Citrate stabilized silver nanoparticles have a surface that is readily displaced by other biomolecules or polymers and is the capping agent of choice when using physisorption (noncovalent interactions such as van der Waals forces) to further modify the nanoparticle surface. Citrate capped colloidal silver particles are suspended in 2mM citrate buffer, pH 7.4.
NOTE: Thiols and amines have a high affinity for the silver surface. Functionalizing silver is difficult because thiols and amines bind strongly to the silver surface. However, the silver bonds are labile and can rearrange, reducing long term stability. To avoid destabilizing try to use bidentate or tridentate molecules (i.e. those that present multiple thiols or amines to the silver surface).
Nanoparticles Developed for Ted Pella, Inc.
The PELCO® NanoXact and BioPure colloidal silver nanoparticles are extensively characterized (see Technical Data below) and designed to meet the rigorous research demands in today’s market. They range in size from 20 to 100nm.
The silver colloids come with comprehensive specification sheets that provide all of the physical and optical characterization data necessary to integrate the nanoparticles into Surface Enhanced Raman Spectroscopy (SERS), plasmonic and photonic applications.
- The colloids are negatively charged. Zeta potential of the NanoXact line is in the -50mV range. Zeta potential of the BioPure line is in the -30mV range.
- The silver colloids are stable in the electron beam.
- NanoXact silver colloids are available in 25, 100 and 500ml volumes - supplied in 2mM citrate buffer, pH 7.4.
- BioPure silver colloids are 50X more concentrated than the NanoXact silver colloids and available in 1, 2 and 5ml volumes - supplied in 2mM citrate buffer, pH 7.4.
- Both silver lines have been extensively washed without centrifugation to remove trace elements from the supernatant (<0.000001% of trace elements).
Stability and Storage
The PELCO® NanoXact and BioPure silver colloids should be stored at 4°C in the dark. The silver colloids are photosensitive.
- DO NOT FREEZE.
- NanoXact line is stable for >6 months after purchase
- BioPure line is stable for >3 months after purchase
Product testing indicates increased stability can be attained by following the storage recommendations.