Fabrication and characterization of a plasmonic biosensor using non-spherical metal nanoparticles

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dc.contributor.advisor Frey , Wolfgang , doctor of physics en_US
dc.identifier.oclc 197082243 en_US
dc.creator Jung , Bong -Su , 1972 - en_US
dc.date.accessioned 2008 -08 -28T23 :58 :54Z
dc.date.accessioned 2014 -02 -19T22 :34 :28Z
dc.date.available 2008 -08 -28T23 :58 :54Z
dc.date.available 2014 -02 -19T22 :34 :28Z
dc.date.created 2007 -12 en_US
dc.date.issued 2008 -08 -28T23 :58 :54Z
dc.identifier.uri http : / /hdl .handle .net /2152 /3614
dc.description.abstract Label -free detection techniques have an important role in many applications , such as situations where few molecules - - rather than low molarity - - need to be detected , such as in single -cell screening . While surface plasmon resonance (SPR ) scattering from metal nanoparticles has been shown to achieve significantly higher sensitivity in gene arrays , such an approach has not been demonstrated for protein arrays . SPR -based sensors could either use simple absorption measurement in a UV -Vis spectrometer or possibly surfaceenhanced Raman spectroscopy as the detection mechanism for molecules of interest . However , non -spherical particles are needed to achieve high sensitivity and field enhancement that is a requirement in both techniques , but these shapes are not easy toproduce reproducibly and preserve for extended periods of time . Here I present a carbonbased template -stripping method combined with nanosphere lithography (NSL ) . This fabrication allows to preserve the sharp features in atomically flat surfaces which are a composite of a non -spherical metal nano -particle (gold or silver ) and a transparent embedding material such as glass . The stripping process is residue -free due to the introduction of a sacrificial carbon layer . The nanometer scale flat surface of our template stripping process is also precious for general protein absorption studies , because an inherent material contrast can resolve binding of layers on the 2 nm scale . These nanocomposite surfaces also allow us to tailor well -defined SPR extinction peaks with locations in the visible or infrared spectrum depending on the metal and the particle size and the degree of non -symmetry . As the particle thickness is reduced and the particle bisector length is increased , the peak position of the resonance shifts to the red . Not only the peak position shifts , but also the sensitivity to environmental changes increases . Therefore , the peak position of the resonance spectrum is dependent on the dielectric environmental changes of each particle , and the particle geometries . The resulting silver or gold nanoparticles in the surface of a glass slide are capable of detecting thiol surface modification , and biotin -streptavidin protein binding events . Since each gold or silver particle principally acts as an independent sensor , on the order of a few thousand molecules can be detected , and the sensor can be miniaturized without loss of sensitivity . UNSL -Au metal nanoparticle (MNP ) sensors achieve the sensitivity of close to 300 nm /RIU which is higher than any other report of localized surface plasmon resonance (LSPR ) sensors except gold nanocrescents . Finite -difference -time -domain (FDTD ) and finite -element -method (FEM ) numerical calculations display the influence of the sharp features on the resonance peak position . The maximum near -field intensity is dependent on the polarization direction , the sharpness of the feature , and the near -field confinement from the substrate . 3D FDTD simulation shows the local refractive index sensitivity of the gold truncated tetrahedron , which is in agreement with our experimental result . Both experimental and numerical calculations show that each particle can act as its own sensor . en_US
dc.format.medium electronic en_US
dc.language.iso eng en_US
dc.rights Copyright © is held by the author . Presentation of this material on the Libraries' web site by University Libraries , The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works . en_US
dc.subject.lcsh Surface plasmon resonance en_US
dc.subject.lcsh Nanoparticles en_US
dc.title Fabrication and characterization of a plasmonic biosensor using non -spherical metal nanoparticles en_US
dc.description.department Biomedical Engineering en_US
dc.identifier.recnum b69708344 en_US
dc.type.genre Thesis en_US
dc.type.material text en_US
thesis.degree.name Doctor of Philosophy en_US
thesis.degree.level Doctoral en_US
thesis.degree.discipline Biomedical Engineering en_US
thesis.degree.grantor The University of Texas at Austin en_US
thesis.degree.department Biomedical Engineering en_US

Citation

Fabrication and characterization of a plasmonic biosensor using non-spherical metal nanoparticles. Doctoral dissertation, The University of Texas at Austin. Available electronically from http : / /hdl .handle .net /2152 /3614 .

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