Editorial

2 pages, 145 KiB

Open AccessEditorial

Editorial for the Special Issue on Wireless Microdevices and Systems for Biomedical Applications

by Paulo Mateus Mendes

Micromachines 2018, 9(3), 112; https://doi.org/10.3390/mi9030112 - 05 Mar 2018

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Wireless microdevices are getting smaller and smaller, and in this special issue seven papers address a few miniaturization challenges in the biomedical field, which are common across different applications. Kargaran et al. [1] proposes a new ultra-low-voltage ultra-low-power LNA, where the reduced current [...] Read more.

Wireless microdevices are getting smaller and smaller, and in this special issue seven papers address a few miniaturization challenges in the biomedical field, which are common across different applications. Kargaran et al. [1] proposes a new ultra-low-voltage ultra-low-power LNA, where the reduced current consumption of only 160 μA, on a supply as low as 0.18 V, has potential to enable future RF receivers for ultra-low-power implantable devices [...]
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(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

Research

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16 pages, 7832 KiB

Open AccessFeature PaperArticle

Design and Performance Assessment of a Solid-State Microcooler for Thermal Neuromodulation

by José Fernandes, Estelle Vendramini, Ana M. Miranda, Cristiana Silva, Hugo Dinis, Veronique Coizet, Olivier David and Paulo Mateus Mendes

Micromachines 2018, 9(2), 47; https://doi.org/10.3390/mi9020047 - 27 Jan 2018

Cited by 11 | Viewed by 5666

Abstract

It is well known that neural activity can be modulated using a cooling device. The applications of this technique range from the treatment of medication-resistant cerebral diseases to brain functional mapping. Despite the potential benefits of such technique, its use has been limited [...] Read more.

It is well known that neural activity can be modulated using a cooling device. The applications of this technique range from the treatment of medication-resistant cerebral diseases to brain functional mapping. Despite the potential benefits of such technique, its use has been limited due to the lack of suitable thermal modulators. This paper presents the design and validation of a solid-state cooler that was able to modulate the neural activity of rodents without the use of large and unpractical water pipes. A miniaturized thermal control solution based exclusively on solid-state devices was designed, occupying only 5 mm × 5 mm × 3 mm, and featuring the potential for wireless power and communications. The cold side of the device was cooled to 26 °C, while the hot side was kept below 43 °C. This range of temperatures is compatible with brain cooling and efficient enough for achieving some control of neural activity. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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11 pages, 2380 KiB

Open AccessArticle

Design Considerations for a Sub-mW Wireless Medical Body-Area Network Receiver Front End

by Ehsan Kargaran, Danilo Manstretta and Rinaldo Castello

Micromachines 2018, 9(1), 31; https://doi.org/10.3390/mi9010031 - 17 Jan 2018

Cited by 2 | Viewed by 3887

Abstract

Wireless medical body-area networks are used to connect sensor nodes that monitor vital parameters. The radio consumes a large portion of the sensor energy budget, and hence its power dissipation should be minimized. The low-noise amplifier (LNA) is an important component of the [...] Read more.

Wireless medical body-area networks are used to connect sensor nodes that monitor vital parameters. The radio consumes a large portion of the sensor energy budget, and hence its power dissipation should be minimized. The low-noise amplifier (LNA) is an important component of the receiver, and must guarantee low-noise amplification and impedance matching. In this work, an ultra-low-voltage ultra-low-power LNA is proposed that, thanks to the proposed transformer-based gate boosting technique, has a reduced current consumption of only 160 μA and can operate with a supply as low as 0.18 V. The LNA was designed using 40 nm Complementary Metal-Oxide Semiconductor (CMOS) technology and features a voltage gain of 14 dB, 5.2 dB NF and −8.6 dBm IIP3. This performance is comparable to a prior work by the same authors, but with the minimum supply voltage reduced by a factor of 4x. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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13 pages, 3722 KiB

Open AccessFeature PaperArticle

A Wireless Implant for Gastrointestinal Motility Disorders

by Yi-Kai Lo, Po-Min Wang, Genia Dubrovsky, Ming-Dao Wu, Michael Chan, James C. Y. Dunn and Wentai Liu

