Interactions of Cells with Magnetic Nanowires and Micro Needles

Handle URI:
http://hdl.handle.net/10754/626274
Title:
Interactions of Cells with Magnetic Nanowires and Micro Needles
Authors:
Perez, Jose E. ( 0000-0002-2206-0034 )
Abstract:
The use of nanowires, nano and micro needles in biomedical applications has markedly increased in the past years, mainly due to attractive properties such as biocompatibility and simple fabrication. Specifically, these structures have shown promise in applications including cell separation, tumor cell capture, intracellular delivery, cell therapy, cancer treatment and as cell growth scaffolds. The work proposed here aims to study two platforms for different applications: a vertical magnetic nanowire array for mesenchymal stem cell differentiation and a micro needle platform for intracellular delivery. First, a thorough evaluation of the cytotoxicity of nanowires was done in order to understand how a biological system interacts with high aspect ratio structures. Nanowires were fabricated through pulsed electrodeposition and characterized by electron microscopy, vibrating sample magnetometry and energy dispersive X-ray spectroscopy. Studies of biocompatibility, cell death, cell membrane integrity, nanowire internalization and intracellular dissolution were all performed in order to characterize the cell response. Results showed a variable biocompatibility depending on nanowire concentration and incubation time, with cell death resulting from an apoptotic pathway arising after internalization. A vertical array of nanowires was then used as a scaffold for the differentiation of human mesenchymal stem cells. Using fluorescence and electron microscopy, the interactions between the dense array of nanowires and the cells were analyzed, as well as the biocompatibility of the array and its effects on cell differentiation. A magnetic field was additionally applied on the substrate to observe a possible differentiation. Stem cells grown on this scaffold showed a cytoskeleton and focal adhesion reorganization, and later expressed the osteogenic marker osteopontin. The application of a magnetic field counteracted this outcome. Lastly, a micro needle platform was fabricated through lithography and electrodeposition, characterized using the previously mentioned techniques and then evaluated as a vector for intracellular delivery. Fluorescence and electron microscopy imaging were first performed to assess the biocompatibility, cell spreading and the interface of the cells and the needles. Intracellular delivery of a fluorescent dye was achieved via inductive heating of the needles, with the results showing a dependency of delivery and cell survivability on the exposure time.
Advisors:
Kosel, Jürgen ( 0000-0002-8998-8275 ) ; Ravasi, Timothy ( 0000-0002-9950-465X )
Committee Member:
Merzaban, Jasmeen ( 0000-0002-7276-2907 ) ; Di Fabrizio, Enzo M. ( 0000-0001-5886-4678 ) ; Stadler, Bethanie
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Program:
Bioscience
Issue Date:
Dec-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorKosel, Jürgenen
dc.contributor.advisorRavasi, Timothy-
dc.contributor.authorPerez, Jose E.en
dc.date.accessioned2017-12-04T12:38:54Z-
dc.date.available2017-12-04T12:38:54Z-
dc.date.issued2017-12-
dc.identifier.urihttp://hdl.handle.net/10754/626274-
dc.description.abstractThe use of nanowires, nano and micro needles in biomedical applications has markedly increased in the past years, mainly due to attractive properties such as biocompatibility and simple fabrication. Specifically, these structures have shown promise in applications including cell separation, tumor cell capture, intracellular delivery, cell therapy, cancer treatment and as cell growth scaffolds. The work proposed here aims to study two platforms for different applications: a vertical magnetic nanowire array for mesenchymal stem cell differentiation and a micro needle platform for intracellular delivery. First, a thorough evaluation of the cytotoxicity of nanowires was done in order to understand how a biological system interacts with high aspect ratio structures. Nanowires were fabricated through pulsed electrodeposition and characterized by electron microscopy, vibrating sample magnetometry and energy dispersive X-ray spectroscopy. Studies of biocompatibility, cell death, cell membrane integrity, nanowire internalization and intracellular dissolution were all performed in order to characterize the cell response. Results showed a variable biocompatibility depending on nanowire concentration and incubation time, with cell death resulting from an apoptotic pathway arising after internalization. A vertical array of nanowires was then used as a scaffold for the differentiation of human mesenchymal stem cells. Using fluorescence and electron microscopy, the interactions between the dense array of nanowires and the cells were analyzed, as well as the biocompatibility of the array and its effects on cell differentiation. A magnetic field was additionally applied on the substrate to observe a possible differentiation. Stem cells grown on this scaffold showed a cytoskeleton and focal adhesion reorganization, and later expressed the osteogenic marker osteopontin. The application of a magnetic field counteracted this outcome. Lastly, a micro needle platform was fabricated through lithography and electrodeposition, characterized using the previously mentioned techniques and then evaluated as a vector for intracellular delivery. Fluorescence and electron microscopy imaging were first performed to assess the biocompatibility, cell spreading and the interface of the cells and the needles. Intracellular delivery of a fluorescent dye was achieved via inductive heating of the needles, with the results showing a dependency of delivery and cell survivability on the exposure time.en
dc.language.isoenen
dc.subjectCell Cultureen
dc.subjectMagnetic Nanowiresen
dc.subjectCytotoxicityen
dc.subjectmesenchymal stem cellsen
dc.subjectosteogenesisen
dc.subjectBiocompatibilityen
dc.titleInteractions of Cells with Magnetic Nanowires and Micro Needlesen
dc.typeDissertationen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberMerzaban, Jasmeenen
dc.contributor.committeememberDi Fabrizio, Enzo M.en
dc.contributor.committeememberStadler, Bethanieen
thesis.degree.disciplineBioscienceen
thesis.degree.nameDoctor of Philosophyen
dc.person.id118450en
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