| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 600832 | Colloids and Surfaces B: Biointerfaces | 2012 | 10 Pages |
In this study, amine-terminated generation 5 poly(amidoamine) dendrimers were used as templates or stabilizers to synthesize dendrimer-entrapped or dendrimer-stabilized Au–Ag alloy nanoparticles (NPs) with different gold atom/silver atom/dendrimer molar ratios with the assistance of sodium borohydride reduction chemistry. Following a one-step acetylation reaction to transform the dendrimer terminal amines to acetyl groups, a series of dendrimer-entrapped or dendrimer-stabilized Au–Ag alloy NPs with terminal acetyl groups were formed. The formed Au–Ag alloy NPs before and after acetylation reaction were characterized using different techniques. We showed that the optical property and the size of the bimetallic NPs were greatly affected by the metal composition. At the constant total metal atom/dendrimer molar ratio, the size of the alloy NPs decreased with the gold content. The formed Au–Ag alloy NPs were stable at different pH (pH 5–8) and temperature (4–50 °C) conditions. X-ray absorption coefficient measurements showed that the attenuation of the binary NPs was dependent on both the gold content and the surface modification. With the increase of gold content in the binary NPs, their X-ray attenuation intensity was significantly enhanced. At a given metal composition, the X-ray attenuation intensity of the binary NPs was enhanced after acetylation. Cytotoxicity assays showed that after acetylation, the cytocompatibility of Au–Ag alloy NPs was significantly improved. With the controllable particle size and optical property, metal composition-dependent X-ray attenuation characteristics, and improved cytocompatibility after acetylation, these dendrimer-entrapped or dendrimer-stabilized Au–Ag alloy NPs should have a promising potential for CT imaging and other biomedical applications.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The optical property and size of the formed Au–Ag alloy DENPs or DSNPs can be controlled by simply regulating the feed ratio of gold atom/silver atom/dendrimer. ► The formed Au–Ag alloy DENPs or DSNPs before and after acetylation were stable under different pH (pH 5–8) and temperature (4–50 °C) conditions. ► X-ray absorption coefficient measurements show that the attenuation of the Au–Ag alloy DENPs or DSNPs is dependent on both gold content and the particle surface characteristics. ► After acetylation to transform the dendrimer terminal amines to acetyl groups, the cytocompatibility of Au–Ag alloy DENPs or DSNPs was significantly improved.
