The Uptake Control SmartFlare was opened first to help us to establish a loading protocol. As such, the physical characterisation of that SmartFlare was performed in an earlier post. Thanks once again go to Joan Comenge for taking the VEGF and Scrambled control SmartFlare to the Transmission Electron Microscope (TEM).
10 μl droplets of the sample were drop casted onto a formvar/carbon filmed 200-mesh copper grid (ordered from TAAB) and left to dry in air. Gold nanoparticles were visualized using a Tecnai G3 spirit TEM at 120 KeV.
All of the data can be viewed on our Open Data Repository date stamped [2015-05-05].
Using the same calibration and analysis protocol as previously, the nanoparticles can be measured and a distribution of sizes can be calculated. Once again we can calculate the distribution of the Major and Minor elliptical axis as a proxy for mean particle diameter:
The Circularity is calculated as (4π*area)/(perimeter2) where a perfect circle will have a value of one and values less than this describe a more elongated shape.
The gold particles appear to be slightly smaller than the Uptake Controls (especially the VEGF SmartFlares). The circularity is basically the same.
Not being hugely familiar with EM, I’m not sure what to make of the grey dappled areas around the VEGF and to a lesser extent the Scrambled SmartFlares (click to go to the full image). Answers on a postcard (or in the comments!)
Authors: Dave Mason & Joan Comenge