Green Synthesis of Nanoparticles and Their Application in Cancer Therapy

Biological systems such as yeasts, fungi, bacteria and plant extracts are recently used as natural sources to synthetize nanoparticles (NPs). These green alternatives to traditional chemical routes have different advantages derived from the use of phytochemicals, carbohydrates and other biomolecules. The possibility to employ organisms as `chemical factories' using neutral pH and low temperatures makes them a powerful eco-friendly tool to synthetize nanomaterials. In particular, plants are the best candidates for the large-scale biosynthesis of metallic NPs such as silver (Ag NPs) and gold nanoparticles (Au NPs) having unique physicochemical properties particularly suitable in the field of cancer therapy. In this chapter, we carefully analyse the main green methods to synthetize metallic NPs, with a particular focus on the use of plants or their derivatives. The role of nontoxic capping and reducing agents and safe solvents and their influence on the NP formations are investigated, especially regarding their size and shape. Successively, the assessment of their anticancer properties in vitro and in vivo together with a life cycle assessment (LCA) is discussed. Also, we report some recent examples on how metallic nanoparticles can be used as self-propelling system, an interesting topic pioneering the concept of nano-robot able to respond and move towards specific stimuli. We finally report the use of green and stimuli-responsive polymeric nanovesicles, mainly used in drug delivery applications.