Eco-Friendly Synthesis of Fucoidan-Stabilized Gold Nanoparticles

Problem statement: Metallic gold nanoparticles (AuNPs) are widely used in many applications including medical, pharmaceutical, diagnostics and sensors. The chemical synthesis of AuNPs normally requires synthetic materials which might cause the toxicological concerns. The use of naturally occurring materials like fucoidans for successful synthesis of AuNPs is of interests. Approach: Fucoidans as sulfated polysaccharides from marine algae Cladosiphon okamuranus (o-fucoidan) and Kjellamaniella crassifolia (t-fucoidan) were used for synthesis of AuNPs. The suitable condition for the synthesis was investigated to obtain the nanometric size of AuNPs. The synthesized AuNPs were characterized for the size, morphology and Surface Plasmon Resonance (SPR). Results: The fucoidan-stabilized AuNPs containing optimum weight ratio of gold atom to fucoidan yielded the spherical sizes with an average of 8-10 nm and the absorption maxima of SPR band around 527-530 nm. The AuNPs stabilized by o-fucoidan structured as linear polymer were more monodisperse than those stabilized by t-fucoidan structured as branched polymer. Conclusion: Fucoidan can be employed solely for AuNP synthesis and the sulfate constituent in fucoidan is important for gold reduction and stabilization. The simple yet eco-friendly synthesis of AuNPs stabilized by fucoidans would be attractive for application use of metallic nanoparticles.