Micromachines 2018, 9(1), 17; https://doi.org/10.3390/mi9010017 - 02 Jan 2018

Cited by 22 | Viewed by 8616

Abstract

Implantable functional electrical stimulation (IFES) has demonstrated its effectiveness as an alternative treatment option for diseases incurable pharmaceutically (e.g., retinal prosthesis, cochlear implant, spinal cord implant for pain relief). However, the development of IFES for gastrointestinal (GI) tract modulation is still limited due [...] Read more.

Implantable functional electrical stimulation (IFES) has demonstrated its effectiveness as an alternative treatment option for diseases incurable pharmaceutically (e.g., retinal prosthesis, cochlear implant, spinal cord implant for pain relief). However, the development of IFES for gastrointestinal (GI) tract modulation is still limited due to the poorly understood GI neural network (gut–brain axis) and the fundamental difference among activating/monitoring smooth muscles, skeletal muscles and neurons. This inevitably imposes different design specifications for GI implants. This paper thus addresses the design requirements for an implant to treat GI dysmotility and presents a miniaturized wireless implant capable of modulating and recording GI motility. This implant incorporates a custom-made system-on-a-chip (SoC) and a heterogeneous system-in-a-package (SiP) for device miniaturization and integration. An in vivo experiment using both rodent and porcine models is further conducted to validate the effectiveness of the implant. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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749 KiB

Open AccessArticle

Design of a Compact Wireless Multi-Channel High Area-Efficient Stimulator with Arbitrary Channel Configuration

by Yuwei Zhang, Deng Luo, Ting Ou, Zhangyi Yuan, Heng Huang, Ling You, Yin Yue, Milin Zhang, Dongmei Li, Guolin Li, Kexin Yuan and Zhihua Wang

Micromachines 2018, 9(1), 6; https://doi.org/10.3390/mi9010006 - 27 Dec 2017

Cited by 45 | Viewed by 5460

Abstract

This paper presents the design of a wireless, implantable, multi-channel, programmable stimulator with arbitrary channel combination. A novel channel management module using a switch array is presented, enabling arbitrary channel configuration with a silicon area reduction of 81%. The chip was fabricated in [...] Read more.

This paper presents the design of a wireless, implantable, multi-channel, programmable stimulator with arbitrary channel combination. A novel channel management module using a switch array is presented, enabling arbitrary channel configuration with a silicon area reduction of 81%. The chip was fabricated in a 0.18-

μ

m Taiwan semiconductor manufacturing company (TSMC) high voltage (HV) complementary metal–oxide semiconductor (CMOS) technology. A stimulator system was realized using the proposed integrated circuit (IC). A wireless communication link was established between a specified Android-based graphical user interface (GUI) and the proposed device for control of the stimulation pattern and wireless battery charging. The size of the entire system occupies a volume of only 14 mm × 14 mm × 4 mm (without the battery). Experimental results demonstrated a successful independent configuration between different channels, as well as an arbitrary channel combination, as expected. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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15773 KiB

Open AccessFeature PaperArticle

Optic Nerve Stimulation System with Adaptive Wireless Powering and Data Telemetry

by Xing Li, Yan Lu, Xiaodong Meng, Chi-Ying Tsui and Wing-Hung Ki

Micromachines 2017, 8(12), 368; https://doi.org/10.3390/mi8120368 - 20 Dec 2017

Cited by 8 | Viewed by 5886

Abstract

To treat retinal degenerative diseases, a transcorneal electrical stimulation-based system is proposed, which consists of an eye implant and an external component. The eye implant is wirelessly powered and controlled by the external component to generate the required bi-polar current pattern for transcorneal [...] Read more.

