Refer the following reference it will be useful for you.
Praveen Kumar et al. 2011Green synthesis of gold nanoparticles with Zingiber officinale extract:Characterization and blood compatibility. Process Biochemistry 46 (2011) 2007–2013
Arunachalam, K. D., & Annamalai, S. K. (2013). Chrysopogon zizanioides aqueous extract mediated synthesis , characterization of crystalline silver and gold nanoparticles for biomedical applications. International journal of nanomedicine, 8(July), 2375–2384.
Arunachalam, K. D., Annamalai, S. K., Arunachalam, A. M., & Kennedy, S. (2013). Green Synthesis of Crystalline Silver Nanoparticles Using Indigofera aspalathoides- Medicinal Plant Extract for Wound Healing Applications †. Asian Journal of Chemistry, 25(S), 311–314.
Arunachalam, K. D., Annamalai, S. K., & Hari, S. (2013). One-step green synthesis and characterization of leaf extract-mediated biocompatible silver and gold nanoparticles from Memecylon umbellatum. International Journal of Nanomedicine, 8(3), 1307–1315.
S, M., Arunachalam, K. D., & Annamalai, S. K. (2013). Screening and Characterisation of silver nanoparticles for the prevention of Bioflim in Urinay Catheters. Asian Journal of Chemistry, 25(S), 347–349.
There are many bio materials (like proteins, vitamins, carbohydrates,etc ) which acts as reducing agents for synthesis of gold and silver nano particles.
You can use plant parts (root, leaf, seeds, pulp, etc) microorganism (bacteria, fungus, etc) supernantent as well as microwaves to speed up the synthesis ( how to use microwaves in green synthesis of nano particles - You can refer to my paper)