Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

Abstract

For a comparative cytotoxicity study, nanoparticles of the noble metals Rh, Pd, Ag, Pt, and Au (spherical, average diameter 4 to 8 nm) were prepared by reduction in water and colloidally stabilized with poly(N-vinyl pyrrolidone) (PVP). Thus, their shape, size, and surface functionalization were all the same. Size and morphology of the nanoparticles were determined by dynamic light scattering (DLS), analytical disc centrifugation (differential centrifugal sedimentation, DCS), and high-resolution transmission electron microscopy (HRTEM). Cell-biological experiments were performed to determine the effect of particle exposure on the viability of human mesenchymal stem cells (hMSCs). Except for silver, no adverse effect of any of the metal nanoparticles was observed for concentrations up to 50 ppm (50 mg L−1) incubated for 24 h, indicating that noble metal nanoparticles (rhodium, palladium, platinum, gold) that do not release ions are not cytotoxic under these conditions.

Synthesis, Structure, Properties, and Applications of Bimetallic Nanoparticles of Noble Metals

“…[ 1b,60 ] In contrast, the other noble metals form nanoparticles which are much less cytotoxic and often have small biological effects, if at all. [ 61 ] In silver‐alloyed nanoparticles, the release of silver can lead to a tunable cytotoxicity, but experience has shown that it is difficult to predict the exact level of cytotoxicity. [ 39f,60a,62 ] The presence of platinum in alloyed silver–platinum nanoparticles causes an osteopromotive activity in contact with human mesenchymal stem cells.…”

Synthesis and biological characterization of alloyed silver–platinum nanoparticles: from compact core–shell nanoparticles to hollow nanoalloys

“…Reports in the literature range from no signicant adverse effects to DNA platination, genotoxicity, cell cycle arrest and an antimicrobial activity against Gram-positive bacteria. [23][24][25][26][27][28] Here, differences in shape, size and surface coating have to be taken into account, as it is now generally accepted for the assessment of the biological activity of nanoparticles. [29][30][31][32][33][34][35][36] Silver is a well-known antimicrobial agent against a broad range of bacteria, viruses, and fungi.…”

X-ray powder diffraction to analyse bimetallic core–shell nanoparticles (gold and palladium; 7–8 nm)

“…The gold and palladium seeds were further analysed by highresolution electron microscopy (HAADF-STEM), showing spherical polycrystalline nanoparticles (see ref. 40 for corresponding images). Both types of core-shell nanoparticles had an almost spherical shape with a diameter in good agreement with the DLS and DCS results.…”

“…44 As expected for the outer layer of palladium metal, palladium seeds and Au-Pd core-shell nanoparticles showed no distinct absorption in the visible range. 40 Clearly, palladium prevented the SPR of gold, conrming a dense layer of palladium metal around the gold core. Aer the addition of a gold layer to the surface of the palladium seeds to form Pd-Au core-shell nanoparticles, the SPR absorption band of gold was observed.…”

“…Pd nanoparticles (seeds), Au nanoparticles (seeds), and Pd-Au core-shell nanoparticles were synthesized as described earlier. 39,40 Au-Pd core-shell nanoparticles were synthesized in analogy to Pd-Au core-shell nanoparticles as follows: In a twoneck round bottom ask, 600 mg (3 mmol) D-glucose and 50 mg (0.125 mmol) PVP were dissolved in 50 mL water. The mixture was vigorously stirred (700 rpm) and heated to 100 C under reux.…”