29 research outputs found
Energy harvesting and wireless transfer in sensor network applications: Concepts and experiences
Advances in micro-electronics and miniaturized mechanical systems are redefining the scope and extent of the energy constraints found in battery-operated wireless sensor networks (WSNs). On one hand, ambient energy harvesting may prolong the systems lifetime or possibly enable perpetual operation. On the other hand, wireless energy transfer allows systems to decouple the energy sources from the sensing locations, enabling deployments previously unfeasible. As a result of applying these technologies to WSNs, the assumption of a finite energy budget is replaced with that of potentially infinite, yet intermittent, energy supply, profoundly impacting the design, implementation, and operation of WSNs. This article discusses these aspects by surveying paradigmatic examples of existing solutions in both fields and by reporting on real-world experiences found in the literature. The discussion is instrumental in providing a foundation for selecting the most appropriate energy harvesting or wireless transfer technology based on the application at hand. We conclude by outlining research directions originating from the fundamental change of perspective that energy harvesting and wireless transfer bring about
Design, characterization and validation of integrated bioelectronics for cellular studies: from inkjet-printed sensors to organic actuators
Mención Internacional en el título de doctorAdvances in bioinspired and biomimetic electronics have enabled
coupling engineering devices to biological systems with unprecedented
integration levels. Major efforts, however, have been devoted to interface
malleable electronic devices externally to the organs and tissues. A promising
alternative is embedding electronics into living tissues/organs or,
turning the concept inside out, lading electronic devices with soft living
matters which may accomplish remote monitoring and control of tissue’s
functions from within. This endeavor may unleash the ability to engineer
“living electronics” for regenerative medicine and biomedical applications.
In this context, it remains a challenge to insert electronic devices efficiently
with living cells in a way that there are minimal adverse reactions
in the biological host while the electronics maintaining the engineered
functionalities. In addition, investigating in real-time and with minimal
invasion the long-term responses of biological systems that are brought
in contact with such bioelectronic devices is desirable.
In this work we introduce the development (design, fabrication and
characterization) and validation of sensors and actuators mechanically
soft and compliant to cells able to properly operate embedded into a
cell culture environment, specifically of a cell line of human epithelial
keratinocytes. For the development of the sensors we propose moving from conventional microtechnology approaches to techniques compatible
with bioprinting in a way to support the eventual fabrication of tissues
and electronic sensors in a single hybrid plataform simultaneously. For
the actuators we explore the use of electroactive, organic, printing-compatible
polymers to induce cellular responses as a drug-free alternative
to the classic chemical route in a way to gain eventual control of biological
behaviors electronically. In particular, the presented work introduces
inkjet-printed interdigitated electrodes to monitor label-freely and
non-invasively cellular migration, proliferation and cell-sensor adhesions
of epidermal cells (HaCaT cells) using impedance spectroscopy and the
effects of (dynamic) mechanical stimulation on proliferation, migration
and morphology of keratinocytes by varying the magnitude, frequency
and duration of mechanical stimuli exploiting the developed biocompatible
actuator.
