Gold Nanoparticle Colorants as Traditional Ceramic Glaze Alternatives

Historically, Roman stained glass has been a standard for high‐temperature color stability since biblical times but was not properly characterized as emission from nanoparticle plasmon resonance until the 1990s. The methods under which it was created have been lost, but some efforts have recently been made to recreate these properties using gold nanoparticle inks on glassy surfaces. This body of work employs gold nanoparticle systems ranging from 0.015% to 0.100% (wt/wt), suspended in a clear glaze body. The glazes are fired with traditional ceramic methods—in both gas reduction and electric oxidation kilns—in which nanoparticles are retained and can be imaged via TEM. Various colors intensities are reported in addition to changes in nanoparticle size after application and firing. The nanoparticle glazes are compared to traditional red glazes, highlighting the significantly lower metal loading required (5%‐10% for traditional glazes vs 0.100% for gold (wt/wt)), therein. Finally, proof of concept is provided with a functional gold nanoparticle mug, fired in reduction, that costs roughly 0.98$ USD in gold used

A photonic crystal cavity-optical fiber tip nanoparticle sensor for biomedical applications

We present a sensor capable of detecting solution-based nanoparticles using an optical fiber tip functionalized with a photonic crystal cavity. When sensor tips are retracted from a nanoparticle solution after being submerged, we find that a combination of convective fluid forces and optically-induced trapping cause an aggregation of nanoparticles to form directly on cavity surfaces. A simple readout of quantum dot photoluminescence coupled to the optical fiber shows that nanoparticle presence and concentration can be detected through modified cavity properties. Our sensor can detect both gold and iron oxide nanoparticles and can be utilized for molecular sensing applications in biomedicine.Comment: 13 pages, 5 figure

DNA-origami-aided lithography for sub-10 nanometer pattern printing

We report the first DNA-based origami technique that can print addressable patterns on surfaces with sub-10 nm resolution. Specifically, we have used a two-dimensional DNA origami as a template (DNA origami stamp) to transfer DNA with pre-programmed patterns (DNA ink) on gold surfaces. The DNA ink is composed of thiol-modified staple strands incorporated at specific positions of the DNA origami stamp to create patterns upon thiol-gold bond formation on the surface (DNA ink). The DNA pattern formed is composed of unique oligonucleotide sequences, each of which is individually addressable. As a proof-of-concept, we created a linear pattern of oligonucleotide-modified gold nanoparticles complementary to the DNA ink pattern. We have developed an in silico model to identify key elements in the formation of our DNA origami-driven lithography and nanoparticle patterning as well as simulate more complex nanoparticle patterns on surfaces

Shape-dependent plasmon resonances of gold nanoparticles

Localized surface plasmon resonances in noble metal nanoparticles cause enhanced optical absorption and scattering that is tunable through the visible and near-infrared. Furthermore, these resonances create large local electric field enhancements at the nanoparticle surfaces, essentially focussing light at the nanometer scale. These properties suggest a range of applications, including biomedical imaging, therapeutics, and molecular sensing. Here we review some recent advances regarding shape-dependent optical properties of two specific nanoparticle geometries: gold nanorods and branched gold nanoparticles

Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form

The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)–thiyl, with Au(I)–thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)–thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s–d hybridization and charge polarization effects that perturbatively mix in some Au(I)–thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)–thiolate involvement. Predictions that Brust–Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)–thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established

Use of Oligonucleotides Carrying Photolabile Groups for the Control of the Deposition of Nanoparticles in Surfaces and Nanoparticle Association

An oligodeoxynucleotide hairpin containing a photolabile 2-nitrobenzyl group in the loop and terminated with a thiol function was prepared. The photocleavage of such a hairpin on gold yields a surface activated with a single stranded oligonucleotide which can be utilised to direct the assembly of nanoparticles conjugated with a complementary strand. Analysis of photocleaved surfaces gives nanoparticle coverage one order of magnitude higher than nonphotocleaved surfaces. This illustrates the ability of photocleavable hairpins to direct the assembly of nanomaterials on conducting materials. The conjugation of the photocleavable hairpin to a gold nanoparticle allows the observation of intermolecular interactions between hairpins linked in different nanoparticles, by comparing the thermal dissociations of a hairpin-nanoparticle conjugates at 260 nm and 520 nm. We have also shown that it is possible to permanently alter the physiochemical properties of DNA-nanoparticles by the introduction of a photocleavable group. Indeed for the first time it has been shown that by exposure to UV light the disassembly of nanoparticle aggregates can be induced

Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form

The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)-thiyl, with Au(I)-thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)-thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s-d hybridization and charge polarization effects that perturbatively mix in some Au(I)-thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)-thiolate involvement. Predictions that Brust-Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)-thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established

A Novel Approach to Fabricating SERS Substrate: Deposition of Gold Nanoparticles on a Glass Surface via Vacuum-assisted Solvent Evaporation

In this presentation a simple method for the fabrication of cost-effective, on-demand Surface-Enhanced Raman Scattering (SERS) substrates from gold nanoparticle colloids on a glass surface will be discussed. The use of SERS substrates can significantly lower the detection limit for an analyte, which can broaden the analytical applications of Raman spectroscopy. The SERS substrates prepared by evaporating a gold nanoparticle solution on a surface is more attractive method compared with those prepared by nanofabrication, because the former is easier to use and more economical than the latter. But, two main problems need to be addressed in preparing a SERS substrate based on gold nanoparticles: Raman signal interferences from stabilizing capping ligands of nanoparticles and the “coffee-ring” effect. To solve these two issues, my research proposed the use of halide ions to replace the capping ligands and the deposition of gold nanoparticles on a surface in the presence of ethanol vapor in a desiccator under a slight vacuum condition, which could promote homogeneous deposition of nanoparticles. To characterize the gold nanoparticle deposits, absorption spectroscopy and Raman microscopy were primarily used. The plasmon bands of gold nanoparticles were probed using the absorption spectroscopy. The Raman bands of bare gold nanoparticle deposits and those of a Raman dye on the nanoparticle deposits were collected to examine the SERS activity of the prepared surfaces. In this talk the efficacy of my proposed research will be discussed mainly based on these data