{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:51748"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:51748","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Nanostrukturierte Metallelektroden zur funktionalen Kopplung an neuronale Zellen","abstract":"The focus of this dissertation was to develop and investigate nanostructured gold interfaces for signal recordings from electroactive cells. Currently, the use of planar microelectrode arrays (MEAs) is an established technique for such extracellular recordings. However, a high impedance and a low signal-to-noise ratio are challenges, which have to be addressed for the recording of high quality measurements with MEAs. The aim of this research project was to improve cell-electrode interfaces via nanostructuring of the metal surface. The characteristics of interest were cell adhesion, spatial resolution, and electronic signal transduction of the novel cell-electrode interfaces. For the fabrication of these interfaces clean room technologies, e.g. photolithography and metallisation, were used. The nanostructures were produced by anodisation of an aluminium film in acid which yielded self-assembled nanopores. This porous membrane was filled with gold using galvanisation to produce freestanding gold nanopillars. Afterwards, the 3D geometrical surface of the nanopillars was characterised via scanning electron microscopy (SEM). It is now possible to control the parameters of the self-ordered process, e.g. acid temperature, applied voltage, and etching time to fabricate nanopillars with reproducible dimensions. Electrochemical methods such as impedance spectroscopy and cyclic voltammetry were employed to measure impedance and capacitance of the pillars in different electrolytes. Both methods yielded higher capacitances and consequently lower impedances for gold nanopillars than for planar gold. This result confirmed the expected increase of the surface area via nanostructuring. In the following cell coupling experiments the viability of different electrogenic cells types (i.e. cells which induce small electric signals) was analysed employing fluorescence microscopy and SEM analysis. Various surface modifications, e.g. proteins and self-assembled monolayers, were employed to influence the cell-adhesive response to the nanostructures. Cardiac muscle (HL1) and human embryonic kidney (HEK) cells adhered and survived on the nanopillars, but primary rat neurons showed unexpectedly low viability and adhesion on the nanopillars. In a crossectional analysis of the cell-nanostructure interface via focussed ion beam large distances between the neuronal cell body and the nanostructures were found. Contrarily, the neurites of these primary cells as well as HL1 and HEK cells adhered tightly. Furthermore, actin assembly within the growth cones of the adherent neurons was drastically modified when growing on the nanopillars. Hence, while gold nanopillars support interactions with some cell types, the cell-adhesive response to the nano-scale environment differs depending on cell type and region of the cell being examined. Finally, MEAs with gold nanopillars were fabricated and could be used for the first time to record extracellular signals from HL1 cells. Good coupling between the HL1 cells and the nanostructured electrodes was observed repeatedly. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In summary, gold nanopillar electrodes showed excellent behaviour for bioelectronic interfaces due to their reduced impedance and biocompatibility. In future applications this nanopillar concept can be adopted for distinct interface materials of electronic circuits and their coupling to cellular and molecular sensing components.","abstract_html":"The focus of this dissertation was to develop and investigate nanostructured gold interfaces for signal recordings from electroactive cells. Currently, the use of planar microelectrode arrays (MEAs) is an established technique for such extracellular recordings. However, a high impedance and a low signal-to-noise ratio are challenges, which have to be addressed for the recording of high quality measurements with MEAs. The aim of this research project was to improve cell-electrode interfaces via nanostructuring of the metal surface. The characteristics of interest were cell adhesion, spatial resolution, and electronic signal transduction of the novel cell-electrode interfaces. For the fabrication of these interfaces clean room technologies, e.g. photolithography and metallisation, were used. The nanostructures were produced by anodisation of an aluminium film in acid which yielded self-assembled nanopores. This porous membrane was filled with gold using galvanisation to produce freestanding gold nanopillars. Afterwards, the 3D geometrical surface of the nanopillars was characterised via scanning electron microscopy (SEM). It is now possible to control the parameters of the self-ordered process, e.g. acid temperature, applied voltage, and etching time to fabricate nanopillars with reproducible dimensions. Electrochemical methods such as impedance spectroscopy and cyclic voltammetry were employed to measure impedance and capacitance of the pillars in different electrolytes. Both methods yielded higher capacitances and consequently lower impedances for gold nanopillars than for planar gold. This result confirmed the expected increase of the surface area via nanostructuring. In the following cell coupling experiments the viability of different electrogenic cells types (i.e. cells which induce small electric signals) was analysed employing fluorescence microscopy and SEM analysis. Various surface modifications, e.g. proteins and self-assembled monolayers, were employed to influence the cell-adhesive