Hi Anie,

as Marite says, you will likely want to adsorb the polyplexes onto a surface (mica), and then image them in solution. Adsorption from solution and then rinsing to remove unbound material is desirable, as you will achieve optimal surface coverage of your polyplexes.

There are well-established protocols for doing this with DNA/Mica, and as long as the polyplexes carry similar charge to DNA, then you should be able to use the same method.

Check out the following link for some information on DNA sample prep by Bruker.

http://nanoscaleworld.bruker-axs.com/nanoscaleworld/forums/p/409/751.aspx

https://www.bruker.com/fileadmin/user_upload/8-PDF-Docs/SurfaceAnalysis/AFM/Webinars/Best_Practices_in_Imaging_Biological_Samples.pdf

Well, this depends on the mode of imaging.... and the overall charge of your polyplexes. You will need to treat your surface so that it carries the opposite charge of the polyplexes and then in that way get adsoption to the surfaces. Then hopefully you do the imaging in wet.

Hi Anie,

as Marite says, you will likely want to adsorb the polyplexes onto a surface (mica), and then image them in solution. Adsorption from solution and then rinsing to remove unbound material is desirable, as you will achieve optimal surface coverage of your polyplexes.

There are well-established protocols for doing this with DNA/Mica, and as long as the polyplexes carry similar charge to DNA, then you should be able to use the same method.

Check out the following link for some information on DNA sample prep by Bruker.

http://nanoscaleworld.bruker-axs.com/nanoscaleworld/forums/p/409/751.aspx

https://www.bruker.com/fileadmin/user_upload/8-PDF-Docs/SurfaceAnalysis/AFM/Webinars/Best_Practices_in_Imaging_Biological_Samples.pdf

Thank you so much Marité Cárdenas and Ashley D Slattery .I really appreciate your efforts.

I wonder Is it ok if i use SiO2 surface instead of mica ?  

Though our materials are different, but just to make samples for AFM, we get silicon wafers and treat them in plasma reactor to make them hydrophilic and then adsorb our liquid materials through spin coating. Finally they are dried and used for AFM images.  

Anie: I'm actually not sure if SiO2 would work, but it wouldn't be hard to try. The surface charge is the important factor, you need the surface to have opposite charge to the particle you are trying to adsorb. Additionally, the SiO2 (while fairly flat) isn't likely to be nearly as flat as freshly-cleaved mica.

Ifttkhar: We use spin-coating for sample preparation also, but usually for nanoparticles such as carbon nanotubes. The trick with spin-coating is to get the concentration right, so that you don't have too much (or too little) material on the surface. The potential issue with spin-coating DNA is that the material may clump up, and you won't be able to observe single-strands easily. Charge-adsorption is excellent for this, as the individual DNA strands will stick to the surface, and stay there while excess material can be rinsed away.

OK got it... I will try soon and will share my experience.. 

Thanks a lot everyone..