Controlled formation of gold nanoparticles with tunable plasmonic properties in tellurite glass

Silicate glasses with metallic nanoparticles (NPs) have been of intense interest in art, science and technology as the plasmonic properties of these NPs equip glass with light modulation capability. The so-called striking technique has enabled precise control of the in situ formation of metallic NPs in silicate glasses for applications from coloured glasses to photonic devices. Since tellurite glasses exhibit the unique combination of comparably easy fabrication, low phonon energy, wide transmission window and high solubility of luminescent rare earth ions, there has been a significant amount of work over the past two decades to adapt the striking technique to form gold or silver NPs in tellurite glasses. Despite this effort, the striking technique has remained insufficient for tellurite glasses to form metal NPs suitable for photonic applications. Here, we first uncover the challenges of the traditional striking technique to create gold NPs in tellurite glass. Then, we demonstrate precise control of the size and concentration of gold NPs in tellurite glass by developing new approaches to both steps of the striking technique: a controlled gold crucible corrosion technique to incorporate gold ions in tellurite glass and a glass powder reheating technique to subsequently transform the gold ions to gold NPs. Using the Mie theory, the size, size distribution and concentration of the gold NPs formed in tellurite glass are determined from the plasmonic properties of the NPs. This fundamental research provides guidance for designing and manipulating the plasmonic properties in tellurite glass for photonics research and applications

Noble metal nanoparticles in glass: A universal pathway towards light modulation

Incorporating metallic nanoparticles (NPs) in glass has been of intense artistic interest and scientific and technical enthusiasm, since the localized surface plasmon resonance (LSPR) of metallic nanoparticles enrich glass with light modulation capability, which allows applications from colored glasses to photonic devices. The conventional method of generating metallic NPs in glass comprises two steps: (1) prepare a parent glass containing metal ions over the entire glass volume by the melting-quenching technique; (2) strike the parent glass by post heat-treatment, during which the metal ions are reduced to metal atoms, which subsequently nucleate and grow into metallic NPs. However, to efficiently stimulate the reduction of metal ions in the striking step, a co-doping reducing agent in the glass batch is often used, which limits the glass compositions/types and/or requires toxic and environmentally hazardous chemicals. Initiated by an accidental discovery (Chapter 1), the research presented in this thesis is dedicated to the development of a novel and universal powder reheating technique capable of creating noble metal (Au, Ag, or Au-Ag alloy) NPs in a wide range of glass types/compositions (Chapter 3 and 4), and further employing this technique to produce eco-friendly coloured glass for glass art application (Chapter 5) and to study the modulation of upconversion emissions of Er³⁺ in glass by the in-situ created Au NPs taking into account both near-field and far-field LSPR effects (Chapter 6).Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 201

Controlled formation of gold nanoparticles with tunable plasmonic properties in tellurite glass

Abstract Silicate glasses with metallic nanoparticles (NPs) have been of intense interest in art, science and technology as the plasmonic properties of these NPs equip glass with light modulation capability. The so-called striking technique has enabled precise control of the in situ formation of metallic NPs in silicate glasses for applications from coloured glasses to photonic devices. Since tellurite glasses exhibit the unique combination of comparably easy fabrication, low phonon energy, wide transmission window and high solubility of luminescent rare earth ions, there has been a significant amount of work over the past two decades to adapt the striking technique to form gold or silver NPs in tellurite glasses. Despite this effort, the striking technique has remained insufficient for tellurite glasses to form metal NPs suitable for photonic applications. Here, we first uncover the challenges of the traditional striking technique to create gold NPs in tellurite glass. Then, we demonstrate precise control of the size and concentration of gold NPs in tellurite glass by developing new approaches to both steps of the striking technique: a controlled gold crucible corrosion technique to incorporate gold ions in tellurite glass and a glass powder reheating technique to subsequently transform the gold ions to gold NPs. Using the Mie theory, the size, size distribution and concentration of the gold NPs formed in tellurite glass are determined from the plasmonic properties of the NPs. This fundamental research provides guidance for designing and manipulating the plasmonic properties in tellurite glass for photonics research and applications

CSN6‐SPOP‐HMGCS1 Axis Promotes Hepatocellular Carcinoma Progression via YAP1 Activation

Abstract Cholesterol metabolism has important roles in maintaining membrane integrity and countering the development of diseases such as obesity and cancers. Cancer cells sustain cholesterol biogenesis for their proliferation and microenvironment reprograming even when sterols are abundant. However, efficacy of targeting cholesterol metabolism for cancer treatment is always compromised. Here it is shown that CSN6 is elevated in HCC and is a positive regulator of hydroxymethylglutaryl‐CoA synthase 1 (HMGCS1) of mevalonate (MVA) pathway to promote tumorigenesis. Mechanistically, CSN6 antagonizes speckle‐type POZ protein (SPOP) ubiquitin ligase to stabilize HMGCS1, which in turn activates YAP1 to promote tumor growth. In orthotopic liver cancer models, targeting CSN6 and HMGCS1 hinders tumor growth in both normal and high fat diet. Significantly, HMGCS1 depletion improves YAP inhibitor efficacy in patient derived xenograft models. The results identify a CSN6‐HMGCS1‐YAP1 axis mediating tumor outgrowth in HCC and propose a therapeutic strategy of targeting non‐alcoholic fatty liver diseases‐ associated HCC