This question can be answered broadly. There might be several applications of biosynthesized nanoparticles. Please check these articles:Potentialt 

Potential theranostics application of biosynthesized silver nanoparticles.

Thanks Sudip for answering the question.

Can you please guide me on as to how the concentration of silver nanoparticles was determined in this paper?? I mean its mentioned in micromolar concentration..

Also, can you give information regarding the yield of nanoparticles obtained via biosynthesis  method?

The silver concentration is determined by ICP-OES or AAS.As it has been synthesized as colloidal form and we are using crude extract it is difficult to calculate the yield. Please feel free to ask any question if you have.

So for performing various assays viz: antimicrobial, cell viability, etc.. How were the silver nanoparticles were used? Did you dried them & then prepared different concentration or it was on the basis of co-relation  from your ICP data, that this much millilitre of nanoparticles solution contain these many micromolar silver nanoparticles.

And for ICP analysis, we should give the washed pellet of nanoparticles or both (pellet as well as supernatent)??

We have ultracentrifuged the nanoparticles and that pellet submitted for Icpoes. All the treatment  were given by the pellet only.no need of giving the supernatant. You can wash depending on your application.

But is there good reproducibility everytime you synthesize nanoparticles?  I mean do u synthesize in bulk or depending on experiment u do fresh synthesis, collect pellet, analyse conc. via ICP & then perform biological assay.

Reproducibility is good enough Nirmala. And everytime I used to synthesize freashly and assume that by keeping all the conditions equal the ultimate nanoparticles concentration also will remain same.

Thanks a lot Sudip  for answering all the doubts in detail..