Optimization of flavonoids extracted from hawthorn （Crataegus pinnatifida） by ultrasonic-assisted deep eutectic solvent

Deep Eutectic Solvents (DESs) are a new class of solvents characterized by a remarkable decrease in melting point compared to those of the starting components. The eutectic mixtures can be simply prepared by mixing a Hydrogen Bond Acceptor (HBA) with a Hydrogen Bond Donor (HBD) at a temperature of about 80 °C. They have found applications in different research fields; for instance, they have been employed in organic synthesis, electrochemistry, and bio-catalysis, showing improved biodegradability and lower toxicity compared to other solvents. Herein, we review the use of DESs in biosensor development. We consider the emerging interest in different fields of this green class of solvents and the possibility of their use for the improvement of biosensor performance. We point out some promising examples of approaches for the assembly of biosensors exploiting their compelling characteristics. Furthermore, the extensive ability of DESs to solubilize a wide range of molecules provides the possibility to set up new devices, even for analytes that are usually insoluble and difficult to quantify.