Microrheology of gel electrolyte biomaterials based on deep eutectic solvents

We report optical tweezers based microrheology measurements of gelatin supported deep eutectic solvent-based gels. These ionically conducting gels are intended for application in the design of flexible biosensors. Gels with 10wt% gelatin from porcine skin in a liquid mixture of choline chloride, 1,2-propanediol, and water in a 1:2:1 molar ratio showed viscosity of the order of 1.1 Pa.sec and shear modulus of greater than 100Pa. Methods included oscillating bead phase and amplitude response measurements, as well the use of particle tracking to monitor Brownian motion. The design of a temperature controlled microscope sample cell is also presented.