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1.
PLoS One ; 16(6): e0252589, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34077459

RESUMO

Electrical stimulation is one of the candidates for elongation-driven regeneration of damaged peripheral nerves. Different organs and tissues have an inherent cell structure and size. This leads to variation in the tissue-specific electrical properties of the frequency of interfacial polarization. Although nervous tissues have a membrane potential, the electrical reaction inside these tissues following electrical stimulation from outside remains unexplored. Furthermore, the pathophysiological reaction of an injured nerve is unclear. Here, we investigated the electrical reaction of injured and non-injured rat sciatic nerves via broadband dielectric spectroscopy. Crush injured and non-injured sciatic nerves of six 12-week-old male Lewis rats were used, 6 days after infliction of the injury. Both sides of the nerves (with and without injury) were exposed, and impedance measurements were performed at room temperature (approximately 25°C) at frequencies ranging from 100 mHz to 5.5 MHz and electric potential ranging from 0.100 to 1.00 V. The measured interfacial polarization potentially originated from the polarization by ion transport around nerve membranes at frequencies between 3.2 kHz and 1.6 MHz. The polarization strength of the injured nerves was smaller than that of non-injured nerves. However, the difference in polarization between injured and non-injured nerves might be caused by inflammation and edema. The suitable frequency range of the interfacial polarization can be expected to be critical for electrical stimulation of injured peripheral nerves.


Assuntos
Lesões por Esmagamento/fisiopatologia , Espectroscopia Dielétrica/métodos , Nervo Isquiático/lesões , Animais , Modelos Animais de Doenças , Estimulação Elétrica , Eletrônica Médica , Masculino , Compressão Nervosa , Regeneração Nervosa , Ratos
2.
IEEE Pulse ; 12(3): 14-17, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34156928

RESUMO

An estimated ten million people in the United States have a condition known as essential tremor (ET). Yet although it's been recognized for over a century-it was originally known as senile tremor-there is relatively little awareness of it as a distinct medical condition. Sometimes mistaken for Parkinson's disease, ET can lead to shaking of the arms and hands, and sometimes the head or torso. When severe, it can interfere with eating or drinking, writing, dressing, and even make some tasks impossible. Now, new approaches for treating the condition are emerging, potentially offering options to many patients whose life activities have been curtailed by ET.


Assuntos
Estimulação Elétrica/instrumentação , Tremor , Dispositivos Eletrônicos Vestíveis , Eletrônica Médica/instrumentação , Humanos , Tremor/diagnóstico , Tremor/terapia
3.
Sci Rep ; 11(1): 9815, 2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-33972649

RESUMO

Lab-on-Chip is a technology that aims to transform the Point-of-Care (PoC) diagnostics field; nonetheless a commercial production compatible technology is yet to be established. Lab-on-Printed Circuit Board (Lab-on-PCB) is currently considered as a promising candidate technology for cost-aware but simultaneously high specification applications, requiring multi-component microsystem implementations, due to its inherent compatibility with electronics and the long-standing industrial manufacturing basis. In this work, we demonstrate the first electrolyte gated field-effect transistor (FET) DNA biosensor implemented on commercially fabricated PCB in a planar layout. Graphene ink was drop-casted to form the transistor channel and PNA probes were immobilized on the graphene channel, enabling label-free DNA detection. It is shown that the sensor can selectively detect the complementary DNA sequence, following a fully inkjet-printing compatible manufacturing process. The results demonstrate the potential for the effortless integration of FET sensors into Lab-on-PCB diagnostic platforms, paving the way for even higher sensitivity quantification than the current Lab-on-PCB state-of-the-art of passive electrode electrochemical sensing. The substitution of such biosensors with our presented FET structures, promises further reduction of the time-to-result in microsystems combining sequential DNA amplification and detection modules to few minutes, since much fewer amplification cycles are required even for low-abundance nucleic acid targets.


