CHAPTER 10: Polysaccharides

The diverse natural abundance of polysaccharides provides a rich source for the green synthesis of colloidal nanoparticles (NPs) at a relatively cheap cost and at a sustainable level. This chapter describes polysaccharides as reducing agents in the synthesis of colloidal NPs. It is pertinent to note that polysaccharides act not only as reducing agents but also as stabilizing and structural directing agents under suitable reaction conditions. These roles are strongly influenced by the chemical composition and the sequence of ordering of the repeating units into macromolecules, as well as the molecular weight. Ionic polysaccharides show an improved stabilizing effect, but the reducing capacity is limited to an increase in the number of ionic functionality and is sensitive to the tuning of reaction conditions to stimulate electron transfer. This chapter also highlights the potential applications of the synthesized colloidal NPs in medicine, catalysis and sensing. The contributions of polysaccharides to these applications are significant, as they provide biocompatibility and large surface area for interaction of the NPs. Looking to the future, polysaccharides are a potential game changer in the synthesis of green colloidal NPs once reaction conditions are optimized toward obtaining NPs with uniform size and morphology with a substantial market value.