Answer for TEM:

No. Even while environmental TEM exists, it is 1) not suited for wet specimens; 2) cells are too thick.

Answer for SEM.

Sometimes Yes. Of course, it should be ESEM, equipped with cooling stage and able to work at dew point (to prevent over-drying). Somewhere on the web there was a movie of some bugs still alive and moving in ESEM chamber. Usually not problem with observation of plants (leave, stems, etc.) I did it, cells were quite visible.

Unfortunately animal (and human) cells do not have cellulose enforced cell walls, as plants do, to prevent rapid dehydration or osmosis damage. For example, cell cultures cannot survive without media or at least buffer. If we put in ESEM culture submerged in liquid, we will see nothing but surface of the liquid. So, we will be forced to change pressure (or temperature) to let liquid evaporate, at least partially. But then cells will be covered with crystals of salts from buffer, or crystals and layer of proteins from media. Not a nice picture. Quite a few years ago, when I got my hands on ESEM for the first time, I have tried different approaches and the best results were with fixed (i.e. dead) and washed in distill water cell cultures. But even these best results were worse than those obtained with conventional SEM. Not a surprise: dehydration in graded alcohol and finishing with CPD preserves details much better than drying in specimen chamber. May be epithelial cells can give better results, but I do not have any experience with them.

Answer for TEM:

No. Even while environmental TEM exists, it is 1) not suited for wet specimens; 2) cells are too thick.

Answer for SEM.

Sometimes Yes. Of course, it should be ESEM, equipped with cooling stage and able to work at dew point (to prevent over-drying). Somewhere on the web there was a movie of some bugs still alive and moving in ESEM chamber. Usually not problem with observation of plants (leave, stems, etc.) I did it, cells were quite visible.

Unfortunately animal (and human) cells do not have cellulose enforced cell walls, as plants do, to prevent rapid dehydration or osmosis damage. For example, cell cultures cannot survive without media or at least buffer. If we put in ESEM culture submerged in liquid, we will see nothing but surface of the liquid. So, we will be forced to change pressure (or temperature) to let liquid evaporate, at least partially. But then cells will be covered with crystals of salts from buffer, or crystals and layer of proteins from media. Not a nice picture. Quite a few years ago, when I got my hands on ESEM for the first time, I have tried different approaches and the best results were with fixed (i.e. dead) and washed in distill water cell cultures. But even these best results were worse than those obtained with conventional SEM. Not a surprise: dehydration in graded alcohol and finishing with CPD preserves details much better than drying in specimen chamber. May be epithelial cells can give better results, but I do not have any experience with them.

What you want to see? Maybe you could use a dark field microscopy, that have resolution to see some organelles and the specimen can be wet.

Thanks Vladimir - interesting reply. What resolution is achievable? Thanks Daniel: I wish to study movement of nanostructures like bacterial type III secretory 'injectisomes' in vivo.

You can reach 250 nm of resolution.

Some details can be seen in this site:

http://www.cytoviva.com/

Thanks Daniel, a resolution of 50 nm shall be required for my study.

I am imaging some PC12 and 3T3 cells under the SEM and He ion microscope by fixing them,which gives good images.

I also tried imaging live 3T3 cells under the EVO. Getting specific details is very difficult for live cells.

Thanks Komal. Are these cells physiologically alive and then what resolution you achieve?