To treat retinal degenerative diseases, a transcorneal electrical stimulation-based system is proposed, which consists of an eye implant and an external component. The eye implant is wirelessly powered and controlled by the external component to generate the required bi-polar current pattern for transcorneal stimulation with an amplitude range of 5 μA to 320 μA, a frequency range of 10 Hz to 160 Hz and a duty ratio range of 2.5% to 20%. Power delivery control includes power boosting in preparation for stimulation, and normal power regulation that adapts to both coupling and load variations. Only one pair of coils is used for both the power link and the bi-directional data link. Except for the secondary coil, the eye implant is fully integrated on chip and is fabricated using UMC (United Microelectronics Corporation, Hsinchu, Taiwan) 0.13 μm complementary metal-oxide-semiconductor (CMOS) process with a size of 1.5 mm × 1.5 mm. The secondary coil is fabricated on a printed circuit board (PCB) with a diameter of only 4.4 mm. After coating with biocompatible silicone, the whole implant has dimensions of 6 mm in diameter with a thickness of less than 1 mm. The whole device can be put onto the sclera and beneath the eye’s conjunctiva. System functionality and electrical performance are demonstrated with measurement results. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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5547 KiB

Open AccessArticle

Miniaturization of Implantable Micro-Robot Propulsion Using a Wireless Power Transfer System

by Dongwook Kim, Karam Hwang, Jaehyoung Park, Hyun Ho Park and Seungyoung Ahn

Micromachines 2017, 8(9), 269; https://doi.org/10.3390/mi8090269 - 01 Sep 2017

Cited by 10 | Viewed by 4812

Abstract

This paper presents an efficient coil design for a mm-sized micro-robot which generates a propulsion force and torque and receives electrical energy using a wireless power transfer system. To determine the most efficient coil structures and produce propulsion and torque on the micro-robot, [...] Read more.

This paper presents an efficient coil design for a mm-sized micro-robot which generates a propulsion force and torque and receives electrical energy using a wireless power transfer system. To determine the most efficient coil structures and produce propulsion and torque on the micro-robot, both helical and spiral coil modeling was conducted, and analytical formulations of the propulsion force and torque were derived for helical and spiral coil structures. Additionally, the dominant dimensional factors for determining propulsion and coil torque were analyzed in detail. Based on the results, an optimum coil structure for generating maximum force on the micro-robot was developed and is herein presented with dimensional analysis. Simulations and experiments were also conducted to verify the design, and good agreement was achieved. A 3-mm micro-robot that simultaneously generated a propulsion force and torque and received electrical energy via wireless power transfer was successfully fabricated using the proposed method and verified. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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Review

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11174 KiB

Open AccessFeature PaperReview

Extending the Limits of Wireless Power Transfer to Miniaturized Implantable Electronic Devices

by Hugo Dinis, Ivo Colmiais and Paulo Mateus Mendes

Micromachines 2017, 8(12), 359; https://doi.org/10.3390/mi8120359 - 12 Dec 2017

Cited by 39 | Viewed by 7800

Abstract

Implantable electronic devices have been evolving at an astonishing pace, due to the development of fabrication techniques and consequent miniaturization, and a higher efficiency of sensors, actuators, processors and packaging. Implantable devices, with sensing, communication, actuation, and wireless power are of high demand, [...] Read more.

Implantable electronic devices have been evolving at an astonishing pace, due to the development of fabrication techniques and consequent miniaturization, and a higher efficiency of sensors, actuators, processors and packaging. Implantable devices, with sensing, communication, actuation, and wireless power are of high demand, as they pave the way for new applications and therapies. Long-term and reliable powering of such devices has been a challenge since they were first introduced. This paper presents a review of representative state of the art implantable electronic devices, with wireless power capabilities, ranging from inductive coupling to ultrasounds. The different power transmission mechanisms are compared, to show that, without new methodologies, the power that can be safely transmitted to an implant is reaching its limit. Consequently, a new approach, capable of multiplying the available power inside a brain phantom for the same specific absorption rate (SAR) value, is proposed. In this paper, a setup was implemented to quadruple the power available in the implant, without breaking the SAR limits. A brain phantom was used for concept verification, with both simulation and measurement data. Full article

(This article belongs to the Special Issue Wireless Microdevices and Systems for Biomedical Applications)

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