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2.
Adv Healthc Mater ; 10(17): e2100383, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-33938638

RESUMO

Indwelling arterial lines, the clinical gold standard for continuous blood pressure (BP) monitoring in the pediatric intensive care unit (PICU), have significant drawbacks due to their invasive nature, ischemic risk, and impediment to natural body movement. A noninvasive, wireless, and accurate alternative would greatly improve the quality of patient care. Recently introduced classes of wireless, skin-interfaced devices offer capabilities in continuous, precise monitoring of physiologic waveforms and vital signs in pediatric and neonatal patients, but have not yet been employed for continuous tracking of systolic and diastolic BP-critical for guiding clinical decision-making in the PICU. The results presented here focus on materials and mechanics that optimize the system-level properties of these devices to enhance their reliable use in this context, achieving full compatibility with the range of body sizes, skin types, and sterilization schemes typically encountered in the PICU. Systematic analysis of the data from these devices on 23 pediatric patients, yields derived, noninvasive BP values that can be quantitatively validated against direct recordings from arterial lines. The results from this diverse cohort, including those under pharmacological protocols, suggest that wireless, skin-interfaced devices can, in certain circumstances of practical utility, accurately and continuously monitor BP in the PICU patient population.


Assuntos
Cuidados Críticos , Sinais Vitais , Pressão Sanguínea , Criança , Humanos , Recém-Nascido , Monitorização Fisiológica , Pele
3.
Proc Natl Acad Sci U S A ; 118(5)2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33468630

RESUMO

Precise, quantitative measurements of the hydration status of skin can yield important insights into dermatological health and skin structure and function, with additional relevance to essential processes of thermoregulation and other features of basic physiology. Existing tools for determining skin water content exploit surrogate electrical assessments performed with bulky, rigid, and expensive instruments that are difficult to use in a repeatable manner. Recent alternatives exploit thermal measurements using soft wireless devices that adhere gently and noninvasively to the surface of the skin, but with limited operating range (∼1 cm) and high sensitivity to subtle environmental fluctuations. This paper introduces a set of ideas and technologies that overcome these drawbacks to enable high-speed, robust, long-range automated measurements of thermal transport properties via a miniaturized, multisensor module controlled by a long-range (∼10 m) Bluetooth Low Energy system on a chip, with a graphical user interface to standard smartphones. Soft contact to the surface of the skin, with almost zero user burden, yields recordings that can be quantitatively connected to hydration levels of both the epidermis and dermis, using computational modeling techniques, with high levels of repeatability and insensitivity to ambient fluctuations in temperature. Systematic studies of polymers in layered configurations similar to those of human skin, of porcine skin with known levels of hydration, and of human subjects with benchmarks against clinical devices validate the measurement approach and associated sensor hardware. The results support capabilities in characterizing skin barrier function, assessing severity of skin diseases, and evaluating cosmetic and medication efficacy, for use in the clinic or in the home.


Assuntos
Eletrônica , Pele/patologia , Água , Tecnologia sem Fio , Adolescente , Adulto , Pré-Escolar , Análise de Elementos Finitos , Humanos , Temperatura
4.
Sci Adv ; 6(49)2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33277263

RESUMO

Therapeutic compression garments (TCGs) are key tools for the management of a wide range of vascular lower extremity conditions. Proper use of TCGs involves application of a minimum and consistent pressure across the lower extremities for extended periods of time. Slight changes in the characteristics of the fabric and the mechanical properties of the tissues lead to requirements for frequent measurements and corresponding adjustments of the applied pressure. Existing sensors are not sufficiently small, thin, or flexible for practical use in this context, and they also demand cumbersome, hard-wired interfaces for data acquisition. Here, we introduce a flexible, wireless monitoring system for tracking both temperature and pressure at the interface between the skin and the TCGs. Detailed studies of the materials and engineering aspects of these devices, together with clinical pilot trials on a range of patients with different pathologies, establish the technical foundations and measurement capabilities.

