Nanofluidic biosensing for beta-amyloid detection

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dc.contributor.advisor Cot ?Gerard L . en_US
dc.contributor.committeeMember Kameoka , Jun en_US
dc.creator Chou , I -Hsien en_US
dc.date.accessioned 2010 -01 -15T00 :10 :16Z
dc.date.accessioned 2014 -02 -19T19 :31 :28Z
dc.date.available 2010 -01 -15T00 :10 :16Z
dc.date.available 2014 -02 -19T19 :31 :28Z
dc.date.created 2007 -12 en_US
dc.date.issued 2009 -05 -15 en_US
dc.identifier.uri http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2439
dc.description.abstract A nanofluidic biosensor using surface -enhanced Raman scattering (SERS ) was developed to detect the ? -amyloid (A ? ) protein , one of the biomarkers of Alzheimer ?s disease (AD ) . Recent studies have indicated that investigating changes in relative concentrations of structure specific A ? oligomers in cerebral spinal fluid (CSF ) during the progression of AD could be important indicators for diagnosing AD pre -mortem . However , there is no definitive pre -mortem diagnosis of AD thus far because of the lack of technology available for sensitive A ? detection . Hence , the development of a system for detecting the structure specific A ? oligomers , along with the concentrations of these oligomers in CSF , would be useful in the investigation of the molecular mechanisms of A ? cytotoxicity associated with AD . In this thesis , a nanofluidic trapping device trapping system for detecting biomolecules at sub -picomolar concentrations was developed for using SERS . The device , with a microchannel leading to a nanochannel , carries out dual functions : encouraging sizedependent trapping of gold nanoparticles (60nm ) at the entrance of the nanochannel as well as restricting the target molecules between the gaps created by the aggregated nanoparticles . Initially , the trapping capability of the nanofluidic device was tested using fluorescent polystyrene and gold nanoparticles . UV -vis absorption spectroscopy was used to characterize the gold nanoparticle clusters at the entrance to the nanochannel . The device established controlled , reproducible , SERS active sites within the interstices of gold nanoparticle clusters and shifted the plasmon resonance to the near infrared , in resonance with incident laser light . Two strongly Raman active molecules , adenine and Congo red , were used to test the feasibility of the SERS nanofluidic device as a platform for the detection of multiple analytes . The results showed that strong SERS signals were obtained from the nanoparticle clusters at the nanochannel entrance . Once the feasibility of the approach was determined with strong Raman molecules , A ? was detected using this nanofluidic SERS platform . Distinct surface -enhanced Raman spectra of A ? was observed in different conformational states as a function of concentration and structure (monomer versus oligomer form ) due to A ? refolding from ? -helical to a predominantly ? -pleated sheet form . The sensor was also shown to potentially distinguish A ? from insulin and albumin , confounder proteins in cerebral spinal fluid . Thus , a novel platform was developed to detect picomoler levels of A ? with the ultimate goal of facilitating the diagnosis and understanding of Alzheimer ?s disease by means of detecting structure specific oligomers of A ? . en_US
dc.format.medium electronic en_US
dc.format.mimetype application /pdf en_US
dc.language.iso en _US en_US
dc.subject Surface Enhanced Raman Spectroscopy (SERS ) en_US
dc.title Nanofluidic biosensing for beta -amyloid detection en_US
dc.type Book en
dc.type.genre Electronic Thesis en_US
dc.type.material text en_US
dc.format.digitalOrigin born digital en_US

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Nanofluidic biosensing for beta-amyloid detection. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2439 .

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