(4cb) High-Throughput Microrheology of Therapeutic Hydrogelators

The design of therapeutic hydrogelators enables the engineering of this material for applications such as wound healing and tissue regeneration. Development of these scarce materials is generally synthetically laborious with small yields. In order to address the need for rapid rheological characterization of therapeutic hydrogelators while conserving material, we use multiple particle tracking microrheology, which requires small sample volumes (4-40 μL) while enabling rheological measurements of both the hydrogelation reaction and the final material properties. During the hydrogelation reaction, the material is monitored with time and the sol-gel transition is measured, yielding the critical gelation time and critical relaxation exponents. High-throughput microrheology, microrheological measurements in a microfluidic device, are then used to screen the equilibrated materials, vastly reducing the time of sample preparation and increasing the amount of samples evaluated. From the data, gelation state diagrams are created, which identify compositions where hydrogels form. Overall, our methods can be used to thoroughly screen the material rheological properties, yielding a high information density, but requiring only small volumetric amounts.