯, μννλ μμ μ΄μν μ κ²½μκ·ΉκΈ°μ μ€κ³κ° νμνλ€.
λ³Έ μ°κ΅¬μμλ μμ λ‘κ² μμ§μ΄λ λλ¬Όμ μ μ©νκΈ° μνμ¬ μ격 μ μ΄κ° κ°λ₯νλ©°, ν¬κΈ°κ° μκ³ , μλͺ¨μ λ ₯μ΄ μ΅μνλ μμ μ΄μν μκ·ΉκΈ°λ₯Ό μ μνλ€. μ€κ³λ μ κ²½μκ·ΉκΈ°λ λͺ©νλ‘ νλ λλ μμμ μ κ·Όν μ μλ νλ©΄ν μ κ·Ήκ³Ό νμΉ¨ν μ κ·Ή, κ·Έλ¦¬κ³ μκ·Ή νμ€ μμ± νλ‘λ₯Ό ν¬ν¨νλ ν¨ν€μ§ λ±μ λͺ¨λλ€λ‘ ꡬμ±λλ©°, κ°κ°μ λͺ¨λμ λ
립μ μΌλ‘ μ μλμ΄ λλ¬Όμ μ΄μλ λ€ μΌμ΄λΈκ³Ό 컀λ₯ν°λ‘ μ°κ²°λλ€. ν¨ν€μ§ λ΄λΆμ νλ‘λ μ μ λ ₯ 무μ ν΅μ μ μν μ§κ·ΈλΉ νΈλμλ², λ¦¬ν¬ λ°°ν°λ¦¬μ μ¬μΆ©μ μ μν μΈλν°λΈ λ§ν¬, κ·Έλ¦¬κ³ μ κ²½μκ·Ήμ μν μ΄μμ± μκ·Ήννμ μμ±νλ ASICμΌλ‘ ꡬμ±λλ€. μ λ ₯ μ κ°μ μν΄ λ κ°μ λͺ¨λλ₯Ό ν΅ν΄ μ¬μ©λ₯ μ μ‘°μ νλ λ°©μμ΄ μ₯μΉμ μ μ©λλ€. λͺ¨λ λͺ¨λλ€μ μ΄μ νμ μλ¬Όνμ , ννμ μμ μ±μ μν΄ μ‘μ ν΄λ¦¬λ¨Έλ‘ ν¨ν€μ§λμλ€. μ μλ μ κ²½μκ·ΉκΈ°λ₯Ό νκ°νκΈ° μν΄ λ¬΄μ λμ ν
μ€νΈκ° μνλμλ€. μ§κ·ΈλΉ ν΅μ μ μ νΈ λ μ‘μλΉκ° μΈ‘μ λμμΌλ©°, ν΄λΉ ν΅μ μ λμ거리 λ° λ°μ΄ν° μ€νΈλ¦¬λ° μ±λ₯μ΄ κ²μ¬λμκ³ , μ₯μΉμ μΆ©μ μ΄ μνλ λ μ½μΌκ°μ 거리μ λ°λΌ μ μ‘λλ μ λ ₯μ ν¬κΈ°κ° μΈ‘μ λμλ€. μ₯μΉμ νκ° μ΄ν, μ κ²½μκ·ΉκΈ°λ μ₯μ μ΄μλμμΌλ©°, ν΄λΉ λλ¬Όμ μ΄μλ μ₯μΉλ₯Ό μ΄μ©ν΄ λ°©ν₯ μ νΈμ λ°λΌ μ’μ°λ‘ μ΄λνλλ‘ νλ ¨λμλ€. λν, 3μ°¨μ λ―Έλ‘ κ΅¬μ‘°μμ μ₯μ μ΄λλ°©ν₯μ μ λνλ μ€νμ ν΅νμ¬ μ₯μΉμ κΈ°λ₯μ±μ μΆκ°μ μΌλ‘ κ²μ¦νμλ€. λ§μ§λ§μΌλ‘, μ μλ μ₯μΉμ νΉμ§μ΄ μ¬λ¬ μΈ‘λ©΄μμ μ¬μΈ΅μ μΌλ‘ λ
Όμλμλ€.Chapter 1 : Introduction 1
1.1. Neural Interface 2
1.1.1. Concept 2
1.1.2. Major Approaches 3
1.2. Neural Stimulator for Animal Brain Stimulation 5
1.2.1. Concept 5
1.2.2. Neural Stimulator for Freely Moving Small Animal 7
1.3. Suggested Approaches 8
1.3.1. Wireless Communication 8
1.3.2. Power Management 9
1.3.2.1. Wireless Power Transmission 10
1.3.2.2. Energy Harvesting 11
1.3.3. Full implantation 14
1.3.3.1. Polymer Packaging 14
1.3.3.2. Modular Configuration 16
1.4. Objectives of This Dissertation 16
Chapter 2 : Methods 18
2.1. Overview 19
2.1.1. Circuit Description 20
2.1.1.1. Pulse Generator ASIC 21
2.1.1.2. ZigBee Transceiver 23
2.1.1.3. Inductive Link 24
2.1.1.4. Energy Harvester 25
2.1.1.5. Surrounding Circuitries 26
2.1.2. Software Description 27
2.2. Antenna Design 29
2.2.1. RF Antenna 30
2.2.1.1. Design of Monopole Antenna 31
2.2.1.2. FEM Simulation 31
2.2.2. Inductive Link 36
2.2.2.1. Design of Coil Antenna 36
2.2.2.2. FEM Simulation 38
2.3. Device Fabrication 41
2.3.1. Circuit Assembly 41
2.3.2. Packaging 42
2.3.3. Electrode, Feedthrough, Cable, and Connector 43
2.4. Evaluations 45
2.4.1. Wireless Operation Test 46
2.4.1.1. Signal-to-Noise Ratio (SNR) Measurement 46
2.4.1.2. Communication Range Test 47
2.4.1.3. Device Operation Monitoring Test 48
2.4.2. Wireless Power Transmission 49
2.4.3. Electrochemical Measurements In Vitro 50
2.4.4. Animal Testing In Vivo 52
Chapter 3 : Results 57
3.1. Fabricated System 58
3.2. Wireless Operation Test 59
3.2.1. Signal-to-Noise Ratio Measurement 59
3.2.2. Communication Range Test 61
3.2.3. Device Operation Monitoring Test 62
3.3. Wireless Power Transmission 64
3.4. Electrochemical Measurements In Vitro 65
3.5. Animal Testing In Vivo 67
Chapter 4 : Discussion 73
4.1. Comparison with Conventional Devices 74
4.2. Safety of Device Operation 76
4.2.1. Safe Electrical Stimulation 76
4.2.2. Safe Wireless Power Transmission 80
4.3. Potential Applications 84
4.4. Opportunities for Further Improvements 86
4.4.1. Weight and Size 86
4.4.2. Long-Term Reliability 93
Chapter 5 : Conclusion 96
Reference 98
Appendix - Liquid Crystal Polymer (LCP) -Based Spinal Cord Stimulator 107
κ΅λ¬Έ μ΄λ‘ 138
κ°μ¬μ κΈ 140Docto
Recommended from our members
Soft mechanical sensors for wearable and implantable applications
Wearable and implantable sensing of biomechanical signals such as pressure, strain, shear, and vibration can enable a multitude of human-integrated applications, including on-skin monitoring of vital signs, motion tracking, monitoring of internal organ condition, restoration of lost/impaired mechanoreception, among many others. The mechanical conformability of such sensors to the human skin and tissue is critical to enhancing their biocompatibility and sensing accuracy. As such, in the recent decade, significant efforts have been made in the development of soft mechanical sensors. To satisfy the requirements of different wearable and implantable applications, such sensors have been imparted with various additional properties to make them better suited for the varied contexts of human-integrated applications. In this review, focusing on the four major types of soft mechanical sensors for pressure, strain, shear, and vibration, we discussed the recent material and device design innovations for achieving several important properties, including flexibility and stretchability, bioresorbability and biodegradability, self-healing properties, breathability, transparency, wireless communication capabilities, and high-density integration. We then went on to discuss the current research state of the use of such novel soft mechanical sensors in wearable and implantable applications, based on which future research needs were further discussed. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > Diagnostic Nanodevices Implantable Materials and Surgical Technologies > Nanomaterials and Implants</p
Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors
This reprint is a collection of the Special Issue "Advance in Energy Harvesters/Nanogenerators and Self-Powered Sensors" published in Nanomaterials, which includes one editorial, six novel research articles and four review articles, showcasing the very recent advances in energy-harvesting and self-powered sensing technologies. With its broad coverage of innovations in transducing/sensing mechanisms, material and structural designs, system integration and applications, as well as the timely reviews of the progress in energy harvesting and self-powered sensing technologies, this reprint could give readers an excellent overview of the challenges, opportunities, advancements and development trends of this rapidly evolving field
Modern Telemetry
Telemetry is based on knowledge of various disciplines like Electronics, Measurement, Control and Communication along with their combination. This fact leads to a need of studying and understanding of these principles before the usage of Telemetry on selected problem solving. Spending time is however many times returned in form of obtained data or knowledge which telemetry system can provide. Usage of telemetry can be found in many areas from military through biomedical to real medical applications. Modern way to create a wireless sensors remotely connected to central system with artificial intelligence provide many new, sometimes unusual ways to get a knowledge about remote objects behaviour. This book is intended to present some new up to date accesses to telemetry problems solving by use of new sensors conceptions, new wireless transfer or communication techniques, data collection or processing techniques as well as several real use case scenarios describing model examples. Most of book chapters deals with many real cases of telemetry issues which can be used as a cookbooks for your own telemetry related problems
Recommended from our members
A hybrid piezoelectric and electrostatic energy harvester for scavenging arterial pulsations
Implantable and wearable biomedical devices suffer from a limited lifespan of on-board batteries which results in a requirement to change the battery or the device itself causing additional physical discomfort. In order to overcome this, various energy harvesters have been developed. The human body possesses several types of energy available for scavenging through appropriately designed energy harvesting devices, while cardiovascular system in particular represents a constant reliable source of mechanical energy from vibration. Most conventional energy harvesters exploit only a single phenomenon, such piezo- or triboelectricity, thus producing reduced power density. As an improvement, hybridisation of energy harvesters intends to negate this drawback by simultaneously scavenging energy by multiple harvesters.
In the present work, the reverse electrowetting on dielectric (REWOD) phenomenon is combined with the piezoelectric effect in a proof-of-concept hybrid harvester for scavenging biomechanical energy from arterial or other type pulsations. A mathematical model of the harvester was developed, and a computational investigation using CFD, and fluid-structure interaction simulations were carried out using the COMSOL Multiphysics software. The effect of the materials of piezoelectric film and geometrical features of the harvester on parameters such as the displacement, the frequency of pulsations and the energy produced were studied. An experimental setup that could imitate the displacements caused from arterial pulsations was designed and the produced electrical energy characteristics were analysed. A comparison between experimental and computational data was carried out and demonstrated a good agreement. Dependencies between geometrical parameters and electrical output were obtained, recommendation on piezoelectric materials and design solutions were provided
Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14
Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences
- β¦