Dear Komal

Assuming that you want to view your cells in transverse section, embedding the cells that are growing in the 24 well plate will be difficult as the embedding resin will stick to the plastic. I would suggest growing them on thermanox coverslips http://www.thermoscientific.com/ecomm/servlet/productsdetail_11152___11953124_-1

Cells grown on 8 well glass slides should not present such a problem.

Once you have fixed, dehydrated and infiltrated your samples with resin (epoxy or acrylic) fill a capsule with resin and place your slide/coverslip cell-side down on the top of it and cure/polymerise. You will be able to remove the capsule, with the monolayer of cells using a cooling/warming cycle. Start be placing the samples in a fridge and then into hot water - the differential thermal contraction/expansion should cause the slide/coverslip to come off easily. If it doesn't increase the temperature difference e.g. -20C/hot water, -70C/hot water until it does.

The monolayer of cells can be sawn off the top of the capsule and re-embedded at right angles to allow transverse sectioning.

Regarding section thickness, start with 100 nm. What are your nanoparticles made of? if they embed poorly, they may fall out of the section and you will see lots of holes.

Unless there are a lot of them in your sample, you will probably not see very many in any single section. You can cut thicker sections e.g 200nm, 300nm, but you may have to increase the kV of the beam. The thicker the section, the less detail you will see.

What microscope do you have? For thick sections e.g. 500nm and thicker, you may wish to use tomography. Acrylic resins are better for this, in my limited experience, probably due to lower beam interaction and cross-scattering.

I assume (as did Christopher von Ruhland) you are using ultramicrotome for TEM specimen prep. We have no idea about hardness of your particles. If they are soft and “cutable” with diamond knife you can follow excellent advice from Christopher. If they are hard (like glass), you will ruin your knife (resharpening is pretty expensive) and sections will be of poor quality (a lot of holes and scratches; most particles will be not cut but broken). For hard particles you may want to consider other methods of preparation, such as ion milling or FIB. 100 nm particles are huge and will chip an edge of a knife on the very first cut.