MNEMONIC · Magnetic Enzyme Metal Organic Framework Composites

Magnetic Enzyme Metal Organic Framework Composites

Catalysis accounts for about 90% of worldwide industrial processes, and 35% of the annual world's GDP. Catalysts may be homogeneous or heterogeneous, if dispersed in the same phase of the chemical reaction, or in another one, respectively. Enzymes, homogeneous highly selective biological catalysts, are very attractive to industry, especially pharmaceutical manufacturing. However, they work efficiently within specific ranges of parameters: pH, temperature, etc. Enzyme engineering modifies them to improve stability and activity in unfavorable conditions, e.g. with organic solvents or inhibitors. Another issue is recyclability, as enzymes are often lost after a cycle of reaction. For this reason, there is a fervent research upon their immobilization, especially using porous materials, for example silicate-based nanosystems. This action aims to tackle the previously mentioned issues of stability and recyclability by utilizing metal-organic frameworks (MOFs), a thriving class of porous materials developed from the 1990s. MOFs are made of metal ions and organic ligands, and thanks to the wide range of organic molecules available, they allow for extremely varied architectures. Thousands of MOFs have already been produced, with a plethora of applications especially in gas adsorption. The recently developed combination of MOFs with biomolecules, through a straightforward approach named biomimetic mineralization, produces MOF/enzyme composite biomaterials in a one-pot reaction, in water, at room temperature, in short time. This eliminates organic solvents and compatibility agents, commonly used in other methods. This project also enriched the combination of MOFs and enzymes with magnetic nanoparticles, removing filtration steps in favor of a simple magnetic collection of the catalyst. The interdisciplinary objectives of this action were to design, produce, and study novel ternary systems composed by one or more enzymes, magnetic nanoparticles and the MOFs. We chose a highly porous MOF called ZIF-8, with a surface area of about 1800 m2/g and small pores of about 1 nm in diameter, based on zinc nodes and 2-methylimidazole organic ligand, because of its simple topology, good biocompatibility, and easy synthesis. An initial phase of variables study and optimization of the synthetic conditions was aided by multiple characterization techniques (porosity, structure, size, shape, composition, enzyme loading). Afterwards, the obtained biocomposites were integrated in a customized fluidic device made by 3D printing, to test the catalytic performance of the encapsulated enzyme.

Data: CORDIS, © European Union