Selective Nanopatterning Using Citrate-Stabilized Au Nanoparticles and Cystein-Modified Amphiphilic Protein (original) (raw)
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Interaction between manufactured gold nanoparticles and naturally occurring organic macromolecules
Science of The Total Environment, 2008
The increasing exploitation of nanomaterials into many consumer and other products is raising concerns as these nanomaterials are likely to be released into the environment. Due to our lack of knowledge about the environmental chemistry, transport and ecotoxicology of nanomaterials, it is of paramount importance to study how natural aquatic colloids can interact with manufactured gold nanoparticles as these interactions will determine their environmental fate and behaviour. In this context, our work aims to quantify the effect of naturally occurring riverine macromolecules -International Humic Substances Society (IHSS) Suwannee River Humic Acid Standard (SRHA)on citrate-and acrylate-stabilized gold nanoparticles. The influence of SRHA on the stability of the gold colloids was studied as a function of pH by UV-visible absorption spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM). At high ionic strengths (0.1 M), extensive and rapid aggregation occurred, while more subtle effects were observed at lower ionic strength values. Evidence was found that SRHA enhances particle stability at extreme pH values (ionic strength b 0.01 M) by substituting and/or over-coating the original stabilizer on the gold nanoparticle surface, thus affecting surface charge and chemistry. These findings have important implications for the fate and behaviour of nanoparticles in the environment and their ecotoxicity.
Nanoscale materials invite immense interest from diverse scientific disciplines as these provide access to precisely understand the physical world at their most fundamental atomic level. In concert with this aim of enhancing our understanding of the fundamental behavior at nanoscale, this dissertation presents research on three nanomaterials: Gold nanoparticles (GNPs), Graphene and ultra-thin Boron Nitride sheets (UTBNSs). The three-fold goals which drive this research are: incorporating mobility in nanoparticle based single-electron junction constructs, developing effective strategies to functionalize graphene with nano-forms of metal, and exfoliating ultrathin sheets of Boron Nitride.
Ultrathin Layer-by-Layer Hydrogels with Incorporated Gold Nanorods as pH-Sensitive Optical Materials
Chemistry of Materials, 2008
We report ultrathin pH-responsive plasmonic membranes of [poly(methacrylic acid)-gold nanorods] 20 (PMAA-Au NRs) 20 with gold nanorods embedded into swollen cross-linked LbL hydrogels. In contrast to the most of known pH responsive materials which rely on pH-triggered change in the intensity of photoluminescence or plasmon bands, the responsive structures suggested here exhibit a significant pHtriggered shift in easily detectable, strong plasmon resonance band. We show that a pH-induced deswelling of the (PMAA-Au NRs) 20 hydrogel film in the pH change from 8 to 5 causes a dramatic blue-shift of the longitudinal plasmon peak by 21 nm due to the increased side-by-side interactions of adjacent gold nanorods. These composite hydrogel multilayer films can be released from the substrates yielding freefloating and optically pH-responsive ultrathin hydrogel films which can be transferred to the appropriate solid substrates.