Yes you can use it direct

Yes,

you have carefully clean plant leaf than directly used extract for nanoparticle preperation.

It is depending on the nature of phytochemicals present in the plant extract. If the compounds are polyphenolic resins, lignin, flavone, flavonoids terpenoids, alkaloids, etc., which may possess easily oxydizable/reactive moieties, it is better to use just after extraction. Extended periods of drying and expose to open environments of the plant extract may affect the quality of phytochemicals as well as the ability of fabrication, size-shape and stabilization of the nanoparticles. It is important that when you using plant extract to synthesize nanoparticles the extract should be completely dust free, I mean there is no chance to have any foreign matters/minute particulates present in the solution which can act as a nucleation center may hampered to obtain the pure nanoparticles.

well, thanks for answering but i mean drying after getting the extract; drying to obtain a gram of sample then re-dissolve it in methanol to be used in nanoparticle synthesis ?

Yes you can use it direct

For detailed see the below articles

Article Biosynthesis of silver nanoparticles: A colorimetric optical...

https://www.degruyter.com/view/j/gps.ahead-of-print/gps-2018-0030/gps-2018-0030.xml