• Title/Summary/Keyword: Implantable

Search Result 316, Processing Time 0.028 seconds

A High-Voltage Compliant Neural Stimulation IC for Implant Devices Using Standard CMOS Process (체내 이식 기기용 표준 CMOS 고전압 신경 자극 집적 회로)

  • Abdi, Alfian;Cha, Hyouk-Kyu
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.52 no.5
    • /
    • pp.58-65
    • /
    • 2015
  • This paper presents the design of an implantable stimulation IC intended for neural prosthetic devices using $0.18-{\mu}m$ standard CMOS technology. The proposed single-channel biphasic current stimulator prototype is designed to deliver up to 1 mA of current to the tissue-equivalent $10-k{\Omega}$ load using 12.8-V supply voltage. To utilize only low-voltage standard CMOS transistors in the design, transistor stacking with dynamic gate biasing technique is used for reliable operation at high-voltage. In addition, active charge balancing circuit is used to maintain zero net charge at the stimulation site over the complete stimulation cycle. The area of the total stimulator IC consisting of DAC, current stimulation output driver, level-shifters, digital logic, and active charge balancer is $0.13mm^2$ and is suitable to be applied for multi-channel neural prosthetic devices.

A 16-channel Neural Stimulator IC with DAC Sharing Scheme for Artificial Retinal Prostheses

  • Seok, Changho;Kim, Hyunho;Im, Seunghyun;Song, Haryong;Lim, Kyomook;Goo, Yong-Sook;Koo, Kyo-In;Cho, Dong-Il;Ko, Hyoungho
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.14 no.5
    • /
    • pp.658-665
    • /
    • 2014
  • The neural stimulators have been employed to the visual prostheses system based on the functional electrical stimulation (FES). Due to the size limitation of the implantable device, the smaller area of the unit current driver pixel is highly desired for higher resolution current stimulation system. This paper presents a 16-channel compact current-mode neural stimulator IC with digital to analog converter (DAC) sharing scheme for artificial retinal prostheses. The individual pixel circuits in the stimulator IC share a single 6 bit DAC using the sample-and-hold scheme. The DAC sharing scheme enables the simultaneous stimulation on multiple active pixels with a single DAC while maintaining small size and low power. The layout size of the stimulator circuit with the DAC sharing scheme is reduced to be 51.98 %, compared to the conventional scheme. The stimulator IC is designed using standard $0.18{\mu}m$ 1P6M process. The chip size except the I/O cells is $437{\mu}m{\times}501{\mu}m$.

Development of Inductive and Capacitive Type Intraocular Pressure (IOP) Sensor to Improve Sensitivity and Minimize Size (민감도 향상과 센서 소형화를 위한 자기 및 용량형 안압센서의 개발)

  • Jang, Cheol In;Shin, Kyeong-Sik;Yun, Kwang-Seok;Kim, Yong Woo;Kang, Ji Yoon;Lee, Soo Hyun
    • Journal of Sensor Science and Technology
    • /
    • v.23 no.6
    • /
    • pp.409-415
    • /
    • 2014
  • We had presented an inductive type intraocular pressure sensor (L-sensor) in previous work. The distance between a micro coil and a ferrite on the membrane was modulated by pressure, and as a result the inductance and resonant frequency were changed. However, L-sensor has some problems to implant in eyes. First problem is low sensitivity. When L-sensor was implanted in rabbit's eyes, resonant frequency of L-sensor was very hard to detect. Second problem is biocompatibility. Size of L-sensor is $6{\times}7{\times}1.2mm$. When L-sensor was implanted in the eyes, it caused the inflammation. Therefore, this study suggests an inductive and capacitive type IOP sensor (LCsensor). The sensitivity of the LC-sensor 27.3 kHz/mmHg under 60mmHg. It is much larger than 14 kHz/mmHg of the L-sensor. And the size of LC-sensor is 47% smaller than L-sensor. After 2 weeks from the implantation of LC-sensor into rabbit eyes, we measured the changes of resonant frequency of LC-sensor according to increased IOP by Balanced Salt Solution (BSS) injection. As a result, the sensitivity of LC-sensor in in vivo test is 25 kHz/mmHg. That is similar to the sensitivity of in vitro test.

Incorporation of silver nanoparticles on the surface of orthodontic microimplants to achieve antimicrobial properties

  • Venugopal, Adith;Muthuchamy, Nallal;Tejani, Harsh;Anantha-Iyengar-Gopalan, Anantha-Iyengar-Gopalan;Lee, Kwang-Pill;Lee, Heon-Jin;Kyung, Hee Moon
    • The korean journal of orthodontics
    • /
    • v.47 no.1
    • /
    • pp.3-10
    • /
    • 2017
  • Objective: Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods: AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results: SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions: Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial.

