Title:
Advancing atomic force microscopy-scanning electrochemical microscopy based sensing platforms for biological applications

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dc.contributor.advisor Mizaikoff, Boris
dc.contributor.advisor Kranz, Christine
dc.contributor.author Wiedemair, Justyna en_US
dc.contributor.committeeMember Eaton, Douglas
dc.contributor.committeeMember Fernandez, Facundo
dc.contributor.committeeMember Loeffler, Frank
dc.contributor.committeeMember Lyon, Andrew
dc.contributor.department Chemistry and Biochemistry en_US
dc.date.accessioned 2010-06-10T17:00:54Z
dc.date.available 2010-06-10T17:00:54Z
dc.date.issued 2009-04-06 en_US
dc.description.abstract Combined atomic force microscopy-scanning electrochemical microscopy (AFM-SECM) is capable of providing simultaneous topographical and electrochemical imaging at sample surfaces. Integration of amperometric biosensors at tip-integrated electrodes recessed from the apex of the AFM tip further enhances the versatility of such bifunctional probes. Of particular interest to this work was the detection of adenosine triphosphate (ATP) at a cellular level, since ATP is involved in many biologically relevant processes. There are challenges concerning the integration of biosensors into bifunctional AFM-SECM probes. This thesis focuses on addressing and advancing several of these limitations. Thin insulation layers are important for AFM-SECM based applications to enhance AFM and SECM performance. Plasma-polymerized fluorocarbon membranes are introduced as novel thin film insulation materials for AFM-SECM probes. Insulation layers with a thickness of < 300 nm were found to exhibit excellent insulating properties and satisfying temporal stability for successful application in AFM-SECM experiments. Furthermore new approaches for increasing the electrode area in conventionally focused ion beam (FIB) fabricated AFM-SECM probes were implemented, since enhancement of the current response in conjunction with biosensing experiments is required. Ion beam induced deposition (IBID) was used to generate platinum carbon (PtC) deposits at AFM-SECM probes, thereby successfully increasing the tip-integrated electrode area. PtC composites were thoroughly characterized in terms of their physical and electrochemical properties. Since a high carbon fraction in the PtC composite was inhibiting the charge transfer kinetics at the electrode surface for certain analytes, several pre-treatment strategies were investigated including annealing, UV/ozone treatment, and FIB milling. FIB milling proved to be the most promising procedure improving charge transfer properties at the electrode along with fabrication compatibility at AFM-SECM probes. The last part of this thesis aimed at providing fundamental studies on AFM-SECM application at live epithelial cell monolayers. AFM was used in different imaging modes to characterize the topography of epithelial cells. ATP detection at epithelial cells was achieved with amperometric biosensors combined with non-invasive SECM. Biosensors were further miniaturized at batch-fabricated AFM-SECM probes enabling laterally-resolved detection of ATP at epithelial cells. Additionally, PtC composite materials were evaluated for applicability as transducer platforms for enzymatic biosensors. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/33960
dc.publisher Georgia Institute of Technology en_US
dc.subject Adenosine triphosphate en_US
dc.subject Electrochemistry en_US
dc.subject Microelectrodes en_US
dc.subject Biosensors en_US
dc.subject Atomic force microscopy en_US
dc.subject Scanning electrochemical microscopy en_US
dc.subject.lcsh Scanning probe microscopy
dc.subject.lcsh Detectors
dc.subject.lcsh Medical instruments and apparatus
dc.subject.lcsh Plasma polymerization
dc.title Advancing atomic force microscopy-scanning electrochemical microscopy based sensing platforms for biological applications en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.corporatename School of Chemistry and Biochemistry
local.contributor.corporatename College of Sciences
relation.isOrgUnitOfPublication f1725b93-3ab8-4c47-a4c3-3596c03d6f1e
relation.isOrgUnitOfPublication 85042be6-2d68-4e07-b384-e1f908fae48a
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