Assuntos
Técnicas Biossensoriais/instrumentação , DNA/isolamento & purificação , Grafite/química , Dispositivos Lab-On-A-Chip , Microtecnologia/instrumentação , DNA/química , Eletrônica Médica/instrumentação , Técnicas de Amplificação de Ácido Nucleico/instrumentação , Técnicas de Amplificação de Ácido Nucleico/métodos
4.
J Orthop Surg Res ; 16(1): 305, 2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-33964958

RESUMO

BACKGROUND: Soft tissue balancing is essential for the success of total knee arthroplasty (TKA) and is mainly dependent on surgeon-defined assessment (SDA) or a gap-balancer (GB). However, an electronic sensor has been developed to objectively measure the gap pressure. This study aimed to evaluate the accuracy of soft tissue balancing using SDA and GB compared with a sensor. METHODS: Forty-eight patients undergoing TKA (60 knees) were prospectively enrolled. Soft tissue balancing was sequentially performed using SDA, a GB, and an electronic sensor. We compared the SDA, GB, and sensor data to calculate the sensitivity, specificity, and accuracy at 0°, 45°, 90°, and 120° flexion. Cumulative summation (CUSUM) analysis was performed to assess the surgeon's performance during the sensor introductory phase. RESULTS: The sensitivity of SDA was 63.3%, 68.3%, 80.0%, and 80.0% at 0°, 45°, 90°, and 120°, respectively. The accuracy of the GB compared with sensor data was 76.7% and 71.7% at 0° and 90°, respectively. Cohen's kappa coefficient for the accuracy of the GB was 0.406 at 0° (moderate agreement) and 0.227 at 90° (fair agreement). The CUSUM 0° line achieved good prior performance at case 45, CUSUM 90° and 120° showed a trend toward good prior performance, while CUSUM 45° reached poor prior performance at case 8. CONCLUSION: SDA was a poor predictor of knee balance. GB improved the accuracy of soft tissue balancing, but was still less accurate than the sensor, particularly for unbalanced knees. SDA improved with ongoing use of the sensor, except at 45° flexion.


Assuntos
Artroplastia do Joelho/métodos , Tecido Conjuntivo/fisiologia , Eletrônica Médica/instrumentação , Prótese do Joelho , Osteoartrite do Joelho/fisiopatologia , Osteoartrite do Joelho/cirurgia , Amplitude de Movimento Articular , Cirurgiões , Fenômenos Biomecânicos , Estudos de Coortes , Humanos , Curva de Aprendizado , Sensibilidade e Especificidade , Resultado do Tratamento
5.
Adv Healthc Mater ; 10(17): e2001916, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33899347

RESUMO

Owing to their excellent mechanical flexibility, mixed-conducting electrical property, and extraordinary chemical turnability, conjugated polymers have been demonstrated to be an ideal bioelectronic interface to deliver therapeutic effect in many different chronic diseases. This review article summarizes the latest advances in implantable electronics using conjugated polymers as electroactive materials and identifies remaining challenges and opportunities for developing electronic medicine. Examples of conjugated polymer-based bioelectronic devices are selectively reviewed in human clinical studies or animal studies with the potential for clinical adoption. The unique properties of conjugated polymers are highlighted and exemplified as potential solutions to address the specific challenges in electronic medicine.


Assuntos
Eletrônica , Polímeros , Animais , Eletrônica Médica , Humanos
6.
Nat Commun ; 12(1): 2399, 2021 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-33893292

