The effects of microgravity on nanoparticle size distributions generated by the ultrasonic reduction of an aqueous gold-chloride solution

Abstract

A solution of gold chloride was reduced using ultrasound irradiation to prepare metallic gold nanoparticles under conditions of microgravity and normal gravity at sea level. Particle size distributions were measured using TEM analysis. A mean particle diameter of 10 nm was obtained in microgravity while a mean diameter of 80 nm was obtained in the laboratory. Absorbance measurements on the reacted solution found an enhanced reduction rate in the reduction of gold chloride in microgravity compared to that in the laboratory.

Polysorbate 80 as a Tool: Synthesis of Gold Nanoparticles

“…Other studies used different protective agents and organic solvents to produce Au 0 from gold salts, however, mostly in the presence of reducing agents15–19 and/or external energies 20–26. Typically, chemical‐ or photo‐induced reduction mechanisms are invoked to describe such processes.…”

“…Especially, gold nanoparticles (Au 0 ) have been well‐studied and widely used for various applications such as catalysis, biological reporters, electronic, and optic materials 8–15. However, in most of the syntheses reported15,16 so far, either reducing agents15–19 and/or external energy sources20–26 have been used. Although some reports have previously showed the potential of some polymers27–29 and amines30,31 to act as reducing agents, to the best of our knowledge, the nonionic surfactants in general, and polysorbate 80 in particular, have not been used in the development of a strategy to obtain stable Au 0 in an aqueous medium at room temperature.…”

Gold Nanoparticles in Biomedical Applications

“…Other physical methods such as thermolysis of gold(I) complex at 180 0 C for 5 h under nitrogen atmosphere, 29 radiolysis of gold salts in aqueous solution using cirradiation-induced reduction in the field of a 60 Coc-ray source, 30 photochemistry, e.g. in the HAuCl4 solution containing certain amounts of protective agent and acetone, the colloidal gold particles with an average diameter of 5 nm (r= 0.86) were prepared by UV 300 nm irradiation, 31 and sonochemistry using ultrasound-induced reduction of gold salts in aqueous solution [32][33][34] have been used to prepare a variety of gold nanoparticles.…”

Biopharmaceutical applications of nanogold

“…Other physical methods such as thermolysis of gold(I) complex at 180°C for 5 h under nitrogen atmosphere (Yamamoto and Nakamoto, 2003), radiolysis of gold salts in aqueous solution using c-irradiation-induced reduction in the field of a 60 Co c-ray source (Henglein and Meisel, 1998;Dawson and Kamat, 2000), photochemistry, e.g. in the HAuCl 4 solution containing certain amounts of protective agent and acetone, the colloidal gold particles with an average diameter of 5 nm (r = 0.86) were prepared by UV 300 nm irradiation (Mallick et al, 2001;Sau et al, 2001), and sonochemistry using ultrasound-induced reduction of gold salts in aqueous solution (Chen et al, 2001;Pol et al, 2003;Reed et al, 2003) have been used to prepare a variety of gold nanoparticles.…”