Need to image mesoporous silica nanoparticles using the TEM. Also, need high resolution TEM images to see the mesoporous structure. Kindly suggest what kind of grids to use.
Dear Shatadru Chakravarty , I´m not an expert on mesoporous silica nanoparticles, but I guess that any conventional TEM copper grid could work for your samples. Though, holey carbon coated TEM grids (Agar Scientific) were used in the following paper by Huang et al. :
Article Characterization and Comparison of Mesoporous Silica Particl...
Holey carbon coated grids have holes of several sizes, smaller than the grid mesh, and therefore help to support the tiny samples and furthermore the holes areas provide a better contrast of specimens placed on top of holes.
for HRTEM imaging of mesoporous particles, both lacey carbon and conventional holey carbon grids should be good enough. What you are looking for when doing TEM imaging are the particles that hang on the edge of the carbon film (see e.g. attachment 1). In this case, the particles are `free-standing`, such that you image only your specimen without any background signal from the amorphous carbon support. The thickness of the amorphous carbon support could range from 10 – 30 nm, depending on the manufacturer.
On the other hand, since the particles on the edges are not firmly attached to the support, they might jitter upon electron illumination, causing image blurring. In this case, the ultrathin carbon film support might be better (see e.g., attachment 2). The carbon membrane has a thickness of only a few nanometers, causing only fairly low background signal in the HRTEM images.
What we do typically in the lab is to transfer CVD graphene onto Quantifoil (https://www.quantifoil.com/products/quantifoil/), lacey or holey carbon grids, and use the graphene grid as a support because its electron transparency. This works pretty well for, e.g., COF particles. Graphene grids are also available from Pelco.