Synthesis of hybrid Fe_3O_4-silica-NiO superstructures and their application as magnetically separable high-performance biocatalysts

摘要

The assembly of NiO nanoparticles at the surface of magnetic silica resulted in a hybrid superstructure which has utility as a carrier for a magnetically separable biocatalyst system.rnOver recent years, nano-sized particles have emerged as excellent supports for immobilizing biocatalysts, such as enzymes. Nanoparticles can support the maximum surface area available to immobilize enzymes with minimal steric hindrance to reactants for accessing their active sites, leading to high activity as free enzymes. Furthermore, magnetic nanoparticles can be separated facilely from the reaction solution by applying an external magnet. This can allow recycling of the immobilized enzymes for the next reaction, which can significantly reduce the cost in terms of large scale applications of expensive enzymes. In most previous approaches, immobilization was achieved though covalent bonding between the enzymes and nanoparticle surface. This may result in a loss of activity because the active site might be hidden or restricted from assuming the conformation needed to initiate catalysis. A method of immobilizing biomolecules on nanoparticles whilst retaining their biological activity is of immense interest. Recently, the concept of histidine-tagged (His-tagged) protein attachment to a metal terminated nitrilotri-acetate group has been demonstrated to efficiently immobilize enzymes on nanoparticles.