RESUMO

Energy autonomy and conformability are essential elements in the next generation of wearable and flexible electronics for healthcare, robotics and cyber-physical systems. This study presents ferroelectric polymer transducers and organic diodes for imperceptible sensing and energy harvesting systems, which are integrated on ultrathin (1-µm) substrates, thus imparting them with excellent flexibility. Simulations show that the sensitivity of ultraflexible ferroelectric polymer transducers is strongly enhanced by using an ultrathin substrate, which allows the mounting on 3D-shaped objects and the stacking in multiple layers. Indeed, ultraflexible ferroelectric polymer transducers have improved sensitivity to strain and pressure, fast response and excellent mechanical stability, thus forming imperceptible wireless e-health patches for precise pulse and blood pressure monitoring. For harvesting biomechanical energy, the transducers are combined with rectifiers based on ultraflexible organic diodes thus comprising an imperceptible, 2.5-µm thin, energy harvesting device with an excellent peak power density of 3 mW·cm-3.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais/instrumentação , Eletrônica Médica/instrumentação , Transdutores , Dispositivos Eletrônicos Vestíveis , Técnicas Biossensoriais/métodos , Eletrônica Médica/métodos , Humanos , Sistemas Microeletromecânicos/instrumentação , Sistemas Microeletromecânicos/métodos , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Reprodutibilidade dos Testes , Robótica/instrumentação , Robótica/métodos
7.
Malar J ; 20(1): 192, 2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33879159

RESUMO

BACKGROUND: Private sector malaria programmes contribute to government-led malaria elimination strategies in Cambodia, Lao PDR, and Myanmar by increasing access to quality malaria services and surveillance data. However, reporting from private sector providers remains suboptimal in many settings. To support surveillance strengthening for elimination, a key programme strategy is to introduce electronic surveillance tools and systems to integrate private sector data with national systems, and enhance the use of data for decision-making. During 2013-2017, an electronic surveillance system based on open source software, District Health Information System 2 (DHIS2), was implemented as part of a private sector malaria case management and surveillance programme. The electronic surveillance system covered 16,000 private providers in Myanmar (electronic reporting conducted by 200 field officers with tablets), 710 in Cambodia (585 providers reporting through mobile app), and 432 in Laos (250 providers reporting through mobile app). METHODS: The purpose of the study was to document the costs of introducing electronic surveillance systems and mobile reporting solutions in Cambodia, Lao PDR, and Myanmar, comparing the cost in different operational settings, the cost of introduction and maintenance over time, and assessing the affordability and financial sustainability of electronic surveillance. The data collection methods included extracting data from PSI's financial and operational records, collecting data on prices and quantities of resources used, and interviewing key informants in each setting. The costing study used an ingredients-based approach and estimated both financial and economic costs. RESULTS: Annual economic costs of electronic surveillance systems were $152,805 in Laos, $263,224 in Cambodia, and $1,310,912 in Myanmar. The annual economic cost per private provider surveilled was $82 in Myanmar, $371 in Cambodia, and $354 in Laos. Cost drivers varied depending on operational settings and number of private sector outlets covered in each country; whether purchased or personal mobile devices were used; and whether electronic (mobile) reporting was introduced at provider level or among field officers who support multiple providers for case reporting. CONCLUSION: The study found that electronic surveillance comprises about 0.5-1.5% of national malaria strategic plan cost and 7-21% of surveillance budgets and deemed to be affordable and financially sustainable.


Assuntos
Administração de Caso/economia , Eletrônica Médica/economia , Monitoramento Epidemiológico , Vigilância da População/métodos , Setor Privado/estatística & dados numéricos , Camboja , Humanos , Laos , Malária/epidemiologia , Mianmar , Setor Privado/economia
8.
Lancet Digit Health ; 3(4): e266-e273, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33640306

RESUMO

Globally, neonatal mortality remains unacceptability high. Physiological monitoring is foundational to the care of these vulnerable patients to assess neonatal cardiopulmonary status, guide medical intervention, and determine readiness for safe discharge. However, most existing physiological monitoring systems require multiple electrodes and sensors, which are linked to wires tethered to wall-mounted display units, to adhere to the skin. For neonates, these systems can cause skin injury, prevent kangaroo mother care, and complicate basic clinical care. Novel, wireless, and biointegrated sensors provide opportunities to enhance monitoring capabilities, reduce iatrogenic injuries, and promote family-centric care. Early validation data have shown performance equivalent to (and sometimes exceeding) standard-of-care monitoring systems in premature neonates cared for in high-income countries. The reusable nature of these sensors and compatibility with low-cost mobile phones have the future potential to enable substantially lower monitoring costs compared with existing systems. Deployment at scale, in low-income countries, holds the promise of substantial improvements in neonatal outcomes.


