The Huge Role of Tiny Impurities in Nanoscale Synthesis.

Nanotechnology is vital to many current industries, including electronics, energy, textiles, agriculture, and theranostics. Understanding the chemical mechanisms of nanomaterial synthesis has contributed to the tunability of their unique properties, although studies frequently overlook the potential impact of impurities. Impurities can show adverse effects, clouding the interpretation of results or limiting the practical utility of the nanomaterial.

Color Transferability from Solution to Solid Using Silica Coated Silver Nanoparticles.

The interpretation of color change in sensors and tests can be linked to incorrect conclusions if the intrinsic color changes are not accounted for. In this work, we study the intrinsic color change associated with the process of embedding nanoparticles in a polymer to create nanocomposite films. We present a safer, faster method to coat silver nanoparticles with silica and employ a seven-factor Plackett-Burman design to identify critical factors in the synthesis.

Linear assembly of gold nanoparticle clusters via centrifugation.

Centrifugation is widely used in the synthesis and handling of solution-phase nanoparticles to improve their purity and to change the composition of the solvent. Herein, we couple the optical properties of citrate-stabilized gold nanoparticles and silica encapsulation to investigate how centrifugation impacts the formation of stabilized nanoparticle clusters in solution without the use of linker molecules or asymmetric functionalization. Gold nanoparticles preconcentrated using a high (9,400) g force result in linear assemblies of gold cores that are spaced by approximately 1-4 nm within Au(n)@SiO(2) structures (n = number of gold nanoparticle cores per silica shell) with approximately 30% monomers, 30% dimers, 20% trimers, and 10% 4-7mers.

310 nm irradiation of atmospherically relevant concentrated aqueous nitrate solutions: nitrite production and quantum yields.

The heterogeneous processing of atmospheric aerosols by reaction with nitrogen oxides results in the formation of particulate and adsorbed nitrates. The water content of these hygroscopic nitrate aerosols and consequently the nitrate ion concentration depend on relative humidity, which can impact the physicochemical properties of these aerosols. This report focuses on the 310 nm photolysis of aqueous sodium and calcium nitrate solutions at pH 4 over a wide concentration range of nitrate ion concentrations representative of atmospheric aerosols.

Silica-void-gold nanoparticles: temporally stable surface-enhanced Raman scattering substrates.

Reproducible detection of a target molecule is demonstrated using temporally stable solution-phase silica-void-gold nanoparticles and surface-enhanced Raman scattering (SERS). These composite nanostructures are homogeneous (diameter = 45 +/- 4 nm) and entrap single 13 nm gold nanoparticle cores inside porous silica membranes which prevent electromagnetic coupling and aggregation between adjacent nanoparticles. The optical properties of the gold nanoparticle cores and structural changes of the composite nanostructures are characterized using extinction spectroscopy and transmission electron microscopy, respectively, and both techniques are used to monitor the formation of the silica membrane.

Probing cells with noble metal nanoparticle aggregates.

This review focuses on the integration of noble metal nanoparticle aggregates as tags and transport vessels in cellular applications. The natural tendency of nanoparticles to aggregate can be reduced through surface modification; however, this stabilization is often compromised in the cellular environment. The degree of nanoparticle aggregation has both positive and negative consequences.