3,353 research outputs found
Development and Characterization of Polymer-based Magnetoelectric Nanofibers
With the rapid development of bionics, where biological systems meet electronics, there is an interest in polymer-based electrode systems that are soft, flexible, easily processed and fabricated. In this research area, magnetoelectric (ME) composites bring new and exciting opportunities, including contactless or “wireless” electrical stimulation, less-invasive integration in the form of dispersible, injectable nanoelectrodes, and applications as biodegradable sensors and bioenergy harvesters in the biomedical field. When ME composites are exposed to a magnetic field, a magnetostrictive (MS) component transfers strain to a piezoelectric (PE) component that generates an output voltage. In doing so, ME composites have the ability to enable magnetic-to-electrical conversion and thus can be utilized to power devices or electrically stimulate tissues or cells from a remote magnetic stimulus. To date, ceramic materials have mostly been applied in nanostructured ME composites, however, these may become fragile and cause deleterious reactions at the interface regions, leading to low electrical resistivity and high dielectric losses and ultimately low output voltage.
To overcome these shortcomings, polymer-based ME composites offer new solutions to develop softer, contactless electrodes, without electrical connections, for easier and unique fabrication approaches (e.g. incorporation into soft gels). Their strain-mediated ME effect in large scale devices has been thoroughly studied both experimentally and theoretically. Polymer-based ME composites have almost exclusively used the PE polymer, poly (vinylidene fluoride) (PVDF), due to its high PE coefficient and as such developments in exploring other types of PE polymers have not been forthcoming. For example, other PE polymers such as poly (vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and poly (lactic acid) (PLA) have yet to be investigated though have the potential to bring added-value and function to polymer-based ME composites. Compared to PVDF and its copolymer P(VDF-TrFE), the piezoelectricity of another copolymer, P(VDF-HFP), is less-well understood. As a biocompatible polymer, PLA has been extensively investigated for applications in drug delivery and tissue engineering. Instead of being used only as a biodegradable and bioactive thermoplastic material, PLA is promising as a PE polymer, which has potential to mimic PE functions of tissues. Thus, in addition to PVDF, the thesis investigates the PE properties of P(VDF-HFP) and PLA and aims to develop ME composite nanofibers based on these polymers
Beyond Tissue replacement: The Emerging role of smart implants in healthcare
Smart implants are increasingly used to treat various diseases, track patient status, and restore tissue and organ function. These devices support internal organs, actively stimulate nerves, and monitor essential functions. With continuous monitoring or stimulation, patient observation quality and subsequent treatment can be improved. Additionally, using biodegradable and entirely excreted implant materials eliminates the need for surgical removal, providing a patient-friendly solution. In this review, we classify smart implants and discuss the latest prototypes, materials, and technologies employed in their creation. Our focus lies in exploring medical devices beyond replacing an organ or tissue and incorporating new functionality through sensors and electronic circuits. We also examine the advantages, opportunities, and challenges of creating implantable devices that preserve all critical functions. By presenting an in-depth overview of the current state-of-the-art smart implants, we shed light on persistent issues and limitations while discussing potential avenues for future advancements in materials used for these devices
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
THE ACOUSTIC WAVE SENSOR AND SOFT LITHOGRAPHY TECHNOLOGIES FOR CELL BIOLOGICAL STUDIES
Recently, cell-based biosensors have attracted many attentions because of their potential applications in fundamental biological research, drug development, and other fields. Acoustic wave biosensors offer powerful tools to probe cell behaviors and properties in a non-invasive, simple, and quantitative manner. Current studies on cell-based acoustic wave sensors are focused on experimental investigation of thickness shear mode (TSM) sensors for monitoring cell attachment and spreading. There are no theoretical models for cell-based TSM biosensors. No studies on other cell biological applications of TSM sensors or on surface acoustic wave cell-based biosensors have been performed. The reliability and sensitivity of current cell-based biosensors are low. Improving them requires studies on engineering cells and understanding the effects of cell morphology on cell function.The overall objective of this dissertation is to develop acoustic wave sensor systems for cell biological studies and to determine the effects of cell shape on cell function. Our study includes three parts: (1) Development of cell-based TSM sensor system; (2) Studies of Love mode devices as cell-based biosensors; (3) Studies of the effects of cell shape on cell function. In the first part, a theoretical model was developed, changes in cell adhesion were monitored and cell viscoelasticity was characterized by TSM sensor systems. The TSM sensor systems were demonstrated to provide a non-invasive, simple, and reliable method to monitor cell adhesion and characterize cell viscoelasticity. In the second part, a theoretical model was developed to determine signal changes in Love mode sensors due to cells attaching on their surface. Experimental results validated the model. In the third part, cell shape was patterned to different aspect ratios. Elongated tendon cells were found to express higher collagen type I than shorter cells. Changes in cell shape induced alterations in cytoskeleton, focal adhesions, and traction forces in cells, which may collectively prompt the observed differential collagen type I expression in cells with different shapes. Overall, our research expanded the applications of acoustic wave cell-based biosensors. Studies on cell shape control and the effects of cell shape on cell function will be useful for increasing the sensitivity of cell-based biosensors in future research