Assuntos
Cuidados Críticos/métodos , Eletrônica Médica/instrumentação , Cuidado do Lactente/métodos , Monitorização Fisiológica/instrumentação , Tecnologia sem Fio/instrumentação , Países em Desenvolvimento , Humanos , Lactente , Recém-Nascido
9.
Adv Mater ; 33(3): e2004425, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33283351

RESUMO

Recent developments in soft functional materials have created opportunities for building bioelectronic devices with tissue-like mechanical properties. Their integration with the human body could enable advanced sensing and stimulation for medical diagnosis and therapies. However, most of the available soft electronics are constructed as planar sheets, which are difficult to interface with the target organs and tissues that have complex 3D structures. Here, the recent approaches are highlighted to building 3D interfaces between soft electronic tools and complex biological organs and tissues. Examples involve mesh devices for conformal contact, imaging-guided fabrication of organ-specific electronics, miniaturized probes for neurointerfaces, instrumented scaffold for tissue engineering, and many other soft 3D systems. They represent diverse routes for reconciling the interfacial mismatches between electronic tools and biological tissues. The remaining challenges include device scaling to approach the complexity of target organs, biological data acquisition and processing, 3D manufacturing techniques, etc., providing a range of opportunities for scientific research and technological innovation.


Assuntos
Eletrônica Médica , Engenharia Tecidual/métodos , Humanos , Próteses e Implantes
10.
IEEE Trans Biomed Circuits Syst ; 15(1): 80-90, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33373302

RESUMO

Battery-less and ultra-low-power implantable medical devices (IMDs) with minimal invasiveness are the latest therapeutic paradigm. This work presents a 13.56-MHz inductive power receiver system-on-a-chip with an input sensitivity of -25.4 dBm (2.88 µW) and an efficiency of 46.4% while driving a light load of 30 µW. In particular, a real-time resonance compensation scheme is proposed to mitigate resonance variations commonly seen in IMDs due to different dielectric environments, loading conditions, and fabrication mismatches, etc. The power-receiving front-end incorporates a 6-bit capacitor bank that is periodically adjusted according to a successive-approximation-resonance-tuning (SART) algorithm. The compensation range is as much as 24 pF and it converges within 12 clock cycles and causes negligible power consumption overhead. The harvested voltage from 1.7 V to 3.3 V is digitized on-chip and transmitted via an ultra-wideband impulse radio (IR-UWB) back-telemetry for closed-loop regulation. The IC is fabricated in 180-nm CMOS process with an overall current dissipation of 750 nA. At a separation distance of 2 cm, the end-to-end power transfer efficiency reaches 16.1% while driving the 30-µW load, which is immune to artificially induced resonance capacitor offsets. The proposed system can be applied to various battery-less IMDs with the potential improvement of the power transfer efficiency on orders of magnitude.


Assuntos
Eletrônica Médica , Dispositivos Lab-On-A-Chip , Desenho de Equipamento , Próteses e Implantes , Processamento de Sinais Assistido por Computador
11.
J Manipulative Physiol Ther ; 44(1): 42-48, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33248749