Caudal Neuromodulation with the Transforaminal Sacral Electrode (InterStim): Experience in a Pain Center Regarding 12 Implants

  • Guardo, Laura Alonso;Gala, Carlos Cano;Poveda, David Sanchez;Juan, Pablo Rueda;Sanchez Montero, Francisco Jose;Garzon Sanchez, Jose Carlos;Lamas, Juan Ignacio Santos;Sanchez Hernandez, Miguel Vicente
    • The Korean Journal of Pain
    • /
    • v.29 no.1
    • /
    • pp.23-28
    • /
    • 2016
  • Background: Sacral nerve stimulation is a therapeutic option with demonstrated efficacy for conditions presenting with perineal pain caused by different etiologies. We aimed to assess whether a sacral electrode ($Interstim^{(R)}$, Medtronic, Minneapolis, MN, USA) inserted through the caudal pathway is able to offer an acceptable level of sacral stimulation and rate of catheter migration. Methods: We present 12 patients with pelvic pain who received sacral neuromodulation via the sacral hiatus with the InterStim electrode. We evaluated patient satisfaction as well as migration and removal of the electrode, if necessary. Results: Our experience included 12 patients, 10 women and two men, with a mean age of 60 years. In eight of the 12 patients, the initial therapy was effective, and the final system implantation was performed. During subsequent follow-up, patient satisfaction was good. To date, there have been no cases of electrode displacement or migration. Conclusions: The caudal insertion of the InterStim electrode, with its own fixation system, and initially designed for transsacral insertion, appears in our experience to be a satisfactory option which can minimize electrode displacements, achieving similar results in therapeutic efficacy and causing no difficulties in removal.

Three-dimensional Bio-printing Technique: Trend and Potential for High Volume Implantable Tissue Generation

  • Duong, Van-Thuy;Kim, Jong Pal;Kim, Kwangsoo;Ko, Hyoungho;Hwang, Chang Ho;Koo, Kyo-in
    • Journal of Biomedical Engineering Research
    • /
    • v.39 no.5
    • /
    • pp.188-207
    • /
    • 2018
  • Recently, three-dimensional (3D) printing of biological tissues and organ has become an attractive interdisciplinary research topic that combines a broad range of fields including engineering, biomaterials science, cell biology, physics, and medicine. The 3D bioprinting can be used to produce complex tissue engineering scaffolds based on computer designs obtained from patient-specific anatomical data. It is a powerful tool for building structures by printing cells together with matrix materials and biochemical factors in spatially predefined positions within confined 3D structures. In the field of the 3D bioprinting, three major categories of the 3D bioprinting include the stereolithography-based, inkjet-based, and dispensing-based bioprinting. Some of them have made significant process. Each technique has its own advantages and limitations. Compared with non-biological printing, the 3D bioprinting should consider additional complexities: biocompatibility, degradability of printing materials, cell types, cell growth, cell viability, and cell proliferation factors. Numerous 3D bioprinting technologies have been proposed, and some of them have been making great progress in printing several tissues including multilayered skin, cartilaginous structures, bone, vasculature even heart and liver. This review summarizes basic principles and key aspects of some frequently utilized printing technologies, and introduces current challenges, and prospects in the 3D bioprinting.

Characteristics of Nifedipine Loaded PLGA Wafer (니페디핀을 함유한 생분해성 PLGA 웨이퍼의 제조와 특성분석)

  • 서선아;최학수;이동헌;강길선;이해방
    • Polymer(Korea)
    • /
    • v.25 no.6
    • /
    • pp.884-892
    • /
    • 2001
  • Biodegradable wafers were prepared with poly (L-lactide-co-glycolide) (50 : 50 mole ratio of lactide to glycolide, molecular weight:5000 g/mole) by direct compression method for the sustained release of nifedipine to investigate the possibility of the treatment of hypertension. PLGA wafers were prepared by altering initial drug/polymer loading ratio, wafer thickness, and hydroxypropyl methylcellulose (HPMC) content. These wafers showed new zero-order release patterns for 11 days, and various biphasic release patterns could be obtained by altering the composition of wafers such as addition of matrix binder as HPMC to the PLGA wafer to reduce release rate of initial phase. The onset of polymer mass loss only occured after 4 days and about 40% of mass loss was observed after 11 days nifedipine release. This system had advantages in terms of simplicity in design and obviousness of drug release rate and may be useful as an implantable dosage form.

