Do silver nanoparticles oxidize?
Yes, silver will oxidize in the presence of sulfur and oxygen. Please see our Guidelines for Nanotoxicology Researchers Using nanoComposix Materials for additional details.
Are your silver nanospheres amorphous or crystalline?
We consider our silver nanospheres to be polycrystalline, as can be seen by the different lines and contrasts of the particles in TEM images. It is the nature of silver nanoparticles to have the silver atoms reduce into a somewhat regular crystal structure since it is a more stable form, even if it subdivides into many crystal domains within the same particle. By having numerous crystal domains, the particles are able to maintain a near spherical shape. These crystal domains can sometimes be seen as lines in the particles or patches that are darker than the rest of the particle.
Do silver nanoparticles have antimicrobial properties?
Yes. Recent research has demonstrated that silver ions are an effective antimicrobial yet have low toxicity for humans. Silver nanoparticles are garnering increasing attention for their antiviral properties and are being investigated for various applications in the medical field. For more information, visit our page about Antimicrobial Silver Nanoparticles.
How do I tell if the silver nanoparticles that I've purchased have gone bad?
Well-dispersed silver nanoparticles typically have a yellow color in solution and a distinct plasmon resonance. Monitoring the UV-Visible signature of silver nanoparticles over time is a good method of ensuring that the particles are still "good". If there is a destabilization event, the color will usually change dramatically and it is clear that the particles have aggregated.
Do you offer "bare" or "uncapped" silver nanoparticles?
Our citrate capping agent is designed such that they can be displaced by other capping agents. Citrate capped nanoparticles are the best choice when using physisorption for subsequent surface modification. For more information regarding our standard capping agents, please visit our Surfaces Knowledge Base pages.
It is important to recognize that all nanoparticles require some type of capping agent or stabilizer on the surface, as truly "bare" nanoparticles would remain stable for only a few seconds before irreversibly aggregating. This is because nanoparticles can be stabilized by two forces: electrostatic repulsion (capping agents are charged, and therefore nearby particles repel each other before van der Waals forces can pull them together), or steric repulsion (the capping agent is large enough that it physically gets in the way of van der Waals forces pulling them together.)
Are there special considerations for 10 nm PVP-capped silver nanoparticles?
See further notes about small PVP-capped silver here.
I used to order silver nanoplates from you - do you still offer those?
Silver nanoplates and silica-shelled silver nanoplates with peak resonances at 660 nm, 800 nm, 980 nm, and 1064 nm have been discontinued as standard catalog products. Please contact us about potential remaining inventory or custom nanoparticle synthesis.