RESUMO

OBJECTIVE: The purpose this study was to investigate the reliability of a handheld myotonometer in measuring the mechanical properties of the neck and orofacial muscles in asymptomatic individuals. METHODS: The study included 16 healthy participants. The mechanical properties (frequency, decrement, stiffness, relaxation time, and creep) of the selected muscles were measured with a MyotonPRO myotonometer (Mumeetria Ltd, Tallinn, Estonia). The sternocleidomastoid, upper trapezius, cervical extensor, and masseter muscles were selected to determine the reliability of the device. Measurements were performed by 2 examiners to determine interrater reliability; for intrarater reliability, an examiner repeated the measurements 1 week after the first measurements. RESULTS: The results revealed moderate to excellent intrarater and interrater reliability (intraclass correlation coefficients: 0.50-0.95) in measuring muscle mechanic properties. The standard error of measurement in the tested muscles ranged from 0.3 to 0.8 Hz for frequency, from 7.4 to 20.9 N/m for stiffness, from 0.1 to 0.2 for decrement, and from 0.8 to 1.4 ms for relaxation time. The minimum detectable change ranged from 0.8 to 2.2 Hz for frequency, from 20.5 to 57.9 N/m for stiffness, from 0.2 to 0.6 for decrement, from 2.2 to 3.9 ms for relaxation time, and from 0.2 to 0.3 for creep. In addition, the coefficients of variation were below 9.1% for all the assessed parameters. CONCLUSION: The obtained results demonstrate that the MyotonPRO device is a reliable and repeatable tool to quantify the frequency, stiffness, decrement, relation time, and creep of the neck and orofacial muscles in asymptomatic individuals.


Assuntos
Eletrônica Médica/instrumentação , Músculos do Pescoço/fisiologia , Músculos Superficiais do Dorso/fisiologia , Adulto , Humanos , Masculino , Manometria/normas , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Adulto Jovem
12.
IEEE Trans Biomed Circuits Syst ; 14(6): 1218-1229, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33170783

RESUMO

This paper presents a millimeter-scale crystal-less wireless transceiver for volume-constrained insertable pills. Operating in the 402-405 MHz medical implant communication service (MICS) band, the phase-tracking receiver-based over-the-air carrier recovery has a ±160 ppm coverage. A fully integrated adaptive antenna impedance matching solution is proposed to calibrate the antenna impedance variation inside the body. A tunable matching network (TMN) with single inductor performs impedance matching for both transmitter (TX) and receiver (RX) and TX/RX mode switching. To dynamically calibrate the antenna impedance variation over different locations and diet conditions, a loop-back power detector using self-mixing is adopted, which expands the power contour up to 4.8 VSWR. The transceiver is implemented in a 40-nm CMOS technology, occupying 2 mm2 die area. The transceiver chip and a miniature antenna are integrated in a 3.5 × 15 mm2 area prototype wireless module. It has a receiver sensitivity of -90 dBm at 200 kbps data rate and delivers up to - 25 dBm EIRP in the wireless measurement with a liquid phantom.


Assuntos
Eletrônica Médica/instrumentação , Gastroscopia/instrumentação , Tecnologia sem Fio/instrumentação , Desenho de Equipamento , Humanos , Modelos Biológicos , Imagens de Fantasmas , Processamento de Sinais Assistido por Computador/instrumentação , Estômago/diagnóstico por imagem
13.
IEEE Trans Biomed Circuits Syst ; 14(6): 1263-1273, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33216718

RESUMO

This paper presents the body-coupled power transmission and ambient energy harvesting ICs. The ICs utilize human body-coupling to deliver power to the entire body, and at the same time, harvest energy from ambient EM waves coupled through the body. The ICs improve the recovered power level by adapting to the varying skin-electrode interface parasitic impedance at both the TX and RX. To maximize the power output from the TX, the dynamic impedance matching is performed amidst environment-induced variations. At the RX, the Detuned Impedance Booster (DIB) and the Bulk Adaptation Rectifier (BAR) are proposed to improve the power recovery and extend the power coverage further. In order to ensure the maximum power extraction despite the loading variations, the Dual-Mode Buck-Boost Converter (DM-BBC) is proposed. The ICs fabricated in 40 nm 1P8M CMOS recover up to 100 µW from the body-coupled power transmission and 2.5 µW from the ambient body-coupled energy harvesting. The ICs achieve the full-body area power delivery, with the power harvested from the ambiance via the body-coupling mechanism independent of placements on the body. Both approaches show power sustainability for wearable electronics all around the human body.