  • PDF

Understanding the Foreign Tech-Trend of Artificial Skin by the Analysis of Patents (특허정보분석을 통한 해외 인공피부 기술동향)

  • 이상필;강종석;이영무
    • Membrane Journal
    • /
    • v.14 no.2
    • /
    • pp.85-98
    • /
    • 2004
  • The situation of technology Predominance and the distribution of core technology were visually mapped thorough the investigation of technical trend during 20 years, which was provided with the analysis of patent information for the artificial skin. Therefore, it was expected that technology mapping by means of multilateral analysis method allowed a good grasp of current technology trend of the artificial skin and the subdivision into nation and a field of research presents the direction of R&D. In the early R&D stage of artificial skin, the preparation technology of filters implantable into the living body including nursing devices, bandages, and dressings or absorbent pads (A6IF-002/10) was on the rise in research field of artificial skin until 1980's. And then the materials technology for coating prostheses (A6l L-027/00)was leading the core technology of artificial skin. Also, Nowadays the fusion technology connected the material technology with the cultivation technology of undifferentiated human or animal cells/tissues including culture media (C l2N-005/00, C 12N-005/06) was highlighted all over the world.

3-D Hetero-Integration Technologies for Multifunctional Convergence Systems

  • Lee, Kang-Wook
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.22 no.2
    • /
    • pp.11-19
    • /
    • 2015
  • Since CMOS device scaling has stalled, three-dimensional (3-D) integration allows extending Moore's law to ever high density, higher functionality, higher performance, and more diversed materials and devices to be integrated with lower cost. 3-D integration has many benefits such as increased multi-functionality, increased performance, increased data bandwidth, reduced power, small form factor, reduced packaging volume, because it vertically stacks multiple materials, technologies, and functional components such as processor, memory, sensors, logic, analog, and power ICs into one stacked chip. Anticipated applications start with memory, handheld devices, and high-performance computers and especially extend to multifunctional convengence systems such as cloud networking for internet of things, exascale computing for big data server, electrical vehicle system for future automotive, radioactivity safety system, energy harvesting system and, wireless implantable medical system by flexible heterogeneous integrations involving CMOS, MEMS, sensors and photonic circuits. However, heterogeneous integration of different functional devices has many technical challenges owing to various types of size, thickness, and substrate of different functional devices, because they were fabricated by different technologies. This paper describes new 3-D heterogeneous integration technologies of chip self-assembling stacking and 3-D heterogeneous opto-electronics integration, backside TSV fabrication developed by Tohoku University for multifunctional convergence systems. The paper introduce a high speed sensing, highly parallel processing image sensor system comprising a 3-D stacked image sensor with extremely fast signal sensing and processing speed and a 3-D stacked microprocessor with a self-test and self-repair function for autonomous driving assist fabricated by 3-D heterogeneous integration technologies.

Experimental Implantation of Moving Actuator Type Total Artificial Heart in Sheep (양에서 시행한 이동작동기 형태(MOVING ACTUATOR TYPE) 인공심장의 삽입실험)

  • 김원곤
    • Journal of Chest Surgery
    • /
    • v.28 no.6
    • /
    • pp.533-541
    • /
    • 1995
  • We recently developed a new model of moving actuator type totally implantable artificial heart[TIAH , based on the reverse position of the aortic and pulmonary conduits. This concept was proposed by one of surgeons in our team[Joon-Ryang Rho, M.D. to facilitate anatomical fitting of TIAHs. The moving actuator type electromechanical TIAH consisted of the left and right blood sacs, and the moving actuator including a motor. The inverted umbrella type polyurethane valves were used in the blood pumps. The aortic conduit was positioned anterior to the pulmonary conduit, which was the opposite relation to the conventional configuration of other total artificial hearts. We also adapted slip-in connectors for the aortic and pulmonary conduits. Two sheep , weighing 60-69 kg, were used for implantation. After small cervical incision and trans-sternal bilateral thoracotomy, cardiopulmonary bypass [CPB was administered using an American Optical 5-head pump and a membrane oxygenator[Univox-IC, Bentley . The anterior and posterior vena cavae were drained separately for venous return. An arterial return cannula was inserted into the right common carotid artery. During CPB, almost all of the ventricular myocardium was excised down to the atrioventricular groove and the artificial heart was implanted. We achieved 3-day survival in the first sheep and 2-day survival in the second. The day after operation the first sheep was successfully extubated and the second sheep was weaned from a respirator with good condition. After extubation, the first sheep walked around in the cage and fed herself. Serial laboratory and hemodynamic examinations were done during the experiments. In both sheep, pulmonary dysfunction was gradually developed, which was accompanied by acute renal failure. The animals were sacrificed and autopsy was done. Unexpected pregnnacy was incidentally found in both sheep. To our knowledge this is the first report of significant survival cases in the orthotopic implantation of electric TIAH using sheep.

  • PDF