5.
Sci Transl Med ; 12(574)2020 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-33328330

RESUMO

Precise form-fitting of prosthetic sockets is important for the comfort and well-being of persons with limb amputations. Capabilities for continuous monitoring of pressure and temperature at the skin-prosthesis interface can be valuable in the fitting process and in monitoring for the development of dangerous regions of increased pressure and temperature as limb volume changes during daily activities. Conventional pressure transducers and temperature sensors cannot provide comfortable, irritation-free measurements because of their relatively rigid construction and requirements for wired interfaces to external data acquisition hardware. Here, we introduce a millimeter-scale pressure sensor that adopts a soft, three-dimensional design that integrates into a thin, flexible battery-free, wireless platform with a built-in temperature sensor to allow operation in a noninvasive, imperceptible fashion directly at the skin-prosthesis interface. The sensor system mounts on the surface of the skin of the residual limb, in single or multiple locations of interest. A wireless reader module attached to the outside of the prosthetic socket wirelessly provides power to the sensor and wirelessly receives data from it, for continuous long-range transmission to a standard consumer electronic device such as a smartphone or tablet computer. Characterization of both the sensor and the system, together with theoretical analysis of the key responses, illustrates linear, accurate responses and the ability to address the entire range of relevant pressures and to capture skin temperature accurately, both in a continuous mode. Clinical application in two prosthesis users demonstrates the functionality and feasibility of this soft, wireless system.


Assuntos
Membros Artificiais , Fontes de Energia Elétrica , Desenho de Prótese , Pele , Temperatura
6.
Nat Med ; 26(3): 418-429, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32161411

RESUMO

Standard clinical care in neonatal and pediatric intensive-care units (NICUs and PICUs, respectively) involves continuous monitoring of vital signs with hard-wired devices that adhere to the skin and, in certain instances, can involve catheter-based pressure sensors inserted into the arteries. These systems entail risks of causing iatrogenic skin injuries, complicating clinical care and impeding skin-to-skin contact between parent and child. Here we present a wireless, non-invasive technology that not only offers measurement equivalency to existing clinical standards for heart rate, respiration rate, temperature and blood oxygenation, but also provides a range of important additional features, as supported by data from pilot clinical studies in both the NICU and PICU. These new modalities include tracking movements and body orientation, quantifying the physiological benefits of skin-to-skin care, capturing acoustic signatures of cardiac activity, recording vocal biomarkers associated with tonality and temporal characteristics of crying and monitoring a reliable surrogate for systolic blood pressure. These platforms have the potential to substantially enhance the quality of neonatal and pediatric critical care.


Assuntos
Técnicas Biossensoriais , Unidades de Terapia Intensiva Neonatal , Unidades de Terapia Intensiva Pediátrica , Monitorização Fisiológica , Pele/anatomia & histologia , Tecnologia sem Fio , Monitorização Ambulatorial da Pressão Arterial , Criança , Pré-Escolar , Eletrocardiografia , Desenho de Equipamento , Humanos , Recém-Nascido , Fotopletismografia , Fatores de Tempo
7.
Science ; 363(6430)2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30819934

RESUMO

Existing vital sign monitoring systems in the neonatal intensive care unit (NICU) require multiple wires connected to rigid sensors with strongly adherent interfaces to the skin. We introduce a pair of ultrathin, soft, skin-like electronic devices whose coordinated, wireless operation reproduces the functionality of these traditional technologies but bypasses their intrinsic limitations. The enabling advances in engineering science include designs that support wireless, battery-free operation; real-time, in-sensor data analytics; time-synchronized, continuous data streaming; soft mechanics and gentle adhesive interfaces to the skin; and compatibility with visual inspection and with medical imaging techniques used in the NICU. Preliminary studies on neonates admitted to operating NICUs demonstrate performance comparable to the most advanced clinical-standard monitoring systems.


