You can use ethanol

Ag2O will slowly dissolve in water forming the hydroxide. This was the basis for older bactericide treatments. See Slide 31 in:

Silver colloids and invisible ink

https://www.brainshark.com/malvern/vu?pi=560497681&b=1&tx=120486&c1=22

As Ag+ is the active ion, there'll not be much dissolution in solvents other than water, and thus, one surmises, limited bactericidal properties.

Use ethanol for your NPs

The use of dispersion media strongly depend on the type of application you are focusing on. Generally Ethanol is a good dispersent for metal oxide nanoparticles.

You can use ethanol

It depends on your application, use DI water

Omar Farhan Ammar I was asking for making dispersion for DLS analysis. (particle size determination using zetasizer)

I used DI water and ethanol and both worked for DLS

Thank you everyone!