Seaweeds: A promising bionanofactory for ecofriendly synthesis of gold and silver nanoparticles

In the last few years, nanotechnology has emerged has a multidisciplinary science with a growing number of applications. Among the nanomaterials developed, gold and silver nanoparticles present physicochemical properties that attract the attention of several researchers all over the world. Seaweeds are a great source of bioactive compounds with a wide variety of applications. Recently, they have been named as “bionanofactories” due to their ability for the synthesis of metal nanoparticles. The development of green synthesis methods is in potential growth because, among other advantages, they reduce the use of toxic and expensive reagents, thus being ecofriendly and cost-effective. In this chapter, we present a review of the synthesis of gold and silver nanoparticles led by macroalgae in the last 5 years (2014–19), with a focus on the different reaction conditions, the size and shape of the nanoparticles synthesized, and their applications.