Silk-Based Biopolymers Promise Extensive Biomedical Applications in Tissue Engineering, Drug Delivery, and BioMEMS
As an FDA-approved biopolymer, silk has been contemplated for a wide range of applications based on its unique merits, such as biocompatibility, biodegradability, and piezoelectricity. As silk, in both crystalline structure and amorphous state, exhibits unique physical, mechanical, and biological properties (promoting cell migration, differentiation, growth, and protein-surface interaction), it is fruitful to understand its potential applications. Sensors, actuators, and drug delivery systems are the best in case. As such, the current effort first introduces silk fibroin (SF) and delineates its characteristics. It then explores the extensive use of this biomaterial in tissue engineering approaches, in addition to its biosensor and electro-active wearable bioelectronic application. To this end, the SF application in cardiovascular, skin, cartilage, and drug delivery systems for cancer therapy and wound healing was studied precisely. Compositing any type of other variables to induce a specific application or improve any SF barriers, namely its hydrophobicity, poor electrical conductivity, or tuning its mechanical properties, especially in tissue engineering applications, has also been discussed wherever it is deemed informative.</p
Silk-Based Biopolymers Promise Extensive Biomedical Applications in Tissue Engineering, Drug Delivery, and BioMEMS
As an FDA-approved biopolymer, silk has been contemplated for a wide range of applications based on its unique merits, such as biocompatibility, biodegradability, and piezoelectricity. As silk, in both crystalline structure and amorphous state, exhibits unique physical, mechanical, and biological properties (promoting cell migration, differentiation, growth, and protein-surface interaction), it is fruitful to understand its potential applications. Sensors, actuators, and drug delivery systems are the best in case. As such, the current effort first introduces silk fibroin (SF) and delineates its characteristics. It then explores the extensive use of this biomaterial in tissue engineering approaches, in addition to its biosensor and electro-active wearable bioelectronic application. To this end, the SF application in cardiovascular, skin, cartilage, and drug delivery systems for cancer therapy and wound healing was studied precisely. Compositing any type of other variables to induce a specific application or improve any SF barriers, namely its hydrophobicity, poor electrical conductivity, or tuning its mechanical properties, especially in tissue engineering applications, has also been discussed wherever it is deemed informative.</p
Frontiers in microfluidics, a teaching resource review
This is a literature teaching resource review for biologically inspired microfluidics courses
or exploring the diverse applications of microfluidics. The structure is around key papers and model
organisms. While courses gradually change over time, a focus remains on understanding how
microfluidics has developed as well as what it can and cannot do for researchers. As a primary
starting point, we cover micro-fluid mechanics principles and microfabrication of devices. A variety
of applications are discussed using model prokaryotic and eukaryotic organisms from the set
of bacteria (Escherichia coli), trypanosomes (Trypanosoma brucei), yeast (Saccharomyces cerevisiae),
slime molds (Physarum polycephalum), worms (Caenorhabditis elegans), flies (Drosophila melangoster),
plants (Arabidopsis thaliana), and mouse immune cells (Mus musculus). Other engineering and
biochemical methods discussed include biomimetics, organ on a chip, inkjet, droplet microfluidics,
biotic games, and diagnostics. While we have not yet reached the end-all lab on a chip,
microfluidics can still be used effectively for specific applications
Wireless Technologies for Implantable Devices
Wireless technologies are incorporated in implantable devices since at least the 1950s. With remote data collection and control of implantable devices, these wireless technologies help researchers and clinicians to better understand diseases and to improve medical treatments. Today, wireless technologies are still more commonly used for research, with limited applications in a number of clinical implantable devices. Recent development and standardization of wireless technologies present a good opportunity for their wider use in other types of implantable devices, which will significantly improve the outcomes of many diseases or injuries. This review briefly describes some common wireless technologies and modern advancements, as well as their strengths and suitability for use in implantable medical devices. The applications of these wireless technologies in treatments of orthopedic and cardiovascular injuries and disorders are described. This review then concludes with a discussion on the technical challenges and potential solutions of implementing wireless technologies in implantable devices
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