The results of this thesis contribute to the envision of three-dimensional
laboratory-growth tissues with built-in electronics, paving exciting
avenues towards the idea of living smart cyborg-skin substitutes.En los útimos años los avances en el desarrollo de dispositivos
electrónicos diseñados imitando las propiedades de sistemas vivos han
logrado acoplar sistemas electrónicos y órganos/tejidos biológicos con
un nivel de integración sin precedentes. Convencionalmente, la forma
en que estos sistemas bioelectrónicos son integrados con órganos o tejidos
ha sido a través del contacto superficial entre ambos sistemas, es
decir acoplando la electrónica externamente al tejido. Lamentablemente
estas aproximaciones no contemplan escenarios donde ha habido una
pérdida o daño del tejido con el cual interactuar, como es el caso de daños
en la piel debido a quemaduras, úlceras u otras lesiones genéticas
o producidas. Una alternativa prometedora para ingeniería de tejidos y
medicina regenerativa, y en particular para implantes de piel, es embeber
la electrónica dentro del tejido, o presentado de otra manera, cargar
el sistema electrónico con células vivas y tejidos fabricados por ingeniería
de tejidos como parte innata del propio dispositivo. Este concepto
permitiría no solo una monitorización remota y un control basado en
señalizaciones eléctricas (sin químicos) de tejidos biológicos fabricados
mediante técnicas de bioingeniería desde dentro del propio tejido, sino
también la fabricación de una “electrónica viva”, biológica y eléctricamente
funcional. En este contexto, es un desafío insertar de manera
eficiente dispositivos electrónicos con células vivas sin desencadenar
reacciones adversas en el sistema biológico receptor ni en el sistema
electrónico diseñado. Además, es deseable monitorizar en tiempo real
y de manera mínimamente invasiva las respuestas de dichos sistemas
biológicos que se han añadido a tales dispositivos bioelectrónicos.
En este trabajo presentamos el desarrollo (diseño, fabricación y caracterización)
y validación de sensores y actuadores mecánicamente suaves y
compatibles con células capaces de funcionar correctamente dentro de un
entorno de cultivo celular, específicamente de una línea celular de células epiteliales
humanas. Para el desarrollo de los sensores hemos propuesto utilizar
técnicas compatibles con la bioimpresión, alejándonos de la micro fabricación
tradicionalmente usada para la manufactura de sensores electrónicos, con el
objetivo a largo plazo de promover la fabricación de los tejidos y los sensores
electrónicos simultáneamente en un mismo sistema de impresión híbrido.
Para el desarrollo de los actuadores hemos explorado el uso de polímeros
electroactivos y compatibles con impresión y hemos investigado el efecto
de estímulos mecánicos dinámicos en respuestas celulares con el objetivo a
largo plazo de autoinducir comportamientos biológicos controlados de forma
electrónica. En concreto, este trabajo presenta sensores basados en electrodos
interdigitados impresos por inyección de tinta para monitorear la migración
celular, proliferación y adhesiones célula-sustrato de una línea celular de
células epiteliales humanas (HaCaT) en tiempo real y de manera no invasiva
mediante espectroscopía de impedancia. Por otro lado, este trabajo presenta
actuadores biocompatibles basados en el polímero piezoeléctrico fluoruro de
poli vinilideno y ha investigado los efectos de estimular mecánicamente células
epiteliales en relación con la proliferación, migración y morfología celular
mediante variaciones dinámicas de la magnitud, frecuencia y duración de
estímulos mecánicos explotando el actuador biocompatible propuesto.
Ambos sistemas presentados como resultado de esta tesis doctoral
contribuyen al desarrollo de tejidos 3D con electrónica incorporada,
promoviendo una investigación hacia la fabricación de sustitutos equivalentes
de piel mitad orgánica mitad electrónica como tejidos funcionales
biónicos inteligentes.The main works presented in this thesis have been
conducted in the facilities of the Universidad Carlos III
de Madrid with support from the program Formación del
Profesorado Universitario FPU015/06208 granted by Spanish Ministry
of Education, Culture and Sports. Some of the work has been also
developed in the facilities of the Fraunhofer-Institut für Zuverlässigkeit
und Mikrointegration (IZM) and University of Applied Sciences (HTW) in
Berlin, under the supervision of Prof. Dr. Ing. H-D. Ngo during a research
visit funded by the Mobility Fellows Program by the Spanish Ministry of
Education, Culture, and Sports.