Assuntos
Eletrônica/instrumentação , Terapia Intensiva Neonatal , Monitorização Fisiológica/instrumentação , Tecnologia sem Fio/instrumentação , Diagnóstico por Imagem , Desenho de Equipamento , Humanos , Recém-Nascido , Dispositivos Lab-On-A-Chip , Pele , Sinais Vitais
8.
Sci Transl Med ; 10(470)2018 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-30518611

RESUMO

Exposure to electromagnetic radiation can have a profound impact on human health. Ultraviolet (UV) radiation from the sun causes skin cancer. Blue light affects the body's circadian melatonin rhythm. At the same time, electromagnetic radiation in controlled quantities has beneficial use. UV light treats various inflammatory skin conditions, and blue light phototherapy is the standard of care for neonatal jaundice. Although quantitative measurements of exposure in these contexts are important, current systems have limited applicability outside of laboratories because of an unfavorable set of factors in bulk, weight, cost, and accuracy. We present optical metrology approaches, optoelectronic designs, and wireless modes of operation that serve as the basis for miniature, low-cost, and battery-free devices for precise dosimetry at multiple wavelengths. These platforms use a system on a chip with near-field communication functionality, a radio frequency antenna, photodiodes, supercapacitors, and a transistor to exploit a continuous accumulation mechanism for measurement. Experimental and computational studies of the individual components, the collective systems, and the performance parameters highlight the operating principles and design considerations. Evaluations on human participants monitored solar UV exposure during outdoor activities, captured instantaneous and cumulative exposure during blue light phototherapy in neonatal intensive care units, and tracked light illumination for seasonal affective disorder phototherapy. Versatile applications of this dosimetry platform provide means for consumers and medical providers to modulate light exposure across the electromagnetic spectrum in a way that can both reduce risks in the context of excessive exposure and optimize benefits in the context of phototherapy.


Assuntos
Fontes de Energia Elétrica , Miniaturização/instrumentação , Fototerapia , Dosímetros de Radiação , Exposição à Radiação , Monitoramento de Radiação/instrumentação , Luz Solar , Tecnologia sem Fio , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Raios Ultravioleta
9.
Adv Funct Mater ; 9(3)2017 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-28989338

RESUMO

A collection of materials and device architectures are introduced for thin, stretchable arrays of ion sensors that mount on open cellular substrates to facilitate solution exchange for use in biointegrated electronics. The results include integration strategies and studies of fundamental characteristics in chemical sensing and mechanical response. The latter involves experimental measurements and theoretical simulations that establish important considerations in the design of low modulus, stretchable properties in cellular substrates, and in the realization of advanced capabilities in spatiotemporal mapping of chemicals' gradients. As the chemical composition of extracellular fluids contains valuable information related to biological function, the concepts introduced here have potential utility across a range of skin- and internal-organ-integrated electronics where soft mechanics, fluidic permeability, and advanced chemical sensing capabilities are key requirements.

10.
Adv Mater ; 29(38)2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28833596

RESUMO

This study describes a conductive ink formulation that exploits electrochemical sintering of Zn microparticles in aqueous solutions at room temperature. This material system has relevance to emerging classes of biologically and environmentally degradable electronic devices. The sintering process involves dissolution of a surface passivation layer of zinc oxide in CH3 COOH/H2 O and subsequent self-exchange of Zn and Zn2+ at the Zn/H2 O interface. The chemical specificity associated with the Zn metal and the CH3 COOH/H2 O solution is critically important, as revealed by studies of other material combinations. The resulting electrochemistry establishes the basis for a remarkably simple procedure for printing highly conductive (3 × 105 S m-1 ) features in degradable materials at ambient conditions over large areas, with key advantages over strategies based on liquid phase (fusion) sintering that requires both oxide-free metal surfaces and high temperature conditions. Demonstrations include printed magnetic loop antennas for near-field communication devices.