Assuntos
Fontes de Energia Elétrica , Eletrônica Médica/instrumentação , Dispositivos Eletrônicos Vestíveis , Impedância Elétrica , Humanos , Processamento de Sinais Assistido por Computador/instrumentação
14.
Adv Biosyst ; 4(11): e2000055, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33084251

RESUMO

The design and benchtop operation of a wireless miniature epiretinal stimulator implant is reported. The implant is optically powered and controlled using safe illumination at near-infrared wavelengths. An application-specific integrated circuit (ASIC) hosting a digital control unit is used to control the implant's electrodes. The ASIC is powered using an advanced photovoltaic (PV) cell and programmed using a single photodiode. Diamond packaging technology is utilized to achieve high-density integration of the implant optoelectronic circuitry, as well as individual connections between a stimulator chip and 256 electrodes, within a 4.6 mm × 3.7 mm × 0.9 mm implant package. An ultrahigh efficiency PV cell with a monochromatic power conversion efficiency of 55% is used to power the implant. On-board photodetection circuity with a bandwidth of 3.7 MHz is used for forward data telemetry of stimulation parameters. In comparison to implants which utilize inductively coupled coils, laser power delivery enables a high degree of miniaturization and lower surgical complexity. The device presented combines the benefits of implant miniaturization and a flexible stimulation strategy provided by a dedicated stimulator chip. This development provides a route to fully wireless miniaturized minimally invasive implants with sophisticated functionalities.


Assuntos
Eletrônica Médica/instrumentação , Lasers , Próteses Visuais , Tecnologia sem Fio/instrumentação , Diamante , Fontes de Energia Elétrica , Eletrodos , Desenho de Equipamento , Miniaturização/instrumentação
15.
IEEE Trans Biomed Circuits Syst ; 14(4): 811-824, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32746334

RESUMO

This paper presents an 8-channel energy-efficient analog front-end (AFE) for neural recording, with improvements in power supply rejection ratio (PSRR) and dynamic range. The input stage in the low noise amplifier (LNA) adopts low voltage supply (0.35 V) and current-reusing to achieve ultralow power. To maintain a high PSRR performance while using such a low-voltage supply, a replica-biasing scheme is proposed to generate a stable bias current for the input stage of the LNA despite large supply interference. By exploiting the signal characteristics in the tetrode recording, an averaged local field potential (A-LFP) servo loop is introduced to extend the dynamic range without consuming too much extra power and chip area. The A-LFP signal is generated by integrating the four-channel PGA outputs from the same tetrode. Furthermore, the outputs of the programmable gain amplifier (PGA) are level shifted to bias the input nodes of the amplifier through large pseudo resistors, thus increase the maximum output range without distortion under the low-voltage supply. The proof-of-concept prototype is fabricated in a 65 nm CMOS process. Each recording channel including an LNA and a PGA occupies 0.04 mm 2 and consumes 340 nW from the 0.35 V and 0.7 V supply. Each A-LFP servo loop, which is shared by four recording channels, occupies 0.04 mm 2 and consumes 190 nW. The maximum gain of the AFE is 54 dB, and the input-referred noise is 6.7 µV over the passband from 0.5 Hz to 6.5 kHz. Measurement also shows that the 0.35 V replica-biasing input stage can tolerate a large interferer up to 200 mVpp with a PSRR of 74 dB, which has been improved to 110 dB with a silicon respin that shields critical wires in the layout.


