In chemical nanoparticle synthesis, a stabilizer is necessary to prevent the aggregation of fine particles to make them stable for a long period of time but with use of biological systems, it is clear from the Transmission electron spectroscopy study that even aggregated nanoparticles don't have direct contact with one another. This is due to the fact that nanoparticles are stabilized in solution by capping proteins, which are secreted from microorganisms. One important enzyme that may be responsible for this is Cytochrome C. The silver nanoparticles formed by this process are quite stable due to capping by bacterial proteins for a period of 5 months at 25°C[28].