Glucosamine Phosphate Induces AuNPs Aggregation and Fusion into Easily Functionalizable Nanowires

The challenge to obtain plasmonic nanosystems absorbing light in the near infrared is always open because of the interest that such systems pose in applications such as nanotherapy or nanodiagnostics. Here we describe the synthesis in an aqueous solution devoid of any surfactant of Au-nanowires of controlled length and reasonably narrow dimensional distribution starting from Au-nanoparticles by taking advantage of the properties of glucosamine phosphate under aerobic conditions and substoichiometric nanoparticle passivation. Oxygen is required to enable the process where glucosamine phosphate is oxidized to glucosaminic acid phosphate and H2O2 is produced. The process leading to the nanosystems comprises nanoparticles growth, their aggregation into necklace-like aggregates, and final fusion into nanowires. The fusion requires the consumption of H2O2. The nanowires can be passivated with an organic thiol, lyophilized, and resuspended in water without losing their dimensional and optical properties. The position of the broad surface plasmon band of the nanowires can be tuned from 630 to >1350 nm.

Synthesis and Characterization of Sliver Nanoparticles in KH-550 DMF Solution

Silver nanoparticles have been synthesized in 3-(aminopropyl)triethoxysilane (KH-550) solution using DMF (N, N-dimethylformamide) as both solvent and reductant at room temperature and 120°C. A characteristic surface plasmon band can be observed for the obtained silver nanoparticles from UV-vis absorption spectra, which indicate that KH-550 can serve as stabilizing agent for the formation of silver nanoparticles. Transmission electron microscopy (TEM) results show that silver nanoparticles with different sizes were obtained by simply controlling the reaction temperature.