Assuntos
Amplificadores Eletrônicos , Eletrônica Médica/instrumentação , Neurociências/instrumentação , Semicondutores , Animais , Encéfalo/fisiologia , Eletrodos Implantados , Desenho de Equipamento , Ratos , Silício/química
16.
IEEE Trans Biomed Circuits Syst ; 14(4): 867-878, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32746346

RESUMO

Sensing implants that can be deployed by catheterization or by injection are preferable over implants requiring invasive surgery. However, present powering methods for active implants and present interrogation methods for passive implants require bulky parts within the implants that hinder the development of such minimally invasive devices. In this article, we propose a novel approach that potentially enables the development of passive sensing systems overcoming the limitations of previous implantable sensing systems in terms of miniaturization. In this approach implants are shaped as thread-like devices suitable for implantation by injection. Their basic structure consists of a thin elongated body with two electrodes at opposite ends and a simple and small circuit made up of a diode, a capacitor and a resistor. The interrogation method to obtain measurements from the implants consists in applying innocuous bursts of high frequency (≥1 MHz) alternating current that reach the implants by volume conduction and in capturing and processing the voltage signals that the implants produce after the bursts. As proof-of-concept, and for illustrating how to put in practice this novel approach, here we describe the development and characterization of a system for measuring the conductivity of tissues surrounding the implant. We also describe the implementation and the in vitro validation of a 0.95 mm-thick, flexible injectable implant made of off-the-shelf components. For conductivities ranging from about 0.2 to 0.8 S/m, when compared to a commercial conductivity meter, the accuracy of the implemented system was about ±10%.


Assuntos
Condutividade Elétrica , Miniaturização/instrumentação , Monitorização Fisiológica/instrumentação , Próteses e Implantes , Eletrônica Médica , Humanos , Perna (Membro)/fisiologia , Músculo Esquelético/fisiologia , Desenho de Prótese , Transdutores
17.
IEEE Trans Biomed Circuits Syst ; 14(4): 658-670, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32746351

RESUMO

For mm-sized implants incorporating silicon integrated circuits, ensuring lifetime operation of the chip within the corrosive environment of the body still remains a critical challenge. For the chip's packaging, various polymeric and thin ceramic coatings have been reported, demonstrating high biocompatibility and barrier properties. Yet, for the evaluation of the packaging and lifetime prediction, the conventional helium leak test method can no longer be applied due to the mm-size of such implants. Alternatively, accelerated soak studies are typically used instead. For such studies, early detection of moisture/ion ingress using an in-situ platform may result in a better prediction of lifetime functionality. In this work, we have developed such a platform on a CMOS chip. Ingress of moisture/ions would result in changes in the resistance of the interlayer dielectrics (ILD) used within the chip and can be tracked using the proposed system, which consists of a sensing array and an on-chip measurement engine. The measurement system uses a novel charge/discharge based time-mode resistance sensor that can be implemented using simple yet highly robust circuitry. The sensor array is implemented together with the measurement engine in a standard 0.18  µm 6-metal CMOS process. The platform was validated through a series of dry and wet measurements. The system can measure the ILD resistance with values of up to 0.504 peta-ohms, with controllable measurement steps that can be as low as 0.8 M Ω. The system works with a supply voltage of 1.8 V, and consumes 4.78 mA. Wet measurements in saline demonstrated the sensitivity of the platform in detecting moisture/ion ingress. Such a platform could be used both in accelerated soak studies and during the implant's life-time for monitoring the integrity of the chip's packaging.


Assuntos
Eletrônica Médica/instrumentação , Desenho de Equipamento/métodos , Próteses e Implantes , Semicondutores , Íons/análise , Metais/química , Falha de Prótese , Silício/química , Água/análise
18.
IEEE Trans Biomed Circuits Syst ; 14(4): 636-645, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32746353