response to the nanostructures. Cardiac muscle (HL1) and human embryonic kidney (HEK) cells adhered and survived on the nanopillars, but primary rat neurons showed unexpectedly low viability and adhesion on the nanopillars. In a crossectional analysis of the cell-nanostructure interface via focussed ion beam large distances between the neuronal cell body and the nanostructures were found. Contrarily, the neurites of these primary cells as well as HL1 and HEK cells adhered tightly. Furthermore, actin assembly within the growth cones of the adherent neurons was drastically modified when growing on the nanopillars. Hence, while gold nanopillars support interactions with some cell types, the cell-adhesive response to the nano-scale environment differs depending on cell type and region of the cell being examined. Finally, MEAs with gold nanopillars were fabricated and could be used for the first time to record extracellular signals from HL1 cells. Good coupling between the HL1 cells and the nanostructured electrodes was observed repeatedly. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In summary, gold nanopillar electrodes showed excellent behaviour for bioelectronic interfaces due to their reduced impedance and biocompatibility. In future applications this nanopillar concept can be adopted for distinct interface materials of electronic circuits and their coupling to cellular and molecular sensing components.","abstract_has_math":false,"creators":["Brüggemann, Dorothea"],"institution":"Forschungszentrum Jülich, Zentralbibliothek, Verl.","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Offenhäusser, Andreas"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010","date_published":"2010","updated_at":"2026-07-30T19:40:42Z","subjects":["info:eu-repo/classification/ddc/530","Bioelektronik","Nanostruktur","Mikroelektrode","Biosensor","Physik","Zellkopplung","microelectrode","cell coupling","nanostructures"],"languages":["ger"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114007%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114007%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114007%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/51748","outbound_label":"Repository record","outbound_source":"dc:identifier"},"source_record":{"url":"https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A51748","prefix":"oai_dc"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Offenhäusser, Andreas"]},{"key":"dc:creator","label":"Author","values":["Brüggemann, Dorothea"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2010"]},{"key":"dc:publisher","label":"Institution","values":["Forschungszentrum Jülich, Zentralbibliothek, Verl."]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/isbn/978-3-89336-627-9","info:eu-repo/semantics/altIdentifier/issn/1866-1777","info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-32549"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/530","Bioelektronik","Nanostruktur","Mikroelektrode","Biosensor","Physik","Zellkopplung","microelectrode","cell coupling","nanostructures"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["ger"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/51748","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114007%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The focus of this dissertation was to develop and investigate nanostructured gold interfaces for signal recordings from electroactive cells. Currently, the use of planar microelectrode arrays (MEAs) is an established technique for such extracellular recordings. However, a high impedance and a low signal-to-noise ratio are challenges, which have to be addressed for the recording of high quality measurements with MEAs. The aim of this research project was to improve cell-electrode interfaces via nanostructuring of the metal surface. The characteristics of interest were cell adhesion, spatial resolution, and electronic signal transduction of the novel cell-electrode interfaces. For the fabrication of these interfaces clean room technologies, e.g. photolithography and metallisation, were used. The nanostructures were produced by anodisation of an aluminium film in acid which yielded self-assembled nanopores. This porous membrane was filled with gold using galvanisation to produce freestanding gold nanopillars. Afterwards, the 3D geometrical surface of the nanopillars was characterised via scanning electron microscopy (SEM). It is now possible to control the parameters of the self-ordered process, e.g. acid temperature, applied voltage, and etching time to fabricate nanopillars with reproducible dimensions. Electrochemical methods such as impedance spectroscopy and cyclic voltammetry were employed to measure impedance and capacitance of the pillars in different electrolytes. Both methods yielded higher capacitances and consequently lower impedances for gold nanopillars than for planar gold. This result confirmed the expected increase of the surface area via nanostructuring. In the following cell coupling experiments the viability of different electrogenic cells types (i.e. cells which induce small electric signals) was analysed employing fluorescence microscopy and SEM analysis. Various surface modifications, e.g. proteins and self-assembled monolayers, were employed to influence the cell-adhesive response to the nanostructures. Cardiac muscle (HL1) and human embryonic kidney (HEK) cells adhered and survived on the nanopillars, but primary rat neurons showed unexpectedly low viability and adhesion on the nanopillars. In a crossectional analysis of the cell-nanostructure interface via focussed ion beam large distances between the neuronal cell body and the nanostructures were found. Contrarily, the neurites of these primary cells as well as HL1 and HEK cells adhered tightly. Furthermore, actin assembly within the growth cones of the adherent neurons was drastically modified when growing on the nanopillars. Hence, while gold nanopillars support interactions with some cell types, the cell-adhesive response to the nano-scale environment differs depending on cell type and region of the cell being examined. Finally, MEAs with gold nanopillars were fabricated and could be used for the first time to record extracellular signals from HL1 cells. Good coupling between the HL1 cells and the nanostructured electrodes was observed repeatedly. