Effect of voltage polarity and supply frequency on properties of plasma contacting liquid electrode and gold nanoparticle synthesis

Plasma contacting with liquid provides many charged particles and reactive species into the liquid. The difficulty in controlling or selecting each specific species has significantly limited its applications in industry. Here, we present a study on using voltage polarity to regulate the type of charged particles absorbing from plasma into liquid. Detailed understanding of the processes at the plasma-liquid interface, electrolysis due to switching in voltage polarity was investigated via a visual pH observation, measuring the concentration of H2O2 and solvated electrons. The results indicated that changing in voltage polarity strongly affects the plasma properties, chemical properties, and electrolysis process in liquid, and further in the types of reducing species for gold nanoparticle synthesis. The results also showed using a suitable frequency could improve the efficiency of absorption of H2O2from plasma into the bulk liquid and the yield in the production of gold nanoparticles. The results provide a way to select desired species from plasma into the liquid for a distinct purpose and accompanying other properties in the system of plasma contacting with liquid.

Simplification of gold nanoparticle synthesis with low cytotoxicity using a greener approach: opening up new possibilities

This method described herein does not need any sophisticated laboratory devices and deploy local resource.

Encased Gold Nanoparticle Synthesis as a Probe for Oleuropein Self-Assembled Structure Formation

Stable oleuropein-coated gold nanoparticles in aqueous media were synthesized for the first time. Oleuropein (OLE) concentration in the reaction medium was found to greatly influence the outcome and stability of the resulting nanocolloid, with a marked decrease in particle size being found for the more concentrated oleuropein solutions. The protection mechanisms involved in the stabilized nanosystems were analyzed. Oleuropein self-assembled structures were found to be formed at a concentration threshold of [OLE] > 5 × 10−5 M, and observed through the use of CryoSEM imaging. Those structures were responsible for both the increased stability and the decrease in size observed at the more concentrated solutions.