Green synthesis of silver nanoparticles using marine macroalga Chaetomorpha linum

The present investigation demonstrates the formation of silver nanoparticles by the reduction of the aqueous silver metal ions during exposure to the seaweed (Chaetomorpha linum) extract. The silver nanoparticles obtained were characterized by UV–visible spectrum, FTIR and scanning electron microscopy. The characteristic absorption peak at 422 nm in UV–vis spectrum confirmed the formation of silver nanoparticles. The colour intensity at 422 nm increased with duration of incubation. The size of nanoparticles synthesized varied from 3 to 44 nm with average of ~30 nm. The FTIR spectrum of C. linum extract showed peaks at 1,020, 1,112, 1,325, 1,512, 1,535, 1,610, 1,725, 1,862, 2,924, 3,330 cm 1. The vibrational bands corresponding to the bonds such as –C=C (ring), –C–O, –C–O–C and C=C (chain) are derived from water-soluble compounds such as amines, peptides, flavonoids and terpenoids present in C. linum extract. Hence, it may be inferred that these biomolecules are responsible for capping and efficient stabilization. Since no synthetic reagents were used in this investigation, it is environmentally safe and have potential for application in biomedicine and agriculture.