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In summary, gold nanopillar electrodes showed excellent behaviour for bioelectronic interfaces due to their reduced impedance and biocompatibility. In future applications this nanopillar concept can be adopted for distinct interface materials of electronic circuits and their coupling to cellular and molecular sensing components."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Forschungszentrum Jülich, Zentralbibliothek, Verl., Schriften des Forschungszentrums Jülich : Reihe Information 9, VII, 160 S. : Ill., graph. Darst. (2010). = Zugl.: Aachen, Techn. Hochsch., Diss., 2010"]},{"key":"dc:title","label":"Title","values":["Nanostrukturierte Metallelektroden zur funktionalen Kopplung an neuronale Zellen"]}]}],"canonical_facts":{"dc:contributor":["Offenhäusser, Andreas"],"dc:coverage":["DE"],"dc:creator":["Brüggemann, Dorothea"],"dc:date":["2010"],"dc:description":["The focus of this dissertation was to develop and investigate nanostructured gold interfaces for signal recordings from electroactive cells. Currently, the use of planar microelectrode arrays (MEAs) is an established technique for such extracellular recordings. However, a high impedance and a low signal-to-noise ratio are challenges, which have to be addressed for the recording of high quality measurements with MEAs. The aim of this research project was to improve cell-electrode interfaces via nanostructuring of the metal surface. The characteristics of interest were cell adhesion, spatial resolution, and electronic signal transduction of the novel cell-electrode interfaces. For the fabrication of these interfaces clean room technologies, e.g. photolithography and metallisation, were used. The nanostructures were produced by anodisation of an aluminium film in acid which yielded self-assembled nanopores. This porous membrane was filled with gold using galvanisation to produce freestanding gold nanopillars. Afterwards, the 3D geometrical surface of the nanopillars was characterised via scanning electron microscopy (SEM). It is now possible to control the parameters of the self-ordered process, e.g. acid temperature, applied voltage, and etching time to fabricate nanopillars with reproducible dimensions. Electrochemical methods such as impedance spectroscopy and cyclic voltammetry were employed to measure impedance and capacitance of the pillars in different electrolytes. Both methods yielded higher capacitances and consequently lower impedances for gold nanopillars than for planar gold. This result confirmed the expected increase of the surface area via nanostructuring. In the following cell coupling experiments the viability of different electrogenic cells types (i.e. cells which induce small electric signals) was analysed employing fluorescence microscopy and SEM analysis. Various surface modifications, e.g. proteins and self-assembled monolayers, were employed to influence the cell-adhesive response to the nanostructures. Cardiac muscle (HL1) and human embryonic kidney (HEK) cells adhered and survived on the nanopillars, but primary rat neurons showed unexpectedly low viability and adhesion on the nanopillars. In a crossectional analysis of the cell-nanostructure interface via focussed ion beam large distances between the neuronal cell body and the nanostructures were found. Contrarily, the neurites of these primary cells as well as HL1 and HEK cells adhered tightly. Furthermore, actin assembly within the growth cones of the adherent neurons was drastically modified when growing on the nanopillars. Hence, while gold nanopillars support interactions with some cell types, the cell-adhesive response to the nano-scale environment differs depending on cell type and region of the cell being examined. Finally, MEAs with gold nanopillars were fabricated and could be used for the first time to record extracellular signals from HL1 cells. Good coupling between the HL1 cells and the nanostructured electrodes was observed repeatedly. The resulting signal-to-noise ratio of nanopillar-MEAs was increased by a factor of 2 compared to planar MEAs. In summary, gold nanopillar electrodes showed excellent behaviour for bioelectronic interfaces due to their reduced impedance and biocompatibility. In future applications this nanopillar concept can be adopted for distinct interface materials of electronic circuits and their coupling to cellular and molecular sensing components."],"dc:identifier":["https://publications.rwth-aachen.de/record/51748","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114007%22"],"dc:language":["ger"],"dc:publisher":["Forschungszentrum Jülich, Zentralbibliothek, Verl."],"dc:relation":["info:eu-repo/semantics/altIdentifier/isbn/978-3-89336-627-9","info:eu-repo/semantics/altIdentifier/issn/1866-1777","info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-32549"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Forschungszentrum Jülich, Zentralbibliothek, Verl., Schriften des Forschungszentrums Jülich : Reihe Information 9, VII, 160 S. : Ill., graph. Darst. (2010). = Zugl.: Aachen, Techn. 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