Polyvinylpyrrolidone (PVP) Surface
PVP (polyvinylpyrrolidone) is a large polymer that associates with the particle surface through Van der Waals forces. The 40 kDa PVP molecule is not easily displaced by other molecules and offers excellent steric stability. It’s a great choice for particles that may be exposed to a broad range of salt, pH, and solvent conditions. PVP is made from the monomer n-vinylpyrrolidone and at nanoComposix we typically use a 40 kDa version that helps prevent particles from directly contacting and aggregating when solution conditions change or when the particles are dried down onto a substrate or thin film.
Many of our PVP-stabilized materials are also available as dried powders that can be readily dispersed in wide variety of solvents. For a list of compatible solvents, see [link to solvent table].
- Provides a stable particle surface in a variety of different solvents. While it is possible to displace PVP with molecules that contain thiols or amines, other surfaces such as citrate are more suitable for ligand exchange.
- Moderately negatively charged Zeta potential with an isoelectric point of ~X
Representative Source: PVP40 (Sigma Aldrich XXX, XXX)
Comparison to Alternatives
- Displaceable: PVP is less displaceable than other surfaces such as citrate, carbonate or tannic acid.
- Weakly negatively charged (zeta approximately –30 mV)
- Good salt stability: stable in salt solutions below X mM
- Toxicity: Generally regarded as safe, low toxicity
- Solvent compatibility: Water, ethanol, chloroform, many other polar solvents
- Color engineering