Physically or chemically? Anyway, I would first stabilize the nanoparticles with polyethyleneglycol (with a reactive moiety). Check this

https://www.researchgate.net/post/How-to-functionalize-silver-nanoparticles-with-thiolated-PEG

Yes, If the peptide consists of tryptophan/tyrosine, then just mix the solution of silver nitrate with peptide and keep it in sunlight for 2-3 minutes. peptide acts as template for silver nanoparticles and can even encapsulate them. in case to fix physical parameters, you can use green/red laser to irradiate the peptide-Ag(I)/Au(III) mixture for 5-10 minutes. Photoinduced electron transfer takes place and Ag(I)/Au(III) ions are converted into nanoparticles.

have a look on the articles:

1. Article Thermoplasmonic effect of silver nanoparticles modulates pep...

2. Article Laser induced fabrication of gold nanoparticles on Shellac d...

3. Article Fabrication of Gold Nanoparticles on Biotin -di-Tryptophan S...

4. Article Solvent mediated photo-induced morphological transformation ...

5. Article Short Peptide Amphiphile Cage Facilitate Engineering of Gold...

Thank you very much sir