Biosynthesis of Inorganic Nanoparticles

Biosynthesis of inorganic nanoparticles is to synthesize inorganic nanoparticles at ambient temperature and pressure without utilizing hazardous agents and generating poisonous by-products by using organisms such as bacteria, actinomyces, fungi or higher plants in nature. It not only is a green and environmentally friendly protocol to synthesize inorganic nanoparticles, but also contributes to understand the biomineralization mechanism, and theoretically guides the design and synthesis of advanced functional materials. Therefore, it has recently attracted widely attention from researchers in the fields of chemistry, biology and materials science. In this review, we present the current development of inorganic nanoparticles synthesized by organisms according to material types including metals, sulphides and oxides, and the biosynthesis mechanism is particularly discussed. It indicates that biosynthesized nanoparticles have many advantages, such as narrow size distribution, high stability, good biocompatibility, high productivity and low cost, etc. In order to resist to heavy metal ions with high concentration, organisms often change their toxicity and solubility via a series of biochemical processes including bioadsorption, bioreduction or precipitation, bioaccumulation or effusion, etc., generating inorganic nanoparticles simultaneously. After the formation of inorganic nanoparticles, these organisms are still able to proliferate, indicating that they can be used to produce nanoparticles as biological factories. However, the physiological process involving in the biosynthesis of inorganic nanoparticles is intricate very much, which is also different among different organisms. Therefore, it needs further research for the elucidation of biosynthesis mechanism, extension of material type and morphology, post-treatment and application of these nanoparticles.