This work has been developed in the framework of the projects
BIOPIELTEC-CM (P2018/BAA-4480), funded by Comunidad de Madrid,
and PARAQUA (TEC2017-86271-R) funded by Ministerio de Ciencia e
Innovación.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: José Antonio García Souto.- Secretario: Carlos Elvira Pujalte.- Vocal: María Dimak
A Hybrid-Powered Wireless System for Multiple Biopotential Monitoring
Chronic diseases are the top cause of human death in the United States and worldwide. A huge amount of healthcare costs is spent on chronic diseases every year. The high medical cost on these chronic diseases facilitates the transformation from in-hospital to out-of-hospital healthcare. The out-of-hospital scenarios require comfortability and mobility along with quality healthcare. Wearable electronics for well-being management provide good solutions for out-of-hospital healthcare. Long-term health monitoring is a practical and effective way in healthcare to prevent and diagnose chronic diseases. Wearable devices for long-term biopotential monitoring are impressive trends for out-of-hospital health monitoring. The biopotential signals in long-term monitoring provide essential information for various human physiological conditions and are usually used for chronic diseases diagnosis.
This study aims to develop a hybrid-powered wireless wearable system for long-term monitoring of multiple biopotentials. For the biopotential monitoring, the non-contact electrodes are deployed in the wireless wearable system to provide high-level comfortability and flexibility for daily use. For providing the hybrid power, an alternative mechanism to harvest human motion energy, triboelectric energy harvesting, has been applied along with the battery to supply energy for long-term monitoring. For power management, an SSHI rectifying strategy associated with triboelectric energy harvester design has been proposed to provide a new perspective on designing TEHs by considering their capacitance concurrently. Multiple biopotentials, including ECG, EMG, and EEG, have been monitored to validate the performance of the wireless wearable system. With the investigations and studies in this project, the wearable system for biopotential monitoring will be more practical and can be applied in the real-life scenarios to increase the economic benefits for the health-related wearable devices
Self-powered mobile sensor for in-pipe potable water quality monitoring
Traditional stationary sensors for potable-water quality monitoring in a wireless sensor network format allow for
continuous data collection and transfer. These stationary sensors have played a key role in reporting contamination
events in order to secure public health. We are developing a self-powered mobile sensor that can move with the water flow, allowing real-time detection of contamination in water distribution pipes, with a higher temporal resolution. Functionality of the mobile sensor was tested for detecting and monitoring pH, Ca2+, Mg2+, HCO3-/CO32-, NH4+, and Clions. Moreover, energy harvest and wireless data transmission capabilities are being designed for the mobile sensor
Biomedical Engineering
Biomedical engineering is currently relatively wide scientific area which has been constantly bringing innovations with an objective to support and improve all areas of medicine such as therapy, diagnostics and rehabilitation. It holds a strong position also in natural and biological sciences. In the terms of application, biomedical engineering is present at almost all technical universities where some of them are targeted for the research and development in this area. The presented book brings chosen outputs and results of research and development tasks, often supported by important world or European framework programs or grant agencies. The knowledge and findings from the area of biomaterials, bioelectronics, bioinformatics, biomedical devices and tools or computer support in the processes of diagnostics and therapy are defined in a way that they bring both basic information to a reader and also specific outputs with a possible further use in research and development
Impedance Spectroscopy
This book covers new advances in the field of impedance spectroscopy including fundamentals, methods and applications. It releases selected extended and peer reviewed scientific contributions from the International Workshop on Impedance Spectroscopy (IWIS 2017) focussing on detailed information about recent scientific research results in electrochemistry and battery research, bioimpedance measurement, sensors, system design, signal processing
Applications of Antenna Technology in Sensors
During the past few decades, information technologies have been evolving at a tremendous rate, causing profound changes to our world and to our ways of living. Emerging applications have opened u[ new routes and set new trends for antenna sensors. With the advent of the Internet of Things (IoT), the adaptation of antenna technologies for sensor and sensing applications has become more important. Now, the antennas must be reconfigurable, flexible, low profile, and low-cost, for applications from airborne and vehicles, to machine-to-machine, IoT, 5G, etc. This reprint aims to introduce and treat a series of advanced and emerging topics in the field of antenna sensors
