Suspended Micro/nanogenerators for cell stimulation

[eng] Our bodies are complex machines whose functioning depends on multiple electrical signals controlled mainly by the nervous system. Afterwards, it is not illogical to think that one day artificial electrical impulses would replace those signals offering supports of medical treatments. Nowadays e...

Descripción completa

Detalles Bibliográficos
Autor: Vargas Estevez, Carolina
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2019
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/130111
Acceso en línea:https://hdl.handle.net/2445/130111
http://hdl.handle.net/10803/666193
Access Level:acceso abierto
Palabra clave:Electrònica
Nanoelectrònica
Estimulació elèctrica
Magnetostricció
Piezoelectricitat
Fotoelectricitat
Electronics
Nanoelectronics
Electric stimulation
Magnetostriction
Piezoelectricity
Photoelectricity
Descripción
Sumario:[eng] Our bodies are complex machines whose functioning depends on multiple electrical signals controlled mainly by the nervous system. Afterwards, it is not illogical to think that one day artificial electrical impulses would replace those signals offering supports of medical treatments. Nowadays electrical stimulation is used in many therapeutic applications to modulate cellular activity, restore biological lost functions or even improve the performance of certain tissues. However, these systems still carry side effects link to the surgical interventions to place them or place their electrodes, their inherent bulkiness or lack in specificity to target only the cells involved in the condition to treat. The future to transcend these constrains would be possible in the extent that technology ease the path to improve precision, autonomy and miniaturization of the actual therapeutic tools. In this context, micro- and nanogenerators play a key role as self-powered devices with high spatial resolution and acute cell specificity. This thesis aims to provide micro/nanogenerators to stimulate single cells in its own liquid media. This work explored two technological branches based on photovoltaic and on magnetoelastic (piezoelectric/magnetostrictive) devices to harvest energy. Their fabrication was accomplished through semiconductors microfabrication technologies and their performance was characterized through several tests to ensure their correct power generation. As these devices were intended to interface biological media, direct cytotoxicity studies were conducted to guarantee their safety. Both branches were biologically validated with in vitro models of excitable cells (embryonic mouse neurons and human osteoblast- like cells) analyzing the electrostimulation effects through morphological changes and through instantaneous ionic responses as calcium signaling. The results gathered in this research demonstrated the feasibility of these micro- and nanogenerators as self-powered electrical stimulators. Furthermore, their reduce size and capability to be suspended in liquid media open the door to further developments towards injected or ingested minimally invasive medical tools.