Nanoparticle purification using molecular biology methods


Nanoparticles are being heavily researched for their use in diagnostics and imaging. In these applications, it is very important to tailor the surface properties of the nanoparticle to the specific application. This is usually done by chemical modification of the surface. Like any chemical reaction, the separation of the product from the precursors is very important. Traditionally this was done by centrifugation. However, centrifugation is very limited. For smaller particles with highly hydrophilic capping getting a good pellet without losing particles in the supernatant is very difficult. For larger particles, aggregation is a common problem during centrifugation. Recently, using molecular biology purification and separation methods – dialysis, ultrafiltration, size exclusion columns and gel electrophoresis have been suggested for small nanoparticles, which have ‘protein-like’ sizes and surface properties.

Figure 1: Gel electrophoresis of gold nanoparticles with different DNA molecules attached. Taken from Ackerson C J et al. PNAS 2005;102:13383-13385.


We will explore the limits of molecular biology separation methods for different nanoparticle sizes, and surface capping. We will look at the failure methods encountered in purification (aggregation, binding to membrane/column packing materials and try to find conditions in which the failures are minimal. In Gel Electrophoresis we will look at how the gel properties – compactness, crosslinking, voltage etc. affect the nanoparticle movement in the gel.



If you are interested in this assignment, please contact:

Dr. Ron Gill

Phone: 053 489 3161