RESUMO

This paper presents a device for time-gated fluorescence imaging in the deep brain, consisting of two on-chip laser diodes and 512 single-photon avalanche diodes (SPADs). The edge-emitting laser diodes deliver fluorescence excitation above the SPAD array, parallel to the imager. In the time domain, laser diode illumination is pulsed and the SPAD is time-gated, allowing a fluorescence excitation rejection up to O.D. 3 at 1 ns of time-gate delay. Each SPAD pixel is masked with Talbot gratings to enable the mapping of 2D array photon counts into a 3D image. The 3D image achieves a resolution of 40, 35, and 73 µm in the x, y, and z directions, respectively, in a noiseless environment, with a maximum frame rate of 50 kilo-frames-per-second. We present measurement results of the spatial and temporal profiles of the dual-pulsed laser diode illumination and of the photon detection characteristics of the SPAD array. Finally, we show the imager's ability to resolve a glass micropipette filled with red fluorescent microspheres. The system's 420 µm-wide cross section allows it to be inserted at arbitrary depths of the brain while achieving a field of view four times larger than fiber endoscopes of equal diameter.


Assuntos
Imageamento Tridimensional/instrumentação , Neuroimagem/instrumentação , Imagem Óptica/instrumentação , Eletrônica Médica/instrumentação , Desenho de Equipamento
19.
IEEE Pulse ; 11(4): 22-25, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841115

RESUMO

Wounds, especially chronic wounds, represent a significant clinical, social, and economic challenge. A recent retrospective analysis of Medicare beneficiaries in the United States identified that about 8.2 million people had at least one type of wound, with surgical wounds and diabetic ulcers among the most common and expensive to treat. The study also found that Medicare expenditures related to wound care are far greater than previously recognized; estimates for acute and chronic wound treatments ranged from US$28.1 billion to $96.8 billion [1].


Assuntos
Bandagens , Engenharia Biomédica , Eletrônica Médica , Cicatrização , Ferimentos e Lesões/terapia , Animais , Pesquisa Biomédica , Humanos , Medicare , Camundongos , Ratos , Telemedicina , Estados Unidos
20.
Nat Commun ; 11(1): 4195, 2020 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-32826916

RESUMO

Realizing a clinical-grade electronic medicine for peripheral nerve disorders is challenging owing to the lack of rational material design that mimics the dynamic mechanical nature of peripheral nerves. Electronic medicine should be soft and stretchable, to feasibly allow autonomous mechanical nerve adaptation. Herein, we report a new type of neural interface platform, an adaptive self-healing electronic epineurium (A-SEE), which can form compressive stress-free and strain-insensitive electronics-nerve interfaces and enable facile biofluid-resistant self-locking owing to dynamic stress relaxation and water-proof self-bonding properties of intrinsically stretchable and self-healable insulating/conducting materials, respectively. Specifically, the A-SEE does not need to be sutured or glued when implanted, thereby significantly reducing complexity and the operation time of microneurosurgery. In addition, the autonomous mechanical adaptability of the A-SEE to peripheral nerves can significantly reduce the mechanical mismatch at electronics-nerve interfaces, which minimizes nerve compression-induced immune responses and device failure. Though a small amount of Ag leaked from the A-SEE is observed in vivo (17.03 ppm after 32 weeks of implantation), we successfully achieved a bidirectional neural signal recording and stimulation in a rat sciatic nerve model for 14 weeks. In view of our materials strategy and in vivo feasibility, the mechanically adaptive self-healing neural interface would be considered a new implantable platform for a wide range application of electronic medicine for neurological disorders in the human nervous system.


Assuntos
Eletrônica Médica/instrumentação , Eletrônica Médica/métodos , Neurocirurgia/instrumentação , Neurocirurgia/métodos , Nervos Periféricos/fisiologia , Animais , Engenharia Biomédica/instrumentação , Engenharia Biomédica/métodos , Sistema Nervoso Central/fisiologia , Sistema Nervoso Central/cirurgia , Ouro , Humanos , Masculino , Teste de Materiais , Modelos Animais , Tecido Nervoso/patologia , Tecido Nervoso/cirurgia , Nervos Periféricos/patologia , Nervos Periféricos/cirurgia , Polímeros/química , Próteses e Implantes , Ratos , Nervo Isquiático , Dispositivos Eletrônicos Vestíveis
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