Hi Moustafa, First immobilize your sample by placing it on a freshly cleaved mica, followed by evaporating the solvent (water or buffer) in a desiccator. Next, rinse it few times with miiliQ and then dry again. This should be enough for your experiment. Good luck!

Thanks Robin. Is there any preference for mica over glass slides for liquid samples? Also can I do the imaging for the liquid sample without evaporating the solvent ?

Glass slides should also work as a substrate, however mica is preferred, because in some cases, glass slides are too rough for imaging adsorbed molecules. Also it has to be properly cleaned before use. Using a freshly cleaved mica eliminates this problem. 

Coming to your second question, i think you can do imaging without evaporating the solvent also.

Hi Moustafa,

You may find answer to your question in the below paper, or attached manuscripts:

Part II: Sample Preparation for AFM Particle ... - nanoparticles.org

www.nanoparticles.org/pdf/Starostina-West.pdf

by N Starostina - ‎2006

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AFM Sample Preparation in Biology - nanoHUB

https://nanohub.org/resources/11467/.../2011.02.17-AFM_Workshop-L06.pdf

Thanks a lot Dr Mozafari, these papers are really helpful.