Fast Fluorescence Laser Tracking Microrheometry, I: Instrument Development ☆

摘要: To gain insight into cellular mechanotransduction pathways, we have developed a fluorescence laser tracking microrheometer (FLTM) to measure material rheological features on micrometer length scales using fluorescent microspheres as tracer particles. The statistical analysis of the Brownian motion particle quantifies viscoelastic properties probe's environment, parameterized by frequency-dependent complex shear modulus G*(ω). This FLTM has nanometer spatial resolution over frequency range extending from 1 Hz 50 kHz. In this work, first describe consecutive stages instrument design, development, and optimization. We subsequently demonstrate accuracy reproducing satisfactorily known characteristics purely viscous glycerol solutions cross-linked polyacrylamide polymer networks. An upcoming companion article will illustrate use in studying solid-like versus liquid-like fibroblast cytoskeletons living biological samples.