MOF-biomolecule nanocomposites for electrosensing

Over the last decade, the usage of metal-organic frameworks (MOFs) for electrochemical applications has grown in popularity. The sensitivity of amperometric sensors, which use current as the sensing response for the targeted analyte, is one of the most often encountered electrochemical sensing systems. Electrocatalysts with high reaction rates and the ability to selectively react with the intended analyte are generally required. Since electrochemical reactions may only occur on the surface of an electrode, depositing or immobilizing the electrocatalyst on the surface of the electrode to produce a modified electrode is a typical technique for constructing the active electrode of an amperometric sensor. As we know, multiple chemical functionalities can be incorporated into the entire pore structure of MOFs with different synthetic routes without losing much porosity. However, because most MOFs are not chemically stable in water, and most electrochemical sensing systems require the use of aqueous electrolytes, water stability of MOFs becomes one of the primary issues for MOF usage in electroanalysis. Only lately have significant attempts been made to manufacture MOFs utilizing biomimetic mineralization methods, in which biomolecules are employed as crystallizing and guiding agents to design a variety of MOFs. MOF-based particles containing biomolecules such as enzymes, proteins, peptides, cells, DNA, and viruses have been synthesized using this technique. This review summarizes recent developments of MOF-biomolecule composites with special emphasis on preparative techniques and the synergistic effects of biomolecules and MOFs. The applications of MOF-biomolecule composites in electrosensing are presented as well.