Biofunctional hydrogels for skeletal muscle constructs
Skeletal muscle tissue damage costs the US government hundreds of billions of dollars annually. Meanwhile, there is great potential to use skeletal muscle as a scalable actuator system, covering wide length scales, frequencies, and force regimes. Hence, the interest in soft robotics and regenerative medicine methods to engineer skeletal muscle has increased in recent years. The challenges to generate a functional muscle strip are typical to those of tissue engineering, where common issues such as cell source, material scaffold, bioreactor method or configuration play key roles. Specifically, it is important to translate the existing body of myogenesis knowledge into engineering muscle constructs by examining the impact of the cell microenvironment on growth, alignment, fusion, and differentiation of skeletal muscle cells. The main motivation behind this thesis was to generate a contractile 3D skeletal muscle construct utilizing organized biochemical and physical cues to guide muscle cell differentiation and maturation. Such a construct is expected to play an important role in medical applications and the development of soft robotics. To do this, 3D, swollen hydrogels were chosen to provide tailorable platforms that support cellular activities to similar extents as native matrices. For this work, we utilized an engineered bio-functionalized poly(ethylene glycol)-(PEG)-hydrogel with maleimide (MAL) cross-linking reaction chemistry that gels rapidly with high reaction efficiency under cytocompatible reaction conditions. PEG alone has been shown to have low protein adsorption, a minimal inflammatory profile, well established chemistry, and a long history of safety in vivo. The PEG-MAL system in particular allows “plug-and-play” design variation, control over polymerization time, and small degradation products. To develop an effective soft biomaterial for the development of an aligned, functional muscle construct, we (i) screened hydrogel properties for differentiation, (ii) recreated alignment of skeletal muscle cells, (iii) determined effective generated force upon action of an external agonist. The impact of this study in generating a controllable force actuator will be significant in the construction of biological machines. Concomitantly, this study will provide a unique regenerative solution for skeletal muscle tissue repair and regeneration.Ph.D
New strategies for peripheral nerve regeneration
Nerve repair is still a major challenge in surgery, regenerative medicine and tissue engineering even if progress has been made over the last 30 years. Functional recovery after severe lesions to a nerve is often incomplete and rarely totally successful.
In this thesis I present a multi-disciplinary approach to improve the regenerative potential of “nerve repair tubes” that aim to reconnect wounded nerves and refine or replace autologous nerve graft, the clinical current gold standard. The efficacy of such tubes has already been shown in the clinic especially for small gap injuries, but the outcomes are still limited, and ought to be improved by e.g. micro/nano-topography, growth factor delivery systems, supportive cells or active features such as electrical stimulation, which have individually been shown to enhance nerve regeneration. In this study organotypic cultures of dorsal root ganglions (DRG) isolated from neonatal rats were used throughout as an in vitro model of nerve regeneration. Here I tested different devices in combination with growth factors to contribute to the fundamental and technical knowledge necessary to improve the regenerative potential of such tubes.
I investigated the interaction between surface features and growth factors in their joined influence on regenerating DRGs. For this polydimethylsiloxane (PDMS), a polymer with adjustable elasticity was used together with photolithography to build devices of different stiffness with different surface microgrooves, on which DRG could be grown. To optimise the use of nerve growth factor (NGF) in conjunction with these devices, and to show how NGF interacts with stiffness and topography the reaction of the DRG was tested. To ease the making of three-dimensional internally microstructured tubes I have developed up a novel, timesaving, fabrication technique for polycaprolactone (PCL) “Swiss roll” nerve repair tubes. This technique improves the reproducibility of the scaffold, and using DRG its potential for nerve regeneration is being demonstrated.
The influence of time-variant, balanced, pulsed electric stimulation is a potentially useful means to influence nerve regeneration. To narrow down the parameter space the effect of various electric fields was tested in their effect on DRG regeneration using commercially available devices. In collaboration with Christopher Martin from the School of Engineering, novel custom-made devices that allowed us to quantify the directional response of the regenerating axons were developed, and the guidance effect of pulsed alternating current (AC) electrical fields on regenerating DRGs axons was investigated in vitro. This approach allows in principle to transfer the use of this nerve guiding strategy to potentially improve nerve repair tubes