11.
Nat Commun ; 8: 15894, 2017 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-28635956

RESUMO

Low modulus, compliant systems of sensors, circuits and radios designed to intimately interface with the soft tissues of the human body are of growing interest, due to their emerging applications in continuous, clinical-quality health monitors and advanced, bioelectronic therapeutics. Although recent research establishes various materials and mechanics concepts for such technologies, all existing approaches involve simple, two-dimensional (2D) layouts in the constituent micro-components and interconnects. Here we introduce concepts in three-dimensional (3D) architectures that bypass important engineering constraints and performance limitations set by traditional, 2D designs. Specifically, open-mesh, 3D interconnect networks of helical microcoils formed by deterministic compressive buckling establish the basis for systems that can offer exceptional low modulus, elastic mechanics, in compact geometries, with active components and sophisticated levels of functionality. Coupled mechanical and electrical design approaches enable layout optimization, assembly processes and encapsulation schemes to yield 3D configurations that satisfy requirements in demanding, complex systems, such as wireless, skin-compatible electronic sensors.

12.
Adv Funct Mater ; 26(40): 7281-7290, 2016 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-28413376

RESUMO

This paper introduces a class of ferromagnetic, folded, soft composite material for skin-interfaced electrodes with releasable interfaces to stretchable, wireless electronic measurement systems. These electrodes establish intimate, adhesive contacts to the skin, in dimensionally stable formats compatible with multiple days of continuous operation, with several key advantages over conventional hydrogel based alternatives. The reported studies focus on aspects ranging from ferromagnetic and mechanical behavior of the materials systems, to electrical properties associated with their skin interface, to system-level integration for advanced electrophysiological monitoring applications. The work combines experimental measurement and theoretical modeling to establish the key design considerations. These concepts have potential uses across a diverse set of skin-integrated electronic technologies.

13.
Adv Funct Mater ; 26(29): 5345-5351, 2016 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-29033714

RESUMO

Recently developed classes of electronics for biomedical applications exploit substrates that offer low elastic modulus and high stretchability, to allow intimate, mechanically biocompatible integration with soft biological tissues. A challenge is that such substrates do not generally offer protection of the electronics from high peak strains that can occur upon large-scale deformation, thereby creating a potential for device failure. The results presented here establish a simple route to compliant substrates with strain-limiting mechanics based on approaches that complement those of recently described alternatives. Here, a thin film or mesh of a high modulus material transferred onto a prestrained compliant substrate transforms into wrinkled geometry upon release of the prestrain. The structure formed by this process offers a low elastic modulus at small strain due to the small effective stiffness of the wrinkled film or mesh; it has a high tangent modulus (e.g., >1000 times the elastic modulus) at large strain, as the wrinkles disappear and the film/mesh returns to a flat geometry. This bilinear stress-strain behavior has an extremely sharp transition point, defined by the magnitude of the prestrain. A theoretical model yields analytical expressions for the elastic and tangent moduli and the transition strain of the bilinear stress-strain relation, with quantitative correspondence to finite element analysis and experiments.

14.
Nat Commun ; 6: 6566, 2015 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-25782446

RESUMO

Hard and soft structural composites found in biology provide inspiration for the design of advanced synthetic materials. Many examples of bio-inspired hard materials can be found in the literature; far less attention has been devoted to soft systems. Here we introduce deterministic routes to low-modulus thin film materials with stress/strain responses that can be tailored precisely to match the non-linear properties of biological tissues, with application opportunities that range from soft biomedical devices to constructs for tissue engineering. The approach combines a low-modulus matrix with an open, stretchable network as a structural reinforcement that can yield classes of composites with a wide range of desired mechanical responses, including anisotropic, spatially heterogeneous, hierarchical and self-similar designs. Demonstrative application examples in thin, skin-mounted electrophysiological sensors with mechanics precisely matched to the human epidermis and in soft, hydrogel-based vehicles for triggered drug release suggest their broad potential uses in biomedical devices.


Assuntos
Materiais Biomiméticos , Teste de Materiais , Materiais Biocompatíveis/química , Biomimética , Sistemas de Liberação de Medicamentos , Módulo de Elasticidade , Eletrônica , Eletrofisiologia , Epiderme/metabolismo , Análise de Elementos Finitos , Dureza , Humanos , Hidrogéis/química , Imidas/química , Pele , Estresse Mecânico , Resistência à Tração , Engenharia Tecidual/métodos
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