This dissertation describes the use of alkanethiols and polymers for the development of lithographic affinity and resist array templates that can be utilized for directing the assembly of biological molecules, for building up multilayered polyelectrolyte thin films, and for fabricating metal solid-state nanostructures. The first two chapters of the work described in this dissertation are focused on the use of nanoarrays, in conjunction with various protein immobilization schemes, to probe fundamental biological processes that cannot be addressed by macro- and microarray methodologies. Covalent and divalent metal ion coordination chemistries are utilized to tether biological molecules onto nanoaffinity templates generated using Dip-pen nanolithography (DPN). This high-resolution lithographic technique enables the fabrication of lithographic arrays of alkanethiol self-assembled monolayers (SAMs) with different functional head groups (carboxylate and N-hydroxysuccinimide), which can be used to coordinate Zn (II) ions and covalently bind protein A/G, respectively. The bound metal ions or small proteins specifically bind to the Fc region of antibodies. Biological molecules that are immobilized in such a fashion exhibit high activity and specificity for antigens and virus particles. Site isolation of single virus particles can be further accomplished by controlling the dot diameter features of the DPN-generated templates. Other "soft" materials that can be assembled onto the DPN-generated alkanethiol templates are polyelectrolytes. Taking advantage of the charged functional pendant groups, these polymers can be electrostatically adsorbed onto the written SAMs. Sequential exposure of the generated alkanethiol SAM templates to oppositely charged polyions afford the fabrication polyelectrolyte multilayer films. The ease of use of the Layer-by-Layer (LbL) assembly in conjunction with the DPN approach offers the ability to tailor and control important parameters such as the sizes and thicknesses of the generated polyelectrolyte multilayer assemblies, and also the chemical functionality at the top most layer of the multilayer films. In principle, any charged materials other than polymers can be immobilized onto the polyelectrolyte multilayered arrays. Raised and recessed metal nanostructures are generated using a combination of DPN and wet-chemical etching methodology. Polyethylene glycol is used either as a resist or sacrificial material to generate positive or negative patterns, respectively. In the case of positive nanostructure fabrication, the DPN-generated PEG nano size features are used to protect the underlying gold films from oxidization by chemical etching solutions. Negative nanostructure fabrication, on the other hand, is accomplished through passivation of the areas surrounding the DPN-generated PEG patterns with 1-ocatadecanethiol (ODT), dissolution of polymer templates using a simple washing step, and oxidation of the gold areas originally occupied by PEG. The positive and negative nanostructures have well defined shape features, and they can be easily scaled-up using parallel-DPN. Finally, this dissertation describes a seed mediated approach for synthesizing Au/Ag core-shell prisms with smooth and corrugated surfaces. The shapes, sizes, and optical properties of these core-shells nanostructures can be tailored using various stoichiometric ratios of silver and gold. Nanoparticles with thicker gold shells and roughened surfaces are produced with decreasing ratios of Au (III) and Ag (I), and their corresponding surface plasmon bands are red shifted to the near-IR region of the spectrum.

Last modified

• 08/27/2018

Creator

• Raymond Jose de Guia Sanedrin

DOI

• https://doi.org/10.21985/N2NF0W

Subject

• Chemistry

Keyword

• Chemistry

Date created

• 2007-12-05

Resource type

• Dissertation

Rights statement

• In Copyright