Silk fibroin-based green colloidal silver nanoparticle synthesis and their antibacterial and anticancer properties

Aqueous silk fibroin (SF), derived from Bombyx mori silk, was used to synthesize colloidal silver nanoparticles (AgNPs) in situ under white light and at ambient temperature. A characteristic surface plasmon resonance (SPR) band at 425-435 nm from the UV-Vis spectrum provided evidence of the formation of AgNPs by UV-Visible spectroscopy. The nanoparticles that were synthesized were spherical with smooth surfaces, as evidenced by the transmission electron microscope (TEM) photographs. The size of the particles was between 35 and 40 nm. Additionally, X-ray diffraction (XRD) investigation supports the existence of silver's nanocrystalline phase with FCC crystal structure. The human bacterial pathogens Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) were significantly inhibited by the biogenic silver nanoparticles' antibacterial activity. The synthesized nanoparticles also show an excellent anti-cancer activity in lowest dosage.