In-plane Tuning Fork Resonator for Shear-Wave Spectroscopy of Small Samples of Complex Liquids

The goal of this work is the analysis of viscoelastic properties of complex liquids like synovial fluid (i.e. the lubricant in joints), where the available volume is in the range of microliters. Viscosity and shear modulus as a function of frequency carry important information about the physiological condition. Our approach utilizes an electrodynamically excited, mechanically balanced inplane resonator, where the resonance frequencies and quality factors of several modes are evaluated under liquid loading. The balanced "tuning fork" design ensures minimal suspension losses which, together with the advanced rapid readout technique, implements unprecedented features paving the way for shear-wave spectroscopy of soft materials.