ABSTRACT
Iron oxide nanoparticles revolutionized several research fields due to their superparamagnetic property, large surface area, small size, and nontoxicity. Synthesis of nanoparticles by physical and chemical methods are very laborious, expensive, and toxic. Microbial enzymes and plant metabolites are capable of producing nanoparticles with lesser variation in shape and size in a cost-effective, eco-friendly manner. Biosynthesized nanoparticles have innate lipoprotein coating which can provide stability for iron oxide nanoparticles. Intracellular synthesis of magnetite nanoparticles is widely reported in magnetotactic bacteria. Other bacteria, fungi, and algae can synthesize iron oxide nanoparticles extracellularly in large quantities compared to intracellular method. Various plant extracts are also used to synthesize iron oxide nanoparticles. Biosynthesized nanoparticles are nontoxic, biocompatible, highly stable, and disperse well in water owing to their natural lipid coating. Iron oxide nanoparticles find applications in biomedicine such as gene vector, drug carrier, magnetic resonance imaging contrast agents, cell separation, and hyperthermia agent.
