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SOME STUDIES of NANOCRYSTAL QUANTUM
DOTS ON CHEMICALLY FUNCTIONALIZED
SUBSTRATES (SEMICONDUCTORS) FOR NOVEL
BIOLOGICAL SENSING
by
Siyuan Lu
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHEN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(PHYSICS)
December 2006
Copyright 2006 Siyuan Lu
Object Description
| Title | Some studies of nanocrystal quantum dots on chemically functionalized substrates (semiconductors) for novel biological sensing |
| Author | Lu, Siyuan |
| Author email | siyuanlu@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Physics |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2006-10-25 |
| Date submitted | 2006 |
| Restricted until | Unrestricted |
| Date published | 2006-12-01 |
| Advisor (committee chair) | Madhukar, Anupam |
| Advisor (committee member) |
Humayun, Mark S. Hellwarth, Robert W. Bozler, Hans M. Bergmann, Gerd |
| Abstract | Integration of epitaxial and colloidal semiconductor nanostructures into hybrid structures can potentially open unprecedented functionalities that combine the strengths of the epitaxial nanostructures as manifest in optoelectronics with the versatility of the colloidal nanocrystal and their application in solution environment. We envision that such hybrid structures can be a promising platform for chip-based, high-sensitivity detection of early disease and biohazard. This dissertation is devoted to several different research grounds that contribute to this envisioned application of colloidal/epitaxial hybrid structure.; In the class of nanocrystal quantum dots (NCQDs), we investigated the synthesis of InAs based NCQDs that emit in the near infrared and thus their compatibility with the existing optoelectronics technology and significance for high-sensitivity biological detection owing to the significantly reduced autofluorescence of cells in this wavelength regime.; A unique optical system was set up which enables simultaneous atomic-force-microscope and near-field-scanning-optical-microscope imaging of the NCQDs and of the morphology and fluorescence of the NCQD labeled cells. The setup is applied to examine the morphology of breast cancer cells and the distribution of their surface receptors Her2/neu.; Solid surface functionalization using self-assembling molecules (SAMs) with appropriate end groups (linkers) was investigated. Hybrid structures of nanocrystals on semiconductor substrates without or with SAM bilinkers were constructed. Substrate surface functionalization with peptide-ligand conjugated SAM is used to achieve selective neuronal cell adhesion on prosthetic surfaces.; As the first step towards signal transduction from a NCQD to an underlying substrate, excitation transfer in hybrid structures composed of nanocrystals in direct contact with a crystalline semiconductor substrate was studied using systematic photoluminescence (PL), PL-excitation and time-resolved PL spectroscopies. The study revealed that at even very low excitation power a unique type of "hot" charge transfer occurs from excited hole states in InAs/ZnSe NCQDs to interfacial states induced by the NCQD adsorption on the GaAs substrate. Such charge transfer may serve to establish the necessary communication between the NCQDs and substrates for chip based sensing of weak signals as expected for the earliest detection of disease or hazard signifying entities. |
| Keyword | quantum dot; nanostructure; biological sensing; excitation transfer; surface functionalization; cell adhesion |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m209 |
| Contributing entity | University of Southern California |
| Rights | Lu, Siyuan |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@dots.usc.edu |
| Filename | etd-Lu-20061201 |
| Archival file | uscthesesreloadpub_Volume48/etd-Lu-20061201.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | SOME STUDIES of NANOCRYSTAL QUANTUM DOTS ON CHEMICALLY FUNCTIONALIZED SUBSTRATES (SEMICONDUCTORS) FOR NOVEL BIOLOGICAL SENSING by Siyuan Lu A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHEN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (PHYSICS) December 2006 Copyright 2006 Siyuan Lu |
